Web client (warp-web) with E2EE, and two sync fixes

apps/web: a Matrix client for the browser on Vue 3, Tailwind and
matrix-js-sdk, built on @warp/ui. Like the admin panel it is an optional,
separate service: warp-web embeds the built app, serves /config.json and
proxies only /_matrix/client and /_matrix/media to the homeserver (or,
with -public-homeserver, lets the browser call it directly).
Sign-in and sign-up with registration tokens, room list, timeline with
back-pagination, text, images, video and files over authenticated media,
local echo with sent/read/failed states, receipts, typing, invites,
creating, joining and leaving rooms, room info, settings, phone layout.
End-to-end encryption through the Rust crypto: encrypted messages and
files, emoji verification, key backup setup and restore.

apps/ui: WRoomItem, WMessageBubble and WComposer from the brand package,
and the icons the client needs.

syncapi fixes found with the client:
- A room joined inside the sync window was sent as the join alone with
  limited: false, so clients thought they had the whole room. It is now
  read like an initial sync; a profile change is not mistaken for a join.
- A live typing notification was reported on every sync, so every long
  poll returned at once while anybody typed. Typing now has a position
  in the sync token and is reported when it changes, including the empty
  list when the last person stops.

Also: Dockerfile, a `web` compose profile, Makefile targets, a CI job
with a proxy smoke test, docs. PLAN.md moves out of the repository.

