feature #895 Replace Monolog middlewares by an event listener (GromNaN)

This PR was merged into the 1.2.x-dev branch.

Discussion
----------

Replace Monolog middlewares by an event listener

This is an alternative to the changes introduced by #894 in order to allow replacement of the logging middlewares.
Instead of having a Closure for each listener, this PR introduces a listener class.
The listener can be used independently from the MonologServiceProvider.

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #870
| License       | MIT
| Doc          | yes

Commits
-------

499a626f Replace Monolog middlewares by an event listener

doc/providers/monolog.rst

@@ -35,6 +35,8 @@ Services
 
     $app['monolog']->addDebug('Testing the Monolog logging.');
 
+* **monolog.listener**: An event listener to log requests, responses and errors.
+
 Registering
 -----------
 
@@ -85,11 +87,9 @@ it by extending the ``monolog`` service::
         return $monolog;
     }));
 
-By default, all requests are logged through a ``before`` and ``after``
-middleware at boot time. You can disable or customize this behavior by
-overriding the ``monolog.boot.before`` and ``monolog.boot.after`` services
-respectively. The provider also registers a default ``error`` handler which
-logs errors; it can be customized via the ``monolog.boot.error`` service.
+By default, all requests, responses and errors are logged by an event listener
+registered as a service called `monolog.listener`. You can replace or remove
+this service if you want to modify or disable the informations logged.
 
 Traits
 ------

src/Silex/EventListener/LogListener.php

+<?php
+
+/*
+ * This file is part of the Silex framework.
+ *
+ * (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 Silex\EventListener;
+
+use Psr\Log\LoggerInterface;
+use Symfony\Component\EventDispatcher\EventSubscriberInterface;
+use Symfony\Component\HttpKernel\HttpKernelInterface;
+use Symfony\Component\HttpKernel\Event\GetResponseEvent;
+use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
+use Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent;
+use Symfony\Component\HttpKernel\KernelEvents;
+use Symfony\Component\HttpKernel\Exception\HttpExceptionInterface;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpFoundation\RedirectResponse;
+
+/**
+ * Log request, response and exceptions
+ */
+class LogListener implements EventSubscriberInterface
+{
+    protected $logger;
+
+    public function __construct(LoggerInterface $logger)
+    {
+        $this->logger = $logger;
+    }
+
+    /**
+     * Logs master requests on event KernelEvents::REQUEST
+     *
+     * @param GetResponseEvent $event
+     */
+    public function onKernelRequest(GetResponseEvent $event)
+    {
+        if (HttpKernelInterface::MASTER_REQUEST !== $event->getRequestType()) {
+            return;
+        }
+
+        $this->logRequest($event->getRequest());
+    }
+
+    /**
+     * Logs master response on event KernelEvents::RESPONSE
+     *
+     * @param FilterResponseEvent $event
+     */
+    public function onKernelResponse(FilterResponseEvent $event)
+    {
+        if (HttpKernelInterface::MASTER_REQUEST !== $event->getRequestType()) {
+            return;
+        }
+
+        $this->logResponse($event->getResponse());
+    }
+
+    /**
+     * Logs uncaught exceptions on event KernelEvents::EXCEPTION
+     *
+     * @param GetResponseForExceptionEvent $event
+     */
+    public function onKernelException(GetResponseForExceptionEvent $event)
+    {
+        $this->logException($event->getException());
+    }
+
+    /**
+     * Logs a request
+     *
+     * @param Request $request
+     */
+    protected function logRequest(Request $request)
+    {
+        $this->logger->info('> '.$request->getMethod().' '.$request->getRequestUri());
+    }
+
+    /**
+     * Logs a response
+     *
+     * @param Response $response
+     */
+    protected function logResponse(Response $response)
+    {
+        if ($response instanceof RedirectResponse) {
+            $this->logger->info('< '.$response->getStatusCode().' '.$response->getTargetUrl());
+        } else {
+            $this->logger->info('< '.$response->getStatusCode());
+        }
+    }
+
+    /**
+     * Logs an exception
+     *
+     * @param Exception $e
+     */
+    protected function logException(\Exception $e)
+    {
+        $message = sprintf('%s: %s (uncaught exception) at %s line %s', get_class($e), $e->getMessage(), $e->getFile(), $e->getLine());
+
+        if ($e instanceof HttpExceptionInterface && $e->getStatusCode() < 500) {
+            $this->logger->error($message, array('exception' => $e));
+        } else {
+            $this->logger->critical($message, array('exception' => $e));
+        }
+    }
+
+    public static function getSubscribedEvents()
+    {
+        return array(
+            KernelEvents::REQUEST => array('onKernelRequest', 0),
+            KernelEvents::RESPONSE => array('onKernelResponse', 0),
+            /*
+             * Priority -4 is used to come after those from SecurityServiceProvider (0)
+             * but before the error handlers added with Silex\Application::error (defaults to -8)
+             */
+            KernelEvents::EXCEPTION => array('onKernelException', -4),
+        );
+    }
+}

