haeaeae/plezy
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

chore(relay): generate reconnect token size and version predicate from the protocol spec

Browse Source 
The 32-byte reconnect token and its 43-character base64url shape were
pinned by hand in both server/main.go and the Dart peer service, and the
supported-version check was spelled out three times in Go. The spec now
carries reconnectTokenBytes and the generator emits the token size,
encoded length, and validator for Dart plus the size and
supportedRelayProtocolVersion for Go, failing before writing either
target when the key is missing. The last handwritten error code in lib/
('not_in_room') uses the generated constant, and releaseSession's
in-flight join is a FutureCoalescer.
This commit is contained in:
edde746
2026-09-03 11:36:29 +02:00
parent 59f44d9ae1
commit ab477c971d
9 changed files with 124 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/watch_together/providers/watch_together_provider.dart
+1 -1
View File
@@ -691,7 +691,7 @@ class WatchTogetherProvider with ChangeNotifier {
_errorSubscription = peerService.onError.listen((error) {
if (_disposed || !identical(_peerService, peerService)) return;
final hostPeerId = _session?.hostPeerId;
if (error.serverCode == 'not_in_room' &&
if (error.serverCode == RelayProtocol.notInRoomCode &&
!isHost &&
hostPeerId != null &&
!peerService.connectedPeers.contains(hostPeerId)) {
lib/watch_together/services/relay_protocol.g.dart
+6
View File
@@ -39,11 +39,17 @@ abstract final class RelayProtocol {
static const int maxSessionIdLength = 64;
static const int maxPeerIdLength = 128;
static const int reconnectTokenBytes = 32;
static const int reconnectTokenLength = 43;
static final RegExp _idPattern = RegExp(r'^[A-Za-z0-9_-]+$');
static final RegExp _reconnectTokenPattern = RegExp(r'^[A-Za-z0-9_-]{43}$');
static bool isValidSessionId(String value) =>
value.isNotEmpty && value.length <= maxSessionIdLength && _idPattern.hasMatch(value);
static bool isValidPeerId(String value) =>
value.isNotEmpty && value.length <= maxPeerIdLength && _idPattern.hasMatch(value);
static bool isValidReconnectToken(String value) => _reconnectTokenPattern.hasMatch(value);
}
lib/watch_together/services/watch_together_peer_service.dart
+5 -14
View File
@@ -8,6 +8,7 @@ import 'package:web_socket_channel/web_socket_channel.dart';
import '../../i18n/strings.g.dart';
import '../../services/base_peer_service.dart';
import '../../services/trackers/future_coalescer.dart';
import '../../utils/app_logger.dart';
import '../models/sync_message.dart';
import 'relay_protocol.g.dart';
@@ -92,7 +93,7 @@ class WatchTogetherPeerService with KeepaliveMixin {
bool _disposed = false;
bool _initialSetupInProgress = false;
bool _teardownInProgress = false;
Future<void>? _releaseFuture;
final FutureCoalescer<void> _release = FutureCoalescer();
/// Called after a successful reconnection so the provider can re-announce join.
void Function()? onReconnected;
@@ -159,7 +160,7 @@ class WatchTogetherPeerService with KeepaliveMixin {
/// retried without relying on server-returned state.