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

apps/web/internal/host/host_test.go

@@ -0,0 +1,306 @@
+package host
+
+import (
+	"encoding/json"
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"strings"
+	"testing"
+	"testing/fstest"
+)
+
+// upstream records what reached the homeserver.
+type upstream struct {
+	srv  *httptest.Server
+	hits []*http.Request
+}
+
+func newUpstream(t *testing.T) *upstream {
+	t.Helper()
+	u := &upstream{}
+	u.srv = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		u.hits = append(u.hits, r.Clone(r.Context()))
+		w.Header().Set("Content-Type", "application/json")
+		w.Header().Set("Set-Cookie", "tracker=1")
+		if strings.HasPrefix(r.URL.Path, "/_matrix/client/v1/media/") {
+			w.Header().Set("Cache-Control", "private, max-age=86400")
+		}
+		_, _ = w.Write([]byte(`{"path":"` + r.URL.EscapedPath() + `"}`))
+	}))
+	t.Cleanup(u.srv.Close)
+	return u
+}
+
+var clientFS = fstest.MapFS{
+	"index.html":         {Data: []byte("<!doctype html><title>client</title>")},
+	"favicon.svg":        {Data: []byte("<svg/>")},
+	"assets/index-a1.js": {Data: []byte("console.log(1)")},
+}
+
+func newHandler(t *testing.T, up *upstream, built bool) http.Handler {
+	t.Helper()
+	target, _ := url.Parse(up.srv.URL)
+	opts := Options{Homeserver: target, Version: "1.2.3"}
+	if built {
+		opts.Client = clientFS
+	}
+	h, err := New(opts)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return h
+}
+
+func do(h http.Handler, method, target string, header http.Header) *httptest.ResponseRecorder {
+	req := httptest.NewRequest(method, target, nil)
+	for k, v := range header {
+		req.Header[k] = v
+	}
+	rec := httptest.NewRecorder()
+	h.ServeHTTP(rec, req)
+	return rec
+}
+
+func TestProxiesClientAndMediaPaths(t *testing.T) {
+	up := newUpstream(t)
+	h := newHandler(t, up, true)
+
+	cases := []struct{ method, path string }{
+		{http.MethodGet, "/_matrix/client/versions"},
+		{http.MethodPost, "/_matrix/client/v3/login"},
+		{http.MethodGet, "/_matrix/client/v3/sync?timeout=30000&since=s1_2"},
+		{http.MethodPut, "/_matrix/client/v3/rooms/%21a%3Awarp.example/send/m.room.message/txn1"},
+		{http.MethodPost, "/_matrix/media/v3/upload?filename=cat.png"},
+		{http.MethodGet, "/_matrix/client/v1/media/download/warp.example/abc"},
+		{http.MethodGet, "/_matrix/client/v3/pushrules/"},
+	}
+	for _, c := range cases {
+		rec := do(h, c.method, c.path, nil)
+		if rec.Code != http.StatusOK {
+			t.Errorf("%s %s: status %d, want 200", c.method, c.path, rec.Code)
+		}
+	}
+	if len(up.hits) != len(cases) {
+		t.Fatalf("upstream saw %d requests, want %d", len(up.hits), len(cases))
+	}
+	// Escaped IDs and the query reach the homeserver unchanged.
+	if got := up.hits[3].URL.EscapedPath(); got != "/_matrix/client/v3/rooms/%21a%3Awarp.example/send/m.room.message/txn1" {
+		t.Errorf("escaped path = %q", got)
+	}
+	if got := up.hits[2].URL.RawQuery; got != "timeout=30000&since=s1_2" {
+		t.Errorf("query = %q", got)
+	}
+}
+
+func TestRefusesOtherHomeserverPaths(t *testing.T) {
+	up := newUpstream(t)
+	h := newHandler(t, up, true)
+
+	for _, p := range []string{
+		"/_matrix/federation/v1/version",
+		"/_matrix/key/v2/server",
+		"/_matrix/app/v1/transactions/1",
+		"/_warp/admin/v1/stats",
+		"/_synapse/admin/v1/users",
+		"/_matrix/client/../federation/v1/version",
+		"/_matrix/client/v3/../../federation/v1/version",
+		"/_matrix/client//v3/sync",
+		"/_matrix/client/v3/pushrules//",
+		"/_matrix/client/v3/../../federation/",
+	} {
+		rec := do(h, http.MethodGet, p, nil)
+		if rec.Code != http.StatusNotFound {
+			t.Errorf("%s: status %d, want 404", p, rec.Code)
+		}
+		var body map[string]string
+		_ = json.Unmarshal(rec.Body.Bytes(), &body)
+		if body["errcode"] != "M_UNRECOGNIZED" {
+			t.Errorf("%s: errcode %q", p, body["errcode"])
+		}
+	}
+	if len(up.hits) != 0 {
+		t.Fatalf("upstream saw %d requests, want none", len(up.hits))
+	}
+}
+
+func TestProxyStripsCookiesAndForwardsToken(t *testing.T) {
+	up := newUpstream(t)
+	h := newHandler(t, up, true)
+
+	rec := do(h, http.MethodGet, "/_matrix/client/v3/account/whoami", http.Header{
+		"Authorization": {"Bearer tok"},
+		"Cookie":        {"session=secret"},
+	})
+	if rec.Header().Get("Set-Cookie") != "" {
+		t.Error("Set-Cookie from the homeserver was passed to the browser")
+	}
+	if rec.Header().Get("Cache-Control") != "no-store" {
+		t.Errorf("Cache-Control = %q, want no-store", rec.Header().Get("Cache-Control"))
+	}
+	got := up.hits[0]
+	if got.Header.Get("Cookie") != "" {
+		t.Error("Cookie was passed to the homeserver")
+	}
+	if got.Header.Get("Authorization") != "Bearer tok" {
+		t.Errorf("Authorization = %q", got.Header.Get("Authorization"))
+	}
+	if got.Header.Get("X-Forwarded-For") == "" {
+		t.Error("X-Forwarded-For not set")
+	}
+
+	// The homeserver's own caching of media is kept.
+	rec = do(h, http.MethodGet, "/_matrix/client/v1/media/download/warp.example/abc", nil)
+	if got := rec.Header().Get("Cache-Control"); got != "private, max-age=86400" {
+		t.Errorf("media Cache-Control = %q", got)