src/Silex/Provider/MonologServiceProvider.php

@@ -15,11 +15,8 @@ use Monolog\Logger;
 use Monolog\Handler\StreamHandler;
 use Silex\Application;
 use Silex\ServiceProviderInterface;
-use Symfony\Component\HttpFoundation\RedirectResponse;
-use Symfony\Component\HttpFoundation\Request;
-use Symfony\Component\HttpFoundation\Response;
 use Symfony\Bridge\Monolog\Handler\DebugHandler;
-use Symfony\Component\HttpKernel\Exception\HttpExceptionInterface;
+use Silex\EventListener\LogListener;
 
 /**
  * Monolog Provider.
@@ -66,47 +63,18 @@ class MonologServiceProvider implements ServiceProviderInterface
             return Logger::DEBUG;
         };
 
-        $app['monolog.boot.before'] = $app->protect(
-            function (Request $request) use ($app) {
-                $app['monolog']->addInfo('> '.$request->getMethod().' '.$request->getRequestUri());
-            }
-        );
-
-        $app['monolog.boot.error'] = $app->protect(
-            function (\Exception $e) use ($app) {
-                $message = sprintf('%s: %s (uncaught exception) at %s line %s', get_class($e), $e->getMessage(), $e->getFile(), $e->getLine());
-                if ($e instanceof HttpExceptionInterface && $e->getStatusCode() < 500) {
-                    $app['monolog']->addError($message, array('exception' => $e));
-                } else {
-                    $app['monolog']->addCritical($message, array('exception' => $e));
-                }
-            }
-        );
-
-        $app['monolog.boot.after'] = $app->protect(
-            function (Request $request, Response $response) use ($app) {
-                if ($response instanceof RedirectResponse) {
-                    $app['monolog']->addInfo('< '.$response->getStatusCode().' '.$response->getTargetUrl());
-                } else {
-                    $app['monolog']->addInfo('< '.$response->getStatusCode());
-                }
-            }
-        );
+        $app['monolog.listener'] = $app->share(function () use ($app) {
+            return new LogListener($app['logger']);
+        });
 
         $app['monolog.name'] = 'myapp';
     }
 
     public function boot(Application $app)
     {
-        $app->before($app['monolog.boot.before']);
-
-        /*
-         * Priority -4 is used to come after those from SecurityServiceProvider (0)
-         * but before the error handlers added with Silex\Application::error (defaults to -8)
-         */
-        $app->error($app['monolog.boot.error'], -4);
-
-        $app->after($app['monolog.boot.after']);
+        if (isset($app['monolog.listener'])) {
+            $app['dispatcher']->addSubscriber($app['monolog.listener']);
+        }
     }
 
     public static function translateLevel($name)