static String _mintReconnectToken() {
final random = Random.secure();
final bytes = List<int>.generate(32, (_) => random.nextInt(256), growable: false);
final bytes = List<int>.generate(RelayProtocol.reconnectTokenBytes, (_) => random.nextInt(256), growable: false);
return base64Url.encode(bytes).replaceAll('=', '');
}
@@ -259,8 +260,6 @@ class WatchTogetherPeerService with KeepaliveMixin {
);
}
static final RegExp _reconnectTokenPattern = RegExp(r'^[A-Za-z0-9_-]{43}$');
PeerError _invalidSetupResponse(String type) {
appLogger.w('WatchTogether: Relay returned an invalid $type response');
return PeerError(type: PeerErrorType.serverError, message: t.watchTogether.errors.invalidRelayResponse);
@@ -278,7 +277,7 @@ class WatchTogetherPeerService with KeepaliveMixin {
(_isHost && hostPeerId != _myPeerId) ||
reconnectToken is! String ||
reconnectToken != _reconnectToken ||
!_reconnectTokenPattern.hasMatch(reconnectToken) ||
!RelayProtocol.isValidReconnectToken(reconnectToken) ||
protocolVersion != _relayProtocolVersion) {
throw _invalidSetupResponse(type);
}
@@ -809,15 +808,7 @@ class WatchTogetherPeerService with KeepaliveMixin {
/// guests release their reserved reconnect identity. If transport was lost,
/// authenticate a fresh connection first so an intentional exit is not
/// mistaken for a transient disconnect.
Future<void> releaseSession() {
final active = _releaseFuture;
if (active != null) return active;
final operation = _releaseSession();
_releaseFuture = operation;
return operation.whenComplete(() {
if (identical(_releaseFuture, operation)) _releaseFuture = null;
});
}
Future<void> releaseSession() => _release.run(_releaseSession);
Future<void> _releaseSession() async {
if (_sessionId == null || _myPeerId == null || _reconnectToken == null) return;
relay_protocol.json
+2 -1
View File
@@ -42,5 +42,6 @@
"maxSessionIdLength": 64,
"maxPeerIdLength": 128
},
"idPattern": "^[A-Za-z0-9_-]+$"
"idPattern": "^[A-Za-z0-9_-]+$",
"reconnectTokenBytes": 32
}
scripts/codegen/generate_relay_protocol.py
+29
View File
@@ -32,8 +32,25 @@ def validated_id_pattern(spec: dict) -> str:
return pattern
def validated_reconnect_token_bytes(spec: dict) -> int:
try:
size = spec["reconnectTokenBytes"]
except KeyError:
raise ValueError("reconnectTokenBytes is required") from None
if isinstance(size, bool) or not isinstance(size, int) or size <= 0:
raise ValueError("reconnectTokenBytes must be a positive integer")
return size
def reconnect_token_length(token_bytes: int) -> int:
"""Length of the unpadded base64url encoding of ``token_bytes`` bytes."""
return (token_bytes * 4 + 2) // 3
def dart_source(spec: dict) -> str:
id_pattern = validated_id_pattern(spec)
token_bytes = validated_reconnect_token_bytes(spec)
token_length = reconnect_token_length(token_bytes)
lines = [
"// Generated by scripts/codegen/generate_relay_protocol.py. Do not edit.",
"",
@@ -56,14 +73,20 @@ def dart_source(spec: dict) -> str:
lines.append(f" static const int {name} = {value};")
lines.extend(
[
"",
f" static const int reconnectTokenBytes = {token_bytes};",
f" static const int reconnectTokenLength = {token_length};",
"",
f" static final RegExp _idPattern = RegExp(r{id_pattern!r});",
f" static final RegExp _reconnectTokenPattern = RegExp(r'^[A-Za-z0-9_-]{{{token_length}}}$');",
"",
" static bool isValidSessionId(String value) =>",
" value.isNotEmpty && value.length <= maxSessionIdLength && _idPattern.hasMatch(value);",
