symfony · fabpot · Dec 31, 2011 · Oct 17, 2011 · Dec 21, 2011 · Dec 21, 2011
diff --git a/CHANGELOG-2.1.md b/CHANGELOG-2.1.md
@@ -141,6 +141,7 @@ To get the diff between two versions, go to https://github.com/symfony/symfony/c
 
 ### HttpFoundation
 
+ * added support for streamed responses
  * made Response::prepare() method the place to enforce HTTP specification
  * [BC BREAK] moved management of the locale from the Session class to the Request class
  * added a generic access to the PHP built-in filter mechanism: ParameterBag::filter()

diff --git a/src/Symfony/Bundle/FrameworkBundle/Controller/Controller.php b/src/Symfony/Bundle/FrameworkBundle/Controller/Controller.php
@@ -13,6 +13,7 @@
 
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpFoundation\RedirectResponse;
+use Symfony\Component\HttpFoundation\StreamedResponse;
 use Symfony\Component\DependencyInjection\ContainerAware;
 use Symfony\Component\HttpKernel\Exception\NotFoundHttpException;
 use Symfony\Component\Form\FormTypeInterface;
@@ -98,6 +99,32 @@ public function render($view, array $parameters = array(), Response $response =
         return $this->container->get('templating')->renderResponse($view, $parameters, $response);
     }
 
+    /**
+     * Streams a view.
+     *
+     * @param string           $view The view name
+     * @param array            $parameters An array of parameters to pass to the view
+     * @param StreamedResponse $response A response instance
+     *
+     * @return StreamedResponse A StreamedResponse instance
+     */
+    public function stream($view, array $parameters = array(), StreamedResponse $response = null)
+    {
+        $templating = $this->container->get('templating');
+
+        $callback = function () use ($templating, $view, $parameters) {
+            $templating->stream($view, $parameters);
+        };
+
+        if (null === $response) {
+            return new StreamedResponse($callback);
+        }
+
+        $response->setCallback($callback);
+
+        return $response;
+    }
+
     /**
      * Returns a NotFoundHttpException.
      *

diff --git a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/FrameworkExtension.php
@@ -389,6 +389,7 @@ function($v, Reference $ref) use ($container) {
         $this->addClassesToCompile(array(
             'Symfony\\Bundle\\FrameworkBundle\\Templating\\GlobalVariables',
             'Symfony\\Bundle\\FrameworkBundle\\Templating\\EngineInterface',
+            'Symfony\\Bundle\\FrameworkBundle\\Templating\\StreamingEngineInterface',
             'Symfony\\Component\\Templating\\TemplateNameParserInterface',
             'Symfony\\Component\\Templating\\TemplateNameParser',
             'Symfony\\Component\\Templating\\EngineInterface',

diff --git a/src/Symfony/Bundle/FrameworkBundle/HttpKernel.php b/src/Symfony/Bundle/FrameworkBundle/HttpKernel.php
@@ -12,6 +12,7 @@
 namespace Symfony\Bundle\FrameworkBundle;
 
 use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\StreamedResponse;
 use Symfony\Component\HttpKernel\HttpKernelInterface;
 use Symfony\Component\HttpKernel\Controller\ControllerResolverInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
@@ -146,7 +147,11 @@ public function render($controller, array $options = array())
                 throw new \RuntimeException(sprintf('Error when rendering "%s" (Status code is %s).', $request->getUri(), $response->getStatusCode()));
             }
 
-            return $response->getContent();
+            if (!$response instanceof StreamedResponse) {
+                return $response->getContent();
+            }
+
+            $response->sendContent();
         } catch (\Exception $e) {
             if ($options['alt']) {
                 $alt = $options['alt'];

diff --git a/src/Symfony/Bundle/FrameworkBundle/Resources/config/web.xml b/src/Symfony/Bundle/FrameworkBundle/Resources/config/web.xml
@@ -8,6 +8,7 @@
         <parameter key="controller_resolver.class">Symfony\Bundle\FrameworkBundle\Controller\ControllerResolver</parameter>
         <parameter key="controller_name_converter.class">Symfony\Bundle\FrameworkBundle\Controller\ControllerNameParser</parameter>
         <parameter key="response_listener.class">Symfony\Component\HttpKernel\EventListener\ResponseListener</parameter>
+        <parameter key="streamed_response_listener.class">Symfony\Component\HttpKernel\EventListener\StreamedResponseListener</parameter>
         <parameter key="locale_listener.class">Symfony\Component\HttpKernel\EventListener\LocaleListener</parameter>
     </parameters>
 
