Introducing dispatcher filters and adding tests for them

lib/Cake/Error/exceptions.php

@@ -438,6 +438,17 @@ class MissingPluginException extends CakeException {
 
 }
 
+/**
+ * Exception raised when a Dispatcher filter could not be found
+ *
+ * @package       Cake.Error
+ */
+class MissingDispatcherFilterException extends CakeException {
+
+	protected $_messageTemplate = 'Dispatcher filter %s could not be found.';
+
+}
+
 /**
  * Exception class for AclComponent and Interface implementations. 
  *

lib/Cake/Routing/Dispatcher.php

@@ -68,6 +68,7 @@ public function getEventManager() {
 		if (!$this->_eventManager) {
 			$this->_eventManager = new CakeEventManager();
 			$this->_eventManager->attach($this);
+			$this->_attachFilters($this->_eventManager);
 		}
 		return $this->_eventManager;
 	}
@@ -87,6 +88,41 @@ public function implementedEvents() {
 		);
 	}
 
+/**
+ * Attaches all event listeners for this dispatcher instance. Loads the
+ * dispatcher filters from the configured locations.
+ *
+ * @param CakeEventManager $manager
+ * @return void
+ **/
+	protected function _attachFilters($manager) {
+		$filters = Configure::read('Dispatcher.filters');
+		if (empty($filters)) {
+			return;
+		}
+
+		foreach ($filters as $filter) {
+			if (is_string($filter)) {
+				$filter = array('callable' => $filter);
+			}
+			if (is_string($filter['callable'])) {
+				list($plugin, $callable) = pluginSplit($filter['callable'], true);
+				App::uses($callable, $plugin . 'Routing/Filter');
+				if (!class_exists($callable)) {
+					throw new MissingDispatcherFilterException($callable);
+				}
+				$manager->attach(new $callable);
+			} else {
+				$on = strtolower($filter['on']);
+				$options = array();
+				if (isset($filter['priority'])) {
+					$options['priority'] = $filter['priority'];
+				}
+				$manager->attach($filter['callable'], 'Dispatcher.' . $on, $options);
+			}
+		}
+	}
+
 /**
  * Dispatches and invokes given Request, handing over control to the involved controller. If the controller is set
  * to autoRender, via Controller::$autoRender, then Dispatcher will render the view.
@@ -102,7 +138,7 @@ public function implementedEvents() {
  * @param CakeRequest $request Request object to dispatch.
  * @param CakeResponse $response Response object to put the results of the dispatch into.
  * @param array $additionalParams Settings array ("bare", "return") which is melded with the GET and POST params
- * @return boolean Success
+ * @return string|void if `$request['return']` is set then it returns response body, null otherwise
  * @throws MissingControllerException When the controller is missing.
  */
 	public function dispatch(CakeRequest $request, CakeResponse $response, $additionalParams = array()) {
@@ -111,7 +147,10 @@ public function dispatch(CakeRequest $request, CakeResponse $response, $addition
 
 		$request = $beforeEvent->data['request'];
 		if ($beforeEvent->result instanceof CakeResponse) {
-			$beforeEvent->result->send();
+			if (isset($request->params['return'])) {
+				return $response->body();
+			}
+			$response->send();
 			return;
 		}
 