"",
" static bool isValidPeerId(String value) =>",
" value.isNotEmpty && value.length <= maxPeerIdLength && _idPattern.hasMatch(value);",
"",
" static bool isValidReconnectToken(String value) => _reconnectTokenPattern.hasMatch(value);",
"}",
"",
]
@@ -73,6 +96,7 @@ def dart_source(spec: dict) -> str:
def go_source(spec: dict) -> str:
validated_id_pattern(spec)
token_bytes = validated_reconnect_token_bytes(spec)
lines = [
"// Code generated by scripts/codegen/generate_relay_protocol.py. DO NOT EDIT.",
"",
@@ -112,6 +136,7 @@ def go_source(spec: dict) -> str:
limit_constants = [
(go_limit_names[name], str(value)) for name, value in spec["limits"].items()
]
limit_constants.append(("reconnectTokenSize", str(token_bytes)))
limit_name_width = max(len(name) for name, _ in limit_constants)
lines.extend(
f"\t{name:<{limit_name_width}} = {value}"
@@ -121,6 +146,10 @@ def go_source(spec: dict) -> str:
[
")",
"",
"func supportedRelayProtocolVersion(version int) bool {",
"\treturn version == legacyRelayProtocolVersion || version == relayProtocolVersion",
"}",
"",
"func validRelayID(value string, maxLength int) bool {",
"\tif len(value) == 0 || len(value) > maxLength {",
"\t\treturn false",
scripts/codegen/test_generate_relay_protocol.py
+59
View File
@@ -86,6 +86,65 @@ class RelayProtocolGeneratorTest(unittest.TestCase):
with self.assertRaisesRegex(ValueError, "idPattern must be a string"):
generator.validated_id_pattern(spec)
def test_reconnect_token_length_is_unpadded_base64url_length(self) -> None:
for token_bytes, expected in ((1, 2), (2, 3), (3, 4), (32, 43), (33, 44)):
with self.subTest(token_bytes=token_bytes):
self.assertEqual(generator.reconnect_token_length(token_bytes), expected)
def test_reconnect_token_bytes_render_derived_symbols(self) -> None:
spec = copy.deepcopy(self.spec)
spec["reconnectTokenBytes"] = 24
dart_output = generator.dart_source(spec)
go_output = generator.go_source(spec)
self.assertIn("static const int reconnectTokenBytes = 24;", dart_output)
self.assertIn("static const int reconnectTokenLength = 32;", dart_output)
self.assertIn("RegExp(r'^[A-Za-z0-9_-]{32}$')", dart_output)
self.assertIn("static bool isValidReconnectToken(String value)", dart_output)
self.assertIn("reconnectTokenSize = 24", go_output)
self.assertIn("func supportedRelayProtocolVersion(version int) bool", go_output)
def test_missing_reconnect_token_bytes_fails_before_writing_either_target(self) -> None:
spec = copy.deepcopy(self.spec)
del spec["reconnectTokenBytes"]
for renderer in (generator.dart_source, generator.go_source):
with self.subTest(renderer=renderer.__name__):
with self.assertRaisesRegex(ValueError, "reconnectTokenBytes is required"):
renderer(spec)
with tempfile.TemporaryDirectory() as temporary_directory:
root = Path(temporary_directory)
spec_path = root / "relay_protocol.json"
dart_path = root / "relay_protocol.g.dart"
go_path = root / "relay_protocol_gen.go"
spec_path.write_text(json.dumps(spec), encoding="utf-8")
dart_path.write_text("dart sentinel\n", encoding="utf-8")
go_path.write_text("go sentinel\n", encoding="utf-8")
with (
mock.patch.object(generator, "SPEC_PATH", spec_path),
mock.patch.object(generator, "DART_PATH", dart_path),
mock.patch.object(generator, "GO_PATH", go_path),
):
with self.assertRaisesRegex(ValueError, "reconnectTokenBytes"):
generator.main()
self.assertEqual(dart_path.read_text(encoding="utf-8"), "dart sentinel\n")
