fix: guard against empty frame data in Swoole onMessage handler

src/WebSocket/Adapter/Swoole.php

@@ -109,6 +109,9 @@ public function onOpen(callable $callback): self
     public function onMessage(callable $callback): self
     {
         $this->server->on('message', function (Server $server, Frame $frame) use ($callback) {
+            if ($frame->data === '' || $frame->data === null) {
+                return;
+            }
             call_user_func($callback, $frame->fd, $frame->data);
         });
 

tests/unit/SwooleAdapterTest.php

@@ -0,0 +1,99 @@
+<?php
+
+namespace Utopia\WebSocket\Tests;
+
+use PHPUnit\Framework\TestCase;
+use Swoole\WebSocket\Frame;
+use Swoole\WebSocket\Server;
+use Utopia\WebSocket\Adapter\Swoole;
+
+class SwooleAdapterTest extends TestCase
+{
+    /**
+     * @return array{0: Swoole, 1: \PHPUnit\Framework\MockObject\MockObject}
+     */
+    private function createAdapterWithMockServer(): array
+    {
+        try {
+            $adapter = $this->getMockBuilder(Swoole::class)
+                ->disableOriginalConstructor()
+                ->onlyMethods([])
+                ->getMock();
+
+            $mockServer = $this->getMockBuilder(Server::class)
+                ->disableOriginalConstructor()
+                ->getMock();
+        } catch (\Error $e) {
+            if (strpos($e->getMessage(), 'enum_exists') !== false) {
+                $this->markTestSkipped('Test skipped due to enum_exists compatibility issue');
+            }
+            throw $e;
+        }
+
+        $reflection = new \ReflectionClass(Swoole::class);
+        $serverProperty = $reflection->getProperty('server');
+        $serverProperty->setAccessible(true);
+        $serverProperty->setValue($adapter, $mockServer);
+
+        return [$adapter, $mockServer];
+    }
+
+    public function testOnMessageSkipsEmptyData(): void
+    {
+        [$adapter, $mockServer] = $this->createAdapterWithMockServer();
+
+        $registeredCallback = null;
+        $mockServer->expects($this->once())
+            ->method('on')
+            ->with('message', $this->callback(function ($callback) use (&$registeredCallback) {
+                $registeredCallback = $callback;
+                return true;
+            }));
+
+        $callbackInvoked = false;
+        $adapter->onMessage(function (int $connection, string $message) use (&$callbackInvoked) {
+            $callbackInvoked = true;
+        });
+
+        $this->assertNotNull($registeredCallback, 'Server on() should have been called');
+
+        // Simulate a frame with empty data
+        $frame = new Frame();
+        $frame->fd = 1;
+        $frame->data = '';
+
+        $registeredCallback($mockServer, $frame);
+
+        $this->assertFalse($callbackInvoked, 'Callback should not be invoked for empty message data');
+    }
+
+    public function testOnMessageCallsCallbackWithValidData(): void
+    {
+        [$adapter, $mockServer] = $this->createAdapterWithMockServer();
+
+        $registeredCallback = null;
+        $mockServer->expects($this->once())
+            ->method('on')
+            ->with('message', $this->callback(function ($callback) use (&$registeredCallback) {
+                $registeredCallback = $callback;
+                return true;
+            }));
+
+        $receivedFd = null;
+        $receivedData = null;
+        $adapter->onMessage(function (int $connection, string $message) use (&$receivedFd, &$receivedData) {
+            $receivedFd = $connection;
+            $receivedData = $message;
+        });
+
+        // Simulate a frame with valid data
+        $frame = new Frame();
+        $frame->fd = 42;
+        $frame->data = '{"type":"authentication"}';
+
+        $registeredCallback($mockServer, $frame);
+
+        $this->assertEquals(42, $receivedFd);
+        $this->assertEquals('{"type":"authentication"}', $receivedData);
+    }
+}