PocketBase as a standalone database server

The pocketbase driver no longer embeds PocketBase: Warp keeps its data as
PocketBase collections on a server of its own and reaches it only through
the REST API, the way the postgres driver reaches PostgreSQL.
database.connection_string is the server's URL, and Warp signs in as the
superuser in WARP_PB_SUPERUSER_EMAIL / WARP_PB_SUPERUSER_PASSWORD (or a
WARP_PB_SUPERUSER_FILE of the two).

Every SQL table is a superuser-only collection of the same name and
columns, created by warp migrate. Reads go through PocketBase's SQL
endpoint with the SQL drivers' queries, via a read-only database/sql
driver that inlines arguments, moves long ones into warp_params and pages
past 1000 rows. Writes are record operations in batch requests under one
write lock in the Warp process. Media is a protected file field in
warp_media, local or in the S3 bucket Warp writes into PocketBase's
settings. Search matches word prefixes with LIKE. The storage tests run
against an in-process PocketBase and pass as on SQLite.

Docker: the PocketBase stacks get a pocketbase service running
tajniak81/pocketbase-docker-root (WARP_PB_IMAGE), with a pb-data volume
and its admin UI on loopback; the AIO images run that PocketBase binary
as a process beside the homeserver, making up a superuser when none is
set. The .env examples, READMEs, docs and warp.yaml.example follow.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

server/internal/config/config.go

@@ -6,6 +6,7 @@ import (
 	"crypto/subtle"
 	"errors"
 	"fmt"
+	"io/fs"
 	"net/url"
 	"os"
 	"path/filepath"
@@ -101,7 +102,7 @@ type Database struct {
 	Driver string `yaml:"driver" env:"WARP_DB_DRIVER"`
 
 	// ConnectionString is driver specific: a DSN for postgres, a file URI
-	// for sqlite, a directory for pocketbase.
+	// for sqlite, the server's URL for pocketbase.
 	ConnectionString string `yaml:"connection_string" env:"WARP_DB_CONNECTION_STRING"`
 
 	MaxOpenConns    int           `yaml:"max_open_conns" env:"WARP_DB_MAX_OPEN_CONNS"`
@@ -112,14 +113,28 @@ type Database struct {
 	// schema changes behind an explicit `warp migrate`.
 	AutoMigrate bool `yaml:"auto_migrate" env:"WARP_DB_AUTO_MIGRATE"`
 
-	// PocketBase configures what the pocketbase driver adds over sqlite.
+	// PocketBase configures the pocketbase driver: how it signs in to the
+	// server, and where that server keeps media.
 	PocketBase PocketBase `yaml:"pocketbase"`
 }
 
 // PocketBase configures the pocketbase storage driver.
 type PocketBase struct {
+	// SuperuserEmail and SuperuserPassword are the PocketBase superuser
+	// Warp signs in as. Warp's collections are superuser-only, so nothing
+	// less can read or write them.
+	SuperuserEmail    string `yaml:"superuser_email" env:"WARP_PB_SUPERUSER_EMAIL"`
+	SuperuserPassword string `yaml:"superuser_password" env:"WARP_PB_SUPERUSER_PASSWORD"`
+
+	// SuperuserFile names a file of WARP_PB_SUPERUSER_EMAIL=... and
+	// WARP_PB_SUPERUSER_PASSWORD=... lines, read for whichever of the two
+	// is not set otherwise. The all-in-one images keep the superuser they
+	// make up there, so that every warp command in the container finds it.
+	SuperuserFile string `yaml:"superuser_file" env:"WARP_PB_SUPERUSER_FILE"`
+
 	// S3 puts media content in an S3-compatible bucket through
-	// PocketBase's filesystem, instead of under the data directory.
+	// PocketBase's filesystem, instead of under its pb_data. Warp writes it
+	// into PocketBase's settings on every start.
 	S3 PocketBaseS3 `yaml:"s3"`
 }
 
@@ -143,6 +158,9 @@ func (d Database) Storage() storage.Config {
 		MaxOpenConns:     d.MaxOpenConns,
 		MaxIdleConns:     d.MaxIdleConns,
 		ConnMaxLifetime:  d.ConnMaxLifetime,
+
+		SuperuserEmail:    d.PocketBase.SuperuserEmail,
+		SuperuserPassword: d.PocketBase.SuperuserPassword,
 		S3: storage.S3Config{
 			Enabled:        s3.Enabled,
 			Bucket:         s3.Bucket,
@@ -709,6 +727,14 @@ func (c *Config) Validate() error {
 			bad("tracing.endpoint: must be an http or https URL")
 		}
 	}
+	if c.Database.Driver == "pocketbase" {
+		if u, err := url.Parse(c.Database.ConnectionString); err != nil || (u.Scheme != "http" && u.Scheme != "https") || u.Host == "" {
+			bad("database.connection_string: must be the PocketBase server's http or https URL for the pocketbase driver")
+		}
+		if c.Database.PocketBase.SuperuserEmail == "" || c.Database.PocketBase.SuperuserPassword == "" {
+			bad("database.pocketbase: superuser_email and superuser_password are required")
+		}
+	}
 	if c.Database.Driver == "pocketbase" && c.Database.PocketBase.S3.Enabled {
 		s3 := c.Database.PocketBase.S3
 		if s3.Bucket == "" || s3.Region == "" || s3.Endpoint == "" || s3.AccessKey == "" || s3.Secret == "" {
@@ -889,8 +915,45 @@ func Load(path string) (*Config, error) {
 	if err := ApplyEnv(cfg, os.Getenv); err != nil {
 		return nil, err
 	}
+	if err := cfg.Database.PocketBase.readSuperuserFile(); err != nil {
+		return nil, err
+	}
 	if err := cfg.Validate(); err != nil {
 		return nil, fmt.Errorf("invalid configuration:\n%w", err)
 	}
 	return cfg, nil
 }
+
+// readSuperuserFile fills in the superuser from SuperuserFile, for whichever
+// of the email and password is still empty. A file that does not exist yet
+// is not an error: the all-in-one entrypoint writes it on first start, and
+// a command run before that finds nothing either way.
+func (p *PocketBase) readSuperuserFile() error {
+	if p.SuperuserFile == "" || (p.SuperuserEmail != "" && p.SuperuserPassword != "") {
+		return nil
+	}
+	data, err := os.ReadFile(p.SuperuserFile)
+	if errors.Is(err, fs.ErrNotExist) {
+		return nil
+	}
+	if err != nil {
+		return fmt.Errorf("read database.pocketbase.superuser_file: %w", err)
+	}
+	for _, line := range strings.Split(string(data), "\n") {
+		key, value, ok := strings.Cut(strings.TrimSpace(line), "=")
+		if !ok {
+			continue
+		}
+		switch key {
+		case "WARP_PB_SUPERUSER_EMAIL":
+			if p.SuperuserEmail == "" {
+				p.SuperuserEmail = value
+			}
+		case "WARP_PB_SUPERUSER_PASSWORD":
+			if p.SuperuserPassword == "" {
+				p.SuperuserPassword = value
+			}
+		}
+	}
+	return nil
+}

server/internal/config/pocketbase_test.go

@@ -0,0 +1,37 @@
+package config
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestSuperuserFileFillsInWhatIsUnset(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "superuser.env")
+	if err := os.WriteFile(path, []byte("WARP_PB_SUPERUSER_EMAIL=warp@warp.local\nWARP_PB_SUPERUSER_PASSWORD=from-the-file\n"), 0o600); err != nil {
+		t.Fatal(err)
+	}
+
+	p := PocketBase{SuperuserFile: path}
+	if err := p.readSuperuserFile(); err != nil {
+		t.Fatalf("readSuperuserFile: %v", err)
+	}
+	if p.SuperuserEmail != "warp@warp.local" || p.SuperuserPassword != "from-the-file" {
+		t.Errorf("read %q / %q", p.SuperuserEmail, p.SuperuserPassword)
+	}
+
+	// What the environment set wins.
+	p = PocketBase{SuperuserFile: path, SuperuserPassword: "from-the-environment"}
+	if err := p.readSuperuserFile(); err != nil {
+		t.Fatalf("readSuperuserFile: %v", err)
+	}
+	if p.SuperuserEmail != "warp@warp.local" || p.SuperuserPassword != "from-the-environment" {
+		t.Errorf("read %q / %q", p.SuperuserEmail, p.SuperuserPassword)
+	}
+
+	// A file not written yet is no error.
+	p = PocketBase{SuperuserFile: filepath.Join(t.TempDir(), "missing.env")}
+	if err := p.readSuperuserFile(); err != nil || p.SuperuserEmail != "" {
+		t.Errorf("missing file: %q, %v", p.SuperuserEmail, err)
+	}
+}

server/internal/setup/phase10_test.go

@@ -10,21 +10,23 @@ import (
 	"time"
 
 	"github.com/dariuszjaniak/warp/server/internal/config"
+	"github.com/dariuszjaniak/warp/server/internal/storage/pocketbase/pbtest"
 )
 
 // The Phase 10 tests: the PocketBase driver and the new endpoints, through
 // the whole stack.
 
-// TestPocketBaseServer runs a server on the pocketbase driver: accounts,
-// rooms, search and media, with the media landing in PocketBase's own
-// filesystem rather than under media.base_path.
+// TestPocketBaseServer runs a server on the pocketbase driver, against a
+// PocketBase server of its own: accounts, rooms, search and media, with the
+// media landing in PocketBase's storage rather than under media.base_path.
 func TestPocketBaseServer(t *testing.T) {
-	dir := t.TempDir()
-	dataDir := filepath.Join(dir, "pb_data")
-	mediaDir := filepath.Join(dir, "media")
+	pb := pbtest.Start(t)
+	mediaDir := filepath.Join(t.TempDir(), "media")
 	srv := newSigningServer(t, func(cfg *config.Config) {
 		cfg.Database.Driver = "pocketbase"
-		cfg.Database.ConnectionString = dataDir
+		cfg.Database.ConnectionString = pb.URL
+		cfg.Database.PocketBase.SuperuserEmail = pbtest.SuperuserEmail
+		cfg.Database.PocketBase.SuperuserPassword = pbtest.SuperuserPassword
 		cfg.Registration.Enabled = true
 		cfg.ClientAPI.RateLimit.Enabled = false
 		cfg.Media.BasePath = mediaDir
@@ -63,7 +65,7 @@ func TestPocketBaseServer(t *testing.T) {
 	}
 
 	var found bool
-	_ = filepath.WalkDir(filepath.Join(dataDir, "storage", "warp_media"), func(_ string, d os.DirEntry, err error) error {
+	_ = filepath.WalkDir(filepath.Join(pb.DataDir, "storage"), func(_ string, d os.DirEntry, err error) error {
 		if err == nil && !d.IsDir() {
 			found = true
 		}

server/internal/storage/pocketbase/admin.go

@@ -0,0 +1,342 @@
+package pocketbase
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/dariuszjaniak/warp/server/internal/storage"
+)
+
+// Admin is the PocketBase implementation of storage.AdminStore.
+type Admin struct{ *base }
+
+// registrationTokenColumns reads uses_allowed as NULL for a token without a
+// limit, as the SQL drivers store it.
+const registrationTokenColumns = `token, CASE WHEN has_uses_allowed THEN uses_allowed END,
+	completed, expires_at_ms, created_at_ms`
+
+// CreateRegistrationToken implements storage.AdminStore.
+func (s *Admin) CreateRegistrationToken(ctx context.Context, rt storage.RegistrationToken) error {
+	err := s.write(ctx, func(t *tx) error {
+		taken, err := t.exists("admin_registration_tokens", `token = ?`, rt.Token)
+		if err != nil {
+			return err
+		}
+		if taken {
+			return storage.ErrRegistrationTokenExists
+		}
+		row := rec{
+			"token": rt.Token, "completed": rt.Completed,
+			"expires_at_ms": rt.ExpiresAtMS, "created_at_ms": rt.CreatedAtMS,
+		}
+		setUsesAllowed(row, rt.UsesAllowed)
+		t.put("admin_registration_tokens", row)
+		return nil
+	})
+	switch {
+	case errors.Is(err, storage.ErrRegistrationTokenExists):
+		return err
+	case err != nil:
+		return fmt.Errorf("create a registration token: %w", err)
+	}
+	return nil
+}
+
+// setUsesAllowed writes an optional use limit into a row.
+func setUsesAllowed(row rec, n *int) {
+	if n == nil {
+		row["uses_allowed"], row["has_uses_allowed"] = int64(0), false
+		return
+	}
+	row["uses_allowed"], row["has_uses_allowed"] = int64(*n), true
+}
+
+// RegistrationToken implements storage.AdminStore.
+func (s *Admin) RegistrationToken(ctx context.Context, token string) (storage.RegistrationToken, error) {
+	rt, err := scanRegistrationToken(s.db.QueryRowContext(ctx, `SELECT `+registrationTokenColumns+`
+		FROM admin_registration_tokens WHERE token = ?`, token).Scan)
+	switch {
+	case errors.Is(err, sql.ErrNoRows):
+		return storage.RegistrationToken{}, storage.ErrNoSuchRegistrationToken
+	case err != nil:
+		return storage.RegistrationToken{}, fmt.Errorf("read a registration token: %w", err)
+	}
+	return rt, nil
+}
+
+// RegistrationTokens implements storage.AdminStore.
+func (s *Admin) RegistrationTokens(ctx context.Context) ([]storage.RegistrationToken, error) {
+	rows, err := s.db.QueryContext(ctx, `SELECT `+registrationTokenColumns+`
+		FROM admin_registration_tokens ORDER BY token`)
+	if err != nil {
+		return nil, fmt.Errorf("list registration tokens: %w", err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	out := []storage.RegistrationToken{}
+	for rows.Next() {
+		rt, err := scanRegistrationToken(rows.Scan)
+		if err != nil {
+			return nil, fmt.Errorf("list registration tokens: %w", err)
+		}
+		out = append(out, rt)
+	}
+	return out, rows.Err()
+}
+
+// UpdateRegistrationToken implements storage.AdminStore.
+func (s *Admin) UpdateRegistrationToken(ctx context.Context, token string, usesAllowed *int, expiresAtMS int64) error {
+	err := s.write(ctx, func(t *tx) error {
+		row := rec{"expires_at_ms": expiresAtMS}
+		setUsesAllowed(row, usesAllowed)
+		n, err := t.setWhere("admin_registration_tokens", row, `token = ?`, token)
+		if err != nil {
+			return fmt.Errorf("update a registration token: %w", err)
+		}
+		if n == 0 {
+			return storage.ErrNoSuchRegistrationToken
+		}
+		return nil
+	})
+	return err
+}
+
+// DeleteRegistrationToken implements storage.AdminStore.
+func (s *Admin) DeleteRegistrationToken(ctx context.Context, token string) error {
+	return s.write(ctx, func(t *tx) error {
+		found, err := t.delKey("admin_registration_tokens", token)
+		if err != nil {
+			return fmt.Errorf("delete a registration token: %w", err)
+		}
+		if !found {
+			return storage.ErrNoSuchRegistrationToken
+		}
+		return nil
+	})
+}
+
+// UseRegistrationToken implements storage.AdminStore. The check and the
+// spend happen under the write lock, so two registrations cannot both take
+// the last use.
+func (s *Admin) UseRegistrationToken(ctx context.Context, token string, nowMS int64) error {
+	return s.write(ctx, func(t *tx) error {
+		var completed int64
+		err := t.queryRow(`SELECT completed FROM admin_registration_tokens
+			WHERE token = ?
+			AND (NOT has_uses_allowed OR completed < uses_allowed)
+			AND (expires_at_ms = 0 OR expires_at_ms > ?)`, token, nowMS).Scan(&completed)
+		switch {
+		case errors.Is(err, sql.ErrNoRows):
+			return storage.ErrNoSuchRegistrationToken
+		case err != nil:
+			return fmt.Errorf("spend a registration token: %w", err)
+		}
+		t.put("admin_registration_tokens", rec{"token": token, "completed": completed + 1})
+		return nil
+	})
+}
+
+// ReleaseRegistrationToken implements storage.AdminStore. A token deleted in
+// the meantime has nothing to give back to, which is not an error.
+func (s *Admin) ReleaseRegistrationToken(ctx context.Context, token string) error {
+	err := s.write(ctx, func(t *tx) error {
+		var completed int64
+		err := t.queryRow(`SELECT completed FROM admin_registration_tokens WHERE token = ? AND completed > 0`, token).
+			Scan(&completed)
+		switch {
+		case errors.Is(err, sql.ErrNoRows):
+			return nil
+		case err != nil:
+			return err
+		}
+		t.put("admin_registration_tokens", rec{"token": token, "completed": completed - 1})
+		return nil
+	})
+	if err != nil {
+		return fmt.Errorf("release a registration token: %w", err)
+	}
+	return nil
+}
+
+func scanRegistrationToken(scan func(...any) error) (storage.RegistrationToken, error) {
+	var (
+		rt   storage.RegistrationToken
+		uses sql.NullInt64
+	)
+	if err := scan(&rt.Token, &uses, &rt.Completed, &rt.ExpiresAtMS, &rt.CreatedAtMS); err != nil {
+		return storage.RegistrationToken{}, err
+	}
+	if uses.Valid {
+		n := int(uses.Int64)
+		rt.UsesAllowed = &n
+	}
+	return rt, nil
+}
+
+const (
+	auditColumns = `audit_id, ts_ms, actor, action, target, details_json`
+
+	defaultAuditPage = 50
+	maxAuditPage     = 1000
+)
+
+// AppendAudit implements storage.AdminStore.
+func (s *Admin) AppendAudit(ctx context.Context, e storage.AuditEntry) (int64, error) {
+	details := string(e.Details)
+	if details == "" {
+		details = "{}"
+	}
+	var id int64
+	err := s.write(ctx, func(t *tx) error {
+		var err error
+		if id, err = t.next(adminSequences, seqAudit); err != nil {
+			return err
+		}
+		t.put("admin_audit_log", rec{
+			"audit_id": id, "ts_ms": e.TSMS, "actor": e.Actor,
+			"action": e.Action, "target": e.Target, "details_json": details,
+		})
+		return nil
+	})
+	if err != nil {
+		return 0, fmt.Errorf("append to the audit log: %w", err)
+	}
+	return id, nil
+}
+
+// AuditLog implements storage.AdminStore.
+func (s *Admin) AuditLog(ctx context.Context, f storage.AuditFilter) ([]storage.AuditEntry, error) {
+	var (
+		conditions []string
+		args       []any
+	)
+	if f.Before > 0 {
+		conditions = append(conditions, `audit_id < ?`)
+		args = append(args, f.Before)
+	}
+	if f.Actor != "" {
+		conditions = append(conditions, `actor = ?`)
+		args = append(args, f.Actor)
+	}
+	if f.Action != "" {
+		conditions = append(conditions, `action = ?`)
+		args = append(args, f.Action)
+	}
+	limit := f.Limit
+	switch {
+	case limit <= 0:
+		limit = defaultAuditPage
+	case limit > maxAuditPage:
+		limit = maxAuditPage
+	}
+	args = append(args, limit)
+
+	query := `SELECT ` + auditColumns + ` FROM admin_audit_log`
+	if len(conditions) > 0 {
+		query += ` WHERE ` + strings.Join(conditions, " AND ")
+	}
+	query += ` ORDER BY audit_id DESC LIMIT ?`
+
+	rows, err := s.db.QueryContext(ctx, query, args...)
+	if err != nil {
+		return nil, fmt.Errorf("read the audit log: %w", err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	out := []storage.AuditEntry{}
+	for rows.Next() {
+		var (
+			e       storage.AuditEntry
+			details string
+		)
+		if err := rows.Scan(&e.ID, &e.TSMS, &e.Actor, &e.Action, &e.Target, &details); err != nil {
+			return nil, fmt.Errorf("read the audit log: %w", err)
+		}
+		e.Details = []byte(details)
+		out = append(out, e)
+	}
+	return out, rows.Err()
+}
+
+// ServerNoticeRoom implements storage.AdminStore.
+func (s *Admin) ServerNoticeRoom(ctx context.Context, localpart string) (string, error) {
+	var roomID string
+	err := s.db.QueryRowContext(ctx, `SELECT room_id FROM admin_server_notice_rooms WHERE localpart = ?`, localpart).
+		Scan(&roomID)
+	switch {
+	case errors.Is(err, sql.ErrNoRows):
+		return "", storage.ErrNoServerNoticeRoom
+	case err != nil:
+		return "", fmt.Errorf("read the server notice room of %q: %w", localpart, err)
+	}
+	return roomID, nil
+}
+
+// SetServerNoticeRoom implements storage.AdminStore.
+func (s *Admin) SetServerNoticeRoom(ctx context.Context, localpart, roomID string) error {
+	err := s.write(ctx, func(t *tx) error {
+		t.put("admin_server_notice_rooms", rec{"localpart": localpart, "room_id": roomID})
+		return nil
+	})
+	if err != nil {
+		return fmt.Errorf("record the server notice room of %q: %w", localpart, err)
+	}
+	return nil
+}
+
+// AppServices is the PocketBase implementation of storage.AppServiceStore.
+type AppServices struct{ *base }
+
+// AppServiceState implements storage.AppServiceStore.
+func (s *AppServices) AppServiceState(ctx context.Context, id string, startPos int64) (storage.AppServiceState, error) {
+	var st storage.AppServiceState
+	err := s.write(ctx, func(t *tx) error {
+		err := t.queryRow(`SELECT as_id, stream_pos, txn_id, txn_to FROM appservice_state WHERE as_id = ?`, id).
+			Scan(&st.ID, &st.StreamPos, &st.TxnID, &st.TxnTo)
+		switch {
+		case errors.Is(err, sql.ErrNoRows):
+			st = storage.AppServiceState{ID: id, StreamPos: startPos}
+			t.put("appservice_state", rec{"as_id": id, "stream_pos": startPos, "txn_id": int64(0), "txn_to": int64(0)})
+			return nil
+		case err != nil:
+			return err
+		}
+		return nil
+	})
+	if err != nil {
+		return storage.AppServiceState{}, fmt.Errorf("read the cursor of application service %q: %w", id, err)
+	}
+	return st, nil
+}
+
+// BeginTransaction implements storage.AppServiceStore.
+func (s *AppServices) BeginTransaction(ctx context.Context, id string, txnID, to int64) error {
+	err := s.write(ctx, func(t *tx) error {
+		_, err := t.setWhere("appservice_state", rec{"txn_id": txnID, "txn_to": to}, `as_id = ?`, id)
+		return err
+	})
+	if err != nil {
+		return fmt.Errorf("begin transaction %d of application service %q: %w", txnID, id, err)
+	}
+	return nil
+}
+
+// CompleteTransaction implements storage.AppServiceStore.
+func (s *AppServices) CompleteTransaction(ctx context.Context, id string, to int64) error {
+	err := s.write(ctx, func(t *tx) error {
+		_, err := t.setWhere("appservice_state", rec{"stream_pos": to, "txn_to": int64(0)}, `as_id = ?`, id)
+		return err
+	})
+	if err != nil {
+		return fmt.Errorf("advance the cursor of application service %q: %w", id, err)
+	}
+	return nil
+}
+
+var (
+	_ storage.AdminStore      = (*Admin)(nil)
+	_ storage.AppServiceStore = (*AppServices)(nil)
+)

server/internal/storage/pocketbase/batch.go

@@ -0,0 +1,282 @@
+package pocketbase
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+	"strings"
+	"sync"
+)
+
+// base is what every store shares: the client, the read-only SQL pool and
+// the write lock.
+//
+// Writes are serialised by the lock, in this process, the way the sqlite
+// driver serialises them onto one connection: PocketBase is SQLite and takes
+// one writer at a time anyway, and holding the lock across a store call's
+// reads and its batch is what makes "read, decide, write" safe without a
+// transaction that spans requests. It does mean one Warp server per
+// PocketBase.
+type base struct {
+	c    *client
+	db   *sql.DB
+	lock *sync.RWMutex
+}
+
+// rec is one row's columns, by name.
+type rec map[string]any
+
+// maxBatch is how many operations go into one batch request. PocketBase is
+// told to allow this many (see configure); a store call that writes more is
+// split, and each part is atomic on its own.
+const maxBatch = 1000
+
+// tx collects the writes of one store call.
+type tx struct {
+	ctx context.Context
+	b   *base
+
+	// seqs are the counters this call has read or advanced, by table and
+	// name, and seqOrder the order they were first touched in.
+	seqs     map[string]int64
+	seqOrder []string
+
+	ops     []batchRequest
+	deleted map[string]bool
+}
+
+// write runs fn with the write lock held and sends what it collected.
+//
+// The counters it advanced are written first, in the first batch, so that a
+// call split over several batches that fails part-way leaves a gap in a
+// stream — which every reader already copes with — and never a position
+// handed out twice.
+func (b *base) write(ctx context.Context, fn func(*tx) error) error {
+	b.lock.Lock()
+	defer b.lock.Unlock()
+
+	t := &tx{ctx: withWriteLock(ctx), b: b, seqs: map[string]int64{}, deleted: map[string]bool{}}
+	if err := fn(t); err != nil {
+		return err
+	}
+	return t.commit()
+}
+
+// read runs fn with the read lock held, so that its queries see one state:
+// no write lands between them. The SQL drivers get that from a
+// transaction; here it is the lock, since every write takes it.
+func (b *base) read(ctx context.Context, fn func(ctx context.Context) error) error {
+	b.lock.RLock()
+	defer b.lock.RUnlock()
+	return fn(withWriteLock(ctx))
+}
+
+func (t *tx) commit() error {
+	ops := make([]batchRequest, 0, len(t.seqOrder)+len(t.ops))
+	for _, key := range t.seqOrder {
+		table, name, _ := strings.Cut(key, "\x00")
+		ops = append(ops, putRequest(table, rec{"name": name, "value": t.seqs[key]}))
+	}
+	ops = append(ops, t.ops...)
+	for len(ops) > 0 {
+		n := min(len(ops), maxBatch)
+		if err := t.b.c.batch(t.ctx, ops[:n]); err != nil {
+			return err
+		}
+		ops = ops[n:]
+	}
+	return nil
+}
+
+// putRequest is an upsert of one row: created if its key is new, otherwise
+// updated in the columns given and left alone in the rest.
+func putRequest(collection string, row rec) batchRequest {
+	tb, ok := tables[collection]
+	if !ok {
+		panic("pocketbase: no collection " + collection)
+	}
+	key := make([]any, len(tb.key))
+	for i, col := range tb.key {
+		v, ok := row[col]
+		if !ok {
+			panic(fmt.Sprintf("pocketbase: a %s row without its key column %s", collection, col))
+		}
+		key[i] = v
+	}
+	return patchRequest(collection, rowID(collection, key...), row)
+}
+
+// patchRequest is an upsert of a row whose id is already known.
+func patchRequest(collection, id string, row rec) batchRequest {
+	body := make(map[string]any, len(row)+1)
+	for col, v := range row {
+		body[col] = jsonValue(v)
+	}
+	body["id"] = id
+	return batchRequest{Method: "PUT", URL: "/api/collections/" + collection + "/records", Body: body}
+}
+
+// jsonValue turns a column value into what the record API takes.
+func jsonValue(v any) any {
+	switch v := v.(type) {
+	case []byte:
+		return string(v)
+	case int:
+		return int64(v)
+	case int32:
+		return int64(v)
+	default:
+		return v
+	}
+}
+
+// put upserts a row; see putRequest.
+func (t *tx) put(collection string, row rec) {
+	req := putRequest(collection, row)
+	delete(t.deleted, collection+"/"+req.Body["id"].(string))
+	t.ops = append(t.ops, req)
+}
+
+// patch upserts columns of the row with this id.
+func (t *tx) patch(collection, id string, row rec) {
+	delete(t.deleted, collection+"/"+id)
+	t.ops = append(t.ops, patchRequest(collection, id, row))
+}
+
+// del deletes a row that exists. Deleting one that does not fails the whole
+// batch, so callers only delete what they have just read.
+func (t *tx) del(collection, id string) bool {
+	key := collection + "/" + id
+	if t.deleted[key] {
+		return false
+	}
+	t.deleted[key] = true
+	t.ops = append(t.ops, batchRequest{Method: "DELETE", URL: "/api/collections/" + collection + "/records/" + id})
+	return true
+}
+
+// delKey deletes the row with this primary key, if it exists.
+func (t *tx) delKey(collection string, key ...any) (bool, error) {
+	id := rowID(collection, key...)
+	found, err := t.exists(collection, `id = ?`, id)
+	if err != nil || !found {
+		return false, err
+	}
+	return t.del(collection, id), nil
+}
+
+// ids reads the ids of the rows matching a condition.
+func (t *tx) ids(collection, where string, args ...any) ([]string, error) {
+	rows, err := t.b.db.QueryContext(t.ctx, `SELECT id FROM `+collection+` WHERE `+where, args...)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = rows.Close() }()
+	var out []string
+	for rows.Next() {
+		var id string
+		if err := rows.Scan(&id); err != nil {
+			return nil, err
+		}
+		out = append(out, id)
+	}
+	return out, rows.Err()
+}
+
+// delWhere deletes the rows matching a condition and reports how many there
+// were.
+func (t *tx) delWhere(collection, where string, args ...any) (int, error) {
+	ids, err := t.ids(collection, where, args...)
+	if err != nil {
+		return 0, fmt.Errorf("find the %s rows to delete: %w", collection, err)
+	}
+	n := 0
+	for _, id := range ids {
+		if t.del(collection, id) {
+			n++
+		}
+	}
+	return n, nil
+}
+
+// setWhere updates columns of the rows matching a condition and reports how
+// many there were.
+func (t *tx) setWhere(collection string, row rec, where string, args ...any) (int, error) {
+	ids, err := t.ids(collection, where, args...)
+	if err != nil {
+		return 0, fmt.Errorf("find the %s rows to update: %w", collection, err)
+	}
+	n := 0
+	for _, id := range ids {
+		if t.deleted[collection+"/"+id] {
+			continue
+		}
+		t.patch(collection, id, row)
+		n++
+	}
+	return n, nil
+}
+
+// exists reports whether a row matches a condition.
+func (t *tx) exists(collection, where string, args ...any) (bool, error) {
+	var one int
+	err := t.b.db.QueryRowContext(t.ctx, `SELECT 1 FROM `+collection+` WHERE `+where+` LIMIT 1`, args...).Scan(&one)
+	switch {
+	case err == sql.ErrNoRows:
+		return false, nil
+	case err != nil:
+		return false, err
+	}
+	return true, nil
+}
+
+// queryRow reads one row inside the call.
+func (t *tx) queryRow(query string, args ...any) *sql.Row {
+	return t.b.db.QueryRowContext(t.ctx, query, args...)
+}
+
+// query reads rows inside the call.
+func (t *tx) query(query string, args ...any) (*sql.Rows, error) {
+	return t.b.db.QueryContext(t.ctx, query, args...)
+}
+
+// next hands out the next value of a counter.
+func (t *tx) next(table, name string) (int64, error) {
+	return t.advance(table, name, 1)
+}
+
+// advance moves a counter by n and returns the last value of the block, as
+// the SQL drivers' advanceSequence does. n may be negative.
+func (t *tx) advance(table, name string, n int64) (int64, error) {
+	cur, err := t.current(table, name)
+	if err != nil {
+		return 0, err
+	}
+	cur += n
+	t.seqs[table+"\x00"+name] = cur
+	return cur, nil
+}
+
+// current reads a counter as this call has left it.
+func (t *tx) current(table, name string) (int64, error) {
+	key := table + "\x00" + name
+	if v, ok := t.seqs[key]; ok {
+		return v, nil
+	}
+	var v int64
+	if err := t.queryRow(`SELECT value FROM `+table+` WHERE name = ?`, name).Scan(&v); err != nil {
+		return 0, fmt.Errorf("read the %s counter: %w", name, err)
+	}
+	t.seqs[key] = v
+	t.seqOrder = append(t.seqOrder, key)
+	return v, nil
+}
+
+// currentSequence reads a counter outside any write.
+func (b *base) currentSequence(ctx context.Context, table, name string) (int64, error) {
+	var v int64
+	if err := b.db.QueryRowContext(ctx, `SELECT value FROM `+table+` WHERE name = ?`, name).Scan(&v); err != nil {
+		return 0, fmt.Errorf("read the %s counter: %w", name, err)
+	}
+	return v, nil
+}