self.assertEqual(go_path.read_text(encoding="utf-8"), "go sentinel\n")
def test_invalid_reconnect_token_bytes_is_rejected(self) -> None:
for value in (None, "32", 32.0, True, 0, -1):
with self.subTest(value=value):
spec = copy.deepcopy(self.spec)
spec["reconnectTokenBytes"] = value
with self.assertRaisesRegex(
ValueError, "reconnectTokenBytes must be a positive integer"
):
generator.validated_reconnect_token_bytes(spec)
if __name__ == "__main__":
unittest.main()
server/main.go
+3 -4
View File
@@ -75,7 +75,6 @@ const (
maxRetainedRooms = 2000
connRateBurst = 5
connRateSustained = 1
reconnectTokenSize = 32
snapshotFormatVersion = 4
snapshotDebounce = 100 * time.Millisecond
snapshotFlushTimeout = 5 * time.Second
@@ -1251,7 +1250,7 @@ func (s *Server) loadSnapshot(path string) (bool, error) {
skipped++
continue
}
if r.ProtocolVersion != legacyRelayProtocolVersion && r.ProtocolVersion != relayProtocolVersion {
if !supportedRelayProtocolVersion(r.ProtocolVersion) {
skipped++
continue
}
@@ -1784,7 +1783,7 @@ func (s *Server) handleWS(w http.ResponseWriter, r *http.Request) {
client.sendJSON(serverMsg{Type: relayTypeError, Code: relayErrorInvalidMessage, Message: "Invalid sessionId or peerId"})
continue
}
if msg.ProtocolVersion != legacyRelayProtocolVersion && msg.ProtocolVersion != relayProtocolVersion {
if !supportedRelayProtocolVersion(msg.ProtocolVersion) {
client.sendJSON(serverMsg{
Type: relayTypeError,
Code: relayErrorProtocolMismatch,
@@ -1930,7 +1929,7 @@ func (s *Server) handleWS(w http.ResponseWriter, r *http.Request) {
client.sendJSON(serverMsg{Type: relayTypeError, Code: relayErrorInvalidMessage, Message: "Invalid sessionId or peerId"})
continue
}
if msg.ProtocolVersion != legacyRelayProtocolVersion && msg.ProtocolVersion != relayProtocolVersion {
if !supportedRelayProtocolVersion(msg.ProtocolVersion) {
client.sendJSON(serverMsg{
Type: relayTypeError,
Code: relayErrorProtocolMismatch,
server/main_test.go
+14
View File
@@ -33,6 +33,7 @@ func TestGeneratedRelayProtocolVersionsMatchSpec(t *testing.T) {
var spec struct {
ProtocolVersion int `json:"protocolVersion"`
LegacyProtocolVersion int `json:"legacyProtocolVersion"`
ReconnectTokenBytes int `json:"reconnectTokenBytes"`
}
if err := json.Unmarshal(data, &spec); err != nil {
t.Fatalf("decode relay protocol spec: %v", err)
@@ -47,6 +48,19 @@ func TestGeneratedRelayProtocolVersionsMatchSpec(t *testing.T) {
spec.LegacyProtocolVersion,
)
}
if reconnectTokenSize != spec.ReconnectTokenBytes {
t.Fatalf("generated reconnectTokenSize=%d, spec=%d", reconnectTokenSize, spec.ReconnectTokenBytes)
}
for _, version := range []int{legacyRelayProtocolVersion, relayProtocolVersion} {
if !supportedRelayProtocolVersion(version) {
t.Fatalf("supportedRelayProtocolVersion(%d)=false", version)
}
}
for _, version := range []int{relayProtocolVersion + 1, -1} {
if supportedRelayProtocolVersion(version) {
t.Fatalf("supportedRelayProtocolVersion(%d)=true", version)
}
}
}
// newTestServer builds a goroutine-free, network-free test server.
server/relay_protocol_gen.go
+5
View File
@@ -40,8 +40,13 @@ const (
maxMessageSize = 65536
maxSessionIDLength = 64
maxPeerIDLength = 128
reconnectTokenSize = 32
)
func supportedRelayProtocolVersion(version int) bool {
return version == legacyRelayProtocolVersion || version == relayProtocolVersion
}
func validRelayID(value string, maxLength int) bool {
if len(value) == 0 || len(value) > maxLength {
return false