fix(socket-handler): Fix socket handler race condition by differentiating between async and sync handlers. Now, async socket handlers complete their setup before initial data is emitted, ensuring that no data is lost. Documentation and tests have been updated to reflect this change.

ts/proxies/smart-proxy/route-connection-handler.ts

@@ -399,6 +399,15 @@ export class RouteConnectionHandler {
         this.handleStaticAction(socket, record, route, initialChunk);
         return;
 
+      case 'socket-handler':
+        logger.log('info', `Handling socket-handler action for route ${route.name}`, {
+          connectionId,
+          routeName: route.name,
+          component: 'route-handler'
+        });
+        this.handleSocketHandlerAction(socket, record, route, initialChunk);
+        return;
+
       default:
         logger.log('error', `Unknown action type '${(route.action as any).type}' for connection ${connectionId}`, {
           connectionId,
@@ -776,6 +785,75 @@ export class RouteConnectionHandler {
     }, record, initialChunk);
   }
 
+  /**
+   * Handle a socket-handler action for a route
+   */
+  private async handleSocketHandlerAction(
+    socket: plugins.net.Socket,
+    record: IConnectionRecord,
+    route: IRouteConfig,
+    initialChunk?: Buffer
+  ): Promise<void> {
+    const connectionId = record.id;
+    
+    if (!route.action.socketHandler) {
+      logger.log('error', 'socket-handler action missing socketHandler function', {
+        connectionId,
+        routeName: route.name,
+        component: 'route-handler'
+      });
+      socket.destroy();
+      this.connectionManager.cleanupConnection(record, 'missing_handler');
+      return;
+    }
+    
+    try {
+      // Call the handler
+      const result = route.action.socketHandler(socket);
+      
+      // Handle async handlers properly
+      if (result instanceof Promise) {
+        result
+          .then(() => {
+            // Emit initial chunk after async handler completes
+            if (initialChunk && initialChunk.length > 0) {
+              socket.emit('data', initialChunk);
+            }
+          })
+          .catch(error => {
+            logger.log('error', 'Socket handler error', {
+              connectionId,
+              routeName: route.name,
+              error: error.message,
+              component: 'route-handler'
+            });
+            if (!socket.destroyed) {
+              socket.destroy();
+            }
+            this.connectionManager.cleanupConnection(record, 'handler_error');
+          });
+      } else {
+        // For sync handlers, emit on next tick
+        if (initialChunk && initialChunk.length > 0) {
+          process.nextTick(() => {
+            socket.emit('data', initialChunk);
+          });
+        }
+      }
+    } catch (error) {
+      logger.log('error', 'Socket handler error', {
+        connectionId,
+        routeName: route.name,
+        error: error.message,
+        component: 'route-handler'
+      });
+      if (!socket.destroyed) {
+        socket.destroy();
+      }
+      this.connectionManager.cleanupConnection(record, 'handler_error');
+    }
+  }
+
   /**
    * Setup improved error handling for the outgoing connection
    */