server/internal/storage/pocketbase/blobs.go

@@ -0,0 +1,210 @@
+package pocketbase
+
+import (
+	"context"
+	"crypto/sha256"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"strconv"
+
+	"github.com/dariuszjaniak/warp/server/internal/storage"
+)
+
+// mediaCollection holds media content: one record per distinct content,
+// keyed by its SHA-256, with the bytes in a protected file field. Where
+// PocketBase keeps the file — its pb_data/storage or an S3 bucket — is its
+// own storage setting.
+const mediaCollection = "warp_media"
+
+// blobStore is storage.BlobStore over warp_media.
+type blobStore struct{ *base }
+
+// validSum reports whether s is a lower-case hex SHA-256: the only names
+// content is stored under, and so the only ones worth asking about.
+func validSum(s string) bool {
+	if len(s) != sha256.Size*2 {
+		return false
+	}
+	for _, c := range s {
+		if (c < '0' || c > '9') && (c < 'a' || c > 'f') {
+			return false
+		}
+	}
+	return true
+}
+
+// Put implements storage.BlobStore.
+//
+// The content is spooled to a temporary file first: its name is its hash,
+// which is not known until the last byte has been read, and the upload has
+// to say both. The spool is also what keeps an oversize upload from reaching
+// PocketBase at all.
+func (b *blobStore) Put(ctx context.Context, r io.Reader, limit int64) (storage.BlobInfo, error) {
+	tmp, err := os.CreateTemp("", "warp-media-*")
+	if err != nil {
+		return storage.BlobInfo{}, fmt.Errorf("create a temporary file: %w", err)
+	}
+	defer func() {
+		_ = tmp.Close()
+		_ = os.Remove(tmp.Name())
+	}()
+
+	hash := sha256.New()
+	n, err := io.Copy(io.MultiWriter(tmp, hash), &ctxReader{ctx: ctx, r: io.LimitReader(r, limit+1)})
+	if err != nil {
+		return storage.BlobInfo{}, fmt.Errorf("store content: %w", err)
+	}
+	if n > limit {
+		return storage.BlobInfo{}, storage.ErrBlobTooLarge
+	}
+	info := storage.BlobInfo{SHA256: hex.EncodeToString(hash.Sum(nil)), Size: n}
+	id := rowID(mediaCollection, info.SHA256)
+
+	if _, err := b.c.getRecord(ctx, mediaCollection, id); err == nil {
+		// The same content is already stored.
+		return info, nil
+	} else if !isNotFound(err) {
+		return storage.BlobInfo{}, fmt.Errorf("look up stored content: %w", err)
+	}
+
+	if _, err := tmp.Seek(0, io.SeekStart); err != nil {
+		return storage.BlobInfo{}, fmt.Errorf("store content: %w", err)
+	}
+	err = b.c.createRecordWithFile(ctx, mediaCollection, map[string]string{
+		"id":     id,
+		"sha256": info.SHA256,
+		"size":   strconv.FormatInt(n, 10),
+	}, "content", info.SHA256, tmp)
+	if err != nil {
+		// Two uploads of the same content can race to create the record;
+		// the loser finds the winner's.
+		if _, getErr := b.c.getRecord(ctx, mediaCollection, id); getErr == nil {
+			return info, nil
+		}
+		return storage.BlobInfo{}, fmt.Errorf("store content: %w", err)
+	}
+	return info, nil
+}
+
+// Open implements storage.BlobStore.
+func (b *blobStore) Open(ctx context.Context, sum string) (io.ReadSeekCloser, error) {
+	if !validSum(sum) {
+		return nil, storage.ErrNoSuchBlob
+	}
+	id := rowID(mediaCollection, sum)
+	record, err := b.c.getRecord(ctx, mediaCollection, id)
+	switch {
+	case isNotFound(err):
+		return nil, storage.ErrNoSuchBlob
+	case err != nil:
+		return nil, fmt.Errorf("open media content: %w", err)
+	}
+	name, _ := record["content"].(string)
+	size, _ := record["size"].(float64)
+	if name == "" {
+		return nil, storage.ErrNoSuchBlob
+	}
+	token, err := b.c.fileToken(ctx)
+	if err != nil {
+		return nil, fmt.Errorf("open media content: %w", err)
+	}
+	return &blobReader{ctx: ctx, c: b.c, id: id, name: name, token: token, size: int64(size)}, nil
+}
+
+// Delete implements storage.BlobStore.
+func (b *blobStore) Delete(ctx context.Context, sum string) error {
+	if !validSum(sum) {
+		return nil
+	}
+	if err := b.c.deleteRecord(ctx, mediaCollection, rowID(mediaCollection, sum)); err != nil && !isNotFound(err) {
+		return fmt.Errorf("delete media content: %w", err)
+	}
+	return nil
+}
+
+// blobReader reads a stored file over HTTP. A seek only moves the offset;
+// the next read starts a ranged download from there, so reading a file
+// through costs one request however it is read.
+type blobReader struct {
+	ctx   context.Context
+	c     *client
+	id    string
+	name  string
+	token string
+	size  int64
+
+	offset int64
+	body   io.ReadCloser
+}
+
+func (r *blobReader) Read(p []byte) (int, error) {
+	if r.offset >= r.size {
+		return 0, io.EOF
+	}
+	if r.body == nil {
+		resp, err := r.c.openFile(r.ctx, mediaCollection, r.id, r.name, r.token, r.offset)
+		if err != nil {
+			return 0, err
+		}
+		if r.offset > 0 && resp.StatusCode != http.StatusPartialContent {
+			_ = resp.Body.Close()
+			return 0, fmt.Errorf("pocketbase: the file server ignored a range request (HTTP %d)", resp.StatusCode)
+		}
+		r.body = resp.Body
+	}
+	n, err := r.body.Read(p)
+	r.offset += int64(n)
+	if errors.Is(err, io.EOF) && r.offset < r.size {
+		err = io.ErrUnexpectedEOF
+	}
+	return n, err
+}
+
+func (r *blobReader) Seek(offset int64, whence int) (int64, error) {
+	var next int64
+	switch whence {
+	case io.SeekStart:
+		next = offset
+	case io.SeekCurrent:
+		next = r.offset + offset
+	case io.SeekEnd:
+		next = r.size + offset
+	default:
+		return 0, errors.New("pocketbase: invalid whence")
+	}
+	if next < 0 {
+		return 0, errors.New("pocketbase: negative position")
+	}
+	if next != r.offset && r.body != nil {
+		_ = r.body.Close()
+		r.body = nil
+	}
+	r.offset = next
+	return next, nil
+}
+
+func (r *blobReader) Close() error {
+	if r.body != nil {
+		return r.body.Close()
+	}
+	return nil
+}
+
+// ctxReader stops a copy when its context ends.
+type ctxReader struct {
+	ctx context.Context
+	r   io.Reader
+}
+
+func (c *ctxReader) Read(p []byte) (int, error) {
+	if err := c.ctx.Err(); err != nil {
+		return 0, err
+	}
+	return c.r.Read(p)
+}
+
+var _ storage.BlobStore = (*blobStore)(nil)

server/internal/storage/pocketbase/client.go

@@ -0,0 +1,331 @@
+package pocketbase
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"mime/multipart"
+	"net/http"
+	"net/url"
+	"strings"
+	"sync"
+)
+
+// client speaks PocketBase's REST API as a superuser. Everything the driver
+// does goes through it: the SQL endpoint for reads, the batch endpoint for
+// writes, and the record and file endpoints for media.
+type client struct {
+	base     *url.URL
+	email    string
+	password string
+	http     *http.Client
+
+	mu    sync.Mutex
+	token string
+}
+
+// newClient parses the server address. Credentials are checked on first use,
+// not here: a PocketBase that is still starting is not a configuration
+// error.
+func newClient(rawURL, email, password string) (*client, error) {
+	if rawURL == "" {
+		return nil, errors.New("pocketbase: connection_string must be the server's URL, e.g. http://pocketbase:8070")
+	}
+	base, err := url.Parse(strings.TrimSuffix(rawURL, "/"))
+	if err != nil || (base.Scheme != "http" && base.Scheme != "https") || base.Host == "" {
+		return nil, fmt.Errorf("pocketbase: connection_string %q is not an http(s) URL", rawURL)
+	}
+	if email == "" || password == "" {
+		return nil, errors.New("pocketbase: a superuser email and password are required")
+	}
+	return &client{base: base, email: email, password: password, http: &http.Client{}}, nil
+}
+
+// apiError is a non-2xx answer from PocketBase.
+type apiError struct {
+	Status  int
+	Message string
+	Data    json.RawMessage
+}
+
+func (e *apiError) Error() string {
+	msg := fmt.Sprintf("pocketbase: HTTP %d: %s", e.Status, e.Message)
+	if len(e.Data) > 0 && string(e.Data) != "{}" && string(e.Data) != "null" {
+		msg += " " + string(e.Data)
+	}
+	return msg
+}
+
+// isNotFound reports a 404 from PocketBase.
+func isNotFound(err error) bool {
+	var apiErr *apiError
+	return errors.As(err, &apiErr) && apiErr.Status == http.StatusNotFound
+}
+
+// url resolves an API path against the server address.
+func (c *client) url(path string) string { return c.base.String() + path }
+
+// authToken returns the current superuser token, signing in if there is
+// none yet.
+func (c *client) authToken(ctx context.Context) (string, error) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.token != "" {
+		return c.token, nil
+	}
+	body, err := json.Marshal(map[string]string{"identity": c.email, "password": c.password})
+	if err != nil {
+		return "", err
+	}
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost,
+		c.url("/api/collections/_superusers/auth-with-password"), bytes.NewReader(body))
+	if err != nil {
+		return "", err
+	}
+	req.Header.Set("Content-Type", "application/json")
+	var out struct {
+		Token string `json:"token"`
+	}
+	if err := c.send(req, &out); err != nil {
+		return "", fmt.Errorf("pocketbase: sign in as superuser %q: %w", c.email, err)
+	}
+	if out.Token == "" {
+		return "", errors.New("pocketbase: sign in returned no token")
+	}
+	c.token = out.Token
+	return c.token, nil
+}
+
+// forgetToken drops a token PocketBase refused, so the next call signs in
+// again. A superuser token outlives most deployments' restarts, but not all.
+func (c *client) forgetToken(token string) {
+	c.mu.Lock()
+	if c.token == token {
+		c.token = ""
+	}
+	c.mu.Unlock()
+}
+
+// do sends one authenticated request, signing in again once if the token has
+// expired. body is JSON-encoded unless it is an io.Reader, which is sent as
+// is with contentType.
+func (c *client) do(ctx context.Context, method, path string, body any, contentType string, out any) error {
+	var payload []byte
+	if body != nil {
+		if r, ok := body.(io.Reader); ok {
+			// A streamed body cannot be replayed, so it is sent once and a
+			// stale token is the caller's error to retry.
+			return c.doOnce(ctx, method, path, r, contentType, out)
+		}
+		var err error
+		if payload, err = json.Marshal(body); err != nil {
+			return err
+		}
+		contentType = "application/json"
+	}
+	for attempt := 0; ; attempt++ {
+		var r io.Reader
+		if payload != nil {
+			r = bytes.NewReader(payload)
+		}
+		err := c.doOnce(ctx, method, path, r, contentType, out)
+		var apiErr *apiError
+		if attempt == 0 && errors.As(err, &apiErr) && apiErr.Status == http.StatusUnauthorized {
+			continue
+		}
+		return err
+	}
+}
+
+func (c *client) doOnce(ctx context.Context, method, path string, body io.Reader, contentType string, out any) error {
+	token, err := c.authToken(ctx)
+	if err != nil {
+		return err
+	}
+	req, err := http.NewRequestWithContext(ctx, method, c.url(path), body)
+	if err != nil {
+		return err
+	}
+	req.Header.Set("Authorization", token)
+	if contentType != "" {
+		req.Header.Set("Content-Type", contentType)
+	}
+	err = c.send(req, out)
+	var apiErr *apiError
+	if errors.As(err, &apiErr) && apiErr.Status == http.StatusUnauthorized {
+		c.forgetToken(token)
+	}
+	return err
+}
+
+// send runs a request and decodes a JSON answer into out, if out is set.
+func (c *client) send(req *http.Request, out any) error {
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return fmt.Errorf("pocketbase: %s %s: %w", req.Method, req.URL.Path, err)
+	}
+	defer func() { _ = resp.Body.Close() }()
+	if resp.StatusCode >= 300 {
+		return readAPIError(resp)
+	}
+	if out == nil || resp.StatusCode == http.StatusNoContent {
+		_, _ = io.Copy(io.Discard, resp.Body)
+		return nil
+	}
+	if err := json.NewDecoder(resp.Body).Decode(out); err != nil {
+		return fmt.Errorf("pocketbase: decode the answer to %s %s: %w", req.Method, req.URL.Path, err)
+	}
+	return nil
+}
+
+func readAPIError(resp *http.Response) error {
+	raw, _ := io.ReadAll(io.LimitReader(resp.Body, 1<<20))
+	apiErr := &apiError{Status: resp.StatusCode}
+	var body struct {
+		Message string          `json:"message"`
+		Data    json.RawMessage `json:"data"`
+	}
+	if json.Unmarshal(raw, &body) == nil && body.Message != "" {
+		apiErr.Message = body.Message
+		apiErr.Data = body.Data
+	} else {
+		apiErr.Message = strings.TrimSpace(string(raw))
+	}
+	return apiErr
+}
+
+// health checks the server answers at all; it needs no token.
+func (c *client) health(ctx context.Context) error {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, c.url("/api/health"), nil)
+	if err != nil {
+		return err
+	}
+	return c.send(req, nil)
+}
+
+// sqlResult is what PocketBase's SQL endpoint answers with. Every value comes
+// back as text, or null.
+type sqlResult struct {
+	Columns []struct {
+		Name string `json:"name"`
+	} `json:"columns"`
+	Rows [][]*string `json:"rows"`
+}
+
+// query runs one SELECT through the SQL endpoint.
+func (c *client) query(ctx context.Context, query string) (*sqlResult, error) {
+	var out sqlResult
+	if err := c.do(ctx, http.MethodPost, "/api/sql", map[string]string{"query": query}, "", &out); err != nil {
+		return nil, err
+	}
+	return &out, nil
+}
+
+// batchRequest is one record operation inside a batch.
+type batchRequest struct {
+	Method string         `json:"method"`
+	URL    string         `json:"url"`
+	Body   map[string]any `json:"body,omitempty"`
+}
+
+// batch runs record operations in one PocketBase transaction: all of them
+// happen, or none do.
+func (c *client) batch(ctx context.Context, reqs []batchRequest) error {
+	if len(reqs) == 0 {
+		return nil
+	}
+	return c.do(ctx, http.MethodPost, "/api/batch", map[string]any{"requests": reqs}, "", nil)
+}
+
+// patchSettings changes part of PocketBase's application settings.
+func (c *client) patchSettings(ctx context.Context, settings map[string]any) error {
+	return c.do(ctx, http.MethodPatch, "/api/settings", settings, "", nil)
+}
+
+// importCollections creates or updates collections, leaving any not named
+// alone.
+func (c *client) importCollections(ctx context.Context, collections []map[string]any) error {
+	return c.do(ctx, http.MethodPut, "/api/collections/import",
+		map[string]any{"collections": collections, "deleteMissing": false}, "", nil)
+}
+
+// getRecord reads one record as JSON fields.
+func (c *client) getRecord(ctx context.Context, collection, id string) (map[string]any, error) {
+	var out map[string]any
+	if err := c.do(ctx, http.MethodGet,
+		"/api/collections/"+collection+"/records/"+url.PathEscape(id), nil, "", &out); err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+// deleteRecord removes one record.
+func (c *client) deleteRecord(ctx context.Context, collection, id string) error {
+	return c.do(ctx, http.MethodDelete,
+		"/api/collections/"+collection+"/records/"+url.PathEscape(id), nil, "", nil)
+}
+
+// createRecordWithFile creates a record with one file field, streaming the
+// file as multipart so that it is never held in memory whole.
+func (c *client) createRecordWithFile(ctx context.Context, collection string, fields map[string]string,
+	fileField, fileName string, file io.Reader) error {
+	pr, pw := io.Pipe()
+	mw := multipart.NewWriter(pw)
+	go func() {
+		err := func() error {
+			for k, v := range fields {
+				if err := mw.WriteField(k, v); err != nil {
+					return err
+				}
+			}
+			part, err := mw.CreateFormFile(fileField, fileName)
+			if err != nil {
+				return err
+			}
+			if _, err := io.Copy(part, file); err != nil {
+				return err
+			}
+			return mw.Close()
+		}()
+		_ = pw.CloseWithError(err)
+	}()
+	err := c.do(ctx, http.MethodPost, "/api/collections/"+collection+"/records", pr, mw.FormDataContentType(), nil)
+	_ = pr.Close()
+	return err
+}
+
+// fileToken mints the short-lived token protected files are read with.
+func (c *client) fileToken(ctx context.Context) (string, error) {
+	var out struct {
+		Token string `json:"token"`
+	}
+	if err := c.do(ctx, http.MethodPost, "/api/files/token", nil, "", &out); err != nil {
+		return "", err
+	}
+	return out.Token, nil
+}
+
+// openFile starts a download of a stored file from offset on.
+func (c *client) openFile(ctx context.Context, collection, id, name, token string, offset int64) (*http.Response, error) {
+	path := "/api/files/" + collection + "/" + url.PathEscape(id) + "/" + url.PathEscape(name) +
+		"?token=" + url.QueryEscape(token)
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, c.url(path), nil)
+	if err != nil {
+		return nil, err
+	}
+	if offset > 0 {
+		req.Header.Set("Range", fmt.Sprintf("bytes=%d-", offset))
+	}
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("pocketbase: download %s: %w", name, err)
+	}
+	if resp.StatusCode >= 300 {
+		defer func() { _ = resp.Body.Close() }()
+		return nil, readAPIError(resp)
+	}
+	return resp, nil
+}

server/internal/storage/pocketbase/delayed.go

@@ -0,0 +1,232 @@
+package pocketbase
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+
+	"github.com/dariuszjaniak/warp/server/internal/storage"
+)
+
+// DelayedEvents is the PocketBase implementation of
+// storage.DelayedEventStore.
+type DelayedEvents struct{ *base }
+
+// delayedEventColumns reads state_key as NULL for a message event, as the
+// SQL drivers store it.
+const delayedEventColumns = `
+	delay_id, user_id, device_id, room_id, event_type, CASE WHEN has_state_key THEN state_key END, content,
+	delay_ms, running_since_ms, send_at_ms,
+	finalised_at_ms, outcome, reason, event_id, error`
+
+// InsertDelayedEvent implements storage.DelayedEventStore.
+func (s *DelayedEvents) InsertDelayedEvent(ctx context.Context, e storage.DelayedEvent) error {
+	stateKey, hasStateKey := "", false
+	if e.StateKey != nil {
+		stateKey, hasStateKey = *e.StateKey, true
+	}
+	err := s.write(ctx, func(t *tx) error {
+		t.put("delayed_events", rec{
+			"delay_id": e.DelayID, "user_id": e.UserID, "device_id": e.DeviceID, "room_id": e.RoomID,
+			"event_type": e.Type, "state_key": stateKey, "has_state_key": hasStateKey,
+			"content": string(e.Content), "delay_ms": e.DelayMS, "running_since_ms": e.RunningSinceMS,
+			"send_at_ms": e.SendAtMS, "finalised_at_ms": int64(0),
+			"outcome": "", "reason": "", "event_id": "", "error": "",
+		})
+		return nil
+	})
+	if err != nil {
+		return fmt.Errorf("insert delayed event: %w", err)
+	}
+	return nil
+}
+
+// DelayedEvent implements storage.DelayedEventStore.
+func (s *DelayedEvents) DelayedEvent(ctx context.Context, userID, delayID string) (storage.DelayedEvent, error) {
+	return s.one(ctx, `SELECT`+delayedEventColumns+`
+		FROM delayed_events WHERE user_id = ? AND delay_id = ?`, userID, delayID)
+}
+
+// ScheduledDelayedEvent implements storage.DelayedEventStore.
+func (s *DelayedEvents) ScheduledDelayedEvent(ctx context.Context, delayID string) (storage.DelayedEvent, error) {
+	return s.one(ctx, `SELECT`+delayedEventColumns+`
+		FROM delayed_events WHERE delay_id = ? AND finalised_at_ms = 0`, delayID)
+}
+
+func (s *DelayedEvents) one(ctx context.Context, query string, args ...any) (storage.DelayedEvent, error) {
+	events, err := s.list(ctx, query, args...)
+	if err != nil {
+		return storage.DelayedEvent{}, err
+	}
+	if len(events) == 0 {
+		return storage.DelayedEvent{}, storage.ErrNoSuchDelayedEvent
+	}
+	return events[0], nil
+}
+
+// DelayedEvents implements storage.DelayedEventStore.
+func (s *DelayedEvents) DelayedEvents(ctx context.Context, userID string) ([]storage.DelayedEvent, error) {
+	return s.list(ctx, `SELECT`+delayedEventColumns+`
+		FROM delayed_events WHERE user_id = ?
+		ORDER BY finalised_at_ms = 0 DESC, send_at_ms ASC, finalised_at_ms DESC`, userID)
+}
+
+// CountScheduledDelayedEvents implements storage.DelayedEventStore.
+func (s *DelayedEvents) CountScheduledDelayedEvents(ctx context.Context, userID string) (int, error) {
+	var n int
+	if err := s.db.QueryRowContext(ctx, `SELECT COUNT(*) FROM delayed_events
+		WHERE user_id = ? AND finalised_at_ms = 0`, userID).Scan(&n); err != nil {
+		return 0, fmt.Errorf("count delayed events: %w", err)
+	}
+	return n, nil
+}
+
+// RestartDelayedEvent implements storage.DelayedEventStore.
+func (s *DelayedEvents) RestartDelayedEvent(ctx context.Context, delayID string, nowMS int64) error {
+	return s.write(ctx, func(t *tx) error {
+		var delay int64
+		err := t.queryRow(`SELECT delay_ms FROM delayed_events WHERE delay_id = ? AND finalised_at_ms = 0`, delayID).
+			Scan(&delay)
+		switch {
+		case errors.Is(err, sql.ErrNoRows):
+			return storage.ErrNoSuchDelayedEvent
+		case err != nil:
+			return fmt.Errorf("restart delayed event: %w", err)
+		}
+		t.put("delayed_events", rec{"delay_id": delayID, "running_since_ms": nowMS, "send_at_ms": nowMS + delay})
+		return nil
+	})
+}
+
+// FinaliseDelayedEvent implements storage.DelayedEventStore.
+func (s *DelayedEvents) FinaliseDelayedEvent(ctx context.Context, e storage.DelayedEvent) error {
+	return s.write(ctx, func(t *tx) error {
+		n, err := t.setWhere("delayed_events", rec{
+			"finalised_at_ms": e.FinalisedAtMS, "outcome": e.Outcome, "reason": e.Reason,
+			"event_id": e.EventID, "error": string(e.Error),
+		}, `delay_id = ? AND finalised_at_ms = 0`, e.DelayID)
+		if err != nil {
+			return fmt.Errorf("finalise delayed event: %w", err)
+		}
+		if n == 0 {
+			return storage.ErrNoSuchDelayedEvent
+		}
+		return nil
+	})
+}
+
+// DueDelayedEvents implements storage.DelayedEventStore.
+func (s *DelayedEvents) DueDelayedEvents(ctx context.Context, nowMS int64, limit int) ([]storage.DelayedEvent, error) {
+	return s.list(ctx, `SELECT`+delayedEventColumns+`
+		FROM delayed_events WHERE finalised_at_ms = 0 AND send_at_ms <= ?
+		ORDER BY send_at_ms LIMIT ?`, nowMS, limit)
+}
+
+// NextDelayedEventDue implements storage.DelayedEventStore.
+func (s *DelayedEvents) NextDelayedEventDue(ctx context.Context) (int64, bool, error) {
+	var next sql.NullInt64
+	if err := s.db.QueryRowContext(ctx, `SELECT MIN(send_at_ms) FROM delayed_events
+		WHERE finalised_at_ms = 0`).Scan(&next); err != nil {
+		return 0, false, fmt.Errorf("next delayed event: %w", err)
+	}
+	return next.Int64, next.Valid, nil
+}
+
+// ScheduledDelayedStateEvents implements storage.DelayedEventStore.
+func (s *DelayedEvents) ScheduledDelayedStateEvents(ctx context.Context, roomID, eventType, stateKey string) ([]storage.DelayedEvent, error) {
+	return s.list(ctx, `SELECT`+delayedEventColumns+`
+		FROM delayed_events
+		WHERE room_id = ? AND event_type = ? AND has_state_key AND state_key = ? AND finalised_at_ms = 0`,
+		roomID, eventType, stateKey)
+}
+
+// PurgeFinalisedDelayedEvents implements storage.DelayedEventStore.
+func (s *DelayedEvents) PurgeFinalisedDelayedEvents(ctx context.Context, beforeMS int64) error {
+	err := s.write(ctx, func(t *tx) error {
+		_, err := t.delWhere("delayed_events", `finalised_at_ms <> 0 AND finalised_at_ms < ?`, beforeMS)
+		return err
+	})
+	if err != nil {
+		return fmt.Errorf("purge delayed events: %w", err)
+	}
+	return nil
+}
+
+func (s *DelayedEvents) list(ctx context.Context, query string, args ...any) ([]storage.DelayedEvent, error) {
+	rows, err := s.db.QueryContext(ctx, query, args...)
+	if err != nil {
+		return nil, fmt.Errorf("read delayed events: %w", err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	var out []storage.DelayedEvent
+	for rows.Next() {
+		var (
+			e                     storage.DelayedEvent
+			stateKey              sql.NullString
+			content, errorContent string
+		)
+		if err := rows.Scan(&e.DelayID, &e.UserID, &e.DeviceID, &e.RoomID, &e.Type, &stateKey, &content,
+			&e.DelayMS, &e.RunningSinceMS, &e.SendAtMS,
+			&e.FinalisedAtMS, &e.Outcome, &e.Reason, &e.EventID, &errorContent,
+		); err != nil {
+			return nil, fmt.Errorf("read delayed event: %w", err)
+		}
+		if stateKey.Valid {
+			e.StateKey = &stateKey.String
+		}
+		e.Content = []byte(content)
+		if errorContent != "" {
+			e.Error = []byte(errorContent)
+		}
+		out = append(out, e)
+	}
+	return out, rows.Err()
+}
+
+// OpenIDTokens is the PocketBase implementation of storage.OpenIDTokenStore.
+type OpenIDTokens struct{ *base }
+
+// InsertOpenIDToken implements storage.OpenIDTokenStore.
+func (s *OpenIDTokens) InsertOpenIDToken(ctx context.Context, tokenHash, userID string, expiresAtMS int64) error {
+	err := s.write(ctx, func(t *tx) error {
+		t.put("openid_tokens", rec{"token_hash": tokenHash, "user_id": userID, "expires_at_ms": expiresAtMS})
+		return nil
+	})
+	if err != nil {
+		return fmt.Errorf("insert OpenID token: %w", err)
+	}
+	return nil
+}
+
+// OpenIDTokenUser implements storage.OpenIDTokenStore.
+func (s *OpenIDTokens) OpenIDTokenUser(ctx context.Context, tokenHash string, nowMS int64) (string, error) {
+	var userID string
+	err := s.db.QueryRowContext(ctx, `SELECT user_id FROM openid_tokens
+		WHERE token_hash = ? AND expires_at_ms > ?`, tokenHash, nowMS).Scan(&userID)
+	if errors.Is(err, sql.ErrNoRows) {
+		return "", storage.ErrNoSuchOpenIDToken
+	}
+	if err != nil {
+		return "", fmt.Errorf("read OpenID token: %w", err)
+	}
+	return userID, nil
+}
+
+// PurgeOpenIDTokens implements storage.OpenIDTokenStore.
+func (s *OpenIDTokens) PurgeOpenIDTokens(ctx context.Context, beforeMS int64) error {
+	err := s.write(ctx, func(t *tx) error {
+		_, err := t.delWhere("openid_tokens", `expires_at_ms < ?`, beforeMS)
+		return err
+	})
+	if err != nil {
+		return fmt.Errorf("purge OpenID tokens: %w", err)
+	}
+	return nil
+}
+
+var (
+	_ storage.DelayedEventStore = (*DelayedEvents)(nil)
+	_ storage.OpenIDTokenStore  = (*OpenIDTokens)(nil)
+)