tests/Silex/Tests/EventListener/LogListenerTest.php

+<?php
+
+/*
+ * This file is part of the Silex framework.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
+namespace Silex\Tests\EventListener;
+
+use Silex\EventListener\LogListener;
+use Symfony\Component\HttpKernel\Event\GetResponseEvent;
+use Symfony\Component\HttpKernel\Event\FilterResponseEvent;
+use Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent;
+use Symfony\Component\HttpKernel\KernelEvents;
+use Symfony\Component\EventDispatcher\EventDispatcher;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpKernel\HttpKernelInterface;
+use Symfony\Component\HttpKernel\Exception\HttpException;
+
+/**
+ * LogListener
+ *
+ * @author Jérôme Tamarelle <jerome@tamarelle.net>
+ */
+class LogListenerTest extends \PHPUnit_Framework_TestCase
+{
+    public function testRequestListener()
+    {
+        $logger = $this->getMock('Psr\\Log\\LoggerInterface');
+        $logger
+            ->expects($this->once())
+            ->method('info')
+            ->with($this->equalTo('> GET /foo'))
+        ;
+
+        $dispatcher = new EventDispatcher();
+        $dispatcher->addSubscriber(new LogListener($logger));
+
+        $kernel = $this->getMock('Symfony\\Component\\HttpKernel\\HttpKernelInterface');
+
+        $dispatcher->dispatch(KernelEvents::REQUEST, new GetResponseEvent($kernel, Request::create('/subrequest'), HttpKernelInterface::SUB_REQUEST), 'Skip sub requests');
+
+        $dispatcher->dispatch(KernelEvents::REQUEST, new GetResponseEvent($kernel, Request::create('/foo'), HttpKernelInterface::MASTER_REQUEST), 'Log master requests');
+    }
+
+    public function testResponseListener()
+    {
+        $logger = $this->getMock('Psr\\Log\\LoggerInterface');
+        $logger
+            ->expects($this->once())
+            ->method('info')
+            ->with($this->equalTo('< 301'))
+        ;
+
+        $dispatcher = new EventDispatcher();
+        $dispatcher->addSubscriber(new LogListener($logger));
+
+        $kernel = $this->getMock('Symfony\\Component\\HttpKernel\\HttpKernelInterface');
+
+        $dispatcher->dispatch(KernelEvents::RESPONSE, new FilterResponseEvent($kernel, Request::create('/foo'), HttpKernelInterface::SUB_REQUEST, Response::create('subrequest', 200)), 'Skip sub requests');
+
+        $dispatcher->dispatch(KernelEvents::RESPONSE, new FilterResponseEvent($kernel, Request::create('/foo'), HttpKernelInterface::MASTER_REQUEST, Response::create('bar', 301)), 'Log master requests');
+    }
+
+    public function testExceptionListener()
+    {
+        $logger = $this->getMock('Psr\\Log\\LoggerInterface');
+        $logger
+            ->expects($this->once())
+            ->method('critical')
+            ->with($this->equalTo('RuntimeException: Fatal error (uncaught exception) at '.__FILE__.' line '.(__LINE__+14)))
+        ;
+
+        $logger
+            ->expects($this->once())
+            ->method('error')
+            ->with($this->equalTo('Symfony\Component\HttpKernel\Exception\HttpException: Http error (uncaught exception) at '.__FILE__.' line '.(__LINE__+10)))
+        ;
+
+        $dispatcher = new EventDispatcher();
+        $dispatcher->addSubscriber(new LogListener($logger));
+
+        $kernel = $this->getMock('Symfony\\Component\\HttpKernel\\HttpKernelInterface');
+
+        $dispatcher->dispatch(KernelEvents::EXCEPTION, new GetResponseForExceptionEvent($kernel, Request::create('/foo'), HttpKernelInterface::SUB_REQUEST, new \RuntimeException('Fatal error')));
+
+        $dispatcher->dispatch(KernelEvents::EXCEPTION, new GetResponseForExceptionEvent($kernel, Request::create('/foo'), HttpKernelInterface::SUB_REQUEST, new HttpException(400, 'Http error')));
+    }
+}

tests/Silex/Tests/Provider/MonologServiceProviderTest.php

@@ -156,6 +156,16 @@ class MonologServiceProviderTest extends \PHPUnit_Framework_TestCase
         $app['monolog.handler']->getLevel();
     }
 
+    public function testDisableListener()
+    {
+        $app = $this->getApplication();
+        unset($app['monolog.listener']);
+
+        $app->handle(Request::create('/404'));
+
+        $this->assertEmpty($app['monolog.handler']->getRecords(), "Expected no logging to occur");
+    }
+
     protected function assertMatchingRecord($pattern, $level, $handler)
     {
         $found = false;
@@ -177,6 +187,7 @@ class MonologServiceProviderTest extends \PHPUnit_Framework_TestCase
 
         $app['monolog.handler'] = $app->share(function () use ($app) {
             $level = MonologServiceProvider::translateLevel($app['monolog.level']);
+
             return new TestHandler($level);
         });