Dispatching Controllers

Phalcon\Mvc\Dispatcher is the component responsible for instantiating controllers and executing the required actions on them in an MVC application. Understanding its operation and capabilities helps us get more out of the services provided by the framework.

The Dispatch Loop

This is an important process that has much to do with the MVC flow itself, especially with the controller part. The work occurs within the controller dispatcher. The controller files are read, loaded, and instantiated. Then the required actions are executed. If an action forwards the flow to another controller/action, the controller dispatcher starts again. To better illustrate this, the following example shows approximately the process performed within Phalcon\Mvc\Dispatcher:

  1. <?php
  2. // Dispatch loop
  3. while (!$finished) {
  4. $finished = true;
  5. $controllerClass = $controllerName . 'Controller';
  6. // Instantiating the controller class via autoloaders
  7. $controller = new $controllerClass();
  8. // Execute the action
  9. call_user_func_array(
  10. [
  11. $controller,
  12. $actionName . 'Action'
  13. ],
  14. $params
  15. );
  16. // '$finished' should be reloaded to check if the flow was forwarded to another controller
  17. $finished = true;
  18. }

The code above lacks validations, filters and additional checks, but it demonstrates the normal flow of operation in the dispatcher.

Dispatch Loop Events

Phalcon\Mvc\Dispatcher is able to send events to an EventsManager if it is present. Events are triggered using the type dispatch. Some events when returning boolean false could stop the active operation. The following events are supported:

Event NameTriggeredCan stop operation?Triggered on
beforeDispatchLoopTriggered before entering in the dispatch loop. At this point the dispatcher don’t know if the controller or the actions to be executed exist. The Dispatcher only knows the information passed by the Router.YesListeners
beforeDispatchTriggered after entering in the dispatch loop. At this point the dispatcher don’t know if the controller or the actions to be executed exist. The Dispatcher only knows the information passed by the Router.YesListeners
beforeExecuteRouteTriggered before executing the controller/action method. At this point the dispatcher has been initialized the controller and know if the action exist.YesListeners/Controllers
initializeAllow to globally initialize the controller in the requestNoControllers
afterExecuteRouteTriggered after executing the controller/action method. As operation cannot be stopped, only use this event to make clean up after execute the actionNoListeners/Controllers
beforeNotFoundActionTriggered when the action was not found in the controllerYesListeners
beforeExceptionTriggered before the dispatcher throws any exceptionYesListeners
afterDispatchTriggered after executing the controller/action method. As operation cannot be stopped, only use this event to make clean up after execute the actionYesListeners
afterDispatchLoopTriggered after exiting the dispatch loopNoListeners
afterBindingTriggered after models are bound but before executing routeYesListeners/Controllers

The INVO tutorial shows how to take advantage of dispatching events implementing a security filter with Acl

The following example demonstrates how to attach listeners to this component:

  1. <?php
  2. use Phalcon\Mvc\Dispatcher as MvcDispatcher;
  3. use Phalcon\Events\Event;
  4. use Phalcon\Events\Manager as EventsManager;
  5. $di->set(
  6. 'dispatcher',
  7. function () {
  8. // Create an event manager
  9. $eventsManager = new EventsManager();
  10. // Attach a listener for type 'dispatch'
  11. $eventsManager->attach(
  12. 'dispatch',
  13. function (Event $event, $dispatcher) {
  14. // ...
  15. }
  16. );
  17. $dispatcher = new MvcDispatcher();
  18. // Bind the eventsManager to the view component
  19. $dispatcher->setEventsManager($eventsManager);
  20. return $dispatcher;
  21. },
  22. true
  23. );

An instantiated controller automatically acts as a listener for dispatch events, so you can implement methods as callbacks:

  1. <?php
  2. use Phalcon\Mvc\Controller;
  3. use Phalcon\Mvc\Dispatcher;
  4. class PostsController extends Controller
  5. {
  6. public function beforeExecuteRoute(Dispatcher $dispatcher)
  7. {
  8. // Executed before every found action
  9. }
  10. public function afterExecuteRoute(Dispatcher $dispatcher)
  11. {
  12. // Executed after every found action
  13. }
  14. }
Methods on event listeners accept an Phalcon\Events\Event object as their first parameter - methods in controllers do not.