server/internal/storage/pocketbase/federation.go

@@ -0,0 +1,247 @@
+package pocketbase
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+
+	"github.com/dariuszjaniak/warp/server/internal/storage"
+)
+
+// Federation is the PocketBase implementation of storage.FederationStore.
+type Federation struct{ *base }
+
+// StoreServerKeys implements storage.FederationStore.
+func (s *Federation) StoreServerKeys(ctx context.Context, keys []storage.ServerKey) error {
+	if len(keys) == 0 {
+		return nil
+	}
+	return s.write(ctx, func(t *tx) error {
+		for _, k := range keys {
+			t.put("federation_server_keys", rec{
+				"server_name": k.ServerName, "key_id": k.KeyID, "public_key": k.PublicKey,
+				"valid_until_ts": k.ValidUntilTS, "expired_ts": k.ExpiredTS, "fetched_at_ms": k.FetchedAtMS,
+			})
+		}
+		return nil
+	})
+}
+
+// ServerKeys implements storage.FederationStore.
+func (s *Federation) ServerKeys(ctx context.Context, serverName string, keyIDs []string) ([]storage.ServerKey, error) {
+	query := `
+		SELECT server_name, key_id, public_key, valid_until_ts, expired_ts, fetched_at_ms
+		FROM federation_server_keys WHERE server_name = ?`
+	args := []any{serverName}
+	if len(keyIDs) > 0 {
+		query += ` AND key_id IN ` + inList
+		args = append(args, jsonList(keyIDs))
+	}
+	query += ` ORDER BY key_id`
+
+	rows, err := s.db.QueryContext(ctx, query, args...)
+	if err != nil {
+		return nil, fmt.Errorf("read the keys of %q: %w", serverName, err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	var out []storage.ServerKey
+	for rows.Next() {
+		var k storage.ServerKey
+		if err := rows.Scan(&k.ServerName, &k.KeyID, &k.PublicKey,
+			&k.ValidUntilTS, &k.ExpiredTS, &k.FetchedAtMS); err != nil {
+			return nil, fmt.Errorf("read the keys of %q: %w", serverName, err)
+		}
+		out = append(out, k)
+	}
+	return out, rows.Err()
+}
+
+// Enqueue implements storage.FederationStore.
+func (s *Federation) Enqueue(ctx context.Context, items []storage.QueuedItem) ([]storage.QueuedItem, error) {
+	if len(items) == 0 {
+		return nil, nil
+	}
+	out := make([]storage.QueuedItem, len(items))
+	copy(out, items)
+	err := s.write(ctx, func(t *tx) error {
+		top, err := t.advance(federationSequences, seqQueue, int64(len(out)))
+		if err != nil {
+			return err
+		}
+		first := top - int64(len(out)) + 1
+		for i := range out {
+			out[i].ID = first + int64(i)
+			item := out[i]
+			t.put("federation_queue", rec{
+				"queue_id": item.ID, "destination": item.Destination, "kind": item.Kind,
+				"room_id": item.RoomID, "event_id": item.EventID,
+				"payload": string(item.Payload), "queued_at_ms": item.QueuedAtMS,
+			})
+		}
+		return nil
+	})
+	if err != nil {
+		return nil, fmt.Errorf("enqueue %d items: %w", len(items), err)
+	}
+	return out, nil
+}
+
+// Queued implements storage.FederationStore.
+func (s *Federation) Queued(ctx context.Context, destination, kind string, limit int) ([]storage.QueuedItem, error) {
+	if limit <= 0 {
+		return nil, nil
+	}
+	rows, err := s.db.QueryContext(ctx, `
+		SELECT queue_id, destination, kind, room_id, event_id, payload, queued_at_ms
+		FROM federation_queue
+		WHERE destination = ? AND kind = ?
+		ORDER BY queue_id
+		LIMIT ?`, destination, kind, limit)
+	if err != nil {
+		return nil, fmt.Errorf("read the queue for %q: %w", destination, err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	var out []storage.QueuedItem
+	for rows.Next() {
+		var (
+			item    storage.QueuedItem
+			payload string
+		)
+		if err := rows.Scan(&item.ID, &item.Destination, &item.Kind, &item.RoomID,
+			&item.EventID, &payload, &item.QueuedAtMS); err != nil {
+			return nil, fmt.Errorf("read the queue for %q: %w", destination, err)
+		}
+		item.Payload = []byte(payload)
+		out = append(out, item)
+	}
+	return out, rows.Err()
+}
+
+// Dequeue implements storage.FederationStore.
+func (s *Federation) Dequeue(ctx context.Context, ids []int64) error {
+	if len(ids) == 0 {
+		return nil
+	}
+	err := s.write(ctx, func(t *tx) error {
+		_, err := t.delWhere("federation_queue", `queue_id IN `+inList, jsonInts(ids))
+		return err
+	})
+	if err != nil {
+		return fmt.Errorf("dequeue %d items: %w", len(ids), err)
+	}
+	return nil
+}
+
+// QueuedDestinations implements storage.FederationStore.
+func (s *Federation) QueuedDestinations(ctx context.Context) ([]string, error) {
+	out, err := s.queryStrings(ctx, `SELECT DISTINCT destination FROM federation_queue ORDER BY destination`)
+	if err != nil {
+		return nil, fmt.Errorf("read the queued destinations: %w", err)
+	}
+	return out, nil
+}
+
+const destinationColumns = `
+	server_name, failures, retry_at_ms, last_success_ms, last_failure_ms, last_error`
+
+// Destination implements storage.FederationStore.
+func (s *Federation) Destination(ctx context.Context, serverName string) (storage.Destination, error) {
+	var d storage.Destination
+	err := s.db.QueryRowContext(ctx, `SELECT `+destinationColumns+`
+		FROM federation_destinations WHERE server_name = ?`, serverName).
+		Scan(&d.ServerName, &d.Failures, &d.RetryAtMS, &d.LastSuccessMS, &d.LastFailureMS, &d.LastError)
+	switch {
+	case errors.Is(err, sql.ErrNoRows):
+		return storage.Destination{ServerName: serverName}, nil
+	case err != nil:
+		return storage.Destination{}, fmt.Errorf("read destination %q: %w", serverName, err)
+	}
+	return d, nil
+}
+
+// SetDestination implements storage.FederationStore.
+func (s *Federation) SetDestination(ctx context.Context, d storage.Destination) error {
+	err := s.write(ctx, func(t *tx) error {
+		t.put("federation_destinations", rec{
+			"server_name": d.ServerName, "failures": d.Failures, "retry_at_ms": d.RetryAtMS,
+			"last_success_ms": d.LastSuccessMS, "last_failure_ms": d.LastFailureMS, "last_error": d.LastError,
+		})
+		return nil
+	})
+	if err != nil {
+		return fmt.Errorf("record destination %q: %w", d.ServerName, err)
+	}
+	return nil
+}
+
+// Destinations implements storage.FederationStore: every server with a
+// health row or something queued.
+func (s *Federation) Destinations(ctx context.Context) ([]storage.DestinationSummary, error) {
+	rows, err := s.db.QueryContext(ctx, `
+		SELECT n.server_name,
+			COALESCE(d.failures, 0), COALESCE(d.retry_at_ms, 0),
+			COALESCE(d.last_success_ms, 0), COALESCE(d.last_failure_ms, 0),
+			COALESCE(d.last_error, ''),
+			(SELECT COUNT(*) FROM federation_queue q WHERE q.destination = n.server_name AND q.kind = 'pdu'),
+			(SELECT COUNT(*) FROM federation_queue q WHERE q.destination = n.server_name AND q.kind = 'edu')
+		FROM (
+			SELECT server_name FROM federation_destinations
+			UNION
+			SELECT DISTINCT destination FROM federation_queue
+		) n
+		LEFT JOIN federation_destinations d ON d.server_name = n.server_name
+		ORDER BY n.server_name`)
+	if err != nil {
+		return nil, fmt.Errorf("read the destinations: %w", err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	var out []storage.DestinationSummary
+	for rows.Next() {
+		var d storage.DestinationSummary
+		if err := rows.Scan(&d.ServerName, &d.Failures, &d.RetryAtMS, &d.LastSuccessMS,
+			&d.LastFailureMS, &d.LastError, &d.QueuedPDUs, &d.QueuedEDUs); err != nil {
+			return nil, fmt.Errorf("read the destinations: %w", err)
+		}
+		out = append(out, d)
+	}
+	return out, rows.Err()
+}
+
+// InboundTransaction implements storage.FederationStore.
+func (s *Federation) InboundTransaction(ctx context.Context, origin, txnID string) ([]byte, bool, error) {
+	var response string
+	err := s.db.QueryRowContext(ctx, `SELECT response_json FROM federation_inbound_txns
+		WHERE origin = ? AND txn_id = ?`, origin, txnID).Scan(&response)
+	switch {
+	case errors.Is(err, sql.ErrNoRows):
+		return nil, false, nil
+	case err != nil:
+		return nil, false, fmt.Errorf("read transaction %q from %q: %w", txnID, origin, err)
+	}
+	return []byte(response), true, nil
+}
+
+// RecordInboundTransaction implements storage.FederationStore. A
+// transaction already recorded keeps its first response.
+func (s *Federation) RecordInboundTransaction(ctx context.Context, origin, txnID string, response []byte, atMS int64) error {
+	err := s.write(ctx, func(t *tx) error {
+		found, err := t.exists("federation_inbound_txns", `origin = ? AND txn_id = ?`, origin, txnID)
+		if err != nil || found {
+			return err
+		}
+		t.put("federation_inbound_txns", rec{
+			"origin": origin, "txn_id": txnID, "response_json": string(response), "received_at_ms": atMS,
+		})
+		return nil
+	})
+	if err != nil {
+		return fmt.Errorf("record transaction %q from %q: %w", txnID, origin, err)
+	}
+	return nil
+}
+
+var _ storage.FederationStore = (*Federation)(nil)

server/internal/storage/pocketbase/helpers.go

@@ -0,0 +1,83 @@
+package pocketbase
+
+import (
+	"encoding/json"
+	"strings"
+)
+
+// The counter tables and the names in them, as the SQL drivers have them.
+const (
+	roomSequences       = "roomserver_sequences"
+	syncSequences       = "sync_sequences"
+	federationSequences = "federation_sequences"
+	keySequences        = "keyserver_sequences"
+	pushSequences       = "push_sequences"
+	adminSequences      = "admin_sequences"
+
+	seqStreamOrdering   = "stream_ordering"
+	seqStateSnapshot    = "state_snapshot"
+	seqBackfillOrdering = "backfill_ordering"
+
+	seqReceipt     = "receipt"
+	seqToDevice    = "to_device"
+	seqAccountData = "account_data"
+	seqPresence    = "presence"
+
+	seqQueue        = "queue"
+	seqDeviceList   = "device_list"
+	seqNotification = "notification"
+	seqAudit        = "audit"
+)
+
+// inList is the IN-list form every store uses: one JSON array argument,
+// expanded by json_each, instead of a placeholder per element. The SQL
+// endpoint takes no parameters and at most 5000 characters, and a single
+// argument is what the driver can move out of a query that would be too
+// long; a few hundred separate ones would each have to be moved.
+const inList = `(SELECT value FROM json_each(?))`
+
+// jsonList renders strings as the JSON array inList takes.
+func jsonList(values []string) string {
+	if values == nil {
+		values = []string{}
+	}
+	raw, _ := json.Marshal(values)
+	return string(raw)
+}
+
+// jsonInts renders integers as the JSON array inList takes.
+func jsonInts(values []int64) string {
+	if values == nil {
+		values = []int64{}
+	}
+	raw, _ := json.Marshal(values)
+	return string(raw)
+}
+
+// pageBounds clamps a caller's limit and offset.
+func pageBounds(limit, offset, defaultLimit, maxLimit int) (int, int) {
+	if limit <= 0 {
+		limit = defaultLimit
+	}
+	if limit > maxLimit {
+		limit = maxLimit
+	}
+	if offset < 0 {
+		offset = 0
+	}
+	return limit, offset
+}
+
+// escapeLike makes a literal string safe to embed in a LIKE pattern that
+// declares '\' as its escape character.
+func escapeLike(s string) string {
+	var b strings.Builder
+	b.Grow(len(s))
+	for _, r := range s {
+		if r == '\\' || r == '%' || r == '_' {
+			b.WriteRune('\\')
+		}
+		b.WriteRune(r)
+	}
+	return b.String()
+}

server/internal/storage/pocketbase/keys.go

@@ -0,0 +1,766 @@
+package pocketbase
+
+import (
+	"cmp"
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+	"slices"
+	"strconv"
+
+	"github.com/dariuszjaniak/warp/server/internal/storage"
+)
+
+// Keys is the PocketBase implementation of storage.KeyStore.
+//
+// Callers hand it key JSON already in canonical form, so "the same key
+// uploaded again" is a byte comparison. Where the SQL store reads back what
+// it has written inside its transaction — a device list position moved
+// earlier in the call, a backup's key count and etag after a change — this
+// one carries the value in the call instead.
+type Keys struct{ *base }
+
+// maxInList caps an IN list, as the SQL store does.
+const maxInList = 500
+
+// keysWrite is one write call's device list positions, as it has left them.
+type keysWrite struct {
+	*tx
+	lists map[string]int64
+}
+
+func newKeysWrite(t *tx) *keysWrite { return &keysWrite{tx: t, lists: map[string]int64{}} }
+
+// --- the device list stream ---------------------------------------------------
+
+// bumpDeviceList moves a user's device list once per device named, or once
+// for the user when none is, and returns an update per move. Each device
+// gets a position of its own, because a remote server treats a stream ID it
+// has already seen as a duplicate.
+func (w *keysWrite) bumpDeviceList(userID string, deviceIDs []string) ([]storage.DeviceListUpdate, error) {
+	if len(deviceIDs) == 0 {
+		deviceIDs = []string{""}
+	}
+	n := int64(len(deviceIDs))
+	last, err := w.advance(keySequences, seqDeviceList, n)
+	if err != nil {
+		return nil, err
+	}
+
+	prev, ok := w.lists[userID]
+	if !ok {
+		err = w.queryRow(`SELECT stream_pos FROM keyserver_device_lists WHERE user_id = ?`, userID).Scan(&prev)
+		if err != nil && !errors.Is(err, sql.ErrNoRows) {
+			return nil, fmt.Errorf("read the device list position of %q: %w", userID, err)
+		}
+	}
+
+	out := make([]storage.DeviceListUpdate, 0, n)
+	for i, deviceID := range deviceIDs {
+		pos := last - n + 1 + int64(i)
+		out = append(out, storage.DeviceListUpdate{
+			UserID: userID, DeviceID: deviceID, StreamPos: pos, PrevPos: prev,
+		})
+		prev = pos
+	}
+	w.put("keyserver_device_lists", rec{"user_id": userID, "stream_pos": last})
+	w.lists[userID] = last
+	return out, nil
+}
+
+// MarkDeviceListsChanged implements storage.KeyStore.
+func (s *Keys) MarkDeviceListsChanged(ctx context.Context, userIDs []string) (int64, error) {
+	var top int64
+	err := s.write(ctx, func(t *tx) error {
+		w := newKeysWrite(t)
+		for _, userID := range dedupe(userIDs) {
+			updates, err := w.bumpDeviceList(userID, nil)
+			if err != nil {
+				return err
+			}
+			top = updates[len(updates)-1].StreamPos
+		}
+		return nil
+	})
+	return top, err
+}
+
+// DeviceListChanges implements storage.KeyStore.
+func (s *Keys) DeviceListChanges(ctx context.Context, userIDs []string, from, to int64) ([]storage.DeviceListChange, error) {
+	var out []storage.DeviceListChange
+	for chunk := range slices.Chunk(dedupe(userIDs), maxInList) {
+		query := `
+			SELECT user_id, stream_pos FROM keyserver_device_lists
+			WHERE user_id IN ` + inList + ` AND stream_pos > ?`
+		args := []any{jsonList(chunk), from}
+		if to > 0 {
+			query += ` AND stream_pos <= ?`
+			args = append(args, to)
+		}
+
+		rows, err := s.db.QueryContext(ctx, query, args...)
+		if err != nil {
+			return nil, fmt.Errorf("read device list changes: %w", err)
+		}
+		for rows.Next() {
+			var c storage.DeviceListChange
+			if err := rows.Scan(&c.UserID, &c.StreamPos); err != nil {
+				_ = rows.Close()
+				return nil, fmt.Errorf("read device list changes: %w", err)
+			}
+			out = append(out, c)
+		}
+		_ = rows.Close()
+		if err := rows.Err(); err != nil {
+			return nil, fmt.Errorf("read device list changes: %w", err)
+		}
+	}
+	slices.SortFunc(out, func(a, b storage.DeviceListChange) int { return cmp.Compare(a.StreamPos, b.StreamPos) })
+	return out, nil
+}
+
+// DeviceListPosition implements storage.KeyStore.
+func (s *Keys) DeviceListPosition(ctx context.Context, userID string) (int64, error) {
+	var pos int64
+	err := s.db.QueryRowContext(ctx, `SELECT stream_pos FROM keyserver_device_lists WHERE user_id = ?`, userID).Scan(&pos)
+	switch {
+	case errors.Is(err, sql.ErrNoRows):
+		return 0, nil
+	case err != nil:
+		return 0, fmt.Errorf("read the device list position of %q: %w", userID, err)
+	}
+	return pos, nil
+}
+
+// --- device keys --------------------------------------------------------------
+
+// SetDeviceKeys implements storage.KeyStore.
+func (s *Keys) SetDeviceKeys(ctx context.Context, keys storage.DeviceKeys) (storage.DeviceListUpdate, error) {
+	var update storage.DeviceListUpdate
+	err := s.write(ctx, func(t *tx) error {
+		var existing string
+		err := t.queryRow(`SELECT key_json FROM keyserver_device_keys WHERE user_id = ? AND device_id = ?`,
+			keys.UserID, keys.DeviceID).Scan(&existing)
+		switch {
+		case err == nil && existing == string(keys.JSON):
+			return nil
+		case err != nil && !errors.Is(err, sql.ErrNoRows):
+			return fmt.Errorf("read the keys of %s/%s: %w", keys.UserID, keys.DeviceID, err)
+		}
+
+		t.put("keyserver_device_keys", rec{"user_id": keys.UserID, "device_id": keys.DeviceID, "key_json": string(keys.JSON)})
+		updates, err := newKeysWrite(t).bumpDeviceList(keys.UserID, []string{keys.DeviceID})
+		if err != nil {
+			return err
+		}
+		update = updates[0]
+		return nil
+	})
+	return update, err
+}
+
+// DeviceKeys implements storage.KeyStore.
+func (s *Keys) DeviceKeys(ctx context.Context, userID string, deviceIDs []string) ([]storage.DeviceKeys, error) {
+	query := `SELECT device_id, key_json FROM keyserver_device_keys WHERE user_id = ?`
+	args := []any{userID}
+	if len(deviceIDs) > 0 {
+		deviceIDs = dedupe(deviceIDs)
+		if len(deviceIDs) > maxInList {
+			deviceIDs = deviceIDs[:maxInList]
+		}
+		query += ` AND device_id IN ` + inList
+		args = append(args, jsonList(deviceIDs))
+	}
+	query += ` ORDER BY device_id`
+
+	rows, err := s.db.QueryContext(ctx, query, args...)
+	if err != nil {
+		return nil, fmt.Errorf("read the device keys of %q: %w", userID, err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	var out []storage.DeviceKeys
+	for rows.Next() {
+		k := storage.DeviceKeys{UserID: userID}
+		var keyJSON string
+		if err := rows.Scan(&k.DeviceID, &keyJSON); err != nil {
+			return nil, fmt.Errorf("read the device keys of %q: %w", userID, err)
+		}
+		k.JSON = []byte(keyJSON)
+		out = append(out, k)
+	}
+	return out, rows.Err()
+}
+
+// DeleteDeviceKeys implements storage.KeyStore.
+func (s *Keys) DeleteDeviceKeys(ctx context.Context, userID string, deviceIDs []string) ([]storage.DeviceListUpdate, error) {
+	var updates []storage.DeviceListUpdate
+	err := s.write(ctx, func(t *tx) error {
+		where := `user_id = ?`
+		args := []any{userID}
+		if len(deviceIDs) > 0 {
+			where += ` AND device_id IN ` + inList
+			args = append(args, jsonList(dedupe(deviceIDs)))
+		}
+
+		// The devices that lose identity keys are the ones whose deletion
+		// moves the stream.
+		had, err := s.queryStringsTx(t, `SELECT device_id FROM keyserver_device_keys WHERE `+where+` ORDER BY device_id`, args...)
+		if err != nil {
+			return fmt.Errorf("read the devices of %q: %w", userID, err)
+		}
+
+		for _, table := range []string{"keyserver_device_keys", "keyserver_one_time_keys", "keyserver_fallback_keys"} {
+			if _, err := t.delWhere(table, where, args...); err != nil {
+				return fmt.Errorf("delete from %s for %q: %w", table, userID, err)
+			}
+		}
+		if len(had) == 0 {
+			return nil
+		}
+		updates, err = newKeysWrite(t).bumpDeviceList(userID, had)
+		return err
+	})
+	return updates, err
+}
+
+// queryStringsTx runs a one-column query inside a write.
+func (s *Keys) queryStringsTx(t *tx, query string, args ...any) ([]string, error) {
+	rows, err := t.query(query, args...)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = rows.Close() }()
+	var out []string
+	for rows.Next() {
+		var v string
+		if err := rows.Scan(&v); err != nil {
+			return nil, err
+		}
+		out = append(out, v)
+	}
+	return out, rows.Err()
+}
+
+// --- one-time and fallback keys -----------------------------------------------
+
+// AddOneTimeKeys implements storage.KeyStore. The same key again is not an
+// error; another key under the same ID is a conflict, and nothing is
+// stored.
+func (s *Keys) AddOneTimeKeys(ctx context.Context, userID, deviceID string, keys []storage.OneTimeKey) error {
+	if len(keys) == 0 {
+		return nil
+	}
+	return s.write(ctx, func(t *tx) error {
+		ids := make([]string, len(keys))
+		for i, k := range keys {
+			ids[i] = k.KeyID
+		}
+		held := map[string]string{}
+		rows, err := t.query(`SELECT key_id, key_json FROM keyserver_one_time_keys
+			WHERE user_id = ? AND device_id = ? AND key_id IN `+inList, userID, deviceID, jsonList(ids))
+		if err != nil {
+			return fmt.Errorf("read the one-time keys of %s/%s: %w", userID, deviceID, err)
+		}
+		for rows.Next() {
+			var id, keyJSON string
+			if err := rows.Scan(&id, &keyJSON); err != nil {
+				_ = rows.Close()
+				return fmt.Errorf("read the one-time keys of %s/%s: %w", userID, deviceID, err)
+			}
+			held[id] = keyJSON
+		}
+		_ = rows.Close()
+		if err := rows.Err(); err != nil {
+			return fmt.Errorf("read the one-time keys of %s/%s: %w", userID, deviceID, err)
+		}
+
+		for _, k := range keys {
+			if existing, ok := held[k.KeyID]; ok {
+				if existing == string(k.JSON) {
+					continue
+				}
+				return fmt.Errorf("%w: %s", storage.ErrKeyConflict, k.KeyID)
+			}
+			t.put("keyserver_one_time_keys", rec{
+				"user_id": userID, "device_id": deviceID, "key_id": k.KeyID,
+				"algorithm": k.Algorithm(), "key_json": string(k.JSON),
+			})
+			held[k.KeyID] = string(k.JSON)
+		}
+		return nil
+	})
+}
+
+// OneTimeKeyCounts implements storage.KeyStore.
+func (s *Keys) OneTimeKeyCounts(ctx context.Context, userID, deviceID string) (map[string]int, error) {
+	rows, err := s.db.QueryContext(ctx, `SELECT algorithm, COUNT(*) FROM keyserver_one_time_keys
+		WHERE user_id = ? AND device_id = ? GROUP BY algorithm`, userID, deviceID)
+	if err != nil {
+		return nil, fmt.Errorf("count the one-time keys of %s/%s: %w", userID, deviceID, err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	out := map[string]int{}
+	for rows.Next() {
+		var (
+			algorithm string
+			n         int
+		)
+		if err := rows.Scan(&algorithm, &n); err != nil {
+			return nil, fmt.Errorf("count the one-time keys of %s/%s: %w", userID, deviceID, err)
+		}
+		out[algorithm] = n
+	}
+	return out, rows.Err()
+}
+
+const selectFallbackKeySQL = `
+	SELECT key_id, key_json FROM keyserver_fallback_keys
+	WHERE user_id = ? AND device_id = ? AND algorithm = ?`
+
+// SetFallbackKeys implements storage.KeyStore. The same key again keeps its
+// used flag; a new one starts unused.
+func (s *Keys) SetFallbackKeys(ctx context.Context, userID, deviceID string, keys []storage.OneTimeKey) error {
+	if len(keys) == 0 {
+		return nil
+	}
+	return s.write(ctx, func(t *tx) error {
+		for _, k := range keys {
+			var existingID, existingJSON string
+			err := t.queryRow(selectFallbackKeySQL, userID, deviceID, k.Algorithm()).Scan(&existingID, &existingJSON)
+			switch {
+			case err == nil && existingID == k.KeyID && existingJSON == string(k.JSON):
+				continue
+			case err != nil && !errors.Is(err, sql.ErrNoRows):
+				return fmt.Errorf("read the fallback key of %s/%s: %w", userID, deviceID, err)
+			}
+			t.put("keyserver_fallback_keys", rec{
+				"user_id": userID, "device_id": deviceID, "algorithm": k.Algorithm(),
+				"key_id": k.KeyID, "key_json": string(k.JSON), "used": false,
+			})
+		}
+		return nil
+	})
+}
+
+// UnusedFallbackKeyTypes implements storage.KeyStore.
+func (s *Keys) UnusedFallbackKeyTypes(ctx context.Context, userID, deviceID string) ([]string, error) {
+	out, err := s.queryStrings(ctx, `SELECT algorithm FROM keyserver_fallback_keys
+		WHERE user_id = ? AND device_id = ? AND used = ? ORDER BY algorithm`, userID, deviceID, false)
+	if err != nil {
+		return nil, fmt.Errorf("read the fallback keys of %s/%s: %w", userID, deviceID, err)
+	}
+	return out, nil
+}
+
+// ClaimKey implements storage.KeyStore. The read and the delete happen under
+// the write lock, so a claim cannot lose the key it read to another one.
+func (s *Keys) ClaimKey(ctx context.Context, userID, deviceID, algorithm string) (storage.ClaimedKey, bool, error) {
+	var (
+		claimed storage.ClaimedKey
+		found   bool
+	)
+	err := s.write(ctx, func(t *tx) error {
+		var keyID, keyJSON string
+		err := t.queryRow(`SELECT key_id, key_json FROM keyserver_one_time_keys
+			WHERE user_id = ? AND device_id = ? AND algorithm = ?
+			ORDER BY key_id LIMIT 1`, userID, deviceID, algorithm).Scan(&keyID, &keyJSON)
+		switch {
+		case err == nil:
+			t.del("keyserver_one_time_keys", rowID("keyserver_one_time_keys", userID, deviceID, keyID))
+			claimed = storage.ClaimedKey{OneTimeKey: storage.OneTimeKey{KeyID: keyID, JSON: []byte(keyJSON)}}
+			found = true
+			return nil
+		case !errors.Is(err, sql.ErrNoRows):
+			return fmt.Errorf("claim a one-time key of %s/%s: %w", userID, deviceID, err)
+		}
+
+		err = t.queryRow(selectFallbackKeySQL, userID, deviceID, algorithm).Scan(&keyID, &keyJSON)
+		switch {
+		case errors.Is(err, sql.ErrNoRows):
+			return nil
+		case err != nil:
+			return fmt.Errorf("claim the fallback key of %s/%s: %w", userID, deviceID, err)
+		}
+		t.put("keyserver_fallback_keys", rec{"user_id": userID, "device_id": deviceID, "algorithm": algorithm, "used": true})
+		claimed = storage.ClaimedKey{OneTimeKey: storage.OneTimeKey{KeyID: keyID, JSON: []byte(keyJSON)}, Fallback: true}
+		found = true
+		return nil
+	})
+	if err != nil {
+		return storage.ClaimedKey{}, false, err
+	}
+	return claimed, found, nil
+}
+
+// --- cross-signing ------------------------------------------------------------
+
+// SetCrossSigningKeys implements storage.KeyStore. A nil key deletes that
+// purpose.
+func (s *Keys) SetCrossSigningKeys(ctx context.Context, userID string, keys map[string][]byte) (storage.DeviceListUpdate, error) {
+	var update storage.DeviceListUpdate
+	err := s.write(ctx, func(t *tx) error {
+		for _, purpose := range sortedKeys(keys) {
+			keyJSON := keys[purpose]
+			if keyJSON == nil {
+				if _, err := t.delKey("keyserver_cross_signing_keys", userID, purpose); err != nil {
+					return fmt.Errorf("store the %s key of %q: %w", purpose, userID, err)
+				}
+				continue
+			}
+			t.put("keyserver_cross_signing_keys", rec{"user_id": userID, "purpose": purpose, "key_json": string(keyJSON)})
+		}
+		updates, err := newKeysWrite(t).bumpDeviceList(userID, nil)
+		if err != nil {
+			return err
+		}
+		update = updates[0]
+		return nil
+	})
+	return update, err
+}
+
+// CrossSigningKeys implements storage.KeyStore.
+func (s *Keys) CrossSigningKeys(ctx context.Context, userID string) (map[string][]byte, error) {
+	rows, err := s.db.QueryContext(ctx, `SELECT purpose, key_json FROM keyserver_cross_signing_keys WHERE user_id = ?`, userID)
+	if err != nil {
+		return nil, fmt.Errorf("read the cross-signing keys of %q: %w", userID, err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	out := map[string][]byte{}
+	for rows.Next() {
+		var purpose, keyJSON string
+		if err := rows.Scan(&purpose, &keyJSON); err != nil {
+			return nil, fmt.Errorf("read the cross-signing keys of %q: %w", userID, err)
+		}
+		out[purpose] = []byte(keyJSON)
+	}
+	return out, rows.Err()
+}
+
+// --- signatures ---------------------------------------------------------------
+
+// AddSignatures implements storage.KeyStore.
+func (s *Keys) AddSignatures(ctx context.Context, sigs []storage.KeySignature) ([]storage.DeviceListUpdate, error) {
+	if len(sigs) == 0 {
+		return nil, nil
+	}
+	var updates []storage.DeviceListUpdate
+	err := s.write(ctx, func(t *tx) error {
+		w := newKeysWrite(t)
+		targets := map[string][]string{}
+		for _, sig := range sigs {
+			t.put("keyserver_signatures", rec{
+				"target_user_id": sig.TargetUserID, "target_key_id": sig.TargetKeyID,
+				"signer_user_id": sig.SignerUserID, "signer_key_id": sig.SignerKeyID,
+				"signature": sig.Signature,
+			})
+			if !slices.Contains(targets[sig.TargetUserID], sig.TargetKeyID) {
+				targets[sig.TargetUserID] = append(targets[sig.TargetUserID], sig.TargetKeyID)
+			}
+		}
+		for _, userID := range sortedKeys(targets) {
+			moved, err := w.bumpDeviceList(userID, targets[userID])
+			if err != nil {
+				return err
+			}
+			updates = append(updates, moved...)
+		}
+		return nil
+	})
+	return updates, err
+}
+
+// Signatures implements storage.KeyStore.
+func (s *Keys) Signatures(ctx context.Context, targetUserID string) ([]storage.KeySignature, error) {
+	rows, err := s.db.QueryContext(ctx, `SELECT target_key_id, signer_user_id, signer_key_id, signature
+		FROM keyserver_signatures WHERE target_user_id = ?
+		ORDER BY target_key_id, signer_user_id, signer_key_id`, targetUserID)
+	if err != nil {
+		return nil, fmt.Errorf("read the signatures of %q's keys: %w", targetUserID, err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	var out []storage.KeySignature
+	for rows.Next() {
+		sig := storage.KeySignature{TargetUserID: targetUserID}
+		if err := rows.Scan(&sig.TargetKeyID, &sig.SignerUserID, &sig.SignerKeyID, &sig.Signature); err != nil {
+			return nil, fmt.Errorf("read the signatures of %q's keys: %w", targetUserID, err)
+		}
+		out = append(out, sig)
+	}
+	return out, rows.Err()
+}
+
+// --- key backup ---------------------------------------------------------------
+
+// parseBackupVersion reads a version number. A version that is not one is a
+// version that does not exist.
+func parseBackupVersion(version string) (int64, bool) {
+	n, err := strconv.ParseInt(version, 10, 64)
+	return n, err == nil && n > 0
+}
+
+// rowQuerier is what readBackup reads through: the pool, or a write.
+type rowQuerier func(query string, args ...any) *sql.Row
+
+func (s *Keys) poolRow(ctx context.Context) rowQuerier {
+	return func(query string, args ...any) *sql.Row { return s.db.QueryRowContext(ctx, query, args...) }
+}
+
+// readBackup reads one live version, with its key count.
+func readBackup(row rowQuerier, userID, version string) (storage.BackupVersion, int64, int64, error) {
+	var n int64
+	if version == "" {
+		if err := row(`SELECT COALESCE(MAX(version), 0) FROM keyserver_backup_versions
+			WHERE user_id = ? AND deleted = ?`, userID, false).Scan(&n); err != nil {
+			return storage.BackupVersion{}, 0, 0, fmt.Errorf("read the backup version of %q: %w", userID, err)
+		}
+		if n == 0 {
+			return storage.BackupVersion{}, 0, 0, storage.ErrNoSuchBackup
+		}
+	} else {
+		var ok bool
+		if n, ok = parseBackupVersion(version); !ok {
+			return storage.BackupVersion{}, 0, 0, storage.ErrNoSuchBackup
+		}
+	}
+
+	out := storage.BackupVersion{UserID: userID, Version: strconv.FormatInt(n, 10)}
+	var (
+		authData string
+		etag     int64
+	)
+	err := row(`SELECT algorithm, auth_data, etag FROM keyserver_backup_versions
+		WHERE user_id = ? AND version = ? AND deleted = ?`, userID, n, false).Scan(&out.Algorithm, &authData, &etag)
+	switch {
+	case errors.Is(err, sql.ErrNoRows):
+		return storage.BackupVersion{}, 0, 0, storage.ErrNoSuchBackup
+	case err != nil:
+		return storage.BackupVersion{}, 0, 0, fmt.Errorf("read backup version %d of %q: %w", n, userID, err)
+	}
+	out.AuthData = []byte(authData)
+	out.ETag = strconv.FormatInt(etag, 10)
+	if err := row(`SELECT COUNT(*) FROM keyserver_backup_keys WHERE user_id = ? AND version = ?`, userID, n).
+		Scan(&out.Count); err != nil {
+		return storage.BackupVersion{}, 0, 0, fmt.Errorf("count the keys of backup version %d of %q: %w", n, userID, err)
+	}
+	return out, n, etag, nil
+}
+
+// CreateBackup implements storage.KeyStore.
+func (s *Keys) CreateBackup(ctx context.Context, userID, algorithm string, authData []byte) (string, error) {
+	var version int64
+	err := s.write(ctx, func(t *tx) error {
+		if err := t.queryRow(`SELECT COALESCE(MAX(version), 0) FROM keyserver_backup_versions WHERE user_id = ?`,
+			userID).Scan(&version); err != nil {
+			return fmt.Errorf("read the backup versions of %q: %w", userID, err)
+		}
+		version++
+		t.put("keyserver_backup_versions", rec{
+			"user_id": userID, "version": version, "algorithm": algorithm,
+			"auth_data": string(authData), "etag": int64(0), "deleted": false,
+		})
+		return nil
+	})
+	if err != nil {
+		return "", err
+	}
+	return strconv.FormatInt(version, 10), nil
+}
+
+// Backup implements storage.KeyStore.
+func (s *Keys) Backup(ctx context.Context, userID, version string) (storage.BackupVersion, error) {
+	out, _, _, err := readBackup(s.poolRow(ctx), userID, version)
+	return out, err
+}
+
+// UpdateBackup implements storage.KeyStore.
+func (s *Keys) UpdateBackup(ctx context.Context, userID, version string, authData []byte) error {
+	n, ok := parseBackupVersion(version)
+	if !ok {
+		return storage.ErrNoSuchBackup
+	}
+	return s.write(ctx, func(t *tx) error {
+		affected, err := t.setWhere("keyserver_backup_versions", rec{"auth_data": string(authData)},
+			`user_id = ? AND version = ? AND deleted = ?`, userID, n, false)
+		if err != nil {
+			return fmt.Errorf("update backup version %d of %q: %w", n, userID, err)
+		}
+		if affected == 0 {
+			return storage.ErrNoSuchBackup
+		}
+		return nil
+	})
+}
+
+// DeleteBackup implements storage.KeyStore.
+func (s *Keys) DeleteBackup(ctx context.Context, userID, version string) error {
+	n, ok := parseBackupVersion(version)
+	if !ok {
+		return storage.ErrNoSuchBackup
+	}
+	return s.write(ctx, func(t *tx) error {
+		affected, err := t.setWhere("keyserver_backup_versions", rec{"deleted": true},
+			`user_id = ? AND version = ? AND deleted = ?`, userID, n, false)
+		if err != nil {
+			return fmt.Errorf("delete backup version %d of %q: %w", n, userID, err)
+		}
+		if affected == 0 {
+			return storage.ErrNoSuchBackup
+		}
+		if _, err := t.delWhere("keyserver_backup_keys", `user_id = ? AND version = ?`, userID, n); err != nil {
+			return fmt.Errorf("delete the keys of backup version %d of %q: %w", n, userID, err)
+		}
+		return nil
+	})
+}
+
+// PutBackupKeys implements storage.KeyStore.
+func (s *Keys) PutBackupKeys(ctx context.Context, userID, version string, keys []storage.BackupKey) (storage.BackupVersion, error) {
+	var out storage.BackupVersion
+	err := s.write(ctx, func(t *tx) error {
+		current, n, etag, err := readBackup(t.queryRow, userID, version)
+		if err != nil {
+			return err
+		}
+
+		changed := false
+		written := map[string]storage.BackupKey{}
+		for _, k := range keys {
+			slot := k.RoomID + "\x00" + k.SessionID
+			existing, have := written[slot]
+			if !have {
+				var sessionData string
+				err := t.queryRow(`SELECT first_message_index, forwarded_count, is_verified, session_data
+					FROM keyserver_backup_keys
+					WHERE user_id = ? AND version = ? AND room_id = ? AND session_id = ?`, userID, n, k.RoomID, k.SessionID).
+					Scan(&existing.FirstMessageIndex, &existing.ForwardedCount, &existing.IsVerified, &sessionData)
+				switch {
+				case err == nil:
+					have = true
+				case !errors.Is(err, sql.ErrNoRows):
+					return fmt.Errorf("read backed-up key %s/%s: %w", k.RoomID, k.SessionID, err)
+				}
+				if !have {
+					current.Count++
+				}
+			}
+			if have && !k.Replaces(existing) {
+				written[slot] = existing
+				continue
+			}
+			t.put("keyserver_backup_keys", rec{
+				"user_id": userID, "version": n, "room_id": k.RoomID, "session_id": k.SessionID,
+				"first_message_index": k.FirstMessageIndex, "forwarded_count": k.ForwardedCount,
+				"is_verified": k.IsVerified, "session_data": string(k.SessionData),
+			})
+			written[slot] = k
+			changed = true
+		}
+		if changed {
+			etag++
+			t.put("keyserver_backup_versions", rec{"user_id": userID, "version": n, "etag": etag})
+		}
+		current.ETag = strconv.FormatInt(etag, 10)
+		out = current
+		return nil
+	})
+	return out, err
+}
+
+// backupKeyScope is the WHERE clause the key reads and deletes share.
+func backupKeyScope(userID string, version int64, roomID, sessionID string) (string, []any) {
+	where := `user_id = ? AND version = ?`
+	args := []any{userID, version}
+	if roomID != "" {
+		where += ` AND room_id = ?`
+		args = append(args, roomID)
+		if sessionID != "" {
+			where += ` AND session_id = ?`
+			args = append(args, sessionID)
+		}
+	}
+	return where, args
+}
+
+// BackupKeys implements storage.KeyStore.
+func (s *Keys) BackupKeys(ctx context.Context, userID, version, roomID, sessionID string) ([]storage.BackupKey, error) {
+	_, n, _, err := readBackup(s.poolRow(ctx), userID, version)
+	if err != nil {
+		return nil, err
+	}
+	where, args := backupKeyScope(userID, n, roomID, sessionID)
+	rows, err := s.db.QueryContext(ctx, `
+		SELECT room_id, session_id, first_message_index, forwarded_count, is_verified, session_data
+		FROM keyserver_backup_keys WHERE `+where+` ORDER BY room_id, session_id`, args...)
+	if err != nil {
+		return nil, fmt.Errorf("read the keys of backup version %d of %q: %w", n, userID, err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	var out []storage.BackupKey
+	for rows.Next() {
+		var (
+			k           storage.BackupKey
+			sessionData string
+		)
+		if err := rows.Scan(&k.RoomID, &k.SessionID, &k.FirstMessageIndex, &k.ForwardedCount,
+			&k.IsVerified, &sessionData); err != nil {
+			return nil, fmt.Errorf("read the keys of backup version %d of %q: %w", n, userID, err)
+		}
+		k.SessionData = []byte(sessionData)
+		out = append(out, k)
+	}
+	return out, rows.Err()
+}
+
+// DeleteBackupKeys implements storage.KeyStore.
+func (s *Keys) DeleteBackupKeys(ctx context.Context, userID, version, roomID, sessionID string) (storage.BackupVersion, error) {
+	var out storage.BackupVersion
+	err := s.write(ctx, func(t *tx) error {
+		current, n, etag, err := readBackup(t.queryRow, userID, version)
+		if err != nil {
+			return err
+		}
+		where, args := backupKeyScope(userID, n, roomID, sessionID)
+		deleted, err := t.delWhere("keyserver_backup_keys", where, args...)
+		if err != nil {
+			return fmt.Errorf("delete keys from backup version %d of %q: %w", n, userID, err)
+		}
+		if deleted > 0 {
+			etag++
+			t.put("keyserver_backup_versions", rec{"user_id": userID, "version": n, "etag": etag})
+		}
+		current.Count -= deleted
+		current.ETag = strconv.FormatInt(etag, 10)
+		out = current
+		return nil
+	})
+	return out, err
+}
+
+// --- helpers ------------------------------------------------------------------
+
+// dedupe returns the distinct values of a list, sorted.
+func dedupe(values []string) []string {
+	out := slices.Clone(values)
+	slices.Sort(out)
+	return slices.Compact(out)
+}
+
+// sortedKeys is the keys of a map in order, which makes the order of writes
+// — and so of the positions handed out — deterministic.
+func sortedKeys[V any](m map[string]V) []string {
+	out := make([]string, 0, len(m))
+	for k := range m {
+		out = append(out, k)
+	}
+	slices.Sort(out)
+	return out
+}
+
+var _ storage.KeyStore = (*Keys)(nil)