lib/Cake/Routing/DispatcherFilter.php

@@ -0,0 +1,85 @@
+<?php
+/**
+ *
+ * PHP 5
+ *
+ * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
+ * Copyright 2005-2012, Cake Software Foundation, Inc. (http://cakefoundation.org)
+ *
+ * Licensed under The MIT License
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright	  Copyright 2005-2012, Cake Software Foundation, Inc. (http://cakefoundation.org)
+ * @link		  http://cakephp.org CakePHP(tm) Project
+ * @package		  Cake.Routing
+ * @since		  CakePHP(tm) v 2.2
+ * @license		  MIT License (http://www.opensource.org/licenses/mit-license.php)
+ */
+
+App::uses('CakeEventListener', 'Event');
+
+/**
+ * This abstract class represents a filter to be applied to a dispatcher cycle. It acts as as
+ * event listener with the ability to alter the request or response as needed before it is handled
+ * by a controller or after the response body has already been built.
+ *
+ * @package Cake.Event
+ */
+abstract class DispatcherFilter implements CakeEventListener {
+
+/**
+ * Default priority for all methods in this filter
+ *
+ * @var int
+ **/
+	public $priority = 10;
+
+/**
+ * Returns the list of events this filter listens to.
+ * Dispatcher notifies 2 different events `Dispatcher.before` and `Dispatcher.after`.
+ * By default this class will attach `preDispatch` and `postDispatch` method respectively.
+ *
+ * Override this method at will to only listen to the events you are interested in.
+ *
+ * @return array
+ **/
+	public function implementedEvents() {
+		return array(
+			'Dispatcher.before' => array('callable' => 'preDispatch', 'priority' => $this->priority),
+			'Dispatcher.after' => array('callable' => 'postDispatch', 'priority' => $this->priority),
+		);
+	}
+
+/**
+ * Method called before the controller is instantiated and called to ser a request.
+ * If used with default priority, it will be called after the Router has parsed the
+ * url and set the routing params into the request object.
+ *
+ * If a CakeResponse object instance is returned, it will be served at the end of the
+ * event cycle, not calling any controller as a result. This will also have the effect of
+ * not calling the after event in the dispatcher.
+ *
+ * If false is returned, the event will be stopped and no more listeners will be notified.
+ * Alternatively you can call `$event->stopPropagation()` to acheive the same result.
+ *
+ * @param CakeEvent $event container object having the `request`, `response` and `additionalParams`
+ *	keys in the data property.
+ * @return CakeResponse|boolean
+ **/
+	public function preDispatch($event) {
+	}
+
+/**
+ * Method called after the controller served a request and generated a response.
+ * It is posible to alter the response object at this point as it is not sent to the
+ * client yet.
+ *
+ * If false is returned, the event will be stopped and no more listeners will be notified.
+ * Alternatively you can call `$event->stopPropagation()` to acheive the same result.
+ *
+ * @param CakeEvent $event container object having the `request` and  `response`
+ *	keys in the data property.
+ * @return mixed boolean to stop the event dispatching or null to continue
+ **/
+	public function postDispatch($event) {}
+}

lib/Cake/Test/Case/Routing/DispatcherTest.php

@@ -63,6 +63,27 @@ protected function _invoke(Controller $controller, CakeRequest $request, CakeRes
 		return parent::_invoke($controller, $request, $response);
 	}
 
+/**
+ * Helper function to test single method attaching for dispatcher filters
+ *
+ * @param CakeEvent
+ * @return void
+ **/
+	public function filterTest($event) {
+		$event->data['request']->params['eventName'] = $event->name();
+	}
+
+/**
+ * Helper function to test single method attaching for dispatcher filters
+ *
+ * @param CakeEvent
+ * @return void
+ **/
+	public function filterTest2($event) {
+		$event->stopPropagation();
+		return $event->data['response'];
+	}
+
 }
 
 /**
@@ -563,6 +584,7 @@ public function tearDown() {
 		Configure::write('App', $this->_app);
 		Configure::write('Cache', $this->_cache);
 		Configure::write('debug', $this->_debug);
+		Configure::write('Dispatcher.filters', array());
 	}
 
 /**
@@ -761,6 +783,7 @@ public function testMissingControllerAbstract() {
 		$Dispatcher->dispatch($url, $response, array('return' => 1));
 	}
 
+
 /**
  * testDispatch method
  *
@@ -1167,6 +1190,129 @@ public function testTestPluginDispatch() {
 		App::build();
 	}
 