@@ -29,6 +30,10 @@
             <argument>%kernel.charset%</argument>
         </service>
 
+        <service id="streamed_response_listener" class="%streamed_response_listener.class%">
+            <tag name="kernel.event_subscriber" />
+        </service>
+
         <service id="locale_listener" class="%locale_listener.class%">
             <tag name="kernel.event_subscriber" />
             <argument>%kernel.default_locale%</argument>

diff --git a/src/Symfony/Bundle/TwigBundle/TwigEngine.php b/src/Symfony/Bundle/TwigBundle/TwigEngine.php
@@ -17,13 +17,14 @@
 use Symfony\Component\Templating\TemplateNameParserInterface;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\Config\FileLocatorInterface;
+use Symfony\Component\Templating\StreamingEngineInterface;
 
 /**
  * This engine knows how to render Twig templates.
  *
  * @author Fabien Potencier <fabien@symfony.com>
  */
-class TwigEngine implements EngineInterface
+class TwigEngine implements EngineInterface, StreamingEngineInterface
 {
     protected $environment;
     protected $parser;
@@ -75,6 +76,19 @@ public function render($name, array $parameters = array())
         }
     }
 
+    /**
+     * Streams a template.
+     *
+     * @param mixed $name       A template name or a TemplateReferenceInterface instance
+     * @param array $parameters An array of parameters to pass to the template
+     *
+     * @throws \RuntimeException if the template cannot be rendered
+     */
+    public function stream($name, array $parameters = array())
+    {
+        $this->load($name)->display($parameters);
+    }
+
     /**
      * Returns true if the template exists.
      *

