fix: maintain forwards compatibility with REST server streaming (goog…

…leapis#371)

VERSION

@@ -1 +1 @@
-1.11.3
+1.11.4

src/RequestBuilder.php

@@ -65,6 +65,16 @@ public function __construct($baseUri, $restConfigPath)
         $this->restConfig = require($restConfigPath);
     }
 
+    /**
+     * @param string $path
+     * @return bool
+     */
+    public function pathExists($path)
+    {
+        list($interface, $method) = explode('/', $path);
+        return isset($this->restConfig['interfaces'][$interface][$method]);
+    }
+
     /**
      * @param string $path
      * @param Message $message

src/Transport/RestTransport.php

@@ -50,7 +50,9 @@ class RestTransport implements TransportInterface
 {
     use ValidationTrait;
     use ServiceAddressTrait;
-    use HttpUnaryTransportTrait;
+    use HttpUnaryTransportTrait {
+        startServerStreamingCall as protected unsupportedServerStreamingCall;
+    }
 
     private $requestBuilder;
 
@@ -145,6 +147,7 @@ function (\Exception $ex) {
 
     /**
      * {@inheritdoc}
+     * @throws BadMethodCallException for forwards compatibility with older GAPIC clients
      */
     public function startServerStreamingCall(Call $call, array $options)
     {
@@ -153,6 +156,12 @@ public function startServerStreamingCall(Call $call, array $options)
             throw new \InvalidArgumentException('A message is required for ServerStreaming calls.');
         }
 
+        // Maintain forwards compatibility with older GAPIC clients not configured for REST server streaming
+        // @see https://github.com/googleapis/gax-php/issues/370
+        if (!$this->requestBuilder->pathExists($call->getMethod())) {
+            $this->unsupportedServerStreamingCall($call, $options);
+        }
+
         $headers = self::buildCommonHeaders($options);
         $callOptions = $this->getCallOptions($options);
         $request = $this->requestBuilder->build(

tests/Tests/Unit/Transport/RestTransportTest.php

@@ -72,6 +72,8 @@ private function getTransport(callable $httpHandler = null, $apiEndpoint = 'http
             ->getMock();
         $requestBuilder->method('build')
             ->willReturn($request);
+        $requestBuilder->method('pathExists')
+            ->willReturn(true);
 
         return new RestTransport(
             $requestBuilder,
@@ -136,6 +138,23 @@ public function testStartUnaryCallThrowsException()
             ->wait();
     }
 
+    /**
+     * @expectedException \BadMethodCallException
+     */
+    public function testServerStreamingCallThrowsBadMethodCallException()
+    {
+        $request = new Request('POST', 'http://www.example.com');
+        $requestBuilder = $this->getMockBuilder(RequestBuilder::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+        $requestBuilder->method('pathExists')
+            ->willReturn(false);
+
+        $transport = new RestTransport($requestBuilder, HttpHandlerFactory::build());
+
+        $transport->startServerStreamingCall($this->call, []);
+    }
+
     /**
      * @expectedException \Google\ApiCore\ApiException
      */