added topic length validator to avoid relying solely on the body limit for more user friendly error message

forms/realtime_subscribe.go

@@ -19,6 +19,9 @@ func NewRealtimeSubscribe() *RealtimeSubscribe {
 func (form *RealtimeSubscribe) Validate() error {
 	return validation.ValidateStruct(form,
 		validation.Field(&form.ClientId, validation.Required, validation.Length(1, 255)),
-		validation.Field(&form.Subscriptions, validation.Length(0, 1000)),
+		validation.Field(&form.Subscriptions,
+			validation.Length(0, 1000),
+			validation.Each(validation.Length(0, 2500)),
+		),
 	)
 }

forms/realtime_subscribe_test.go

@@ -43,15 +43,25 @@ func TestRealtimeSubscribeValidate(t *testing.T) {
 			[]string{},
 		},
 		{
-			"subscriptions > max limit",
+			"total subscriptions > max limit",
 			`{"clientId":"test", "subscriptions":[` + strings.Join(invalidSubscriptionsLimit, ",") + `]}`,
 			[]string{"subscriptions"},
 		},
 		{
-			"subscriptions <= max limit",
+			"total subscriptions <= max limit",
 			`{"clientId":"test", "subscriptions":[` + strings.Join(validSubscriptionsLimit, ",") + `]}`,
 			[]string{},
 		},
+		{
+			"single subscription > max limit",
+			`{"clientId":"test", "subscriptions":["abc", "` + strings.Repeat("a", 2501) + `"]}`,
+			[]string{"subscriptions"},
+		},
+		{
+			"single subscription <= max limit",
+			`{"clientId":"test", "subscriptions":["abc", "` + strings.Repeat("a", 2500) + `"]}`,
+			[]string{},
+		},
 	}
 
 	for _, s := range scenarios {