diff --git a/src/Symfony/Component/HttpFoundation/StreamedResponse.php b/src/Symfony/Component/HttpFoundation/StreamedResponse.php
@@ -0,0 +1,122 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpFoundation;
+
+/**
+ * StreamedResponse represents a streamed HTTP response.
+ *
+ * A StreamedResponse uses a callback for its content.
+ *
+ * The callback should use the standard PHP functions like echo
+ * to stream the response back to the client. The flush() method
+ * can also be used if needed.
+ *
+ * @see flush()
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @api
+ */
+class StreamedResponse extends Response
+{
+    protected $callback;
+    protected $streamed;
+
+    /**
+     * Constructor.
+     *
+     * @param mixed   $callback A valid PHP callback
+     * @param integer $status   The response status code
+     * @param array   $headers  An array of response headers
+     *
+     * @api
+     */
+    public function __construct($callback = null, $status = 200, $headers = array())
+    {
+        parent::__construct(null, $status, $headers);
+
+        if (null !== $callback) {
+            $this->setCallback($callback);
+        }
+        $this->streamed = false;
+    }
+
+    /**
+     * Sets the PHP callback associated with this Response.
+     *
+     * @param mixed $callback A valid PHP callback
+     */
+    public function setCallback($callback)
+    {
+        $this->callback = $callback;
+        if (!is_callable($this->callback)) {
+            throw new \LogicException('The Response callback must be a valid PHP callable.');
+        }
+    }
+
+    /**
+     * @{inheritdoc}
+     */
+    public function prepare(Request $request)
+    {
+        if ('1.0' != $request->server->get('SERVER_PROTOCOL')) {
+            $this->setProtocolVersion('1.1');
+            $this->headers->set('Transfer-Encoding', 'chunked');
+        }
+
+        $this->headers->set('Cache-Control', 'no-cache');
+
+        parent::prepare($request);
+    }
+
+    /**
+     * @{inheritdoc}
+     *
+     * This method only sends the content once.
+     */
+    public function sendContent()
+    {
+        if ($this->streamed) {
+            return;
+        }
+
+        $this->streamed = true;
+
+        if (null === $this->callback) {
+            throw new \LogicException('The Response callback must not be null.');
+        }
+
+        call_user_func($this->callback);
+    }
+
+    /**
+     * @{inheritdoc}
+     *
+     * @throws \LogicException when the content is not null
+     */
+    public function setContent($content)
+    {
+        if (null !== $content) {
+            throw new \LogicException('The content cannot be set on a StreamedResponse instance.');
+        }
+    }
+
+    /**
+     * @{inheritdoc}
+     *
+     * @return false
+     */
+    public function getContent()
+    {
+        return false;
+    }
+}
diff --git a/src/Symfony/Component/HttpKernel/EventListener/StreamedResponseListener.php b/src/Symfony/Component/HttpKernel/EventListener/StreamedResponseListener.php
@@ -0,0 +1,52 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\HttpKernel\EventListener;
+
+use Symfony\Component\HttpFoundation\StreamedResponse;
+use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
+use Symfony\Component\HttpKernel\HttpKernelInterface;
+use Symfony\Component\HttpKernel\KernelEvents;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+
+/**
+ * StreamedResponseListener is responsible for sending the Response
+ * to the client.
+ *
+ * @author Fabien Potencier <fabien@symfony.com>
+ */
+class StreamedResponseListener implements EventSubscriberInterface
+{
+    /**
+     * Filters the Response.
+     *
+     * @param FilterResponseEvent $event A FilterResponseEvent instance
+     */
+    public function onKernelResponse(FilterResponseEvent $event)
+    {
+        if (HttpKernelInterface::MASTER_REQUEST !== $event->getRequestType()) {
+            return;
+        }
+
+        $response = $event->getResponse();
+
+        if ($response instanceof StreamedResponse) {
+            $response->send();
+        }
+    }
+
+    static public function getSubscribedEvents()
+    {
+        return array(
+            KernelEvents::RESPONSE => array('onKernelResponse', -1024),
+        );
+    }
+}
diff --git a/src/Symfony/Component/Templating/DelegatingEngine.php b/src/Symfony/Component/Templating/DelegatingEngine.php
@@ -18,7 +18,7 @@
  *
  * @api
  */
-class DelegatingEngine implements EngineInterface
+class DelegatingEngine implements EngineInterface, StreamingEngineInterface
 {
     protected $engines;
 
@@ -55,6 +55,26 @@ public function render($name, array $parameters = array())
         return $this->getEngine($name)->render($name, $parameters);
     }
 
+    /**
+     * Streams a template.
+     *
+     * @param mixed $name       A template name or a TemplateReferenceInterface instance
+     * @param array $parameters An array of parameters to pass to the template
+     *
+     * @throws \RuntimeException if the template cannot be rendered
+     *
+     * @api
+     */
+    public function stream($name, array $parameters = array())
+    {
+        $engine = $this->getEngine($name);
+        if (!$engine instanceof StreamingEngineInterface) {
+            throw new \LogicException(sprintf('Template "%s" cannot be streamed as the engine supporting it does not implement StreamingEngineInterface.', $name));
+        }
+
+        $engine->stream($name, $parameters);
+    }
+
     /**
      * Returns true if the template exists.
      *

diff --git a/src/Symfony/Component/Templating/PhpEngine.php b/src/Symfony/Component/Templating/PhpEngine.php
@@ -28,7 +28,7 @@
  *
  * @api
  */
-class PhpEngine implements EngineInterface, \ArrayAccess
+class PhpEngine implements EngineInterface, StreamingEngineInterface, \ArrayAccess
 {
     protected $loader;
     protected $current;
@@ -107,6 +107,21 @@ public function render($name, array $parameters = array())
         return $content;
     }
 
+    /**
+     * Streams a template.
+     *
+     * @param mixed $name       A template name or a TemplateReferenceInterface instance
+     * @param array $parameters An array of parameters to pass to the template
+     *
+     * @throws \RuntimeException if the template cannot be rendered
+     *
+     * @api
+     */
+    public function stream($name, array $parameters = array())
+    {
+        throw new \LogicException('The PHP engine does not support streaming.');
+    }
+
     /**
      * Returns true if the template exists.
      *