server/internal/storage/pocketbase/media.go

@@ -0,0 +1,195 @@
+package pocketbase
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+
+	"github.com/dariuszjaniak/warp/server/internal/storage"
+)
+
+// Media is the PocketBase implementation of storage.MediaStore: the
+// metadata of media. The content is the blob store's.
+type Media struct{ *base }
+
+// CreateMedia implements storage.MediaStore.
+func (s *Media) CreateMedia(ctx context.Context, m storage.Media) error {
+	return s.write(ctx, func(t *tx) error {
+		taken, err := t.exists("media_repository", `media_origin = ? AND media_id = ?`, m.Origin, m.MediaID)
+		if err != nil {
+			return fmt.Errorf("store media %s/%s: %w", m.Origin, m.MediaID, err)
+		}
+		if taken {
+			return storage.ErrMediaExists
+		}
+		t.put("media_repository", mediaRow(m))
+		return nil
+	})
+}
+
+func mediaRow(m storage.Media) rec {
+	return rec{
+		"media_origin": m.Origin, "media_id": m.MediaID, "content_type": m.ContentType,
+		"upload_name": m.UploadName, "file_size": m.Size, "sha256": m.SHA256,
+		"user_id": m.UserID, "created_at_ms": m.CreatedAtMS, "pending": m.Pending,
+		"expires_at_ms": m.ExpiresAtMS,
+	}
+}
+
+// Media implements storage.MediaStore.
+func (s *Media) Media(ctx context.Context, origin, mediaID string) (storage.Media, error) {
+	var m storage.Media
+	err := s.db.QueryRowContext(ctx, `
+		SELECT media_origin, media_id, content_type, upload_name, file_size, sha256,
+			user_id, created_at_ms, pending, expires_at_ms
+		FROM media_repository WHERE media_origin = ? AND media_id = ?`, origin, mediaID).Scan(
+		&m.Origin, &m.MediaID, &m.ContentType, &m.UploadName, &m.Size, &m.SHA256,
+		&m.UserID, &m.CreatedAtMS, &m.Pending, &m.ExpiresAtMS)
+	switch {
+	case err == nil:
+		return m, nil
+	case errors.Is(err, sql.ErrNoRows):
+		return storage.Media{}, storage.ErrNoSuchMedia
+	default:
+		return storage.Media{}, fmt.Errorf("read media %s/%s: %w", origin, mediaID, err)
+	}
+}
+
+// CompleteUpload implements storage.MediaStore. Only pending media is
+// completed, so that two uploads for the same ID cannot both win.
+func (s *Media) CompleteUpload(ctx context.Context, origin, mediaID string, c storage.MediaContent) error {
+	var completed bool
+	err := s.write(ctx, func(t *tx) error {
+		n, err := t.setWhere("media_repository", rec{
+			"content_type": c.ContentType, "upload_name": c.UploadName, "file_size": c.Size,
+			"sha256": c.SHA256, "pending": false, "expires_at_ms": int64(0),
+		}, `media_origin = ? AND media_id = ? AND pending = ?`, origin, mediaID, true)
+		completed = n == 1
+		return err
+	})
+	if err != nil {
+		return fmt.Errorf("complete upload %s/%s: %w", origin, mediaID, err)
+	}
+	if completed {
+		return nil
+	}
+	// Nothing pending matched: either there is no such media, or its
+	// content is already there.
+	if _, err := s.Media(ctx, origin, mediaID); err != nil {
+		return err
+	}
+	return storage.ErrMediaUploaded
+}
+
+// PendingUploads implements storage.MediaStore.
+func (s *Media) PendingUploads(ctx context.Context, userID string, nowMS int64) (int, error) {
+	var n int
+	if err := s.db.QueryRowContext(ctx, `SELECT COUNT(*) FROM media_repository
+		WHERE pending = ? AND user_id = ? AND expires_at_ms > ?`, true, userID, nowMS).Scan(&n); err != nil {
+		return 0, fmt.Errorf("count the pending uploads of %s: %w", userID, err)
+	}
+	return n, nil
+}
+
+// DeleteExpiredUploads implements storage.MediaStore.
+func (s *Media) DeleteExpiredUploads(ctx context.Context, nowMS int64) (int, error) {
+	var n int
+	err := s.write(ctx, func(t *tx) error {
+		var err error
+		n, err = t.delWhere("media_repository", `pending = ? AND expires_at_ms <= ?`, true, nowMS)
+		return err
+	})
+	if err != nil {
+		return 0, fmt.Errorf("delete expired uploads: %w", err)
+	}
+	return n, nil
+}
+
+// Thumbnail implements storage.MediaStore.
+func (s *Media) Thumbnail(ctx context.Context, origin, mediaID string, width, height int, method string) (storage.Thumbnail, error) {
+	var t storage.Thumbnail
+	err := s.db.QueryRowContext(ctx, `
+		SELECT media_origin, media_id, width, height, method, content_type,
+			file_size, sha256, created_at_ms
+		FROM media_thumbnails
+		WHERE media_origin = ? AND media_id = ? AND width = ? AND height = ? AND method = ?`,
+		origin, mediaID, width, height, method).Scan(
+		&t.Origin, &t.MediaID, &t.Width, &t.Height, &t.Method, &t.ContentType,
+		&t.Size, &t.SHA256, &t.CreatedAtMS)
+	switch {
+	case err == nil:
+		return t, nil
+	case errors.Is(err, sql.ErrNoRows):
+		return storage.Thumbnail{}, storage.ErrNoSuchMedia
+	default:
+		return storage.Thumbnail{}, fmt.Errorf("read a thumbnail of %s/%s: %w", origin, mediaID, err)
+	}
+}
+
+// StoreThumbnail implements storage.MediaStore.
+func (s *Media) StoreThumbnail(ctx context.Context, t storage.Thumbnail) error {
+	err := s.write(ctx, func(w *tx) error {
+		w.put("media_thumbnails", rec{
+			"media_origin": t.Origin, "media_id": t.MediaID, "width": t.Width, "height": t.Height,
+			"method": t.Method, "content_type": t.ContentType, "file_size": t.Size,
+			"sha256": t.SHA256, "created_at_ms": t.CreatedAtMS,
+		})
+		return nil
+	})
+	if err != nil {
+		return fmt.Errorf("store a thumbnail of %s/%s: %w", t.Origin, t.MediaID, err)
+	}
+	return nil
+}
+
+// MediaUsage implements storage.MediaStore. It counts every upload at its
+// own size, even when two of them are the same bytes.
+func (s *Media) MediaUsage(ctx context.Context, origin, userID string) (storage.MediaUsage, error) {
+	var u storage.MediaUsage
+	if err := s.db.QueryRowContext(ctx, `SELECT COUNT(*), COALESCE(SUM(file_size), 0) FROM media_repository
+		WHERE user_id = ? AND media_origin = ? AND pending = ?`, userID, origin, false).
+		Scan(&u.Count, &u.Bytes); err != nil {
+		return storage.MediaUsage{}, fmt.Errorf("total the uploads of %s: %w", userID, err)
+	}
+	return u, nil
+}
+
+// MediaQuota implements storage.MediaStore.
+func (s *Media) MediaQuota(ctx context.Context, userID string) (int64, bool, error) {
+	var maxBytes int64
+	err := s.db.QueryRowContext(ctx, `SELECT max_bytes FROM media_quotas WHERE user_id = ?`, userID).Scan(&maxBytes)
+	switch {
+	case errors.Is(err, sql.ErrNoRows):
+		return 0, false, nil
+	case err != nil:
+		return 0, false, fmt.Errorf("read the media quota of %s: %w", userID, err)
+	}
+	return maxBytes, true, nil
+}
+
+// SetMediaQuota implements storage.MediaStore.
+func (s *Media) SetMediaQuota(ctx context.Context, userID string, maxBytes int64) error {
+	err := s.write(ctx, func(t *tx) error {
+		t.put("media_quotas", rec{"user_id": userID, "max_bytes": maxBytes})
+		return nil
+	})
+	if err != nil {
+		return fmt.Errorf("set the media quota of %s: %w", userID, err)
+	}
+	return nil
+}
+
+// DeleteMediaQuota implements storage.MediaStore.
+func (s *Media) DeleteMediaQuota(ctx context.Context, userID string) error {
+	err := s.write(ctx, func(t *tx) error {
+		_, err := t.delKey("media_quotas", userID)
+		return err
+	})
+	if err != nil {
+		return fmt.Errorf("delete the media quota of %s: %w", userID, err)
+	}
+	return nil
+}
+
+var _ storage.MediaStore = (*Media)(nil)

server/internal/storage/pocketbase/pbtest/pbtest.go

@@ -0,0 +1,64 @@
+// Package pbtest runs a real PocketBase server in-process for tests, so the
+// pocketbase driver is tested against the same REST API it uses in
+// production, with no container to start.
+package pbtest
+
+import (
+	"net/http/httptest"
+	"testing"
+
+	"github.com/pocketbase/pocketbase/apis"
+	"github.com/pocketbase/pocketbase/core"
+	_ "github.com/pocketbase/pocketbase/migrations" // PocketBase's system migrations; without them its bootstrap has no tables
+)
+
+// Superuser is the account the server is started with.
+const (
+	SuperuserEmail    = "warp-tests@example.com"
+	SuperuserPassword = "warp-tests-password"
+)
+
+// Server is a running PocketBase.
+type Server struct {
+	// URL is the server's address, for database.connection_string.
+	URL string
+
+	// DataDir is its pb_data, where a test can look for what it stored.
+	DataDir string
+}
+
+// Start runs a fresh PocketBase with an empty data directory. It is stopped
+// when the test ends.
+func Start(tb testing.TB) Server {
+	tb.Helper()
+
+	dataDir := tb.TempDir()
+	app := core.NewBaseApp(core.BaseAppConfig{DataDir: dataDir})
+	if err := app.Bootstrap(); err != nil {
+		tb.Fatalf("pocketbase: bootstrap: %v", err)
+	}
+	tb.Cleanup(func() { _ = app.ResetBootstrapState() })
+
+	superusers, err := app.FindCollectionByNameOrId(core.CollectionNameSuperusers)
+	if err != nil {
+		tb.Fatalf("pocketbase: %v", err)
+	}
+	su := core.NewRecord(superusers)
+	su.SetEmail(SuperuserEmail)
+	su.SetPassword(SuperuserPassword)
+	if err := app.Save(su); err != nil {
+		tb.Fatalf("pocketbase: create the superuser: %v", err)
+	}
+
+	router, err := apis.NewRouter(app)
+	if err != nil {
+		tb.Fatalf("pocketbase: router: %v", err)
+	}
+	mux, err := router.BuildMux()
+	if err != nil {
+		tb.Fatalf("pocketbase: router: %v", err)
+	}
+	server := httptest.NewServer(mux)
+	tb.Cleanup(server.Close)
+	return Server{URL: server.URL, DataDir: dataDir}
+}

server/internal/storage/pocketbase/pocketbase.go

@@ -1,278 +1,338 @@
-// Package pocketbase is the PocketBase storage driver: Warp on an embedded
-// PocketBase app, for "appliance" deployments that want one binary and one
-// data directory.
+// Package pocketbase is the PocketBase storage driver: Warp's data in a
+// standalone PocketBase server, as collections, reached only through
+// PocketBase's REST API — the way the postgres driver reaches PostgreSQL
+// over its wire protocol.
 //
-// PLAN.md section 4 set out the shape, and open question 4 asked how far
-// to take it. The answer here is the cheaper of the two: the event DAG and
-// everything else Warp stores are a poor fit for PocketBase's record
-// model, so the Warp tables are the sqlite driver's own, migrated by Warp
-// and written through the same shared store, on PocketBase's underlying
-// SQLite connection rather than through its collection API. What PocketBase
-// adds is everything around that: its data directory and its system
-// tables, which a PocketBase admin or a later Warp feature can build on, and
-// its filesystem abstraction, which puts media content on local disk or in
-// an S3 bucket.
-//
-// The result is at parity with the sqlite driver by construction — it is
-// the same SQL on the same engine — and the storage tests run against it
-// to keep it that way.
+// Each of the SQL drivers' tables is a collection of the same name and
+// columns (see schema.go), so a PocketBase admin sees Warp's rooms, events
+// and accounts as records. The stores read them through the superuser SQL
+// endpoint with the same queries the SQL drivers use (sqldriver.go), and
+// write them as record operations in batch requests (batch.go), which
+// PocketBase runs as one transaction each. Media content goes into a file
+// field, which is PocketBase's own storage: its pb_data/storage, or an S3
+// bucket.
 package pocketbase
 
 import (
 	"context"
-	"crypto/sha256"
-	"encoding/hex"
+	"database/sql"
 	"errors"
 	"fmt"
-	"io"
 	"log/slog"
-	"os"
-	"path/filepath"
-
-	"github.com/pocketbase/dbx"
-	"github.com/pocketbase/pocketbase/core"
-	_ "github.com/pocketbase/pocketbase/migrations" // PocketBase's system migrations; without them its bootstrap has no tables
-	"github.com/pocketbase/pocketbase/tools/filesystem"
+	"sync"
+	"time"
 
 	"github.com/dariuszjaniak/warp/server/internal/storage"
-	"github.com/dariuszjaniak/warp/server/internal/storage/sqlite"
-	"github.com/dariuszjaniak/warp/server/internal/storage/sqlstore"
 )
 
 func init() {
 	storage.Register(storage.DriverPocketBase, Open)
 }
 
-// mediaPrefix is where media content lives in PocketBase's filesystem,
-// apart from the files of PocketBase's own collections.
-const mediaPrefix = "warp_media"
-
 // Database is the PocketBase implementation of storage.Database.
 type Database struct {
-	*sqlstore.Store
-	app   *core.BaseApp
-	blobs *blobStore
+	*base
+	log *slog.Logger
+	s3  storage.S3Config
+
+	settings *Settings
+	users    *Users
+	rooms    *Rooms
+	sync     *Sync
+	fed      *Federation
+	media    *Media
+	keys     *Keys
+	push     *Push
+	admin    *Admin
+	apps     *AppServices
+	delayed  *DelayedEvents
+	openID   *OpenIDTokens
+	blobs    *blobStore
 }
 
-// Open bootstraps a PocketBase app in the directory named by
-// cfg.ConnectionString — PocketBase's pb_data — and opens the Warp store on
-// its database.
-func Open(ctx context.Context, cfg storage.Config, log *slog.Logger) (storage.Database, error) {
-	dir := cfg.ConnectionString
-	if dir == "" {
-		return nil, errors.New("pocketbase: connection_string must name the data directory")
-	}
-	if err := ctx.Err(); err != nil {
-		return nil, err
-	}
-
-	app := core.NewBaseApp(core.BaseAppConfig{
-		DataDir:          dir,
-		DataMaxOpenConns: cfg.MaxOpenConns,
-		DataMaxIdleConns: cfg.MaxIdleConns,
-	})
-	if err := app.Bootstrap(); err != nil {
-		_ = app.ResetBootstrapState()
-		return nil, fmt.Errorf("pocketbase: bootstrap %s: %w", dir, err)
-	}
-	if cfg.S3.Enabled {
-		// Applied in memory on every start rather than saved: the Warp
-		// config is the authority, and PocketBase's own settings would
-		// otherwise be a second place for the bucket to be set, and to
-		// disagree.
-		app.Settings().S3 = core.S3Config{
-			Enabled:        true,
-			Bucket:         cfg.S3.Bucket,
-			Region:         cfg.S3.Region,
-			Endpoint:       cfg.S3.Endpoint,
-			AccessKey:      cfg.S3.AccessKey,
-			Secret:         cfg.S3.Secret,
-			ForcePathStyle: cfg.S3.ForcePathStyle,
-		}
-	}
-
-	// The writer pool: one connection, the way the sqlite driver runs, and
-	// the way PocketBase itself writes. Warp's store reads in the same
-	// transactions it writes in, so it is given the one pool for both.
-	writer, ok := app.NonconcurrentDB().(*dbx.DB)
-	if !ok {
-		_ = app.ResetBootstrapState()
-		return nil, errors.New("pocketbase: the app's database is not a *dbx.DB")
-	}
-
-	opts := sqlite.StoreOptions(writer.DB(), log)
-	opts.DriverName = storage.DriverPocketBase
-	store, err := sqlstore.New(opts)
-	if err != nil {
-		_ = app.ResetBootstrapState()
-		return nil, err
-	}
-	return &Database{
-		Store: store,
-		app:   app,
-		blobs: &blobStore{app: app, tmpDir: filepath.Join(app.DataDir(), ".warp_tmp")},
-	}, nil
-}
-
-// App is the PocketBase app, for code that wants PocketBase's own
-// features: its collections, its auth, its realtime.
-func (d *Database) App() core.App { return d.app }
-
-// Blobs implements storage.BlobProvider: media content goes into
-// PocketBase's filesystem.
-func (d *Database) Blobs() storage.BlobStore { return d.blobs }
-
-// Close implements storage.Database. The app owns the connection pools.
-func (d *Database) Close() error { return d.app.ResetBootstrapState() }
-
-// blobStore is storage.BlobStore over PocketBase's filesystem: the local
-// pb_data/storage directory, or the S3 bucket the settings name.
+// Open connects to the PocketBase server at cfg.ConnectionString and signs
+// in as the configured superuser.
 //
-// The filesystem can only be written a whole file at a time, and a blob's
-// name is its hash, which is not known until the last byte has been read.
-// So an upload is spooled to a temporary file first, hashed on the way, and
-// handed over once it is complete — which is also what keeps a half-written
-// object from ever appearing under a hash.
-type blobStore struct {
-	app    *core.BaseApp
-	tmpDir string
-}
-
-func blobKey(sum string) (string, bool) {
-	if len(sum) != sha256.Size*2 {
-		return "", false
-	}
-	for _, c := range sum {
-		if (c < '0' || c > '9') && (c < 'a' || c > 'f') {
-			return "", false
-		}
-	}
-	return mediaPrefix + "/" + sum[0:2] + "/" + sum[2:4] + "/" + sum, true
-}
-
-// fs opens the filesystem for one operation. It is cheap for both kinds,
-// and an instance per operation is what lets each carry its own context.
-func (b *blobStore) fs(ctx context.Context) (*filesystem.System, error) {
-	fsys, err := b.app.NewFilesystem()
-	if err != nil {
-		return nil, fmt.Errorf("open the media filesystem: %w", err)
-	}
-	fsys.SetContext(ctx)
-	return fsys, nil
-}
-
-// Put implements storage.BlobStore.
-func (b *blobStore) Put(ctx context.Context, r io.Reader, limit int64) (storage.BlobInfo, error) {
-	if err := os.MkdirAll(b.tmpDir, 0o750); err != nil {
-		return storage.BlobInfo{}, fmt.Errorf("create the media spool directory: %w", err)
-	}
-	tmp, err := os.CreateTemp(b.tmpDir, "upload-*")
-	if err != nil {
-		return storage.BlobInfo{}, fmt.Errorf("create a temporary file: %w", err)
-	}
-	defer func() {
-		_ = tmp.Close()
-		_ = os.Remove(tmp.Name())
-	}()
-
-	hash := sha256.New()
-	n, err := io.Copy(io.MultiWriter(tmp, hash), &ctxReader{ctx: ctx, r: io.LimitReader(r, limit+1)})
-	if err != nil {
-		return storage.BlobInfo{}, fmt.Errorf("store content: %w", err)
-	}
-	if n > limit {
-		return storage.BlobInfo{}, storage.ErrBlobTooLarge
-	}
-	if err := tmp.Close(); err != nil {
-		return storage.BlobInfo{}, fmt.Errorf("store content: %w", err)
-	}
-
-	info := storage.BlobInfo{SHA256: hex.EncodeToString(hash.Sum(nil)), Size: n}
-	key, _ := blobKey(info.SHA256)
-
-	fsys, err := b.fs(ctx)
-	if err != nil {
-		return storage.BlobInfo{}, err
-	}
-	defer func() { _ = fsys.Close() }()
-
-	if exists, err := fsys.Exists(key); err == nil && exists {
-		// The same content is already stored.
-		return info, nil
-	}
-	file, err := filesystem.NewFileFromPath(tmp.Name())
-	if err != nil {
-		return storage.BlobInfo{}, fmt.Errorf("store content: %w", err)
-	}
-	if err := fsys.UploadFile(file, key); err != nil {
-		return storage.BlobInfo{}, fmt.Errorf("store content: %w", err)
-	}
-	return info, nil
-}
-
-// Open implements storage.BlobStore.
-func (b *blobStore) Open(ctx context.Context, sum string) (io.ReadSeekCloser, error) {
-	key, ok := blobKey(sum)
-	if !ok {
-		return nil, storage.ErrNoSuchBlob
-	}
-	fsys, err := b.fs(ctx)
+// It configures the server for Warp before anything else — batch requests
+// on, and the S3 bucket when one is configured — so a server that cannot
+// be reached or refuses the account fails here, at startup.
+func Open(ctx context.Context, cfg storage.Config, log *slog.Logger) (storage.Database, error) {
+	c, err := newClient(cfg.ConnectionString, cfg.SuperuserEmail, cfg.SuperuserPassword)
 	if err != nil {
 		return nil, err
 	}
-	reader, err := fsys.GetReader(key)
-	if err != nil {
-		_ = fsys.Close()
-		if errors.Is(err, filesystem.ErrNotFound) {
-			return nil, storage.ErrNoSuchBlob
-		}
-		return nil, fmt.Errorf("open media content: %w", err)
+	lock := &sync.RWMutex{}
+	db := sql.OpenDB(&sqlConnector{c: c, lock: lock})
+	// The connections hold nothing, so the pool only bounds how many reads
+	// are in flight at once.
+	maxConns := cfg.MaxOpenConns
+	if maxConns <= 0 {
+		maxConns = 16
 	}
-	return &blobReader{ReadSeekCloser: reader, fsys: fsys}, nil
+	db.SetMaxOpenConns(maxConns)
+
+	b := &base{c: c, db: db, lock: lock}
+	d := &Database{
+		base:     b,
+		log:      log,
+		s3:       cfg.S3,
+		settings: &Settings{base: b},
+		users:    &Users{base: b},
+		rooms:    &Rooms{base: b},
+		sync:     &Sync{base: b},
+		fed:      &Federation{base: b},
+		media:    &Media{base: b},
+		keys:     &Keys{base: b},
+		push:     &Push{base: b},
+		admin:    &Admin{base: b},
+		apps:     &AppServices{base: b},
+		delayed:  &DelayedEvents{base: b},
+		openID:   &OpenIDTokens{base: b},
+		blobs:    &blobStore{base: b},
+	}
+	if err := d.configure(ctx); err != nil {
+		_ = db.Close()
+		return nil, err
+	}
+	return d, nil
 }
 
-// Delete implements storage.BlobStore.
-func (b *blobStore) Delete(ctx context.Context, sum string) error {
-	key, ok := blobKey(sum)
-	if !ok {
-		return nil
+// configure applies the PocketBase settings Warp depends on.
+//
+// The S3 settings are written from Warp's configuration on every start
+// rather than left to the PocketBase admin UI: Warp's config is the
+// authority, and a second place for the bucket to be set would be a second
+// place for it to disagree. A deployment without S3 in Warp's config leaves
+// PocketBase's own setting as it is.
+func (d *Database) configure(ctx context.Context) error {
+	settings := map[string]any{
+		"batch": map[string]any{
+			"enabled":     true,
+			"maxRequests": maxBatch,
+			"timeout":     300,
+			"maxBodySize": 0,
+		},
 	}
-	fsys, err := b.fs(ctx)
-	if err != nil {
-		return err
+	if d.s3.Enabled {
+		settings["s3"] = map[string]any{
+			"enabled":        true,
+			"bucket":         d.s3.Bucket,
+			"region":         d.s3.Region,
+			"endpoint":       d.s3.Endpoint,
+			"accessKey":      d.s3.AccessKey,
+			"secret":         d.s3.Secret,
+			"forcePathStyle": d.s3.ForcePathStyle,
+		}
 	}
-	defer func() { _ = fsys.Close() }()
-	if err := fsys.Delete(key); err != nil && !errors.Is(err, filesystem.ErrNotFound) {
-		return fmt.Errorf("delete media content: %w", err)
+	if err := d.c.patchSettings(ctx, settings); err != nil {
+		return fmt.Errorf("pocketbase: configure the server: %w", err)
 	}
 	return nil
 }
 
-// blobReader closes the filesystem with the reader it opened.
-type blobReader struct {
-	io.ReadSeekCloser
-	fsys *filesystem.System
-}
+// DB exposes the read-only SQL pool, for tests and diagnostics: queries run
+// on the PocketBase server through its SQL endpoint, and anything else is
+// refused.
+func (d *Database) DB() *sql.DB { return d.db }
 
-func (r *blobReader) Close() error {
-	return errors.Join(r.ReadSeekCloser.Close(), r.fsys.Close())
-}
+// Driver implements storage.Database.
+func (d *Database) Driver() string { return storage.DriverPocketBase }
 
-// ctxReader stops a copy when its context ends.
-type ctxReader struct {
-	ctx context.Context
-	r   io.Reader
-}
+// Ping implements storage.Database.
+func (d *Database) Ping(ctx context.Context) error { return d.db.PingContext(ctx) }
 