+/**
+ * Tests that it is possible to attach filter classes to the dispatch cycle
+ *
+ * @return void
+ **/
+	public function testDispatcherFilterSuscriber() {
+		App::build(array(
+			'View' => array(CAKE . 'Test' . DS . 'test_app' . DS . 'View' . DS),
+			'Plugin' => array(CAKE . 'Test' . DS . 'test_app' . DS . 'Plugin' . DS)
+		), App::RESET);
+
+		CakePlugin::load('TestPlugin');
+		Configure::write('Dispatcher.filters', array(
+			array('callable' => 'TestPlugin.TestDispatcherFilter')
+		));
+		$dispatcher = new TestDispatcher();
+		$request = new CakeRequest('/');
+		$request->params['altered'] = false;
+		$response = $this->getMock('CakeResponse', array('send'));
+
+		$dispatcher->dispatch($request, $response);
+		$this->assertTrue($request->params['altered']);
+		$this->assertEquals(304, $response->statusCode());
+
+		Configure::write('Dispatcher.filters', array(
+			'TestPlugin.Test2DispatcherFilter',
+			'TestPlugin.TestDispatcherFilter'
+		));
+		$dispatcher = new TestDispatcher();
+		$request = new CakeRequest('/');
+		$request->params['altered'] = false;
+		$response = $this->getMock('CakeResponse', array('send'));
+
+		$dispatcher->dispatch($request, $response);
+		$this->assertFalse($request->params['altered']);
+		$this->assertEquals(500, $response->statusCode());
+		$this->assertNull($dispatcher->controller);
+	}
+
+/**
+ * Tests that attaching an inexistent class as filter will throw an exception
+ *
+ * @expectedException MissingDispatcherFilterException
+ * @return void
+ **/
+	public function testDispatcherFilterSuscriberMissing() {
+		App::build(array(
+			'Plugin' => array(CAKE . 'Test' . DS . 'test_app' . DS . 'Plugin' . DS)
+		), App::RESET);
+
+		CakePlugin::load('TestPlugin');
+		Configure::write('Dispatcher.filters', array(
+			array('callable' => 'TestPlugin.NotAFilter')
+		));
+		$dispatcher = new TestDispatcher();
+		$request = new CakeRequest('/');
+		$response = $this->getMock('CakeResponse', array('send'));
+		$dispatcher->dispatch($request, $response);
+	}
+
+
+/**
+ * Tests it is possible to attach single callables as filters
+ *
+ * @return void
+ **/
+	public function testDispatcherFilterCallable() {
+		App::build(array(
+			'View' => array(CAKE . 'Test' . DS . 'test_app' . DS . 'View' . DS)
+		), App::RESET);
+
+		$dispatcher = new TestDispatcher();
+		Configure::write('Dispatcher.filters', array(
+			array('callable' => array($dispatcher, 'filterTest'), 'on' => 'before')
+		));
+
+		$request = new CakeRequest('/');
+		$response = $this->getMock('CakeResponse', array('send'));
+		$dispatcher->dispatch($request, $response);
+		$this->assertEquals('Dispatcher.before', $request->params['eventName']);
+
+		$dispatcher = new TestDispatcher();
+		Configure::write('Dispatcher.filters', array(
+			array('callable' => array($dispatcher, 'filterTest'), 'on' => 'after')
+		));
+
+		$request = new CakeRequest('/');
+		$response = $this->getMock('CakeResponse', array('send'));
+		$dispatcher->dispatch($request, $response);
+		$this->assertEquals('Dispatcher.after', $request->params['eventName']);
+
+		// Test that it is possible to skip the route connection process
+		$dispatcher = new TestDispatcher();
+		Configure::write('Dispatcher.filters', array(
+			array('callable' => array($dispatcher, 'filterTest2'), 'on' => 'before', 'priority' => 1)
+		));
+
+		$request = new CakeRequest('/');
+		$response = $this->getMock('CakeResponse', array('send'));
+		$dispatcher->dispatch($request, $response);
+		$this->assertEmpty($dispatcher->controller);
+		$this->assertEquals(array('controller' => null, 'action' => null, 'plugin' => null), $request->params);
+
+		$dispatcher = new TestDispatcher();
+		Configure::write('Dispatcher.filters', array(
+			array('callable' => array($dispatcher, 'filterTest2'), 'on' => 'before', 'priority' => 1)
+		));
+
+		$request = new CakeRequest('/');
+		$request->params['return'] = true;
+		$response = $this->getMock('CakeResponse', array('send'));
+		$response->body('this is a body');
+		$result = $dispatcher->dispatch($request, $response);
+		$this->assertEquals('this is a body', $result);
+
+		$request = new CakeRequest('/');
+		$response = $this->getMock('CakeResponse', array('send'));
+		$response->expects($this->once())->method('send');
+		$response->body('this is a body');
+		$result = $dispatcher->dispatch($request, $response);
+		$this->assertNull($result);
+	}
+
 /**
  * testChangingParamsFromBeforeFilter method
  *

lib/Cake/Test/test_app/Plugin/TestPlugin/Lib/Routing/Filter/Test2DispatcherFilter.php

@@ -0,0 +1,33 @@
+<?php
+/**
+ *
+ * PHP 5
+ *
+ * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
+ * Copyright 2005-2012, Cake Software Foundation, Inc. (http://cakefoundation.org)
+ *
+ * Licensed under The MIT License
+ * Redistributions of files must retain the above copyright notice.
+ *
+ * @copyright	  Copyright 2005-2012, Cake Software Foundation, Inc. (http://cakefoundation.org)
+ * @link		  http://cakephp.org CakePHP(tm) Project
+ * @package		  Cake.Test.test_app.Routing.Filter
+ * @since		  CakePHP(tm) v 2.2
+ * @license		  MIT License (http://www.opensource.org/licenses/mit-license.php)
+ */
+
+App::uses('DispatcherFilter', 'Routing');
+
+class Test2DispatcherFilter extends DispatcherFilter {
+
+	public function preDispatch($event) {
+		$event->data['response']->statusCode(500);
+		$event->stopPropagation();
+		return $event->data['response'];
+	}
+
+	public function postDispatch($event) {
+		$event->data['response']->statusCode(200);
+	}
+
+}