Forwarding to other actions

The dispatch loop allows us to forward the execution flow to another controller/action. This is very useful to check if the user can access to certain options, redirect users to other screens or simply reuse code.

  1. <?php
  2. use Phalcon\Mvc\Controller;
  3. class PostsController extends Controller
  4. {
  5. public function indexAction()
  6. {
  7. }
  8. public function saveAction($year, $postTitle)
  9. {
  10. // ... Store some product and forward the user
  11. // Forward flow to the index action
  12. $this->dispatcher->forward(
  13. [
  14. 'controller' => 'posts',
  15. 'action' => 'index',
  16. ]
  17. );
  18. }
  19. }

Keep in mind that making a forward is not the same as making a HTTP redirect. Although they apparently got the same result. The forward doesn’t reload the current page, all the redirection occurs in a single request, while the HTTP redirect needs two requests to complete the process.

More forwarding examples:

  1. <?php
  2. // Forward flow to another action in the current controller
  3. $this->dispatcher->forward(
  4. [
  5. 'action' => 'search'
  6. ]
  7. );
  8. // Forward flow to another action in the current controller
  9. // passing parameters
  10. $this->dispatcher->forward(
  11. [
  12. 'action' => 'search',
  13. 'params' => [1, 2, 3]
  14. ]
  15. );

A forward action accepts the following parameters:

ParameterDescription
controllerA valid controller name to forward to.
actionA valid action name to forward to.
paramsAn array of parameters for the action.
namespaceA valid namespace name where the controller is part of.

Using the Events Manager

You can use the dispatcher::beforeForward event to change modules and redirect easier and “cleaner”:

  1. <?php
  2. use Phalcon\Di;
  3. use Phalcon\Events\Manager;
  4. use Phalcon\Mvc\Dispatcher;
  5. use Phalcon\Events\Event;
  6. $di = new Di();
  7. $modules = [
  8. 'backend' => [
  9. 'className' => 'App\Backend\Bootstrap',
  10. 'path' => '/app/Modules/Backend/Bootstrap.php',
  11. 'metadata' => [
  12. 'controllersNamespace' => 'App\Backend\Controllers',
  13. ],
  14. ],
  15. ];
  16. $manager = new Manager();
  17. $manager->attach(
  18. 'dispatch:beforeForward',
  19. function (Event $event, Dispatcher $dispatcher, array $forward) use ($modules) {
  20. $metadata = $modules[$forward['module']]['metadata'];
  21. $dispatcher->setModuleName($forward['module']);
  22. $dispatcher->setNamespaceName($metadata['controllersNamespace']);
  23. }
  24. );
  25. $dispatcher = new Dispatcher();
  26. $dispatcher->setDI($di);
  27. $dispatcher->setEventsManager($manager);
  28. $di->set('dispatcher', $dispatcher);
  29. $dispatcher->forward(
  30. [
  31. 'module' => 'backend',
  32. 'controller' => 'posts',
  33. 'action' => 'index',
  34. ]
  35. );
  36. echo $dispatcher->getModuleName(); // will display properly 'backend'

Preparing Parameters

Thanks to the hook points provided by Phalcon\Mvc\Dispatcher you can easily adapt your application to any URL schema; i.e. you might want your URLs look like: http://example.com/controller/key1/value1/key2/value. Since parameters are passed with the order that they are defined in the URL to actions, you can transform them to adopt the desired schema:

  1. <?php
  2. use Phalcon\Dispatcher;
  3. use Phalcon\Mvc\Dispatcher as MvcDispatcher;
  4. use Phalcon\Events\Event;
  5. use Phalcon\Events\Manager as EventsManager;
  6. $di->set(
  7. 'dispatcher',
  8. function () {
  9. // Create an EventsManager
  10. $eventsManager = new EventsManager();
  11. // Attach a listener
  12. $eventsManager->attach(
  13. 'dispatch:beforeDispatchLoop',
  14. function (Event $event, $dispatcher) {
  15. $params = $dispatcher->getParams();
  16. $keyParams = [];
  17. // Use odd parameters as keys and even as values
  18. foreach ($params as $i => $value) {
  19. if ($i & 1) {
  20. // Previous param
  21. $key = $params[$i - 1];
  22. $keyParams[$key] = $value;
  23. }
  24. }
  25. // Override parameters
  26. $dispatcher->setParams($keyParams);
  27. }
  28. );
  29. $dispatcher = new MvcDispatcher();
  30. $dispatcher->setEventsManager($eventsManager);
  31. return $dispatcher;
  32. }
  33. );