-func (c *ctxReader) Read(p []byte) (int, error) {
-	if err := c.ctx.Err(); err != nil {
-		return 0, err
+// Close implements storage.Database.
+func (d *Database) Close() error { return d.db.Close() }
+
+// Settings implements storage.Database.
+func (d *Database) Settings() storage.SettingsStore { return d.settings }
+
+// Users implements storage.Database.
+func (d *Database) Users() storage.UserStore { return d.users }
+
+// Rooms implements storage.Database.
+func (d *Database) Rooms() storage.RoomStore { return d.rooms }
+
+// Sync implements storage.Database.
+func (d *Database) Sync() storage.SyncStore { return d.sync }
+
+// Federation implements storage.Database.
+func (d *Database) Federation() storage.FederationStore { return d.fed }
+
+// Media implements storage.Database.
+func (d *Database) Media() storage.MediaStore { return d.media }
+
+// Keys implements storage.Database.
+func (d *Database) Keys() storage.KeyStore { return d.keys }
+
+// Push implements storage.Database.
+func (d *Database) Push() storage.PushStore { return d.push }
+
+// Admin implements storage.Database.
+func (d *Database) Admin() storage.AdminStore { return d.admin }
+
+// AppServices implements storage.Database.
+func (d *Database) AppServices() storage.AppServiceStore { return d.apps }
+
+// DelayedEvents implements storage.Database.
+func (d *Database) DelayedEvents() storage.DelayedEventStore { return d.delayed }
+
+// OpenIDTokens implements storage.Database.
+func (d *Database) OpenIDTokens() storage.OpenIDTokenStore { return d.openID }
+
+// Blobs implements storage.BlobProvider: media content goes into
+// PocketBase's storage.
+func (d *Database) Blobs() storage.BlobStore { return d.blobs }
+
+// schemaMetaKey is the warp_meta row holding the schema version applied.
+const schemaMetaKey = "schema"
+
+// Migrate implements storage.Database.
+//
+// There are no numbered migrations: the schema is declared in schema.go
+// and imported as it is, which PocketBase applies as a diff — a new
+// collection is created, a new field added, an unchanged one left alone.
+// The version stamped afterwards is a hash of the declaration, so any
+// change to it is a pending migration.
+func (d *Database) Migrate(ctx context.Context) error {
+	pending, err := d.PendingMigrations(ctx)
+	if err != nil {
+		return err
 	}
-	return c.r.Read(p)
+	if len(pending) == 0 {
+		d.log.Debug("database schema is up to date", "version", schemaVersion)
+		return nil
+	}
+
+	collections := make([]map[string]any, len(schema))
+	for i := range schema {
+		collections[i] = schema[i].collectionJSON()
+	}
+	if err := d.c.importCollections(ctx, collections); err != nil {
+		return fmt.Errorf("pocketbase: import the schema: %w", err)
+	}
+
+	err = d.write(ctx, func(t *tx) error {
+		for table, names := range sequenceRows {
+			for _, name := range names {
+				found, err := t.exists(table, `name = ?`, name)
+				if err != nil {
+					return err
+				}
+				if !found {
+					t.put(table, rec{"name": name, "value": int64(0)})
+				}
+			}
+		}
+		// Arguments a crashed query left behind.
+		if _, err := t.delWhere(paramsCollection, `1 = 1`); err != nil {
+			return err
+		}
+		t.put("warp_meta", rec{"meta_key": schemaMetaKey, "meta_value": schemaVersion})
+		return nil
+	})
+	if err != nil {
+		return fmt.Errorf("pocketbase: initialise the schema: %w", err)
+	}
+	d.log.Info("applied the database schema", "version", schemaVersion)
+	return nil
+}
+
+// PendingMigrations implements storage.Database.
+func (d *Database) PendingMigrations(ctx context.Context) ([]string, error) {
+	pending := []string{"pocketbase_schema_" + schemaVersion}
+
+	var n int
+	if err := d.db.QueryRowContext(ctx,
+		`SELECT COUNT(*) FROM sqlite_master WHERE type = 'table' AND name = 'warp_meta'`).Scan(&n); err != nil {
+		return nil, fmt.Errorf("pocketbase: read the schema version: %w", err)
+	}
+	if n == 0 {
+		return pending, nil
+	}
+	var version string
+	err := d.db.QueryRowContext(ctx,
+		`SELECT meta_value FROM warp_meta WHERE meta_key = ?`, schemaMetaKey).Scan(&version)
+	switch {
+	case errors.Is(err, sql.ErrNoRows):
+		return pending, nil
+	case err != nil:
+		return nil, fmt.Errorf("pocketbase: read the schema version: %w", err)
+	case version != schemaVersion:
+		return pending, nil
+	}
+	return nil, nil
+}
+
+// Settings is the server_settings store.
+type Settings struct{ *base }
+
+// Get implements storage.SettingsStore.
+func (s *Settings) Get(ctx context.Context, key string) (string, bool, error) {
+	var value string
+	err := s.db.QueryRowContext(ctx,
+		`SELECT setting_value FROM server_settings WHERE setting_key = ?`, key).Scan(&value)
+	switch {
+	case errors.Is(err, sql.ErrNoRows):
+		return "", false, nil
+	case err != nil:
+		return "", false, fmt.Errorf("get setting %q: %w", key, err)
+	}
+	return value, true, nil
+}
+
+// GetAll implements storage.SettingsStore.
+func (s *Settings) GetAll(ctx context.Context) (map[string]string, error) {
+	rows, err := s.db.QueryContext(ctx, `SELECT setting_key, setting_value FROM server_settings`)
+	if err != nil {
+		return nil, fmt.Errorf("list settings: %w", err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	out := map[string]string{}
+	for rows.Next() {
+		var k, v string
+		if err := rows.Scan(&k, &v); err != nil {
+			return nil, fmt.Errorf("scan setting: %w", err)
+		}
+		out[k] = v
+	}
+	if err := rows.Err(); err != nil {
+		return nil, fmt.Errorf("list settings: %w", err)
+	}
+	return out, nil
+}
+
+// Set implements storage.SettingsStore.
+func (s *Settings) Set(ctx context.Context, key, value string) error {
+	err := s.write(ctx, func(t *tx) error {
+		t.put("server_settings", rec{
+			"setting_key":   key,
+			"setting_value": value,
+			"updated_at":    time.Now().UTC().Format(time.RFC3339Nano),
+		})
+		return nil
+	})
+	if err != nil {
+		return fmt.Errorf("set setting %q: %w", key, err)
+	}
+	return nil
+}
+
+// Delete implements storage.SettingsStore.
+func (s *Settings) Delete(ctx context.Context, key string) error {
+	err := s.write(ctx, func(t *tx) error {
+		_, err := t.delKey("server_settings", key)
+		return err
+	})
+	if err != nil {
+		return fmt.Errorf("delete setting %q: %w", key, err)
+	}
+	return nil
 }
 
 var (
-	_ storage.Database     = (*Database)(nil)
-	_ storage.BlobProvider = (*Database)(nil)
-	_ storage.BlobStore    = (*blobStore)(nil)
+	_ storage.Database      = (*Database)(nil)
+	_ storage.BlobProvider  = (*Database)(nil)
+	_ storage.SettingsStore = (*Settings)(nil)
 )

server/internal/storage/pocketbase/push.go

@@ -0,0 +1,328 @@
+package pocketbase
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+
+	"github.com/dariuszjaniak/warp/server/internal/storage"
+)
+
+// Push is the PocketBase implementation of storage.PushStore.
+type Push struct{ *base }
+
+const pusherColumns = `localpart, app_id, pushkey, device_id, kind, app_display_name,
+	device_display_name, profile_tag, lang, data_json, pushkey_ts_ms`
+
+// Pushers implements storage.PushStore.
+func (s *Push) Pushers(ctx context.Context, localpart string) ([]storage.Pusher, error) {
+	rows, err := s.db.QueryContext(ctx, `SELECT `+pusherColumns+` FROM push_pushers
+		WHERE localpart = ? ORDER BY app_id, pushkey`, localpart)
+	if err != nil {
+		return nil, fmt.Errorf("read the pushers of %q: %w", localpart, err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	var out []storage.Pusher
+	for rows.Next() {
+		var p storage.Pusher
+		var data string
+		if err := rows.Scan(&p.Localpart, &p.AppID, &p.PushKey, &p.DeviceID, &p.Kind, &p.AppDisplayName,
+			&p.DeviceDisplayName, &p.ProfileTag, &p.Lang, &data, &p.PushKeyTSMS); err != nil {
+			return nil, fmt.Errorf("read the pushers of %q: %w", localpart, err)
+		}
+		p.Data = []byte(data)
+		out = append(out, p)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, fmt.Errorf("read the pushers of %q: %w", localpart, err)
+	}
+	return out, nil
+}
+
+// SetPusher implements storage.PushStore.
+func (s *Push) SetPusher(ctx context.Context, p storage.Pusher, appendOthers bool) error {
+	return s.write(ctx, func(t *tx) error {
+		if !appendOthers {
+			if _, err := t.delWhere("push_pushers", `app_id = ? AND pushkey = ? AND localpart <> ?`,
+				p.AppID, p.PushKey, p.Localpart); err != nil {
+				return fmt.Errorf("remove other users' pushers for the key: %w", err)
+			}
+		}
+		t.put("push_pushers", rec{
+			"localpart": p.Localpart, "app_id": p.AppID, "pushkey": p.PushKey, "device_id": p.DeviceID,
+			"kind": p.Kind, "app_display_name": p.AppDisplayName, "device_display_name": p.DeviceDisplayName,
+			"profile_tag": p.ProfileTag, "lang": p.Lang, "data_json": string(p.Data), "pushkey_ts_ms": p.PushKeyTSMS,
+		})
+		return nil
+	})
+}
+
+// DeletePusher implements storage.PushStore.
+func (s *Push) DeletePusher(ctx context.Context, localpart, appID, pushKey string) error {
+	err := s.write(ctx, func(t *tx) error {
+		_, err := t.delKey("push_pushers", localpart, appID, pushKey)
+		return err
+	})
+	if err != nil {
+		return fmt.Errorf("delete a pusher of %q: %w", localpart, err)
+	}
+	return nil
+}
+
+// DeletePushersForDevices implements storage.PushStore.
+func (s *Push) DeletePushersForDevices(ctx context.Context, localpart string, deviceIDs []string) error {
+	where, args := `localpart = ?`, []any{localpart}
+	if len(deviceIDs) > 0 {
+		where += ` AND device_id IN ` + inList
+		args = append(args, jsonList(deviceIDs))
+	}
+	err := s.write(ctx, func(t *tx) error {
+		_, err := t.delWhere("push_pushers", where, args...)
+		return err
+	})
+	if err != nil {
+		return fmt.Errorf("delete the pushers of %q's devices: %w", localpart, err)
+	}
+	return nil
+}
+
+const notificationColumns = `notification_id, user_id, room_id, event_id, event_pos, thread_id, ts_ms, highlight, actions, is_read`
+
+// roomCounts is one room's counts for one user, as a write leaves them.
+type roomCounts struct{ notifications, highlights int64 }
+
+// AddNotifications implements storage.PushStore. Every notification takes a
+// position of its own, which is both its ID and the stamp on its room's
+// counts.
+func (s *Push) AddNotifications(ctx context.Context, ns []storage.NewNotification) (int64, error) {
+	if len(ns) == 0 {
+		return s.currentSequence(ctx, pushSequences, seqNotification)
+	}
+	var last int64
+	err := s.write(ctx, func(t *tx) error {
+		counts := map[[2]string]roomCounts{}
+		for _, n := range ns {
+			pos, err := t.next(pushSequences, seqNotification)
+			if err != nil {
+				return err
+			}
+			t.put("push_notifications", rec{
+				"notification_id": pos, "user_id": n.UserID, "room_id": n.RoomID, "event_id": n.EventID,
+				"event_pos": n.EventPos, "thread_id": n.ThreadID, "ts_ms": n.TimestampMS,
+				"highlight": n.Highlight, "actions": string(n.Actions), "is_read": false,
+			})
+
+			key := [2]string{n.UserID, n.RoomID}
+			c, ok := counts[key]
+			if !ok {
+				err := t.queryRow(`SELECT notification_count, highlight_count FROM push_room_counts
+					WHERE user_id = ? AND room_id = ?`, n.UserID, n.RoomID).Scan(&c.notifications, &c.highlights)
+				if err != nil && !errors.Is(err, sql.ErrNoRows) {
+					return fmt.Errorf("count a notification for %q: %w", n.UserID, err)
+				}
+			}
+			c.notifications++
+			if n.Highlight {
+				c.highlights++
+			}
+			counts[key] = c
+			t.put("push_room_counts", rec{
+				"user_id": n.UserID, "room_id": n.RoomID,
+				"notification_count": c.notifications, "highlight_count": c.highlights, "stream_pos": pos,
+			})
+			last = pos
+		}
+		return nil
+	})
+	return last, err
+}
+
+// MarkNotificationsRead implements storage.PushStore.
+//
+// The counts are recounted from the rows that stay unread rather than
+// decremented, so whatever got them out of step is put right by the next
+// receipt. The room's counts stay the room's total across every thread.
+func (s *Push) MarkNotificationsRead(ctx context.Context, userID, roomID, thread string, upTo int64) (int64, bool, error) {
+	var (
+		pos   int64
+		moved bool
+	)
+	err := s.write(ctx, func(t *tx) error {
+		marked := `event_pos <= ?`
+		markedArgs := []any{upTo}
+		if thread != storage.AllThreads {
+			marked += ` AND thread_id = ?`
+			markedArgs = append(markedArgs, thread)
+		}
+		n, err := t.setWhere("push_notifications", rec{"is_read": true},
+			`user_id = ? AND room_id = ? AND is_read = ? AND `+marked,
+			append([]any{userID, roomID, false}, markedArgs...)...)
+		if err != nil {
+			return fmt.Errorf("mark %q's notifications read: %w", userID, err)
+		}
+		if n == 0 {
+			pos, err = t.current(pushSequences, seqNotification)
+			return err
+		}
+
+		var notifications, highlights int64
+		if err := t.queryRow(`SELECT COUNT(*), CAST(COALESCE(SUM(CASE WHEN highlight THEN 1 ELSE 0 END), 0) AS BIGINT)
+			FROM push_notifications WHERE user_id = ? AND room_id = ? AND is_read = ? AND NOT (`+marked+`)`,
+			append([]any{userID, roomID, false}, markedArgs...)...).
+			Scan(&notifications, &highlights); err != nil {
+			return fmt.Errorf("count %q's unread notifications: %w", userID, err)
+		}
+		if pos, err = t.next(pushSequences, seqNotification); err != nil {
+			return err
+		}
+		t.put("push_room_counts", rec{
+			"user_id": userID, "room_id": roomID,
+			"notification_count": notifications, "highlight_count": highlights, "stream_pos": pos,
+		})
+		moved = true
+		return nil
+	})
+	return pos, moved, err
+}
+
+// NotificationCounts implements storage.PushStore.
+func (s *Push) NotificationCounts(ctx context.Context, userID string, roomIDs []string) (map[string]storage.NotificationCounts, error) {
+	out := make(map[string]storage.NotificationCounts, len(roomIDs))
+	if len(roomIDs) == 0 {
+		return out, nil
+	}
+	for _, id := range roomIDs {
+		out[id] = storage.NotificationCounts{}
+	}
+
+	rows, err := s.db.QueryContext(ctx, `SELECT room_id, notification_count, highlight_count FROM push_room_counts
+		WHERE user_id = ? AND room_id IN `+inList, userID, jsonList(roomIDs))
+	if err != nil {
+		return nil, fmt.Errorf("read %q's notification counts: %w", userID, err)
+	}
+	defer func() { _ = rows.Close() }()
+	for rows.Next() {
+		var roomID string
+		var c storage.NotificationCounts
+		if err := rows.Scan(&roomID, &c.Notifications, &c.Highlights); err != nil {
+			return nil, fmt.Errorf("read %q's notification counts: %w", userID, err)
+		}
+		out[roomID] = c
+	}
+	if err := rows.Err(); err != nil {
+		return nil, fmt.Errorf("read %q's notification counts: %w", userID, err)
+	}
+	return out, nil
+}
+
+// ThreadNotificationCounts implements storage.PushStore. These are counted
+// from the unread rows rather than kept like the room totals.
+func (s *Push) ThreadNotificationCounts(ctx context.Context, userID string, roomIDs []string) (map[string]map[string]storage.NotificationCounts, error) {
+	out := make(map[string]map[string]storage.NotificationCounts, len(roomIDs))
+	if len(roomIDs) == 0 {
+		return out, nil
+	}
+
+	rows, err := s.db.QueryContext(ctx, `SELECT room_id, thread_id, COUNT(*),
+			CAST(COALESCE(SUM(CASE WHEN highlight THEN 1 ELSE 0 END), 0) AS BIGINT)
+		FROM push_notifications
+		WHERE user_id = ? AND is_read = ? AND room_id IN `+inList+`
+		GROUP BY room_id, thread_id`, userID, false, jsonList(roomIDs))
+	if err != nil {
+		return nil, fmt.Errorf("read %q's thread notification counts: %w", userID, err)
+	}
+	defer func() { _ = rows.Close() }()
+	for rows.Next() {
+		var roomID, thread string
+		var notifications, highlights int64
+		if err := rows.Scan(&roomID, &thread, &notifications, &highlights); err != nil {
+			return nil, fmt.Errorf("read %q's thread notification counts: %w", userID, err)
+		}
+		if out[roomID] == nil {
+			out[roomID] = map[string]storage.NotificationCounts{}
+		}
+		out[roomID][thread] = storage.NotificationCounts{
+			Notifications: int(notifications),
+			Highlights:    int(highlights),
+		}
+	}
+	if err := rows.Err(); err != nil {
+		return nil, fmt.Errorf("read %q's thread notification counts: %w", userID, err)
+	}
+	return out, nil
+}
+
+// NotificationCountChanges implements storage.PushStore.
+func (s *Push) NotificationCountChanges(ctx context.Context, userID string, from, to int64) ([]string, error) {
+	out, err := s.queryStrings(ctx, `SELECT room_id FROM push_room_counts
+		WHERE user_id = ? AND stream_pos > ? AND stream_pos <= ? ORDER BY room_id`, userID, from, to)
+	if err != nil {
+		return nil, fmt.Errorf("read %q's notification count changes: %w", userID, err)
+	}
+	return out, nil
+}
+
+// UnreadNotifications implements storage.PushStore.
+func (s *Push) UnreadNotifications(ctx context.Context, userID string) (int, error) {
+	var n int64
+	if err := s.db.QueryRowContext(ctx, `SELECT CAST(COALESCE(SUM(notification_count), 0) AS BIGINT)
+		FROM push_room_counts WHERE user_id = ?`, userID).Scan(&n); err != nil {
+		return 0, fmt.Errorf("count %q's unread notifications: %w", userID, err)
+	}
+	return int(n), nil
+}
+
+// Notifications implements storage.PushStore.
+func (s *Push) Notifications(ctx context.Context, userID string, before int64, limit int, onlyHighlight bool) ([]storage.Notification, error) {
+	query := `SELECT ` + notificationColumns + ` FROM push_notifications WHERE user_id = ?`
+	args := []any{userID}
+	if before > 0 {
+		query += ` AND notification_id < ?`
+		args = append(args, before)
+	}
+	if onlyHighlight {
+		query += ` AND highlight = ?`
+		args = append(args, true)
+	}
+	query += ` ORDER BY notification_id DESC LIMIT ?`
+	args = append(args, limit)
+
+	rows, err := s.db.QueryContext(ctx, query, args...)
+	if err != nil {
+		return nil, fmt.Errorf("read %q's notifications: %w", userID, err)
+	}
+	defer func() { _ = rows.Close() }()
+	var out []storage.Notification
+	for rows.Next() {
+		var n storage.Notification
+		var actions string
+		if err := rows.Scan(&n.ID, &n.UserID, &n.RoomID, &n.EventID, &n.EventPos, &n.ThreadID, &n.TimestampMS,
+			&n.Highlight, &actions, &n.Read); err != nil {
+			return nil, fmt.Errorf("read %q's notifications: %w", userID, err)
+		}
+		n.Actions = []byte(actions)
+		out = append(out, n)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, fmt.Errorf("read %q's notifications: %w", userID, err)
+	}
+	return out, nil
+}
+
+// PruneNotifications implements storage.PushStore.
+func (s *Push) PruneNotifications(ctx context.Context, beforeMS int64) (int64, error) {
+	var n int
+	err := s.write(ctx, func(t *tx) error {
+		var err error
+		n, err = t.delWhere("push_notifications", `is_read = ? AND ts_ms < ?`, true, beforeMS)
+		return err
+	})
+	if err != nil {
+		return 0, fmt.Errorf("prune read notifications: %w", err)
+	}
+	return int64(n), nil
+}
+
+var _ storage.PushStore = (*Push)(nil)

server/internal/storage/pocketbase/relations.go

@@ -0,0 +1,369 @@
+package pocketbase
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"github.com/dariuszjaniak/warp/server/internal/storage"
+)
+
+// The relation and search half of the room store.
+//
+// Relations are the SQL store's queries. Search has no full-text engine to
+// lean on — PocketBase does not expose FTS5 — so roomserver_event_search
+// holds each event's searchable text as its words, lower-cased and padded
+// with spaces, and a search matches every word of the term as the start of
+// a word: what the SQLite driver's prefix query matches, short of folding
+// diacritics. Every match ranks the same, so a ranked search comes back
+// newest first.
+
+// searchText is how an event's text is stored for searching: its words,
+// lower-cased, each with a space before it and the whole with one after.
+func searchText(text string) string {
+	words := storage.SearchWords(text)
+	if len(words) == 0 {
+		return ""
+	}
+	return " " + strings.Join(words, " ") + " "
+}
+
+// indexEvent adds an event that has just joined a timeline to the search
+// index, if it has anything to find it by.
+func (w *roomWrite) indexEvent(e storage.StoredEvent, ordering int64) {
+	body := searchText(e.SearchText)
+	if e.SearchKey == "" || body == "" {
+		return
+	}
+	w.put("roomserver_event_search", rec{
+		"stream_ordering": ordering,
+		"room_id":         e.RoomID,
+		"event_id":        e.EventID,
+		"search_key":      e.SearchKey,
+		"sender":          e.Sender,
+		"event_type":      e.Type,
+		"body":            body,
+	})
+}
+
+// Relations implements storage.RoomStore.
+func (s *Rooms) Relations(ctx context.Context, req storage.RelationsRequest) ([]storage.StoredEvent, error) {
+	if req.Limit <= 0 || len(req.ParentIDs) == 0 {
+		return nil, nil
+	}
+
+	conditions := []string{
+		`e.room_id = ?`,
+		`e.relates_to_id IN ` + inList,
+		`NOT e.outlier`,
+	}
+	args := []any{req.RoomID, jsonList(req.ParentIDs)}
+	if req.RelType != "" {
+		conditions = append(conditions, `e.rel_type = ?`)
+		args = append(args, req.RelType)
+	} else {
+		conditions = append(conditions, `e.rel_type <> ''`)
+	}
+	if req.EventType != "" {
+		conditions = append(conditions, `e.event_type = ?`)
+		args = append(args, req.EventType)
+	}
+	if req.Low != 0 {
+		conditions = append(conditions, `e.stream_ordering > ?`)
+		args = append(args, req.Low)
+	}
+	if req.High != 0 {
+		conditions = append(conditions, `e.stream_ordering <= ?`)
+		args = append(args, req.High)
+	}
+	order := `ASC`
+	if req.Direction == storage.DirectionBackward {
+		order = `DESC`
+	}
+	args = append(args, req.Limit)
+
+	rows, err := s.db.QueryContext(ctx, `SELECT `+eventColumns+`
+		FROM roomserver_events e
+		WHERE `+strings.Join(conditions, " AND ")+`
+		ORDER BY e.stream_ordering `+order+`
+		LIMIT ?`, args...)
+	if err != nil {
+		return nil, fmt.Errorf("read the relations of %v in %q: %w", req.ParentIDs, req.RoomID, err)
+	}
+	events, err := scanEvents(rows)
+	if err != nil {
+		return nil, fmt.Errorf("read the relations of %v in %q: %w", req.ParentIDs, req.RoomID, err)
+	}
+	return events, nil
+}
+
+// ChildEventIDs implements storage.RoomStore.
+func (s *Rooms) ChildEventIDs(ctx context.Context, roomID string, parentIDs []string, relType, eventType string) ([]string, error) {
+	if len(parentIDs) == 0 {
+		return nil, nil
+	}
+	query := `SELECT event_id FROM roomserver_events
+		WHERE room_id = ? AND relates_to_id IN ` + inList + `
+		AND rel_type <> '' AND NOT outlier`
+	args := []any{roomID, jsonList(parentIDs)}
+	if relType != "" {
+		query += ` AND rel_type = ?`
+		args = append(args, relType)
+	}
+	if eventType != "" {
+		query += ` AND event_type = ?`
+		args = append(args, eventType)
+	}
+	query += ` ORDER BY stream_ordering`
+
+	ids, err := s.queryStrings(ctx, query, args...)
+	if err != nil {
+		return nil, fmt.Errorf("read the children of %v in %q: %w", parentIDs, roomID, err)
+	}
+	return ids, nil
+}
+
+// RelationAggregates implements storage.RoomStore.
+func (s *Rooms) RelationAggregates(ctx context.Context, roomID string, parentIDs []string, high int64) ([]storage.RelationAggregate, error) {
+	if len(parentIDs) == 0 {
+		return nil, nil
+	}
+	inner := `SELECT relates_to_id, rel_type, sender, COUNT(*) AS n, MAX(stream_ordering) AS latest
+		FROM roomserver_events
+		WHERE room_id = ? AND relates_to_id IN ` + inList + `
+		AND rel_type IN (?, ?, ?) AND NOT outlier`
+	args := []any{roomID, jsonList(parentIDs), storage.RelThread, storage.RelReplace, storage.RelReference}
+	if high != 0 {
+		inner += ` AND stream_ordering <= ?`
+		args = append(args, high)
+	}
+	inner += ` GROUP BY relates_to_id, rel_type, sender`
+
+	rows, err := s.db.QueryContext(ctx, `SELECT g.relates_to_id, g.rel_type, g.sender, g.n, g.latest, e.event_id
+		FROM (`+inner+`) g
+		JOIN roomserver_events e ON e.stream_ordering = g.latest`, args...)
+	if err != nil {
+		return nil, fmt.Errorf("summarise the relations of %d events in %q: %w", len(parentIDs), roomID, err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	var out []storage.RelationAggregate
+	for rows.Next() {
+		var a storage.RelationAggregate
+		if err := rows.Scan(&a.ParentID, &a.RelType, &a.Sender, &a.Count, &a.LatestOrdering, &a.LatestEventID); err != nil {
+			return nil, fmt.Errorf("summarise the relations in %q: %w", roomID, err)
+		}
+		out = append(out, a)
+	}
+	return out, rows.Err()
+}
+
+// RelationEventIDs implements storage.RoomStore.
+func (s *Rooms) RelationEventIDs(ctx context.Context, roomID string, parentIDs []string, relType string, high int64, limit int) (map[string][]string, error) {
+	if len(parentIDs) == 0 || limit <= 0 {
+		return nil, nil
+	}
+	query := `SELECT relates_to_id, event_id FROM roomserver_events
+		WHERE room_id = ? AND relates_to_id IN ` + inList + `
+		AND rel_type = ? AND NOT outlier`
+	args := []any{roomID, jsonList(parentIDs), relType}
+	if high != 0 {
+		query += ` AND stream_ordering <= ?`
+		args = append(args, high)
+	}
+	query += ` ORDER BY stream_ordering LIMIT ?`
+	args = append(args, limit*len(parentIDs))
+
+	rows, err := s.db.QueryContext(ctx, query, args...)
+	if err != nil {
+		return nil, fmt.Errorf("read the %s relations in %q: %w", relType, roomID, err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	out := map[string][]string{}
+	for rows.Next() {
+		var parent, id string
+		if err := rows.Scan(&parent, &id); err != nil {
+			return nil, fmt.Errorf("read the %s relations in %q: %w", relType, roomID, err)
+		}
+		if len(out[parent]) < limit {
+			out[parent] = append(out[parent], id)
+		}
+	}
+	return out, rows.Err()
+}
+
+// Threads implements storage.RoomStore.
+func (s *Rooms) Threads(ctx context.Context, req storage.ThreadsRequest) ([]storage.Thread, error) {
+	if req.Limit <= 0 {
+		return nil, nil
+	}
+	inner := `SELECT relates_to_id AS root, MAX(stream_ordering) AS latest
+		FROM roomserver_events
+		WHERE room_id = ? AND rel_type = ? AND NOT outlier`
+	args := []any{req.RoomID, storage.RelThread}
+	if req.High != 0 {
+		inner += ` AND stream_ordering <= ?`
+		args = append(args, req.High)
+	}
+	inner += ` GROUP BY relates_to_id`
+
+	conditions := []string{`r.room_id = ?`, `NOT r.outlier`}
+	args = append(args, req.RoomID)
+	if req.Before != 0 {
+		conditions = append(conditions, `g.latest < ?`)
+		args = append(args, req.Before)
+	}
+	if req.ParticipatedBy != "" {
+		conditions = append(conditions, `(r.sender = ? OR EXISTS (
+			SELECT 1 FROM roomserver_events p
+			WHERE p.room_id = r.room_id AND p.relates_to_id = g.root AND p.rel_type = ? AND p.sender = ?))`)
+		args = append(args, req.ParticipatedBy, storage.RelThread, req.ParticipatedBy)
+	}
+	args = append(args, req.Limit)
+
+	rows, err := s.db.QueryContext(ctx, `SELECT g.root, g.latest
+		FROM (`+inner+`) g
+		JOIN roomserver_events r ON r.event_id = g.root
+		WHERE `+strings.Join(conditions, " AND ")+`
+		ORDER BY g.latest DESC
+		LIMIT ?`, args...)
+	if err != nil {
+		return nil, fmt.Errorf("read the threads of %q: %w", req.RoomID, err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	var out []storage.Thread
+	for rows.Next() {
+		var t storage.Thread
+		if err := rows.Scan(&t.RootID, &t.LatestOrdering); err != nil {
+			return nil, fmt.Errorf("read the threads of %q: %w", req.RoomID, err)
+		}
+		out = append(out, t)
+	}
+	return out, rows.Err()
+}
+
+// searchKeys are the fields the index holds.
+var searchKeys = []string{"content.body", "content.name", "content.topic"}
+
+// Search implements storage.RoomStore.
+func (s *Rooms) Search(ctx context.Context, req storage.SearchRequest) ([]storage.SearchResult, int, error) {
+	if req.Limit <= 0 || len(req.Rooms) == 0 {
+		return nil, 0, nil
+	}
+	words := storage.SearchWords(req.Term)
+	if len(words) == 0 {
+		return nil, 0, nil
+	}
+
+	var (
+		conditions []string
+		args       []any
+	)
+	for _, w := range words {
+		conditions = append(conditions, `body LIKE ? ESCAPE '\'`)
+		args = append(args, `% `+escapeLike(w)+`%`)
+	}
+
+	// One bounded clause per room: what a user may search of a room is a
+	// window of its stream, and the windows differ from room to room.
+	rooms := make([]string, 0, len(req.Rooms))
+	for _, r := range req.Rooms {
+		clause := `room_id = ?`
+		args = append(args, r.RoomID)
+		if r.Low != 0 {
+			clause += ` AND stream_ordering > ?`
+			args = append(args, r.Low)
+		}
+		if r.High != 0 {
+			clause += ` AND stream_ordering <= ?`
+			args = append(args, r.High)
+		}
+		rooms = append(rooms, `(`+clause+`)`)
+	}
+	conditions = append(conditions, `(`+strings.Join(rooms, ` OR `)+`)`)
+
+	keys := req.Keys
+	if len(keys) == 0 {
+		keys = searchKeys
+	}
+	conditions = append(conditions, `search_key IN `+inList)
+	args = append(args, jsonList(keys))
+
+	if clause, filterArgs := filterConditionsOn(`event_type`, `sender`, req.Filter); clause != "" {
+		conditions = append(conditions, clause)
+		args = append(args, filterArgs...)
+	}
+	where := strings.Join(conditions, " AND ")
+
+	var total int
+	if err := s.db.QueryRowContext(ctx, `SELECT COUNT(*) FROM roomserver_event_search WHERE `+where, args...).
+		Scan(&total); err != nil {
+		return nil, 0, fmt.Errorf("count search results: %w", err)
+	}
+
+	pageWhere := where
+	pageArgs := append([]any{}, args...)
+	if req.Order == storage.SearchByRecent && req.Before != 0 {
+		pageWhere += ` AND stream_ordering < ?`
+		pageArgs = append(pageArgs, req.Before)
+	}
+	offset := req.Offset
+	if req.Order == storage.SearchByRecent {
+		offset = 0
+	}
+	pageArgs = append(pageArgs, req.Limit, offset)
+
+	positions, err := s.queryInts(ctx, `SELECT stream_ordering FROM roomserver_event_search
+		WHERE `+pageWhere+`
+		ORDER BY stream_ordering DESC
+		LIMIT ? OFFSET ?`, pageArgs...)
+	if err != nil {
+		return nil, 0, fmt.Errorf("search: %w", err)
+	}
+	if len(positions) == 0 {
+		return nil, total, nil
+	}
+
+	eventRows, err := s.db.QueryContext(ctx, `SELECT `+eventColumns+`
+		FROM roomserver_events e WHERE e.stream_ordering IN `+inList, jsonInts(positions))
+	if err != nil {
+		return nil, 0, fmt.Errorf("read search results: %w", err)
+	}
+	events, err := scanEvents(eventRows)
+	if err != nil {
+		return nil, 0, fmt.Errorf("read search results: %w", err)
+	}
+	byPos := make(map[int64]storage.StoredEvent, len(events))
+	for _, e := range events {
+		byPos[e.StreamOrdering] = e
+	}
+
+	out := make([]storage.SearchResult, 0, len(positions))
+	for _, pos := range positions {
+		if e, ok := byPos[pos]; ok {
+			out = append(out, storage.SearchResult{Event: e, Rank: 1})
+		}
+	}
+	return out, total, nil
+}
+
+// queryInts runs a query returning one integer column.
+func (b *base) queryInts(ctx context.Context, query string, args ...any) ([]int64, error) {
+	rows, err := b.db.QueryContext(ctx, query, args...)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = rows.Close() }()
+
+	var out []int64
+	for rows.Next() {
+		var v int64
+		if err := rows.Scan(&v); err != nil {
+			return nil, err
+		}
+		out = append(out, v)
+	}
+	return out, rows.Err()
+}

