From 64b8b9689d089c056e1f1665df749aa21b893aad Mon Sep 17 00:00:00 2001
From: Tyler <18113850+dshukertjr@users.noreply.github.com>
Date: Sun, 10 Sep 2023 22:52:01 +0900
Subject: [PATCH] fix(realtime_client): No exception is thrown when connection
 is closed.  (#620)

* fix: realtime throwing error when connection is closed

* fix: adjust test case to align with js client
---
 .../lib/src/realtime_channel.dart             |  2 +-
 .../lib/src/realtime_client.dart              | 28 +++++++++++++++++--
 packages/realtime_client/test/mock_test.dart  |  4 +--
 3 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/packages/realtime_client/lib/src/realtime_channel.dart b/packages/realtime_client/lib/src/realtime_channel.dart
index 0557b7fa..dfe9bb72 100644
--- a/packages/realtime_client/lib/src/realtime_channel.dart
+++ b/packages/realtime_client/lib/src/realtime_channel.dart
@@ -328,7 +328,7 @@ class RealtimeChannel {
   /// Registers a callback that will be executed when the channel encounteres an error.
   void onError(void Function(String?) callback) {
     onEvents(ChannelEvents.error.eventName(), ChannelFilter(),
-        (reason, [ref]) => callback(reason.toString()));
+        (reason, [ref]) => callback(reason?.toString()));
   }
 
   RealtimeChannel on(
diff --git a/packages/realtime_client/lib/src/realtime_client.dart b/packages/realtime_client/lib/src/realtime_client.dart
index c85b8299..5b85a78c 100644
--- a/packages/realtime_client/lib/src/realtime_client.dart
+++ b/packages/realtime_client/lib/src/realtime_client.dart
@@ -26,6 +26,26 @@ typedef RealtimeDecode = void Function(
   void Function(dynamic result) callback,
 );
 
+/// Event details for when the connection closed.
+class RealtimeCloseEvent {
+  /// Web socket protocol status codes for when a connection is closed.
+  ///
+  /// The full list can be found at the following:
+  ///
+  /// https://datatracker.ietf.org/doc/html/rfc6455#section-7.4
+  final int code;
+
+  /// Connection closed reason sent from the server
+  ///
+  /// https://datatracker.ietf.org/doc/html/rfc6455#section-7.1.6
+  final String? reason;
+
+  const RealtimeCloseEvent({
+    required this.code,
+    required this.reason,
+  });
+}
+
 class RealtimeClient {
   String? accessToken;
   List<RealtimeChannel> channels = [];
@@ -387,13 +407,17 @@ class RealtimeClient {
 
   /// communication has been closed
   void _onConnClose() {
-    final event = conn?.closeReason ?? '';
+    final statusCode = conn?.closeCode;
+    RealtimeCloseEvent? event;
+    if (statusCode != null) {
+      event = RealtimeCloseEvent(code: statusCode, reason: conn?.closeReason);
+    }
     log('transport', 'close', event);
 
     /// SocketStates.disconnected: by user with socket.disconnect()
     /// SocketStates.closed: NOT by user, should try to reconnect
     if (connState == SocketStates.closed) {
-      _triggerChanError(event);
+      _triggerChanError();
       reconnectTimer.scheduleTimeout();
     }
     if (heartbeatTimer != null) heartbeatTimer!.cancel();
diff --git a/packages/realtime_client/test/mock_test.dart b/packages/realtime_client/test/mock_test.dart
index ecde69df..64272e70 100644
--- a/packages/realtime_client/test/mock_test.dart
+++ b/packages/realtime_client/test/mock_test.dart
@@ -289,9 +289,9 @@ void main() {
     });
 
     test("correct CHANNEL_ERROR data on heartbeat timeout", () async {
-      final subscribeCallback = expectAsync2((event, [data]) {
+      final subscribeCallback = expectAsync2((event, [error]) {
         if (event == "CHANNEL_ERROR") {
-          expect(data, "heartbeat timeout");
+          expect(error, isNull);
         } else {
           expect(event, "CLOSED");
         }