+	}
+}
+
+func TestUnreachableHomeserverIs502(t *testing.T) {
+	target, _ := url.Parse("http://127.0.0.1:1")
+	h, err := New(Options{Homeserver: target, Client: clientFS})
+	if err != nil {
+		t.Fatal(err)
+	}
+	rec := do(h, http.MethodGet, "/_matrix/client/versions", nil)
+	if rec.Code != http.StatusBadGateway {
+		t.Fatalf("status %d, want 502", rec.Code)
+	}
+	if !strings.Contains(rec.Body.String(), "M_UNKNOWN") {
+		t.Errorf("body %q", rec.Body.String())
+	}
+}
+
+func TestServesClient(t *testing.T) {
+	up := newUpstream(t)
+	h := newHandler(t, up, true)
+
+	cases := []struct {
+		path, wantBody, wantCache string
+		wantCode                  int
+	}{
+		{"/", "client", "no-cache", 200},
+		{"/room/!abc:warp.example", "client", "no-cache", 200},
+		{"/room/%21abc%3Awarp.example", "client", "no-cache", 200},
+		{"/index.html", "client", "no-cache", 200},
+		{"/assets/index-a1.js", "console.log", "public, max-age=31536000, immutable", 200},
+		{"/favicon.svg", "<svg", "public, max-age=3600", 200},
+		{"/assets/gone-b2.js", "", "", 404},
+		{"/robots.txt", "", "", 404},
+	}
+	for _, c := range cases {
+		rec := do(h, http.MethodGet, c.path, nil)
+		if rec.Code != c.wantCode {
+			t.Errorf("%s: status %d, want %d", c.path, rec.Code, c.wantCode)
+			continue
+		}
+		if c.wantCode != 200 {
+			continue
+		}
+		body, _ := io.ReadAll(rec.Body)
+		if !strings.Contains(string(body), c.wantBody) {
+			t.Errorf("%s: body %q", c.path, body)
+		}
+		if got := rec.Header().Get("Cache-Control"); got != c.wantCache {
+			t.Errorf("%s: Cache-Control %q, want %q", c.path, got, c.wantCache)
+		}
+		if csp := rec.Header().Get("Content-Security-Policy"); !strings.Contains(csp, "connect-src 'self';") {
+			t.Errorf("%s: CSP %q", c.path, csp)
+		}
+		// WebAssembly for end-to-end encryption, and no JavaScript eval.
+		if csp := rec.Header().Get("Content-Security-Policy"); !strings.Contains(csp, "script-src 'self' 'wasm-unsafe-eval';") {
+			t.Errorf("%s: CSP %q lacks wasm-unsafe-eval", c.path, csp)
+		}
+		if rec.Header().Get("X-Frame-Options") != "DENY" {
+			t.Errorf("%s: X-Frame-Options %q", c.path, rec.Header().Get("X-Frame-Options"))
+		}
+	}
+
+	if rec := do(h, http.MethodPost, "/", nil); rec.Code != http.StatusMethodNotAllowed {
+		t.Errorf("POST /: status %d, want 405", rec.Code)
+	}
+}
+
+func TestConfigProxied(t *testing.T) {
+	up := newUpstream(t)
+	h := newHandler(t, up, true)
+
+	rec := do(h, http.MethodGet, "/config.json", nil)
+	if rec.Code != 200 {
+		t.Fatalf("status %d", rec.Code)
+	}
+	var cfg Config
+	if err := json.Unmarshal(rec.Body.Bytes(), &cfg); err != nil {
+		t.Fatal(err)
+	}
+	if cfg.HomeserverURL != "" || cfg.Version != "1.2.3" {
+		t.Errorf("config = %+v, want same-origin and the version", cfg)
+	}
+	if rec.Header().Get("Cache-Control") != "no-cache" {
+		t.Errorf("Cache-Control %q", rec.Header().Get("Cache-Control"))
+	}
+}
+
+func TestDirectModeProxiesNothing(t *testing.T) {
+	public, _ := url.Parse("https://matrix.warp.example")
+	h, err := New(Options{PublicHomeserver: public, Client: clientFS})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	rec := do(h, http.MethodGet, "/config.json", nil)
+	var cfg Config
+	_ = json.Unmarshal(rec.Body.Bytes(), &cfg)
+	if cfg.HomeserverURL != "https://matrix.warp.example" {
+		t.Errorf("homeserver_url = %q", cfg.HomeserverURL)
+	}
+
+	if rec := do(h, http.MethodGet, "/_matrix/client/versions", nil); rec.Code != http.StatusNotFound {
+		t.Errorf("proxy in direct mode: status %d, want 404", rec.Code)
+	}
+
+	// The browser may now connect to the homeserver, and only there.
+	rec = do(h, http.MethodGet, "/", nil)
+	if csp := rec.Header().Get("Content-Security-Policy"); !strings.Contains(csp, "connect-src 'self' https://matrix.warp.example;") {
+		t.Errorf("CSP %q", csp)
+	}
+}
+
+func TestNotBuiltClient(t *testing.T) {
+	up := newUpstream(t)
+	h := newHandler(t, up, false)
+
+	rec := do(h, http.MethodGet, "/", nil)
+	if rec.Code != http.StatusServiceUnavailable || !strings.Contains(rec.Body.String(), "isn’t built") {
+		t.Fatalf("status %d body %q", rec.Code, rec.Body.String())
+	}
+	// The proxy still works without the client.
+	if rec := do(h, http.MethodGet, "/_matrix/client/versions", nil); rec.Code != http.StatusOK {
+		t.Errorf("proxy status %d", rec.Code)
+	}
+}
+
+func TestHealthz(t *testing.T) {
+	up := newUpstream(t)
+	h := newHandler(t, up, true)
+	if rec := do(h, http.MethodGet, "/healthz", nil); rec.Code != 200 || rec.Body.String() != "ok\n" {
+		t.Fatalf("status %d body %q", rec.Code, rec.Body.String())
+	}
+}
+
+func TestNewValidatesHomeserver(t *testing.T) {
+	rel, _ := url.Parse("warp:8008")
+	ftp, _ := url.Parse("ftp://warp.example")
+	ok, _ := url.Parse("http://warp:8008")
+	for name, opts := range map[string]Options{
+		"relative": {Homeserver: rel},
+		"scheme":   {PublicHomeserver: ftp},
+		"neither":  {},
+		"both":     {Homeserver: ok, PublicHomeserver: ok},
+	} {
+		if _, err := New(opts); err == nil {
+			t.Errorf("%s: want an error", name)
+		}
+	}
+}