server/internal/storage/pocketbase/remotekeys.go

@@ -0,0 +1,247 @@
+package pocketbase
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+	"slices"
+
+	"github.com/dariuszjaniak/warp/server/internal/storage"
+)
+
+// The cache of other servers' users' keys, as the SQL store keeps it.
+
+var remoteKeyTables = []string{
+	"keyserver_remote_users", "keyserver_remote_device_keys", "keyserver_remote_cross_signing_keys",
+}
+
+// remoteMarker reads a cached user's marker row.
+func remoteMarker(row rowQuerier, userID string) (streamID int64, stale, ok bool, err error) {
+	err = row(`SELECT stream_id, stale FROM keyserver_remote_users WHERE user_id = ?`, userID).Scan(&streamID, &stale)
+	switch {
+	case errors.Is(err, sql.ErrNoRows):
+		return 0, false, false, nil
+	case err != nil:
+		return 0, false, false, fmt.Errorf("read the cached keys of %q: %w", userID, err)
+	}
+	return streamID, stale, true, nil
+}
+
+// RemoteKeys implements storage.KeyStore. The marker and the keys are read
+// under one read lock, so that a copy halfway through its replacement is
+// never served.
+func (s *Keys) RemoteKeys(ctx context.Context, userID string) (storage.RemoteKeys, bool, error) {
+	out := storage.RemoteKeys{UserID: userID, CrossSigning: map[string][]byte{}}
+	var found bool
+	err := s.read(ctx, func(ctx context.Context) error {
+		var err error
+		out.StreamID, out.Stale, found, err = remoteMarker(s.poolRow(ctx), userID)
+		if err != nil || !found {
+			return err
+		}
+		if out.Devices, err = s.remoteDevices(ctx, userID); err != nil {
+			return err
+		}
+		out.CrossSigning, err = s.remoteCrossSigning(ctx, userID)
+		return err
+	})
+	if err != nil || !found {
+		return storage.RemoteKeys{}, false, err
+	}
+	return out, true, nil
+}
+
+func (s *Keys) remoteDevices(ctx context.Context, userID string) ([]storage.RemoteDevice, error) {
+	rows, err := s.db.QueryContext(ctx, `SELECT device_id, display_name, key_json FROM keyserver_remote_device_keys
+		WHERE user_id = ? ORDER BY device_id`, userID)
+	if err != nil {
+		return nil, fmt.Errorf("read the cached devices of %q: %w", userID, err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	var out []storage.RemoteDevice
+	for rows.Next() {
+		var d storage.RemoteDevice
+		var keyJSON string
+		if err := rows.Scan(&d.DeviceID, &d.DisplayName, &keyJSON); err != nil {
+			return nil, fmt.Errorf("read the cached devices of %q: %w", userID, err)
+		}
+		d.JSON = []byte(keyJSON)
+		out = append(out, d)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, fmt.Errorf("read the cached devices of %q: %w", userID, err)
+	}
+	return out, nil
+}
+
+func (s *Keys) remoteCrossSigning(ctx context.Context, userID string) (map[string][]byte, error) {
+	rows, err := s.db.QueryContext(ctx, `SELECT purpose, key_json FROM keyserver_remote_cross_signing_keys
+		WHERE user_id = ?`, userID)
+	if err != nil {
+		return nil, fmt.Errorf("read the cached cross-signing keys of %q: %w", userID, err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	out := map[string][]byte{}
+	for rows.Next() {
+		var purpose, keyJSON string
+		if err := rows.Scan(&purpose, &keyJSON); err != nil {
+			return nil, fmt.Errorf("read the cached cross-signing keys of %q: %w", userID, err)
+		}
+		out[purpose] = []byte(keyJSON)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, fmt.Errorf("read the cached cross-signing keys of %q: %w", userID, err)
+	}
+	return out, nil
+}
+
+// SetRemoteKeys implements storage.KeyStore. A snapshot older than what is
+// held is not stored: it was fetched while an update was on its way in.
+func (s *Keys) SetRemoteKeys(ctx context.Context, keys storage.RemoteKeys) (bool, error) {
+	stored := false
+	err := s.write(ctx, func(t *tx) error {
+		held, _, ok, err := remoteMarker(t.queryRow, keys.UserID)
+		if err != nil {
+			return err
+		}
+		if ok && held > keys.StreamID {
+			return nil
+		}
+
+		if err := deleteRemote(t, keys.UserID); err != nil {
+			return err
+		}
+		t.put("keyserver_remote_users", rec{"user_id": keys.UserID, "stream_id": keys.StreamID, "stale": false})
+		for _, d := range keys.Devices {
+			t.put("keyserver_remote_device_keys", rec{
+				"user_id": keys.UserID, "device_id": d.DeviceID,
+				"display_name": d.DisplayName, "key_json": string(d.JSON),
+			})
+		}
+		putRemoteCrossSigning(t, keys.UserID, keys.CrossSigning)
+		stored = true
+		return nil
+	})
+	return stored, err
+}
+
+// UpdateRemoteDevice implements storage.KeyStore.
+func (s *Keys) UpdateRemoteDevice(ctx context.Context, u storage.RemoteDeviceUpdate) (storage.RemoteUpdateResult, error) {
+	var result storage.RemoteUpdateResult
+	err := s.write(ctx, func(t *tx) error {
+		held, stale, ok, err := remoteMarker(t.queryRow, u.UserID)
+		if err != nil {
+			return err
+		}
+
+		// A stale copy keeps the highest position it has heard of, so that
+		// a snapshot fetched before this update cannot be stored over it.
+		markStale := func(r storage.RemoteUpdateResult) error {
+			result = r
+			t.put("keyserver_remote_users", rec{"user_id": u.UserID, "stream_id": max(held, u.StreamID), "stale": true})
+			return nil
+		}
+
+		switch {
+		case !ok:
+			return markStale(storage.RemoteUpdateNotCached)
+		case stale:
+			return markStale(storage.RemoteUpdateStale)
+		case u.StreamID <= held:
+			result = storage.RemoteUpdateDuplicate
+			return nil
+		case !followsOn(held, u.PrevIDs):
+			return markStale(storage.RemoteUpdateStale)
+		case !u.Deleted && u.JSON == nil:
+			return markStale(storage.RemoteUpdateStale)
+		}
+
+		if u.Deleted {
+			if _, err := t.delKey("keyserver_remote_device_keys", u.UserID, u.DeviceID); err != nil {
+				return fmt.Errorf("apply an update to the cached keys of %s/%s: %w", u.UserID, u.DeviceID, err)
+			}
+		} else {
+			t.put("keyserver_remote_device_keys", rec{
+				"user_id": u.UserID, "device_id": u.DeviceID,
+				"display_name": u.DisplayName, "key_json": string(u.JSON),
+			})
+		}
+		t.put("keyserver_remote_users", rec{"user_id": u.UserID, "stream_id": u.StreamID, "stale": false})
+		result = storage.RemoteUpdateApplied
+		return nil
+	})
+	return result, err
+}
+
+// followsOn reports whether an update with the given prev_id comes right
+// after the position held.
+func followsOn(held int64, prevIDs []int64) bool {
+	if len(prevIDs) == 0 {
+		return held == 0
+	}
+	return slices.Contains(prevIDs, held)
+}
+
+// SetRemoteCrossSigningKeys implements storage.KeyStore.
+func (s *Keys) SetRemoteCrossSigningKeys(ctx context.Context, userID string, keys map[string][]byte) (bool, error) {
+	stored := false
+	err := s.write(ctx, func(t *tx) error {
+		_, stale, ok, err := remoteMarker(t.queryRow, userID)
+		if err != nil || !ok || stale {
+			return err
+		}
+		if _, err := t.delWhere("keyserver_remote_cross_signing_keys", `user_id = ?`, userID); err != nil {
+			return fmt.Errorf("replace the cached cross-signing keys of %q: %w", userID, err)
+		}
+		putRemoteCrossSigning(t, userID, keys)
+		stored = true
+		return nil
+	})
+	return stored, err
+}
+
+func putRemoteCrossSigning(t *tx, userID string, keys map[string][]byte) {
+	for _, purpose := range sortedKeys(keys) {
+		if keys[purpose] == nil {
+			continue
+		}
+		t.put("keyserver_remote_cross_signing_keys", rec{"user_id": userID, "purpose": purpose, "key_json": string(keys[purpose])})
+	}
+}
+
+// RemoteKeyUsers implements storage.KeyStore.
+func (s *Keys) RemoteKeyUsers(ctx context.Context) ([]string, error) {
+	out, err := s.queryStrings(ctx, `SELECT user_id FROM keyserver_remote_users ORDER BY user_id`)
+	if err != nil {
+		return nil, fmt.Errorf("read the users with cached keys: %w", err)
+	}
+	return out, nil
+}
+
+// DeleteRemoteKeys implements storage.KeyStore.
+func (s *Keys) DeleteRemoteKeys(ctx context.Context, userIDs []string) error {
+	if len(userIDs) == 0 {
+		return nil
+	}
+	return s.write(ctx, func(t *tx) error {
+		for _, userID := range dedupe(userIDs) {
+			if err := deleteRemote(t, userID); err != nil {
+				return err
+			}
+		}
+		return nil
+	})
+}
+
+// deleteRemote drops every row cached for a user.
+func deleteRemote(t *tx, userID string) error {
+	for _, table := range remoteKeyTables {
+		if _, err := t.delWhere(table, `user_id = ?`, userID); err != nil {
+			return fmt.Errorf("delete from %s for %q: %w", table, userID, err)
+		}
+	}
+	return nil
+}

server/internal/storage/pocketbase/schema.go

@@ -0,0 +1,449 @@
+package pocketbase
+
+import (
+	"crypto/sha256"
+	"encoding/base32"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+// The schema is the SQL drivers' tables as PocketBase collections: the same
+// names and columns, so that the reads can be the same SQL, with three
+// differences PocketBase forces.
+//
+//   - Every record has a text `id`, which is the primary key. Warp's own keys
+//     are kept as ordinary fields under a unique index, and a record's id is
+//     derived from them (see rowID): a row is always addressed by its key.
+//   - Nothing can be NULL. The two nullable state_key columns and
+//     admin_registration_tokens.uses_allowed get a has_* flag beside them.
+//   - `id` is taken, so push_notifications.id is notification_id and
+//     admin_audit_log.id is audit_id.
+//
+// Full-text search has no FTS5 here — it is a plain collection searched with
+// LIKE — and media content lives in warp_media's file field, which is
+// PocketBase's own storage: its pb_data/storage or an S3 bucket.
+
+type fieldKind int
+
+const (
+	text fieldKind = iota
+	number
+	boolean
+	file
+)
+
+type field struct {
+	name string
+	kind fieldKind
+}
+
+// table is one collection.
+type table struct {
+	name string
+
+	// key is the primary key the SQL drivers declare; the record id is a
+	// hash of its values. Empty for a collection whose ids are chosen by
+	// the writer (warp_params).
+	key []string
+
+	fields []field
+
+	// indexes are column lists; a leading "unique:" makes one unique.
+	indexes []string
+}
+
+func tbl(name string, key []string, fields []field, indexes ...string) table {
+	return table{name: name, key: key, fields: fields, indexes: indexes}
+}
+
+func pk(cols ...string) []string { return cols }
+
+func fld(name string, kind fieldKind) field { return field{name: name, kind: kind} }
+
+func texts(names ...string) []field {
+	out := make([]field, len(names))
+	for i, n := range names {
+		out[i] = field{name: n, kind: text}
+	}
+	return out
+}
+
+func numbers(names ...string) []field {
+	out := make([]field, len(names))
+	for i, n := range names {
+		out[i] = field{name: n, kind: number}
+	}
+	return out
+}
+
+func fields(groups ...[]field) []field {
+	var out []field
+	for _, g := range groups {
+		out = append(out, g...)
+	}
+	return out
+}
+
+func sequenceTable(name string) table {
+	return tbl(name, pk("name"), fields(texts("name"), numbers("value")))
+}
+
+// The sequence rows each table starts with, as the SQL migrations insert
+// them.
+var sequenceRows = map[string][]string{
+	"roomserver_sequences": {"stream_ordering", "state_snapshot", "backfill_ordering"},
+	"sync_sequences":       {"receipt", "to_device", "account_data", "presence"},
+	"federation_sequences": {"queue"},
+	"keyserver_sequences":  {"device_list"},
+	"push_sequences":       {"notification"},
+	"admin_sequences":      {"audit"},
+}
+
+var schema = []table{
+	tbl("warp_meta", pk("meta_key"), texts("meta_key", "meta_value")),
+	{name: paramsCollection, fields: texts("value")},
+	tbl("warp_media", pk("sha256"), fields(texts("sha256"), numbers("size"), []field{fld("content", file)})),
+
+	tbl("server_settings", pk("setting_key"), texts("setting_key", "setting_value", "updated_at")),
+
+	// userapi
+	tbl("user_accounts", pk("localpart"), fields(
+		texts("localpart", "password_hash", "display_name", "avatar_url"),
+		[]field{fld("admin", boolean), fld("deactivated", boolean)},
+		numbers("created_at_ms"))),
+	tbl("user_devices", pk("localpart", "device_id"), fields(
+		texts("localpart", "device_id", "display_name"),
+		numbers("created_at_ms", "last_seen_ms"),
+		texts("last_seen_ip", "user_agent"))),
+	tbl("user_access_tokens", pk("token_hash"), fields(
+		texts("token_hash", "localpart", "device_id"), numbers("created_at_ms", "expires_at_ms")),
+		"localpart, device_id"),
+	tbl("user_refresh_tokens", pk("token_hash"), fields(
+		texts("token_hash", "localpart", "device_id"), numbers("created_at_ms", "expires_at_ms")),
+		"localpart, device_id"),
+	tbl("user_account_data", pk("localpart", "room_id", "data_type"), fields(
+		texts("localpart", "room_id", "data_type", "content"), numbers("stream_pos")),
+		"localpart, stream_pos"),
+
+	// roomserver
+	tbl("roomserver_rooms", pk("room_id"), fields(
+		texts("room_id", "room_version", "creator"),
+		[]field{fld("is_published", boolean)},
+		numbers("created_at_ms"),
+		texts("name", "topic", "avatar_url", "canonical_alias",
+			"join_rule", "history_visibility", "guest_access", "room_type"),
+		numbers("joined_members")),
+		"is_published, joined_members"),
+	sequenceTable("roomserver_sequences"),
+	tbl("roomserver_state_snapshots", pk("snapshot_id"), fields(
+		numbers("snapshot_id"), texts("room_id", "state_hash")),
+		"unique: room_id, state_hash"),
+	tbl("roomserver_state_entries", pk("snapshot_id", "event_type", "state_key"), fields(
+		numbers("snapshot_id"), texts("event_type", "state_key", "event_id"))),
+	tbl("roomserver_events", pk("event_id"), fields(
+		texts("event_id", "room_id"),
+		numbers("stream_ordering"),
+		texts("event_type", "state_key"),
+		[]field{fld("has_state_key", boolean)},
+		texts("sender"),
+		numbers("depth", "origin_server_ts"),
+		texts("event_json"),
+		numbers("state_before_id"),
+		texts("redacted_by"),
+		[]field{fld("outlier", boolean)},
+		texts("relates_to_id", "rel_type")),
+		"unique: stream_ordering",
+		"room_id, stream_ordering",
+		"room_id, relates_to_id, rel_type, stream_ordering",
+		"event_type, state_key"),
+	tbl("roomserver_extremities", pk("room_id", "event_id"), texts("room_id", "event_id")),
+	tbl("roomserver_current_state", pk("room_id", "event_type", "state_key"),
+		texts("room_id", "event_type", "state_key", "event_id", "membership"),
+		"event_type, state_key, membership"),
+	tbl("roomserver_transactions", pk("localpart", "device_id", "txn_id"), fields(
+		texts("localpart", "device_id", "txn_id", "event_id", "room_id"), numbers("sent_at_ms"))),
+	tbl("roomserver_aliases", pk("alias"), fields(
+		texts("alias", "room_id", "creator"), numbers("created_at_ms")),
+		"room_id"),
+	tbl("roomserver_invite_state", pk("room_id", "user_id"), texts("room_id", "user_id", "state_json")),
+	tbl("roomserver_event_search", pk("stream_ordering"), fields(
+		numbers("stream_ordering"),
+		texts("room_id", "event_id", "search_key", "sender", "event_type", "body")),
+		"room_id, stream_ordering"),
+
+	// syncapi
+	sequenceTable("sync_sequences"),
+	tbl("sync_receipts", pk("room_id", "user_id", "receipt_type", "thread_id"), fields(
+		texts("room_id", "user_id", "receipt_type", "thread_id", "event_id"), numbers("ts_ms", "stream_pos")),
+		"stream_pos", "room_id, stream_pos"),
+	tbl("sync_to_device", pk("stream_pos"), fields(
+		numbers("stream_pos"),
+		texts("localpart", "device_id", "sender", "event_type", "content"),
+		numbers("sent_at_ms")),
+		"localpart, device_id, stream_pos"),
+	tbl("sync_presence", pk("user_id"), fields(
+		texts("user_id", "presence", "status_msg"), numbers("last_active_ms", "stream_pos")),
+		"stream_pos"),
+	tbl("sync_filters", pk("localpart", "filter_id"), fields(
+		texts("localpart", "filter_id", "filter_json"), numbers("created_at_ms"))),
+
+	// federation
+	tbl("federation_server_keys", pk("server_name", "key_id"), fields(
+		texts("server_name", "key_id", "public_key"),
+		numbers("valid_until_ts", "expired_ts", "fetched_at_ms"))),
+	sequenceTable("federation_sequences"),
+	tbl("federation_queue", pk("queue_id"), fields(
+		numbers("queue_id"),
+		texts("destination", "kind", "room_id", "event_id", "payload"),
+		numbers("queued_at_ms")),
+		"destination, kind, queue_id"),
+	tbl("federation_destinations", pk("server_name"), fields(
+		texts("server_name"),
+		numbers("failures", "retry_at_ms", "last_success_ms", "last_failure_ms"),
+		texts("last_error"))),
+	tbl("federation_inbound_txns", pk("origin", "txn_id"), fields(
+		texts("origin", "txn_id", "response_json"), numbers("received_at_ms"))),
+
+	// mediaapi
+	tbl("media_repository", pk("media_origin", "media_id"), fields(
+		texts("media_origin", "media_id", "content_type", "upload_name"),
+		numbers("file_size"),
+		texts("sha256", "user_id"),
+		numbers("created_at_ms"),
+		[]field{fld("pending", boolean)},
+		numbers("expires_at_ms")),
+		"pending, user_id, expires_at_ms", "user_id, media_origin", "sha256"),
+	tbl("media_thumbnails", pk("media_origin", "media_id", "width", "height", "method"), fields(
+		texts("media_origin", "media_id"),
+		numbers("width", "height"),
+		texts("method", "content_type"),
+		numbers("file_size"),
+		texts("sha256"),
+		numbers("created_at_ms")),
+		"sha256"),
+	tbl("media_quotas", pk("user_id"), fields(texts("user_id"), numbers("max_bytes"))),
+
+	// keyserver
+	sequenceTable("keyserver_sequences"),
+	tbl("keyserver_device_keys", pk("user_id", "device_id"), texts("user_id", "device_id", "key_json")),
+	tbl("keyserver_one_time_keys", pk("user_id", "device_id", "key_id"),
+		texts("user_id", "device_id", "key_id", "algorithm", "key_json"),
+		"user_id, device_id, algorithm"),
+	tbl("keyserver_fallback_keys", pk("user_id", "device_id", "algorithm"), fields(
+		texts("user_id", "device_id", "algorithm", "key_id", "key_json"),
+		[]field{fld("used", boolean)})),
+	tbl("keyserver_cross_signing_keys", pk("user_id", "purpose"), texts("user_id", "purpose", "key_json")),
+	tbl("keyserver_signatures", pk("target_user_id", "target_key_id", "signer_user_id", "signer_key_id"),
+		texts("target_user_id", "target_key_id", "signer_user_id", "signer_key_id", "signature")),
+	tbl("keyserver_device_lists", pk("user_id"), fields(texts("user_id"), numbers("stream_pos")),
+		"stream_pos"),
+	tbl("keyserver_backup_versions", pk("user_id", "version"), fields(
+		texts("user_id"), numbers("version"), texts("algorithm", "auth_data"), numbers("etag"),
+		[]field{fld("deleted", boolean)})),
+	tbl("keyserver_backup_keys", pk("user_id", "version", "room_id", "session_id"), fields(
+		texts("user_id"), numbers("version"), texts("room_id", "session_id"),
+		numbers("first_message_index", "forwarded_count"),
+		[]field{fld("is_verified", boolean)},
+		texts("session_data"))),
+	tbl("keyserver_remote_users", pk("user_id"), fields(
+		texts("user_id"), numbers("stream_id"), []field{fld("stale", boolean)})),
+	tbl("keyserver_remote_device_keys", pk("user_id", "device_id"),
+		texts("user_id", "device_id", "display_name", "key_json")),
+	tbl("keyserver_remote_cross_signing_keys", pk("user_id", "purpose"), texts("user_id", "purpose", "key_json")),
+
+	// push
+	sequenceTable("push_sequences"),
+	tbl("push_pushers", pk("localpart", "app_id", "pushkey"), fields(
+		texts("localpart", "app_id", "pushkey", "device_id", "kind", "app_display_name",
+			"device_display_name", "profile_tag", "lang", "data_json"),
+		numbers("pushkey_ts_ms")),
+		"app_id, pushkey"),
+	tbl("push_notifications", pk("notification_id"), fields(
+		numbers("notification_id"),
+		texts("user_id", "room_id", "event_id"),
+		numbers("event_pos", "ts_ms"),
+		[]field{fld("highlight", boolean)},
+		texts("actions"),
+		[]field{fld("is_read", boolean)},
+		texts("thread_id")),
+		"user_id, notification_id",
+		"user_id, room_id, is_read, event_pos",
+		"is_read, ts_ms",
+		"user_id, room_id, thread_id, is_read, event_pos"),
+	tbl("push_room_counts", pk("user_id", "room_id"), fields(
+		texts("user_id", "room_id"), numbers("notification_count", "highlight_count", "stream_pos")),
+		"user_id, stream_pos"),
+
+	// admin and application services
+	tbl("admin_registration_tokens", pk("token"), fields(
+		texts("token"),
+		numbers("uses_allowed"),
+		[]field{fld("has_uses_allowed", boolean)},
+		numbers("completed", "expires_at_ms", "created_at_ms"))),
+	tbl("admin_server_notice_rooms", pk("localpart"), texts("localpart", "room_id")),
+	sequenceTable("admin_sequences"),
+	tbl("admin_audit_log", pk("audit_id"), fields(
+		numbers("audit_id", "ts_ms"), texts("actor", "action", "target", "details_json")),
+		"actor, audit_id", "action, audit_id"),
+	tbl("appservice_state", pk("as_id"), fields(texts("as_id"), numbers("stream_pos", "txn_id", "txn_to"))),
+
+	// delayed events and OpenID tokens
+	tbl("delayed_events", pk("delay_id"), fields(
+		texts("delay_id", "user_id", "device_id", "room_id", "event_type", "state_key"),
+		[]field{fld("has_state_key", boolean)},
+		texts("content"),
+		numbers("delay_ms", "running_since_ms", "send_at_ms", "finalised_at_ms"),
+		texts("outcome", "reason", "event_id", "error")),
+		"user_id, finalised_at_ms",
+		"finalised_at_ms, send_at_ms",
+		"room_id, event_type, state_key, finalised_at_ms"),
+	tbl("openid_tokens", pk("token_hash"), fields(texts("token_hash", "user_id"), numbers("expires_at_ms")),
+		"expires_at_ms"),
+}
+
+// tables indexes the schema by collection name.
+var tables = func() map[string]*table {
+	out := make(map[string]*table, len(schema))
+	for i := range schema {
+		out[schema[i].name] = &schema[i]
+	}
+	return out
+}()
+
+// maxText is the longest a text field may be. PocketBase's default is 5000
+// characters, which an event can pass; this is far above the 64 KiB a
+// Matrix event may be, and above any account data a client sends.
+const maxText = 1 << 24
+
+// maxFileSize bounds one media file. The media API enforces the configured
+// upload limit before content ever gets here.
+const maxFileSize = 1 << 40
+
+// shortHash is a lower-case base32 digest, which fits PocketBase's id
+// alphabet of [a-z0-9].
+func shortHash(n int, parts ...string) string {
+	h := sha256.New()
+	for _, p := range parts {
+		_, _ = fmt.Fprintf(h, "%d:%s", len(p), p)
+	}
+	enc := base32.StdEncoding.WithPadding(base32.NoPadding).EncodeToString(h.Sum(nil))
+	return strings.ToLower(enc)[:n]
+}
+
+// rowID is the record id of the row whose primary key has these values.
+func rowID(collection string, key ...any) string {
+	parts := make([]string, 0, len(key)+1)
+	parts = append(parts, collection)
+	for _, v := range key {
+		parts = append(parts, keyString(v))
+	}
+	return shortHash(15, parts...)
+}
+
+func keyString(v any) string {
+	switch v := v.(type) {
+	case string:
+		return v
+	case int64:
+		return strconv.FormatInt(v, 10)
+	case int:
+		return strconv.Itoa(v)
+	case bool:
+		return strconv.FormatBool(v)
+	default:
+		return fmt.Sprint(v)
+	}
+}
+
+// collectionJSON renders a table as PocketBase's collection import format.
+// Collection and field ids are derived from their names, so that importing
+// the same schema again changes nothing, and a later version that adds a
+// field adds just that field.
+func (tb *table) collectionJSON() map[string]any {
+	out := []map[string]any{{
+		"id": "text3208210256", "name": "id", "type": "text", "system": true,
+		"primaryKey": true, "required": true, "hidden": false, "presentable": false,
+		"min": 15, "max": 15, "pattern": "^[a-z0-9]+$", "autogeneratePattern": "[a-z0-9]{15}",
+	}}
+	for _, fd := range tb.fields {
+		m := map[string]any{
+			"id":     "f" + shortHash(12, tb.name, fd.name),
+			"name":   fd.name,
+			"system": false, "required": false, "hidden": false, "presentable": false,
+		}
+		switch fd.kind {
+		case text:
+			m["type"] = "text"
+			m["min"] = 0
+			m["max"] = maxText
+			m["pattern"] = ""
+			m["autogeneratePattern"] = ""
+			m["primaryKey"] = false
+		case number:
+			m["type"] = "number"
+			m["onlyInt"] = true
+			m["min"] = nil
+			m["max"] = nil
+		case boolean:
+			m["type"] = "bool"
+		case file:
+			m["type"] = "file"
+			m["maxSelect"] = 1
+			m["maxSize"] = maxFileSize
+			m["mimeTypes"] = []string{}
+			m["thumbs"] = []string{}
+			m["protected"] = true
+		}
+		out = append(out, m)
+	}
+
+	indexes := []string{}
+	if len(tb.key) > 0 {
+		indexes = append(indexes, indexSQL(tb.name, "unique: "+strings.Join(tb.key, ", ")))
+	}
+	for _, idx := range tb.indexes {
+		indexes = append(indexes, indexSQL(tb.name, idx))
+	}
+
+	return map[string]any{
+		"id":         "warp" + shortHash(11, tb.name),
+		"name":       tb.name,
+		"type":       "base",
+		"system":     false,
+		"listRule":   nil,
+		"viewRule":   nil,
+		"createRule": nil,
+		"updateRule": nil,
+		"deleteRule": nil,
+		"fields":     out,
+		"indexes":    indexes,
+	}
+}
+
+func indexSQL(tableName, spec string) string {
+	unique := ""
+	if cols, ok := strings.CutPrefix(spec, "unique:"); ok {
+		unique, spec = "UNIQUE ", cols
+	}
+	var cols []string
+	for _, c := range strings.Split(spec, ",") {
+		cols = append(cols, strings.TrimSpace(c))
+	}
+	name := "idx_" + shortHash(10, tableName, unique, strings.Join(cols, ","))
+	return fmt.Sprintf("CREATE %sINDEX `%s` ON `%s` (%s)", unique, name, tableName, "`"+strings.Join(cols, "`, `")+"`")
+}
+
+// schemaVersion identifies the schema: any change to a table changes it, and
+// a database stamped with another one has a migration pending.
+var schemaVersion = func() string {
+	cols := make([]map[string]any, len(schema))
+	for i := range schema {
+		cols[i] = schema[i].collectionJSON()
+	}
+	raw, _ := json.Marshal(cols)
+	sum := sha256.Sum256(raw)
+	return hex.EncodeToString(sum[:])[:12]
+}()

