[Fix] WebSocket close bug (#238)

Author: stevensJourney

.changeset/pretty-zebras-brush.md

@@ -0,0 +1,5 @@
+---
+'@powersync/common': patch
+---
+
+Fix issue where WebSockets might not close under some error conditions.

packages/common/src/client/sync/stream/AbstractRemote.ts

@@ -253,9 +253,18 @@ export abstract class AbstractRemote {
       socketIsClosed = true;
       rsocket.close();
     };
+    // Helps to prevent double close scenarios
+    rsocket.onClose(() => (socketIsClosed = true));
     // We initially request this amount and expect these to arrive eventually
     let pendingEventsCount = SYNC_QUEUE_REQUEST_N;
 
+    const disposeClosedListener = stream.registerListener({
+      closed: () => {
+        closeSocket();
+        disposeClosedListener();
+      }
+    });
+
     const socket = await new Promise<Requestable>((resolve, reject) => {
       let connectionEstablished = false;
 
@@ -275,9 +284,8 @@ export abstract class AbstractRemote {
             if (e.message !== 'Closed. ') {
               this.logger.error(e);
             }
-            // RSocket will close this automatically
-            // Attempting to close multiple times causes a console warning
-            socketIsClosed = true;
+            // RSocket will close the RSocket stream automatically
+            // Close the downstream stream as well - this will close the RSocket connection and WebSocket
             stream.close();
             // Handles cases where the connection failed e.g. auth error or connection error
             if (!connectionEstablished) {
@@ -318,8 +326,7 @@ export abstract class AbstractRemote {
         }
       },
       closed: () => {
-        closeSocket();
-        l?.();
+        l();
       }
     });