server/internal/storage/pocketbase/sqldriver.go

@@ -0,0 +1,362 @@
+package pocketbase
+
+import (
+	"context"
+	"crypto/rand"
+	"database/sql/driver"
+	"encoding/hex"
+	"errors"
+	"fmt"
+	"io"
+	"slices"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+	"unicode/utf8"
+)
+
+// The read side of the driver is a database/sql driver over PocketBase's SQL
+// endpoint, so that the stores can read the way the SQL drivers do: with
+// `?` placeholders, joins and aggregates, and rows.Scan. It cannot write —
+// every write goes through the batch endpoint, as record operations — and
+// it cannot begin a transaction.
+//
+// The endpoint has three limits the driver hides. It takes no parameters, so
+// every argument is inlined as a SQL literal. It takes at most 5000
+// characters, so a query that would be longer has its longest arguments
+// moved into temporary records of warp_params and read back by subquery. And
+// it returns at most 1000 rows, so a result that fills a page is read on in
+// further pages.
+
+// errReadOnly is returned for anything but a query.
+var errReadOnly = errors.New("pocketbase: the SQL connection is read-only; writes go through the batch API")
+
+const (
+	// maxQueryLength is the SQL endpoint's limit, with room for the paging
+	// wrapper.
+	maxQueryLength = 5000 - len(pageWrapperPrefix) - len(pageWrapperSuffix) - 32
+
+	// pageSize is how many rows the SQL endpoint returns at most.
+	pageSize = 1000
+
+	pageWrapperPrefix = `SELECT * FROM (`
+	pageWrapperSuffix = `) LIMIT 1000 OFFSET `
+
+	// paramsCollection holds the arguments too long to inline.
+	paramsCollection = "warp_params"
+)
+
+// sqlConnector opens connections to one PocketBase.
+type sqlConnector struct {
+	c *client
+
+	// lock is held for reading around every query that runs outside a
+	// write, so that a query read in several pages is not split by one.
+	lock *sync.RWMutex
+}
+
+func (k *sqlConnector) Connect(context.Context) (driver.Conn, error) { return &sqlConn{k: k}, nil }
+func (k *sqlConnector) Driver() driver.Driver                        { return sqlDriver{k: k} }
+
+// sqlDriver exists because database/sql wants one; connections come from the
+// connector.
+type sqlDriver struct{ k *sqlConnector }
+
+func (d sqlDriver) Open(string) (driver.Conn, error) { return &sqlConn{k: d.k}, nil }
+
+type sqlConn struct{ k *sqlConnector }
+
+func (c *sqlConn) Prepare(query string) (driver.Stmt, error) {
+	return &sqlStmt{c: c, query: query}, nil
+}
+func (c *sqlConn) Close() error              { return nil }
+func (c *sqlConn) Begin() (driver.Tx, error) { return nil, errReadOnly }
+
+// Ping implements driver.Pinger.
+func (c *sqlConn) Ping(ctx context.Context) error { return c.k.c.health(ctx) }
+
+// QueryContext implements driver.QueryerContext.
+func (c *sqlConn) QueryContext(ctx context.Context, query string, args []driver.NamedValue) (driver.Rows, error) {
+	if !holdsWriteLock(ctx) {
+		c.k.lock.RLock()
+		defer c.k.lock.RUnlock()
+	}
+	return c.k.run(ctx, query, args)
+}
+
+type sqlStmt struct {
+	c     *sqlConn
+	query string
+}
+
+func (s *sqlStmt) Close() error                               { return nil }
+func (s *sqlStmt) NumInput() int                              { return -1 }
+func (s *sqlStmt) Exec([]driver.Value) (driver.Result, error) { return nil, errReadOnly }
+func (s *sqlStmt) Query(args []driver.Value) (driver.Rows, error) {
+	named := make([]driver.NamedValue, len(args))
+	for i, v := range args {
+		named[i] = driver.NamedValue{Ordinal: i + 1, Value: v}
+	}
+	return s.c.QueryContext(context.Background(), s.query, named)
+}
+
+// writeLockKey marks a context whose caller already holds the store's lock,
+// for writing or for a multi-query read, so that its queries do not take
+// the read lock again behind it.
+type writeLockKey struct{}
+
+func withWriteLock(ctx context.Context) context.Context {
+	return context.WithValue(ctx, writeLockKey{}, true)
+}
+
+func holdsWriteLock(ctx context.Context) bool {
+	held, _ := ctx.Value(writeLockKey{}).(bool)
+	return held
+}
+
+// run inlines the arguments, moves what does not fit into warp_params, and
+// reads every page of the result.
+func (k *sqlConnector) run(ctx context.Context, query string, args []driver.NamedValue) (driver.Rows, error) {
+	parts, literals, err := splitPlaceholders(query, args)
+	if err != nil {
+		return nil, err
+	}
+
+	params, err := k.fitLiterals(ctx, parts, literals)
+	if err != nil {
+		return nil, err
+	}
+	if len(params) > 0 {
+		defer k.dropParams(params)
+	}
+	full := joinLiterals(parts, literals)
+
+	res, err := k.c.query(ctx, full)
+	if err != nil {
+		return nil, fmt.Errorf("%w\n\tin query: %s", err, abbreviate(full))
+	}
+	rows := &sqlRows{columns: make([]string, len(res.Columns)), data: res.Rows}
+	for i, col := range res.Columns {
+		rows.columns[i] = col.Name
+	}
+	for page := 1; len(res.Rows) == pageSize; page++ {
+		res, err = k.c.query(ctx, pageWrapperPrefix+full+pageWrapperSuffix+strconv.Itoa(page*pageSize))
+		if err != nil {
+			return nil, fmt.Errorf("%w\n\tin page %d of query: %s", err, page, abbreviate(full))
+		}
+		rows.data = append(rows.data, res.Rows...)
+	}
+	return rows, nil
+}
+
+// splitPlaceholders cuts a query at its `?` placeholders, skipping those
+// inside quoted strings and identifiers, and renders each argument as a SQL
+// literal.
+func splitPlaceholders(query string, args []driver.NamedValue) ([]string, []string, error) {
+	var (
+		parts    []string
+		literals []string
+		start    int
+		quote    byte
+	)
+	for i := 0; i < len(query); i++ {
+		ch := query[i]
+		switch {
+		case quote != 0:
+			if ch == quote {
+				quote = 0
+			}
+		case ch == '\'' || ch == '"':
+			quote = ch
+		case ch == '?':
+			n := len(literals)
+			if n >= len(args) {
+				return nil, nil, fmt.Errorf("pocketbase: query has more placeholders than its %d arguments", len(args))
+			}
+			lit, err := literal(args[n].Value)
+			if err != nil {
+				return nil, nil, err
+			}
+			parts = append(parts, query[start:i])
+			literals = append(literals, lit)
+			start = i + 1
+		}
+	}
+	if len(literals) != len(args) {
+		return nil, nil, fmt.Errorf("pocketbase: query has %d placeholders for %d arguments", len(literals), len(args))
+	}
+	return append(parts, query[start:]), literals, nil
+}
+
+// literal renders one value as SQLite would read it back.
+func literal(v any) (string, error) {
+	switch v := v.(type) {
+	case nil:
+		return "NULL", nil
+	case bool:
+		if v {
+			return "1", nil
+		}
+		return "0", nil
+	case int64:
+		return strconv.FormatInt(v, 10), nil
+	case float64:
+		return strconv.FormatFloat(v, 'g', -1, 64), nil
+	case string:
+		return textLiteral(v), nil
+	case []byte:
+		return textLiteral(string(v)), nil
+	case time.Time:
+		return textLiteral(v.UTC().Format(time.RFC3339Nano)), nil
+	default:
+		return "", fmt.Errorf("pocketbase: cannot inline a %T into SQL", v)
+	}
+}
+
+// textLiteral quotes a string. Text that is not valid UTF-8, or holds a NUL,
+// goes in as hex and is cast back, so that nothing in it can end the literal
+// early.
+func textLiteral(s string) string {
+	if utf8.ValidString(s) && !strings.ContainsRune(s, 0) {
+		return "'" + strings.ReplaceAll(s, "'", "''") + "'"
+	}
+	return "CAST(X'" + hex.EncodeToString([]byte(s)) + "' AS TEXT)"
+}
+
+func joinLiterals(parts, literals []string) string {
+	var b strings.Builder
+	for i, p := range parts {
+		b.WriteString(p)
+		if i < len(literals) {
+			b.WriteString(literals[i])
+		}
+	}
+	return b.String()
+}
+
+// queryLength is what the SQL endpoint counts: characters, not bytes.
+func queryLength(parts, literals []string) int {
+	n := 0
+	for _, p := range parts {
+		n += utf8.RuneCountInString(p)
+	}
+	for _, l := range literals {
+		n += utf8.RuneCountInString(l)
+	}
+	return n
+}
+
+// fitLiterals moves the longest text literals into warp_params until the
+// query fits, rewriting each into a subquery reading it back. It returns the
+// IDs of the records it created.
+func (k *sqlConnector) fitLiterals(ctx context.Context, parts, literals []string) ([]string, error) {
+	if queryLength(parts, literals) <= maxQueryLength {
+		return nil, nil
+	}
+	order := make([]int, len(literals))
+	for i := range order {
+		order[i] = i
+	}
+	slices.SortFunc(order, func(a, b int) int { return len(literals[b]) - len(literals[a]) })
+
+	var (
+		ids  []string
+		reqs []batchRequest
+	)
+	for _, i := range order {
+		if queryLength(parts, literals) <= maxQueryLength {
+			break
+		}
+		text, ok := unquote(literals[i])
+		if !ok {
+			continue
+		}
+		id, err := randomID()
+		if err != nil {
+			return nil, err
+		}
+		reqs = append(reqs, batchRequest{
+			Method: "POST",
+			URL:    "/api/collections/" + paramsCollection + "/records",
+			Body:   map[string]any{"id": id, "value": text},
+		})
+		ids = append(ids, id)
+		literals[i] = `(SELECT value FROM ` + paramsCollection + ` WHERE id = '` + id + `')`
+	}
+	if queryLength(parts, literals) > maxQueryLength {
+		return nil, fmt.Errorf("pocketbase: query is too long for the SQL endpoint even with its arguments moved out")
+	}
+	if err := k.c.batch(ctx, reqs); err != nil {
+		return nil, fmt.Errorf("pocketbase: store query arguments: %w", err)
+	}
+	return ids, nil
+}
+
+// dropParams deletes the records a query's arguments were moved into. It
+// runs after the query whatever happened to it, on a context of its own, and
+// a failure only leaves rows behind for the next start to clear.
+func (k *sqlConnector) dropParams(ids []string) {
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+	reqs := make([]batchRequest, len(ids))
+	for i, id := range ids {
+		reqs[i] = batchRequest{Method: "DELETE", URL: "/api/collections/" + paramsCollection + "/records/" + id}
+	}
+	_ = k.c.batch(ctx, reqs)
+}
+
+// unquote recovers the text of a literal textLiteral made.
+func unquote(lit string) (string, bool) {
+	if strings.HasPrefix(lit, "'") {
+		return strings.ReplaceAll(lit[1:len(lit)-1], "''", "'"), true
+	}
+	if hexText, ok := strings.CutPrefix(lit, "CAST(X'"); ok {
+		raw, err := hex.DecodeString(strings.TrimSuffix(hexText, "' AS TEXT)"))
+		return string(raw), err == nil
+	}
+	return "", false
+}
+
+// randomID makes a record ID in PocketBase's default alphabet.
+func randomID() (string, error) {
+	var raw [8]byte
+	if _, err := rand.Read(raw[:]); err != nil {
+		return "", err
+	}
+	return "p" + hex.EncodeToString(raw[:])[:14], nil
+}
+
+func abbreviate(query string) string {
+	query = strings.Join(strings.Fields(query), " ")
+	if len(query) > 500 {
+		return query[:500] + "…"
+	}
+	return query
+}
+
+// sqlRows is a whole result, already read.
+type sqlRows struct {
+	columns []string
+	data    [][]*string
+	next    int
+}
+
+func (r *sqlRows) Columns() []string { return r.columns }
+func (r *sqlRows) Close() error      { return nil }
+
+func (r *sqlRows) Next(dest []driver.Value) error {
+	if r.next >= len(r.data) {
+		return io.EOF
+	}
+	row := r.data[r.next]
+	r.next++
+	for i := range dest {
+		if i < len(row) && row[i] != nil {
+			dest[i] = *row[i]
+		} else {
+			dest[i] = nil
+		}
+	}
+	return nil
+}

server/internal/storage/pocketbase/sync.go

@@ -0,0 +1,461 @@
+package pocketbase
+
+import (
+	"context"
+	"crypto/rand"
+	"database/sql"
+	"encoding/base64"
+	"errors"
+	"fmt"
+
+	"github.com/dariuszjaniak/warp/server/internal/storage"
+)
+
+// Sync is the PocketBase implementation of storage.SyncStore. Every stream
+// here is a counter row advanced in the same batch as the row it stamps.
+type Sync struct{ *base }
+
+// maxToDeviceBatch bounds how many to-device messages one sync carries.
+const maxToDeviceBatch = 100
+
+// StreamPositions implements storage.SyncStore. The positions are read under
+// one read lock, so that a caller gets one consistent set.
+func (s *Sync) StreamPositions(ctx context.Context) (storage.StreamPositions, error) {
+	var out storage.StreamPositions
+	err := s.read(ctx, func(ctx context.Context) error {
+		err := s.db.QueryRowContext(ctx, `SELECT COALESCE(MAX(stream_ordering), 0) FROM roomserver_events`).Scan(&out.PDU)
+		if err != nil {
+			return fmt.Errorf("read the top of the event stream: %w", err)
+		}
+
+		rows, err := s.db.QueryContext(ctx, `SELECT name, value FROM sync_sequences`)
+		if err != nil {
+			return fmt.Errorf("read the stream positions: %w", err)
+		}
+		defer func() { _ = rows.Close() }()
+		for rows.Next() {
+			var (
+				name  string
+				value int64
+			)
+			if err := rows.Scan(&name, &value); err != nil {
+				return fmt.Errorf("read the stream positions: %w", err)
+			}
+			switch name {
+			case seqReceipt:
+				out.Receipt = value
+			case seqToDevice:
+				out.ToDevice = value
+			case seqAccountData:
+				out.AccountData = value
+			case seqPresence:
+				out.Presence = value
+			}
+		}
+		if err := rows.Err(); err != nil {
+			return fmt.Errorf("read the stream positions: %w", err)
+		}
+
+		if out.DeviceList, err = s.currentSequence(ctx, keySequences, seqDeviceList); err != nil {
+			return err
+		}
+		out.Notification, err = s.currentSequence(ctx, pushSequences, seqNotification)
+		return err
+	})
+	if err != nil {
+		return storage.StreamPositions{}, err
+	}
+	return out, nil
+}
+
+// SetReceipt implements storage.SyncStore. A receipt that would move
+// backwards is dropped: the comparison is on the position of the event
+// being acknowledged, not on when the receipt arrived.
+func (s *Sync) SetReceipt(ctx context.Context, r storage.Receipt) (int64, bool, error) {
+	var (
+		pos   int64
+		moved bool
+	)
+	err := s.write(ctx, func(t *tx) error {
+		var target int64
+		err := t.queryRow(`SELECT e.stream_ordering FROM roomserver_events e
+			WHERE e.room_id = ? AND e.event_id = ?`, r.RoomID, r.EventID).Scan(&target)
+		switch {
+		case errors.Is(err, sql.ErrNoRows):
+			return fmt.Errorf("event %q: %w", r.EventID, storage.ErrNoSuchEvent)
+		case err != nil:
+			return fmt.Errorf("locate the event a receipt names: %w", err)
+		}
+
+		var (
+			haveEventID string
+			havePos     sql.NullInt64
+			haveStream  int64
+		)
+		err = t.queryRow(`SELECT r.event_id, e.stream_ordering, r.stream_pos
+			FROM sync_receipts r
+			LEFT JOIN roomserver_events e ON e.event_id = r.event_id
+			WHERE r.room_id = ? AND r.user_id = ? AND r.receipt_type = ? AND r.thread_id = ?`,
+			r.RoomID, r.UserID, r.ReceiptType, r.ThreadID).Scan(&haveEventID, &havePos, &haveStream)
+		switch {
+		case err == nil:
+			if havePos.Valid && havePos.Int64 >= target {
+				pos, moved = haveStream, false
+				return nil
+			}
+		case !errors.Is(err, sql.ErrNoRows):
+			return fmt.Errorf("read the current receipt: %w", err)
+		}
+
+		if pos, err = t.next(syncSequences, seqReceipt); err != nil {
+			return err
+		}
+		t.put("sync_receipts", rec{
+			"room_id": r.RoomID, "user_id": r.UserID, "receipt_type": r.ReceiptType, "thread_id": r.ThreadID,
+			"event_id": r.EventID, "ts_ms": r.TimestampMS, "stream_pos": pos,
+		})
+		moved = true
+		return nil
+	})
+	if err != nil {
+		return 0, false, fmt.Errorf("set receipt in %q: %w", r.RoomID, err)
+	}
+	return pos, moved, nil
+}
+
+const receiptColumns = `
+	room_id, user_id, receipt_type, thread_id, event_id, ts_ms, stream_pos`
+
+func scanReceipts(rows *sql.Rows) ([]storage.Receipt, error) {
+	defer func() { _ = rows.Close() }()
+
+	var out []storage.Receipt
+	for rows.Next() {
+		var r storage.Receipt
+		if err := rows.Scan(&r.RoomID, &r.UserID, &r.ReceiptType, &r.ThreadID,
+			&r.EventID, &r.TimestampMS, &r.StreamPos); err != nil {
+			return nil, err
+		}
+		out = append(out, r)
+	}
+	return out, rows.Err()
+}
+
+// Receipts implements storage.SyncStore.
+func (s *Sync) Receipts(ctx context.Context, roomIDs []string, from, to int64) ([]storage.Receipt, error) {
+	if len(roomIDs) == 0 {
+		return nil, nil
+	}
+
+	query := `SELECT ` + receiptColumns + ` FROM sync_receipts
+		WHERE room_id IN ` + inList + ` AND stream_pos > ?`
+	args := []any{jsonList(roomIDs), from}
+	if to > 0 {
+		query += ` AND stream_pos <= ?`
+		args = append(args, to)
+	}
+	query += ` ORDER BY stream_pos`
+
+	rows, err := s.db.QueryContext(ctx, query, args...)
+	if err != nil {
+		return nil, fmt.Errorf("read receipts: %w", err)
+	}
+	receipts, err := scanReceipts(rows)
+	if err != nil {
+		return nil, fmt.Errorf("read receipts: %w", err)
+	}
+	return receipts, nil
+}
+
+// ReceiptsForUser implements storage.SyncStore.
+func (s *Sync) ReceiptsForUser(ctx context.Context, userID string, roomIDs []string) ([]storage.Receipt, error) {
+	if len(roomIDs) == 0 {
+		return nil, nil
+	}
+	rows, err := s.db.QueryContext(ctx, `SELECT `+receiptColumns+` FROM sync_receipts
+		WHERE user_id = ? AND room_id IN `+inList+`
+		ORDER BY stream_pos`, userID, jsonList(roomIDs))
+	if err != nil {
+		return nil, fmt.Errorf("read the receipts of %q: %w", userID, err)
+	}
+	receipts, err := scanReceipts(rows)
+	if err != nil {
+		return nil, fmt.Errorf("read the receipts of %q: %w", userID, err)
+	}
+	return receipts, nil
+}
+
+// SendToDevice implements storage.SyncStore. Each message takes a position
+// of its own, so that one device acknowledging its copy does not drop
+// another's.
+func (s *Sync) SendToDevice(ctx context.Context, msgs []storage.NewToDeviceMessage) (int64, error) {
+	if len(msgs) == 0 {
+		top, err := s.currentSequence(ctx, syncSequences, seqToDevice)
+		if err != nil {
+			return 0, fmt.Errorf("send to-device messages: %w", err)
+		}
+		return top, nil
+	}
+	var top int64
+	err := s.write(ctx, func(t *tx) error {
+		for _, m := range msgs {
+			pos, err := t.next(syncSequences, seqToDevice)
+			if err != nil {
+				return err
+			}
+			t.put("sync_to_device", rec{
+				"stream_pos": pos, "localpart": m.Localpart, "device_id": m.DeviceID,
+				"sender": m.Sender, "event_type": m.Type, "content": string(m.Content), "sent_at_ms": m.SentAtMS,
+			})
+			top = pos
+		}
+		return nil
+	})
+	if err != nil {
+		return 0, fmt.Errorf("send to-device messages: %w", err)
+	}
+	return top, nil
+}
+
+// ToDeviceMessages implements storage.SyncStore.
+func (s *Sync) ToDeviceMessages(ctx context.Context, localpart, deviceID string, from, to int64, limit int) ([]storage.ToDeviceMessage, error) {
+	if limit <= 0 || limit > maxToDeviceBatch {
+		limit = maxToDeviceBatch
+	}
+
+	query := `SELECT stream_pos, localpart, device_id, sender, event_type, content, sent_at_ms
+		FROM sync_to_device
+		WHERE localpart = ? AND device_id = ? AND stream_pos > ?`
+	args := []any{localpart, deviceID, from}
+	if to > 0 {
+		query += ` AND stream_pos <= ?`
+		args = append(args, to)
+	}
+	query += ` ORDER BY stream_pos LIMIT ?`
+	args = append(args, limit)
+
+	rows, err := s.db.QueryContext(ctx, query, args...)
+	if err != nil {
+		return nil, fmt.Errorf("read to-device messages for %s/%s: %w", localpart, deviceID, err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	var out []storage.ToDeviceMessage
+	for rows.Next() {
+		var (
+			m       storage.ToDeviceMessage
+			content string
+		)
+		if err := rows.Scan(&m.StreamPos, &m.Localpart, &m.DeviceID,
+			&m.Sender, &m.Type, &content, &m.SentAtMS); err != nil {
+			return nil, fmt.Errorf("read to-device messages for %s/%s: %w", localpart, deviceID, err)
+		}
+		m.Content = []byte(content)
+		out = append(out, m)
+	}
+	return out, rows.Err()
+}
+
+// DeleteToDeviceMessages implements storage.SyncStore.
+func (s *Sync) DeleteToDeviceMessages(ctx context.Context, localpart, deviceID string, pos int64) error {
+	if pos <= 0 {
+		return nil
+	}
+	err := s.write(ctx, func(t *tx) error {
+		_, err := t.delWhere("sync_to_device", `localpart = ? AND device_id = ? AND stream_pos <= ?`,
+			localpart, deviceID, pos)
+		return err
+	})
+	if err != nil {
+		return fmt.Errorf("delete to-device messages for %s/%s: %w", localpart, deviceID, err)
+	}
+	return nil
+}
+
+const presenceColumns = `user_id, presence, status_msg, last_active_ms, stream_pos`
+
+// SetPresence implements storage.SyncStore. A write that changes nothing a
+// peer would notice refreshes the last-active timestamp and leaves the
+// stream where it was.
+func (s *Sync) SetPresence(ctx context.Context, p storage.PresenceState) (int64, bool, error) {
+	var (
+		pos   int64
+		moved bool
+	)
+	err := s.write(ctx, func(t *tx) error {
+		var existing storage.PresenceState
+		err := t.queryRow(`SELECT `+presenceColumns+` FROM sync_presence WHERE user_id = ?`, p.UserID).Scan(
+			&existing.UserID, &existing.Presence, &existing.StatusMsg,
+			&existing.LastActiveMS, &existing.StreamPos)
+		switch {
+		case err == nil:
+			if existing.Presence == p.Presence && existing.StatusMsg == p.StatusMsg {
+				pos = existing.StreamPos
+				t.put("sync_presence", rec{"user_id": p.UserID, "last_active_ms": p.LastActiveMS})
+				return nil
+			}
+		case !errors.Is(err, sql.ErrNoRows):
+			return fmt.Errorf("read the current presence: %w", err)
+		}
+
+		if pos, err = t.next(syncSequences, seqPresence); err != nil {
+			return err
+		}
+		t.put("sync_presence", rec{
+			"user_id": p.UserID, "presence": p.Presence, "status_msg": p.StatusMsg,
+			"last_active_ms": p.LastActiveMS, "stream_pos": pos,
+		})
+		moved = true
+		return nil
+	})
+	if err != nil {
+		return 0, false, fmt.Errorf("set the presence of %q: %w", p.UserID, err)
+	}
+	return pos, moved, nil
+}
+
+// Presence implements storage.SyncStore.
+func (s *Sync) Presence(ctx context.Context, userID string) (storage.PresenceState, error) {
+	var p storage.PresenceState
+	err := s.db.QueryRowContext(ctx, `SELECT `+presenceColumns+` FROM sync_presence WHERE user_id = ?`, userID).
+		Scan(&p.UserID, &p.Presence, &p.StatusMsg, &p.LastActiveMS, &p.StreamPos)
+	switch {
+	case errors.Is(err, sql.ErrNoRows):
+		return storage.PresenceState{}, fmt.Errorf("presence of %q: %w", userID, storage.ErrNoSuchUser)
+	case err != nil:
+		return storage.PresenceState{}, fmt.Errorf("read the presence of %q: %w", userID, err)
+	}
+	return p, nil
+}
+
+// PresenceForUsers implements storage.SyncStore.
+func (s *Sync) PresenceForUsers(ctx context.Context, userIDs []string, from, to int64) ([]storage.PresenceState, error) {
+	if len(userIDs) == 0 {
+		return nil, nil
+	}
+
+	query := `SELECT ` + presenceColumns + ` FROM sync_presence
+		WHERE user_id IN ` + inList + ` AND stream_pos > ?`
+	args := []any{jsonList(userIDs), from}
+	if to > 0 {
+		query += ` AND stream_pos <= ?`
+		args = append(args, to)
+	}
+	query += ` ORDER BY stream_pos`
+
+	rows, err := s.db.QueryContext(ctx, query, args...)
+	if err != nil {
+		return nil, fmt.Errorf("read presence: %w", err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	var out []storage.PresenceState
+	for rows.Next() {
+		var p storage.PresenceState
+		if err := rows.Scan(&p.UserID, &p.Presence, &p.StatusMsg, &p.LastActiveMS, &p.StreamPos); err != nil {
+			return nil, fmt.Errorf("read presence: %w", err)
+		}
+		out = append(out, p)
+	}
+	return out, rows.Err()
+}
+
+// AccountDataChanges implements storage.SyncStore.
+func (s *Sync) AccountDataChanges(ctx context.Context, localpart string, from, to int64) ([]storage.AccountDataEntry, error) {
+	query := `SELECT room_id, data_type, stream_pos FROM user_account_data
+		WHERE localpart = ? AND stream_pos > ?`
+	args := []any{localpart, from}
+	if to > 0 {
+		query += ` AND stream_pos <= ?`
+		args = append(args, to)
+	}
+	query += ` ORDER BY stream_pos`
+	return s.accountData(ctx, localpart, query, args)
+}
+
+// AccountDataAt implements storage.SyncStore.
+func (s *Sync) AccountDataAt(ctx context.Context, localpart string, to int64) ([]storage.AccountDataEntry, error) {
+	query := `SELECT room_id, data_type, stream_pos FROM user_account_data WHERE localpart = ?`
+	args := []any{localpart}
+	if to > 0 {
+		query += ` AND stream_pos <= ?`
+		args = append(args, to)
+	}
+	query += ` ORDER BY room_id, data_type`
+	return s.accountData(ctx, localpart, query, args)
+}
+
+func (s *Sync) accountData(ctx context.Context, localpart, query string, args []any) ([]storage.AccountDataEntry, error) {
+	rows, err := s.db.QueryContext(ctx, query, args...)
+	if err != nil {
+		return nil, fmt.Errorf("read the account data of %q: %w", localpart, err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	var out []storage.AccountDataEntry
+	for rows.Next() {
+		var e storage.AccountDataEntry
+		if err := rows.Scan(&e.RoomID, &e.DataType, &e.StreamPos); err != nil {
+			return nil, fmt.Errorf("read the account data of %q: %w", localpart, err)
+		}
+		out = append(out, e)
+	}
+	return out, rows.Err()
+}
+
+// SaveFilter implements storage.SyncStore. The ID is random rather than a
+// counter, so that it says nothing about whose filter it is.
+func (s *Sync) SaveFilter(ctx context.Context, localpart string, filter []byte, createdAtMS int64) (string, error) {
+	var filterID string
+	err := s.write(ctx, func(t *tx) error {
+		for range 3 {
+			id, err := newFilterID()
+			if err != nil {
+				return err
+			}
+			taken, err := t.exists("sync_filters", `localpart = ? AND filter_id = ?`, localpart, id)
+			if err != nil {
+				return err
+			}
+			if taken {
+				continue
+			}
+			t.put("sync_filters", rec{
+				"localpart": localpart, "filter_id": id,
+				"filter_json": string(filter), "created_at_ms": createdAtMS,
+			})
+			filterID = id
+			return nil
+		}
+		return errors.New("could not find an unused filter ID")
+	})
+	if err != nil {
+		return "", fmt.Errorf("save a filter for %q: %w", localpart, err)
+	}
+	return filterID, nil
+}
+
+// newFilterID mints a filter ID: 12 random bytes, URL-safe base64.
+func newFilterID() (string, error) {
+	var raw [12]byte
+	if _, err := rand.Read(raw[:]); err != nil {
+		return "", fmt.Errorf("generate a filter ID: %w", err)
+	}
+	return base64.RawURLEncoding.EncodeToString(raw[:]), nil
+}
+
+// Filter implements storage.SyncStore.
+func (s *Sync) Filter(ctx context.Context, localpart, filterID string) ([]byte, error) {
+	var body string
+	err := s.db.QueryRowContext(ctx, `SELECT filter_json FROM sync_filters
+		WHERE localpart = ? AND filter_id = ?`, localpart, filterID).Scan(&body)
+	switch {
+	case errors.Is(err, sql.ErrNoRows):
+		return nil, fmt.Errorf("filter %q: %w", filterID, storage.ErrNoSuchFilter)
+	case err != nil:
+		return nil, fmt.Errorf("read filter %q: %w", filterID, err)
+	}
+	return []byte(body), nil
+}
+
+var _ storage.SyncStore = (*Sync)(nil)

server/internal/storage/pocketbase/timeline.go

@@ -0,0 +1,334 @@
+package pocketbase
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/dariuszjaniak/warp/server/internal/storage"
+)
+
+// The stream reads of the room store: the queries the sync API and
+// /messages are built on. They are the SQL store's.
+
+// MaxStreamOrdering implements storage.RoomStore. It reads the events, not
+// the counter: a batch writes both at once, but an event skipped as a
+// duplicate leaves the counter above every event there is.
+func (s *Rooms) MaxStreamOrdering(ctx context.Context) (int64, error) {
+	var top int64
+	if err := s.db.QueryRowContext(ctx,
+		`SELECT COALESCE(MAX(stream_ordering), 0) FROM roomserver_events`).Scan(&top); err != nil {
+		return 0, fmt.Errorf("read the top of the event stream: %w", err)
+	}
+	return top, nil
+}
+
+// MembershipsForUser implements storage.RoomStore.
+func (s *Rooms) MembershipsForUser(ctx context.Context, userID string, memberships []string) ([]storage.SyncMembership, error) {
+	query := `
+		SELECT cs.room_id, cs.membership, cs.event_id, e.stream_ordering
+		FROM roomserver_current_state cs
+		JOIN roomserver_events e ON e.event_id = cs.event_id
+		WHERE cs.event_type = 'm.room.member' AND cs.state_key = ?`
+	args := []any{userID}
+	if len(memberships) > 0 {
+		query += ` AND cs.membership IN ` + inList
+		args = append(args, jsonList(memberships))
+	}
+	query += ` ORDER BY cs.room_id`
+
+	rows, err := s.db.QueryContext(ctx, query, args...)
+	if err != nil {
+		return nil, fmt.Errorf("read the memberships of %q: %w", userID, err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	var out []storage.SyncMembership
+	for rows.Next() {
+		var m storage.SyncMembership
+		if err := rows.Scan(&m.RoomID, &m.Membership, &m.EventID, &m.StreamOrdering); err != nil {
+			return nil, fmt.Errorf("read the memberships of %q: %w", userID, err)
+		}
+		out = append(out, m)
+	}
+	return out, rows.Err()
+}
+
+// UserMembershipEvents implements storage.RoomStore.
+func (s *Rooms) UserMembershipEvents(ctx context.Context, roomID, userID string) ([]storage.StoredEvent, error) {
+	rows, err := s.db.QueryContext(ctx, `SELECT `+eventColumns+`
+		FROM roomserver_events e
+		WHERE e.room_id = ? AND e.event_type = 'm.room.member' AND e.has_state_key AND e.state_key = ?
+			AND NOT e.outlier
+		ORDER BY e.stream_ordering`, roomID, userID)
+	if err != nil {
+		return nil, fmt.Errorf("read the membership events of %q in %q: %w", userID, roomID, err)
+	}
+	events, err := scanEvents(rows)
+	if err != nil {
+		return nil, fmt.Errorf("read the membership events of %q in %q: %w", userID, roomID, err)
+	}
+	return events, nil
+}
+
+// Timeline implements storage.RoomStore.
+func (s *Rooms) Timeline(ctx context.Context, req storage.TimelineRequest) ([]storage.StoredEvent, error) {
+	if req.Limit <= 0 {
+		return nil, nil
+	}
+
+	conditions := []string{`e.room_id = ?`, `NOT e.outlier`}
+	args := []any{req.RoomID}
+	if req.Low != 0 {
+		conditions = append(conditions, `e.stream_ordering > ?`)
+		args = append(args, req.Low)
+	}
+	if req.High != 0 {
+		conditions = append(conditions, `e.stream_ordering <= ?`)
+		args = append(args, req.High)
+	}
+
+	order := `ASC`
+	if req.Direction == storage.DirectionBackward {
+		order = `DESC`
+	}
+
+	if clause, filterArgs := filterConditions(req.Filter); clause != "" {
+		conditions = append(conditions, clause)
+		args = append(args, filterArgs...)
+	}
+	args = append(args, req.Limit)
+
+	rows, err := s.db.QueryContext(ctx, `SELECT `+eventColumns+`
+		FROM roomserver_events e
+		WHERE `+strings.Join(conditions, " AND ")+`
+		ORDER BY e.stream_ordering `+order+`
+		LIMIT ?`, args...)
+	if err != nil {
+		return nil, fmt.Errorf("read the timeline of %q: %w", req.RoomID, err)
+	}
+	events, err := scanEvents(rows)
+	if err != nil {
+		return nil, fmt.Errorf("read the timeline of %q: %w", req.RoomID, err)
+	}
+	return events, nil
+}
+
+// StreamEvents implements storage.RoomStore.
+func (s *Rooms) StreamEvents(ctx context.Context, after, upTo int64, limit int) ([]storage.StoredEvent, error) {
+	if limit <= 0 {
+		return nil, nil
+	}
+	conditions := []string{`e.stream_ordering > ?`, `NOT e.outlier`}
+	args := []any{after}
+	if upTo != 0 {
+		conditions = append(conditions, `e.stream_ordering <= ?`)
+		args = append(args, upTo)
+	}
+	args = append(args, limit)
+
+	rows, err := s.db.QueryContext(ctx, `SELECT `+eventColumns+`
+		FROM roomserver_events e
+		WHERE `+strings.Join(conditions, " AND ")+`
+		ORDER BY e.stream_ordering
+		LIMIT ?`, args...)
+	if err != nil {
+		return nil, fmt.Errorf("read the event stream after %d: %w", after, err)
+	}
+	events, err := scanEvents(rows)
+	if err != nil {
+		return nil, fmt.Errorf("read the event stream after %d: %w", after, err)
+	}
+	return events, nil
+}
+
+// filterConditions renders the part of an event filter the store applies in
+// SQL. The exclusions are ANDed in after the inclusions, which is what makes
+// not_types win over types.
+func filterConditions(f storage.TimelineFilter) (string, []any) {
+	return filterConditionsOn(`e.event_type`, `e.sender`, f)
+}
+
+// filterConditionsOn is filterConditions against named columns.
+func filterConditionsOn(typeColumn, senderColumn string, f storage.TimelineFilter) (string, []any) {
+	var (
+		clauses []string
+		args    []any
+	)
+	add := func(column string, patterns []string, negate bool) {
+		if len(patterns) == 0 {
+			return
+		}
+		clause, clauseArgs := patternMatch(column, patterns)
+		if negate {
+			clause = `NOT (` + clause + `)`
+		}
+		clauses = append(clauses, clause)
+		args = append(args, clauseArgs...)
+	}
+	add(typeColumn, f.Types, false)
+	add(typeColumn, f.NotTypes, true)
+	add(senderColumn, f.Senders, false)
+	add(senderColumn, f.NotSenders, true)
+
+	if len(clauses) == 0 {
+		return "", nil
+	}
+	return strings.Join(clauses, " AND "), args
+}
+
+// patternMatch renders "this column matches any of these patterns", where a
+// trailing '*' matches any suffix.
+func patternMatch(column string, patterns []string) (string, []any) {
+	var (
+		exact    []string
+		wildcard []string
+		args     []any
+	)
+	for _, p := range patterns {
+		if prefix, isWildcard := strings.CutSuffix(p, "*"); isWildcard {
+			wildcard = append(wildcard, prefix)
+			continue
+		}
+		exact = append(exact, p)
+	}
+
+	var parts []string
+	if len(exact) > 0 {
+		parts = append(parts, column+` IN `+inList)
+		args = append(args, jsonList(exact))
+	}
+	for _, prefix := range wildcard {
+		parts = append(parts, column+` LIKE ? ESCAPE '\'`)
+		args = append(args, escapeLike(prefix)+`%`)
+	}
+	return strings.Join(parts, " OR "), args
+}
+
+// RoomsWithEvents implements storage.RoomStore.
+func (s *Rooms) RoomsWithEvents(ctx context.Context, roomIDs []string, from, to int64) ([]string, error) {
+	if len(roomIDs) == 0 {
+		return nil, nil
+	}
+
+	query := `
+		SELECT DISTINCT room_id FROM roomserver_events
+		WHERE room_id IN ` + inList + ` AND NOT outlier`
+	args := []any{jsonList(roomIDs)}
+	if from != 0 {
+		query += ` AND stream_ordering > ?`
+		args = append(args, from)
+	}
+	if to != 0 {
+		query += ` AND stream_ordering <= ?`
+		args = append(args, to)
+	}
+	query += ` ORDER BY room_id`
+
+	out, err := s.queryStrings(ctx, query, args...)
+	if err != nil {
+		return nil, fmt.Errorf("find the rooms with events after %d: %w", from, err)
+	}
+	return out, nil
+}
+
+// LatestEventPositions implements storage.RoomStore.
+func (s *Rooms) LatestEventPositions(ctx context.Context, roomIDs, types []string, upTo int64) (map[string]int64, error) {
+	if len(roomIDs) == 0 || len(types) == 0 {
+		return map[string]int64{}, nil
+	}
+	query := `
+		SELECT room_id, MAX(stream_ordering) FROM roomserver_events
+		WHERE room_id IN ` + inList + `
+		AND event_type IN ` + inList + ` AND NOT outlier`
+	args := []any{jsonList(roomIDs), jsonList(types)}
+	if upTo != 0 {
+		query += ` AND stream_ordering <= ?`
+		args = append(args, upTo)
+	}
+	query += ` GROUP BY room_id`
+
+	rows, err := s.db.QueryContext(ctx, query, args...)
+	if err != nil {
+		return nil, fmt.Errorf("find the latest activity of %d rooms: %w", len(roomIDs), err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	out := make(map[string]int64, len(roomIDs))
+	for rows.Next() {
+		var (
+			roomID string
+			pos    int64
+		)
+		if err := rows.Scan(&roomID, &pos); err != nil {
+			return nil, fmt.Errorf("find the latest activity of %d rooms: %w", len(roomIDs), err)
+		}
+		out[roomID] = pos
+	}
+	return out, rows.Err()
+}
+
+// StateAtStream implements storage.RoomStore: the snapshot recorded against
+// the last event at or before the position, plus that event itself when it
+// is a state event.
+func (s *Rooms) StateAtStream(ctx context.Context, roomID string, pos int64) ([]storage.StateEntry, error) {
+	if pos == 0 {
+		return nil, nil
+	}
+
+	var (
+		eventID    string
+		eventType  string
+		stateKey   sql.NullString
+		snapshotID int64
+	)
+	err := s.db.QueryRowContext(ctx, `
+		SELECT e.event_id, e.event_type, CASE WHEN e.has_state_key THEN e.state_key END, e.state_before_id
+		FROM roomserver_events e
+		WHERE e.room_id = ? AND NOT e.outlier AND e.stream_ordering <= ?
+		ORDER BY e.stream_ordering DESC
+		LIMIT 1`, roomID, pos).
+		Scan(&eventID, &eventType, &stateKey, &snapshotID)
+	switch {
+	case errors.Is(err, sql.ErrNoRows):
+		return nil, nil
+	case err != nil:
+		return nil, fmt.Errorf("read the state of %q at %d: %w", roomID, pos, err)
+	}
+
+	var entries []storage.StateEntry
+	if snapshotID != 0 {
+		rows, qErr := s.db.QueryContext(ctx, `
+			SELECT se.event_type, se.state_key, se.event_id, ''
+			FROM roomserver_state_entries se
+			WHERE se.snapshot_id = ?
+			ORDER BY se.event_type, se.state_key`, snapshotID)
+		if qErr != nil {
+			return nil, fmt.Errorf("read the state of %q at %d: %w", roomID, pos, qErr)
+		}
+		if entries, err = scanStateEntries(rows); err != nil {
+			return nil, fmt.Errorf("read the state of %q at %d: %w", roomID, pos, err)
+		}
+	}
+	if stateKey.Valid {
+		entries = upsertStateEntry(entries, storage.StateEntry{
+			Type:     eventType,
+			StateKey: stateKey.String,
+			EventID:  eventID,
+		})
+	}
+	return entries, nil
+}
+
+// upsertStateEntry replaces the matching tuple in entries, or appends it.
+func upsertStateEntry(entries []storage.StateEntry, entry storage.StateEntry) []storage.StateEntry {
+	for i, existing := range entries {
+		if existing.Type == entry.Type && existing.StateKey == entry.StateKey {
+			entries[i] = entry
+			return entries
+		}
+	}
+	return append(entries, entry)
+}

server/internal/storage/pocketbase/users.go

@@ -0,0 +1,557 @@
+package pocketbase
+
+import (
+	"context"
+	"database/sql"
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/dariuszjaniak/warp/server/internal/storage"
+)
+
+// Users is the PocketBase implementation of storage.UserStore.
+//
+// The reads are the SQL store's statements. The writes are record
+// operations, and where the SQL store lets a primary key or an UPDATE's
+// affected-row count answer a question — is this localpart taken, does
+// this account exist — this one asks first: the write lock is held from
+// the question to the batch, so the answer cannot change in between.
+type Users struct{ *base }
+
+const (
+	defaultAccountPageSize = 100
+	maxAccountPageSize     = 1000
+)
+
+// CreateAccount implements storage.UserStore.
+func (u *Users) CreateAccount(ctx context.Context, acc storage.NewAccount) (storage.Account, error) {
+	err := u.write(ctx, func(t *tx) error {
+		taken, err := t.exists("user_accounts", `localpart = ?`, acc.Localpart)
+		if err != nil {
+			return err
+		}
+		if taken {
+			return storage.ErrUserExists
+		}
+		t.put("user_accounts", rec{
+			"localpart":     acc.Localpart,
+			"password_hash": acc.PasswordHash,
+			"display_name":  acc.DisplayName,
+			"avatar_url":    "",
+			"admin":         acc.Admin,
+			"deactivated":   false,
+			"created_at_ms": acc.CreatedAtMS,
+		})
+		return nil
+	})
+	if err != nil {
+		return storage.Account{}, fmt.Errorf("create account %q: %w", acc.Localpart, err)
+	}
+	return storage.Account{
+		Localpart:   acc.Localpart,
+		DisplayName: acc.DisplayName,
+		Admin:       acc.Admin,
+		CreatedAtMS: acc.CreatedAtMS,
+	}, nil
+}
+
+const selectAccountSQL = `
+	SELECT localpart, display_name, avatar_url, admin, deactivated, created_at_ms
+	FROM user_accounts WHERE localpart = ?`
+
+// Account implements storage.UserStore.
+func (u *Users) Account(ctx context.Context, localpart string) (storage.Account, error) {
+	var acc storage.Account
+	err := u.db.QueryRowContext(ctx, selectAccountSQL, localpart).Scan(
+		&acc.Localpart, &acc.DisplayName, &acc.AvatarURL,
+		&acc.Admin, &acc.Deactivated, &acc.CreatedAtMS)
+	switch {
+	case errors.Is(err, sql.ErrNoRows):
+		return storage.Account{}, fmt.Errorf("account %q: %w", localpart, storage.ErrNoSuchUser)
+	case err != nil:
+		return storage.Account{}, fmt.Errorf("account %q: %w", localpart, err)
+	}
+	return acc, nil
+}
+
+// PasswordHash implements storage.UserStore.
+func (u *Users) PasswordHash(ctx context.Context, localpart string) (string, error) {
+	var hash string
+	err := u.db.QueryRowContext(ctx, `SELECT password_hash FROM user_accounts WHERE localpart = ?`, localpart).Scan(&hash)
+	switch {
+	case errors.Is(err, sql.ErrNoRows):
+		return "", fmt.Errorf("password for %q: %w", localpart, storage.ErrNoSuchUser)
+	case err != nil:
+		return "", fmt.Errorf("password for %q: %w", localpart, err)
+	}
+	return hash, nil
+}
+
+// SetPasswordHash implements storage.UserStore.
+func (u *Users) SetPasswordHash(ctx context.Context, localpart, hash string) error {
+	return u.updateAccount(ctx, localpart, rec{"password_hash": hash})
+}
+
+// SetAdmin implements storage.UserStore.
+func (u *Users) SetAdmin(ctx context.Context, localpart string, admin bool) error {
+	return u.updateAccount(ctx, localpart, rec{"admin": admin})
+}
+
+// SetDeactivated implements storage.UserStore.
+func (u *Users) SetDeactivated(ctx context.Context, localpart string, deactivated bool) error {
+	return u.updateAccount(ctx, localpart, rec{"deactivated": deactivated})
+}
+
+// SetDisplayName implements storage.UserStore.
+func (u *Users) SetDisplayName(ctx context.Context, localpart, displayName string) error {
+	return u.updateAccount(ctx, localpart, rec{"display_name": displayName})
+}
+
+// SetAvatarURL implements storage.UserStore.
+func (u *Users) SetAvatarURL(ctx context.Context, localpart, avatarURL string) error {
+	return u.updateAccount(ctx, localpart, rec{"avatar_url": avatarURL})
+}
+
+// updateAccount changes columns of one account, returning ErrNoSuchUser for
+// an account that is not there.
+func (u *Users) updateAccount(ctx context.Context, localpart string, row rec) error {
+	err := u.write(ctx, func(t *tx) error {
+		n, err := t.setWhere("user_accounts", row, `localpart = ?`, localpart)
+		if err != nil {
+			return err
+		}
+		if n == 0 {
+			return storage.ErrNoSuchUser
+		}
+		return nil
+	})
+	if err != nil {
+		return fmt.Errorf("update account %q: %w", localpart, err)
+	}
+	return nil
+}
+
+// likeEscape is the escape character the search patterns use.
+const likeEscape = '!'
+
+const (
+	countAccountsSQL = `
+		SELECT COUNT(*) FROM user_accounts
+		WHERE LOWER(localpart) LIKE ? ESCAPE '!' OR LOWER(display_name) LIKE ? ESCAPE '!'`
+
+	listAccountsSQL = `
+		SELECT localpart, display_name, avatar_url, admin, deactivated, created_at_ms
+		FROM user_accounts
+		WHERE LOWER(localpart) LIKE ? ESCAPE '!' OR LOWER(display_name) LIKE ? ESCAPE '!'
+		ORDER BY localpart
+		LIMIT ? OFFSET ?`
+)
+
+// ListAccounts implements storage.UserStore.
+func (u *Users) ListAccounts(ctx context.Context, filter storage.AccountFilter) ([]storage.Account, int, error) {
+	pattern := likeContains(filter.Search)
+
+	limit := filter.Limit
+	switch {
+	case limit <= 0:
+		limit = defaultAccountPageSize
+	case limit > maxAccountPageSize:
+		limit = maxAccountPageSize
+	}
+	offset := max(filter.Offset, 0)
+
+	var total int
+	if err := u.db.QueryRowContext(ctx, countAccountsSQL, pattern, pattern).Scan(&total); err != nil {
+		return nil, 0, fmt.Errorf("count accounts: %w", err)
+	}
+
+	rows, err := u.db.QueryContext(ctx, listAccountsSQL, pattern, pattern, limit, offset)
+	if err != nil {
+		return nil, 0, fmt.Errorf("list accounts: %w", err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	accounts := []storage.Account{}
+	for rows.Next() {
+		var acc storage.Account
+		if err := rows.Scan(&acc.Localpart, &acc.DisplayName, &acc.AvatarURL,
+			&acc.Admin, &acc.Deactivated, &acc.CreatedAtMS); err != nil {
+			return nil, 0, fmt.Errorf("scan account: %w", err)
+		}
+		accounts = append(accounts, acc)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, 0, fmt.Errorf("list accounts: %w", err)
+	}
+	return accounts, total, nil
+}
+
+// likeContains turns a search term into a LIKE pattern matching it
+// anywhere, with the wildcards and the escape character escaped.
+func likeContains(search string) string {
+	search = strings.ToLower(strings.TrimSpace(search))
+	var b strings.Builder
+	b.Grow(len(search) + 2)
+	b.WriteByte('%')
+	for _, r := range search {
+		if r == '%' || r == '_' || r == likeEscape {
+			b.WriteByte(likeEscape)
+		}
+		b.WriteRune(r)
+	}
+	b.WriteByte('%')
+	return b.String()
+}
+
+const statsSQL = `
+	SELECT
+		(SELECT COUNT(*) FROM user_accounts),
+		(SELECT COUNT(*) FROM user_accounts WHERE admin = ?),
+		(SELECT COUNT(*) FROM user_accounts WHERE deactivated = ?),
+		(SELECT COUNT(*) FROM user_devices)`
+
+// Stats implements storage.UserStore.
+func (u *Users) Stats(ctx context.Context) (storage.Stats, error) {
+	var s storage.Stats
+	err := u.db.QueryRowContext(ctx, statsSQL, true, true).
+		Scan(&s.Users, &s.Admins, &s.Deactivated, &s.Devices)
+	if err != nil {
+		return storage.Stats{}, fmt.Errorf("user stats: %w", err)
+	}
+	return s, nil
+}
+
+// CreateSession implements storage.UserStore.
+//
+// Logging in on a device ID that already exists keeps the device and its
+// display name but revokes the tokens it held, which is what the spec
+// requires.
+func (u *Users) CreateSession(ctx context.Context, s storage.NewSession) (storage.Device, error) {
+	device := storage.Device{
+		Localpart:   s.Localpart,
+		ID:          s.DeviceID,
+		DisplayName: s.DisplayName,
+		CreatedAtMS: s.CreatedAtMS,
+		LastSeenMS:  s.CreatedAtMS,
+		LastSeenIP:  s.LastSeenIP,
+		UserAgent:   s.UserAgent,
+	}
+
+	err := u.write(ctx, func(t *tx) error {
+		found, err := t.exists("user_accounts", `localpart = ?`, s.Localpart)
+		if err != nil {
+			return fmt.Errorf("create session for %q: %w", s.Localpart, err)
+		}
+		if !found {
+			return fmt.Errorf("create session for %q: %w", s.Localpart, storage.ErrNoSuchUser)
+		}
+
+		var existingName string
+		var existingCreated int64
+		err = t.queryRow(`SELECT display_name, created_at_ms FROM user_devices
+			WHERE localpart = ? AND device_id = ?`, s.Localpart, s.DeviceID).
+			Scan(&existingName, &existingCreated)
+		switch {
+		case errors.Is(err, sql.ErrNoRows):
+			t.put("user_devices", rec{
+				"localpart":     s.Localpart,
+				"device_id":     s.DeviceID,
+				"display_name":  s.DisplayName,
+				"created_at_ms": s.CreatedAtMS,
+				"last_seen_ms":  s.CreatedAtMS,
+				"last_seen_ip":  s.LastSeenIP,
+				"user_agent":    s.UserAgent,
+			})
+		case err != nil:
+			return fmt.Errorf("read device %q: %w", s.DeviceID, err)
+		default:
+			device.DisplayName = existingName
+			device.CreatedAtMS = existingCreated
+			t.put("user_devices", rec{
+				"localpart":    s.Localpart,
+				"device_id":    s.DeviceID,
+				"last_seen_ms": s.CreatedAtMS,
+				"last_seen_ip": s.LastSeenIP,
+				"user_agent":   s.UserAgent,
+			})
+			if err := revokeDeviceTokens(t, `localpart = ? AND device_id = ?`, s.Localpart, s.DeviceID); err != nil {
+				return err
+			}
+		}
+
+		t.put("user_access_tokens", rec{
+			"token_hash":    s.AccessTokenHash,
+			"localpart":     s.Localpart,
+			"device_id":     s.DeviceID,
+			"created_at_ms": s.CreatedAtMS,
+			"expires_at_ms": s.AccessTokenExpiresAtMS,
+		})
+		if s.RefreshTokenHash != "" {
+			t.put("user_refresh_tokens", rec{
+				"token_hash":    s.RefreshTokenHash,
+				"localpart":     s.Localpart,
+				"device_id":     s.DeviceID,
+				"created_at_ms": s.CreatedAtMS,
+				"expires_at_ms": s.RefreshTokenExpiresAtMS,
+			})
+		}
+		return nil
+	})
+	if err != nil {
+		return storage.Device{}, err
+	}
+	return device, nil
+}
+
+// revokeDeviceTokens deletes the access and refresh tokens matching a
+// condition on (localpart, device_id).
+func revokeDeviceTokens(t *tx, where string, args ...any) error {
+	for _, table := range []string{"user_access_tokens", "user_refresh_tokens"} {
+		if _, err := t.delWhere(table, where, args...); err != nil {
+			return fmt.Errorf("revoke tokens: %w", err)
+		}
+	}
+	return nil
+}
+
+// RefreshSession implements storage.UserStore.
+//
+// The spent refresh token and the access token it had minted both go away
+// immediately.
+func (u *Users) RefreshSession(ctx context.Context, r storage.RefreshedSession) (storage.TokenInfo, error) {
+	var info storage.TokenInfo
+	var expired bool
+
+	err := u.write(ctx, func(t *tx) error {
+		var expiresAt int64
+		err := t.queryRow(`SELECT localpart, device_id, expires_at_ms FROM user_refresh_tokens WHERE token_hash = ?`,
+			r.RefreshTokenHash).Scan(&info.Localpart, &info.DeviceID, &expiresAt)
+		switch {
+		case errors.Is(err, sql.ErrNoRows):
+			return fmt.Errorf("refresh token: %w", storage.ErrNoSuchToken)
+		case err != nil:
+			return fmt.Errorf("refresh token: %w", err)
+		}
+		if _, err := t.delKey("user_refresh_tokens", r.RefreshTokenHash); err != nil {
+			return fmt.Errorf("spend refresh token: %w", err)
+		}
+		if expiresAt != 0 && expiresAt <= r.RefreshedAtMS {
+			// The dead token is cleaned up on the way past: the batch is
+			// still sent, and the error reported after it.
+			expired = true
+			return nil
+		}
+
+		if _, err := t.delWhere("user_access_tokens", `localpart = ? AND device_id = ?`,
+			info.Localpart, info.DeviceID); err != nil {
+			return fmt.Errorf("revoke previous access token: %w", err)
+		}
+		t.put("user_access_tokens", rec{
+			"token_hash":    r.NewAccessTokenHash,
+			"localpart":     info.Localpart,
+			"device_id":     info.DeviceID,
+			"created_at_ms": r.RefreshedAtMS,
+			"expires_at_ms": r.AccessTokenExpiresAtMS,
+		})
+		if r.NewRefreshTokenHash != "" {
+			t.put("user_refresh_tokens", rec{
+				"token_hash":    r.NewRefreshTokenHash,
+				"localpart":     info.Localpart,
+				"device_id":     info.DeviceID,
+				"created_at_ms": r.RefreshedAtMS,
+				"expires_at_ms": r.RefreshTokenExpiresAtMS,
+			})
+		}
+
+		if err := t.queryRow(`SELECT admin, deactivated FROM user_accounts WHERE localpart = ?`, info.Localpart).
+			Scan(&info.Admin, &info.Deactivated); err != nil {
+			return fmt.Errorf("read account %q: %w", info.Localpart, err)
+		}
+		info.ExpiresAtMS = r.AccessTokenExpiresAtMS
+		return nil
+	})
+	if err != nil {
+		return storage.TokenInfo{}, err
+	}
+	if expired {
+		return storage.TokenInfo{}, fmt.Errorf("refresh token has expired: %w", storage.ErrNoSuchToken)
+	}
+	return info, nil
+}
+
+const selectTokenInfoSQL = `
+	SELECT t.localpart, t.device_id, t.expires_at_ms, a.admin, a.deactivated
+	FROM user_access_tokens t
+	JOIN user_accounts a ON a.localpart = t.localpart
+	WHERE t.token_hash = ?`
+
+// TokenInfo implements storage.UserStore.
+func (u *Users) TokenInfo(ctx context.Context, tokenHash string) (storage.TokenInfo, error) {
+	var info storage.TokenInfo
+	err := u.db.QueryRowContext(ctx, selectTokenInfoSQL, tokenHash).Scan(
+		&info.Localpart, &info.DeviceID, &info.ExpiresAtMS, &info.Admin, &info.Deactivated)
+	switch {
+	case errors.Is(err, sql.ErrNoRows):
+		return storage.TokenInfo{}, storage.ErrNoSuchToken
+	case err != nil:
+		return storage.TokenInfo{}, fmt.Errorf("look up access token: %w", err)
+	}
+	return info, nil
+}
+
+// TouchDevice implements storage.UserStore. A device that has gone away
+// between authenticating and recording the visit is not an error.
+func (u *Users) TouchDevice(ctx context.Context, localpart, deviceID, ip, userAgent string, seenAtMS int64) error {
+	err := u.write(ctx, func(t *tx) error {
+		_, err := t.setWhere("user_devices", rec{
+			"last_seen_ms": seenAtMS,
+			"last_seen_ip": ip,
+			"user_agent":   userAgent,
+		}, `localpart = ? AND device_id = ?`, localpart, deviceID)
+		return err
+	})
+	if err != nil {
+		return fmt.Errorf("touch device %q: %w", deviceID, err)
+	}
+	return nil
+}
+
+const deviceColumns = `localpart, device_id, display_name, created_at_ms, last_seen_ms, last_seen_ip, user_agent`
+
+// Device implements storage.UserStore.
+func (u *Users) Device(ctx context.Context, localpart, deviceID string) (storage.Device, error) {
+	var d storage.Device
+	err := u.db.QueryRowContext(ctx, `SELECT `+deviceColumns+`
+		FROM user_devices WHERE localpart = ? AND device_id = ?`, localpart, deviceID).Scan(
+		&d.Localpart, &d.ID, &d.DisplayName, &d.CreatedAtMS,
+		&d.LastSeenMS, &d.LastSeenIP, &d.UserAgent)
+	switch {
+	case errors.Is(err, sql.ErrNoRows):
+		return storage.Device{}, fmt.Errorf("device %q: %w", deviceID, storage.ErrNoSuchDevice)
+	case err != nil:
+		return storage.Device{}, fmt.Errorf("device %q: %w", deviceID, err)
+	}
+	return d, nil
+}
+
+// Devices implements storage.UserStore.
+func (u *Users) Devices(ctx context.Context, localpart string) ([]storage.Device, error) {
+	rows, err := u.db.QueryContext(ctx, `SELECT `+deviceColumns+`
+		FROM user_devices WHERE localpart = ? ORDER BY device_id`, localpart)
+	if err != nil {
+		return nil, fmt.Errorf("list devices of %q: %w", localpart, err)
+	}
+	defer func() { _ = rows.Close() }()
+
+	devices := []storage.Device{}
+	for rows.Next() {
+		var d storage.Device
+		if err := rows.Scan(&d.Localpart, &d.ID, &d.DisplayName, &d.CreatedAtMS,
+			&d.LastSeenMS, &d.LastSeenIP, &d.UserAgent); err != nil {
+			return nil, fmt.Errorf("scan device: %w", err)
+		}
+		devices = append(devices, d)
+	}
+	if err := rows.Err(); err != nil {
+		return nil, fmt.Errorf("list devices of %q: %w", localpart, err)
+	}
+	return devices, nil
+}
+
+// SetDeviceDisplayName implements storage.UserStore.
+func (u *Users) SetDeviceDisplayName(ctx context.Context, localpart, deviceID, displayName string) error {
+	err := u.write(ctx, func(t *tx) error {
+		n, err := t.setWhere("user_devices", rec{"display_name": displayName},
+			`localpart = ? AND device_id = ?`, localpart, deviceID)
+		if err != nil {
+			return err
+		}
+		if n == 0 {
+			return storage.ErrNoSuchDevice
+		}
+		return nil
+	})
+	if err != nil {
+		return fmt.Errorf("rename device %q: %w", deviceID, err)
+	}
+	return nil
+}
+
+// DeleteDevices implements storage.UserStore.
+func (u *Users) DeleteDevices(ctx context.Context, localpart string, deviceIDs []string) (int, error) {
+	if len(deviceIDs) == 0 {
+		return 0, nil
+	}
+	var deleted int
+	err := u.write(ctx, func(t *tx) error {
+		where := `localpart = ? AND device_id IN (SELECT value FROM json_each(?))`
+		list := jsonList(deviceIDs)
+		if err := revokeDeviceTokens(t, where, localpart, list); err != nil {
+			return err
+		}
+		n, err := t.delWhere("user_devices", where, localpart, list)
+		if err != nil {
+			return fmt.Errorf("delete devices: %w", err)
+		}
+		deleted = n
+		return nil
+	})
+	return deleted, err
+}
+
+// DeleteAllDevices implements storage.UserStore.
+func (u *Users) DeleteAllDevices(ctx context.Context, localpart string) (int, error) {
+	var deleted int
+	err := u.write(ctx, func(t *tx) error {
+		if err := revokeDeviceTokens(t, `localpart = ?`, localpart); err != nil {
+			return err
+		}
+		n, err := t.delWhere("user_devices", `localpart = ?`, localpart)
+		if err != nil {
+			return fmt.Errorf("delete devices of %q: %w", localpart, err)
+		}
+		deleted = n
+		return nil
+	})
+	return deleted, err
+}
+
+// AccountData implements storage.UserStore.
+func (u *Users) AccountData(ctx context.Context, localpart, roomID, dataType string) ([]byte, error) {
+	var content string
+	err := u.db.QueryRowContext(ctx, `SELECT content FROM user_account_data
+		WHERE localpart = ? AND room_id = ? AND data_type = ?`, localpart, roomID, dataType).Scan(&content)
+	switch {
+	case errors.Is(err, sql.ErrNoRows):
+		return nil, fmt.Errorf("account data %q: %w", dataType, storage.ErrNoSuchAccountData)
+	case err != nil:
+		return nil, fmt.Errorf("account data %q: %w", dataType, err)
+	}
+	return []byte(content), nil
+}
+
+// SetAccountData implements storage.UserStore. The write stamps the row with
+// a position in the account data stream, in the same batch as the content.
+func (u *Users) SetAccountData(ctx context.Context, localpart, roomID, dataType string, content []byte) error {
+	err := u.write(ctx, func(t *tx) error {
+		pos, err := t.next(syncSequences, seqAccountData)
+		if err != nil {
+			return err
+		}
+		t.put("user_account_data", rec{
+			"localpart":  localpart,
+			"room_id":    roomID,
+			"data_type":  dataType,
+			"content":    string(content),
+			"stream_pos": pos,
+		})
+		return nil
+	})
+	if err != nil {
+		return fmt.Errorf("set account data %q: %w", dataType, err)
+	}
+	return nil
+}
+
+var _ storage.UserStore = (*Users)(nil)

server/internal/storage/storage.go

@@ -27,7 +27,7 @@ const (
 )
 
 // ErrNotImplemented is returned by a driver that is compiled in but not
-// finished — currently PocketBase.
+// finished.
 var ErrNotImplemented = errors.New("not implemented by this storage driver")
 
 // ErrNoSuchSetting is returned by SettingsStore.Get for an unknown key.
@@ -41,6 +41,12 @@ type Config struct {
 	MaxIdleConns     int
 	ConnMaxLifetime  time.Duration
 
+	// SuperuserEmail and SuperuserPassword are the account the pocketbase
+	// driver signs in to its server with. Only the pocketbase driver reads
+	// them.
+	SuperuserEmail    string
+	SuperuserPassword string
+
 	// S3 is the bucket a driver with its own file storage puts media in.
 	// Only the pocketbase driver reads it.
 	S3 S3Config

server/internal/storage/storage_test.go

@@ -11,11 +11,13 @@ import (
 
 	"github.com/dariuszjaniak/warp/server/internal/storage"
 	_ "github.com/dariuszjaniak/warp/server/internal/storage/drivers"
+	"github.com/dariuszjaniak/warp/server/internal/storage/pocketbase/pbtest"
 )
 
 // openTestDB opens each driver that can run without external services. The
 // postgres driver joins in when WARP_TEST_POSTGRES_DSN is set, which is how
-// CI runs the same tests against both engines.
+// CI runs the same tests against both engines; the pocketbase driver gets a
+// real PocketBase server of its own, run in-process.
 func openTestDB(t *testing.T, driver string) storage.Database {
 	t.Helper()
 
@@ -31,7 +33,9 @@ func openTestDB(t *testing.T, driver string) storage.Database {
 		}
 		cfg.ConnectionString = dsn
 	case storage.DriverPocketBase:
-		cfg.ConnectionString = filepath.Join(t.TempDir(), "pb_data")
+		cfg.ConnectionString = pbtest.Start(t).URL
+		cfg.SuperuserEmail = pbtest.SuperuserEmail
+		cfg.SuperuserPassword = pbtest.SuperuserPassword
 	default:
 		t.Fatalf("no test setup for driver %q", driver)
 	}
@@ -45,7 +49,7 @@ func openTestDB(t *testing.T, driver string) storage.Database {
 }
 
 // testDrivers are run by every storage test. PocketBase is here because
-// parity with sqlite is its whole contract.
+// parity with the SQL drivers is its whole contract.
 var testDrivers = []string{storage.DriverSQLite, storage.DriverPostgres, storage.DriverPocketBase}
 
 func TestDriversRegistered(t *testing.T) {
@@ -64,14 +68,26 @@ func TestOpenUnknownDriver(t *testing.T) {
 	}
 }
 
-func TestPocketBaseNeedsADataDirectory(t *testing.T) {
+func TestPocketBaseNeedsAServer(t *testing.T) {
 	if _, err := storage.Open(t.Context(), storage.Config{Driver: storage.DriverPocketBase}, nil); err == nil {
-		t.Fatal("expected an error for a pocketbase driver with no data directory")
+		t.Fatal("expected an error for a pocketbase driver with no server URL")
+	}
+	_, err := storage.Open(t.Context(), storage.Config{
+		Driver:            storage.DriverPocketBase,
+		ConnectionString:  pbtest.Start(t).URL,
+		SuperuserEmail:    pbtest.SuperuserEmail,
+		SuperuserPassword: "not-the-password",
+	}, nil)
+	if err == nil {
+		t.Fatal("expected an error for a superuser password the server refuses")
 	}
 }
 
-func TestPocketBaseKeepsMediaInItsFilesystem(t *testing.T) {
+func TestPocketBaseKeepsMediaInItsStorage(t *testing.T) {
 	db := openTestDB(t, storage.DriverPocketBase)
+	if err := db.Migrate(t.Context()); err != nil {
+		t.Fatalf("Migrate: %v", err)
+	}
 	provider, ok := db.(storage.BlobProvider)
 	if !ok {
 		t.Fatal("the pocketbase driver does not provide its own blob store")