If the desired schema is: http://example.com/controller/key1:value1/key2:value, the following code is required:

  1. <?php
  2. use Phalcon\Dispatcher;
  3. use Phalcon\Mvc\Dispatcher as MvcDispatcher;
  4. use Phalcon\Events\Event;
  5. use Phalcon\Events\Manager as EventsManager;
  6. $di->set(
  7. 'dispatcher',
  8. function () {
  9. // Create an EventsManager
  10. $eventsManager = new EventsManager();
  11. // Attach a listener
  12. $eventsManager->attach(
  13. 'dispatch:beforeDispatchLoop',
  14. function (Event $event, $dispatcher) {
  15. $params = $dispatcher->getParams();
  16. $keyParams = [];
  17. // Explode each parameter as key,value pairs
  18. foreach ($params as $number => $value) {
  19. $parts = explode(':', $value);
  20. $keyParams[$parts[0]] = $parts[1];
  21. }
  22. // Override parameters
  23. $dispatcher->setParams($keyParams);
  24. }
  25. );
  26. $dispatcher = new MvcDispatcher();
  27. $dispatcher->setEventsManager($eventsManager);
  28. return $dispatcher;
  29. }
  30. );

Getting Parameters

When a route provides named parameters you can receive them in a controller, a view or any other component that extends Phalcon\Di\Injectable.

  1. <?php
  2. use Phalcon\Mvc\Controller;
  3. class PostsController extends Controller
  4. {
  5. public function indexAction()
  6. {
  7. }
  8. public function saveAction()
  9. {
  10. // Get the post's title passed in the URL as parameter
  11. // or prepared in an event
  12. $title = $this->dispatcher->getParam('title');
  13. // Get the post's year passed in the URL as parameter
  14. // or prepared in an event also filtering it
  15. $year = $this->dispatcher->getParam('year', 'int');
  16. // ...
  17. }
  18. }

Preparing actions

You can also define an arbitrary schema for actions before in the dispatch loop.

Camelize action names

If the original URL is: http://example.com/admin/products/show-latest-products, and for example you want to camelize show-latest-products to ShowLatestProducts, the following code is required:

  1. <?php
  2. use Phalcon\Text;
  3. use Phalcon\Mvc\Dispatcher as MvcDispatcher;
  4. use Phalcon\Events\Event;
  5. use Phalcon\Events\Manager as EventsManager;
  6. $di->set(
  7. 'dispatcher',
  8. function () {
  9. // Create an EventsManager
  10. $eventsManager = new EventsManager();
  11. // Camelize actions
  12. $eventsManager->attach(
  13. 'dispatch:beforeDispatchLoop',
  14. function (Event $event, $dispatcher) {
  15. $dispatcher->setActionName(
  16. Text::camelize($dispatcher->getActionName())
  17. );
  18. }
  19. );
  20. $dispatcher = new MvcDispatcher();
  21. $dispatcher->setEventsManager($eventsManager);
  22. return $dispatcher;
  23. }
  24. );

Remove legacy extensions

If the original URL always contains a .php extension:

  1. http://example.com/admin/products/show-latest-products.php
  2. http://example.com/admin/products/index.php

You can remove it before dispatch the controller/action combination:

  1. <?php
  2. use Phalcon\Mvc\Dispatcher as MvcDispatcher;
  3. use Phalcon\Events\Event;
  4. use Phalcon\Events\Manager as EventsManager;
  5. $di->set(
  6. 'dispatcher',
  7. function () {
  8. // Create an EventsManager
  9. $eventsManager = new EventsManager();
  10. // Remove extension before dispatch
  11. $eventsManager->attach(
  12. 'dispatch:beforeDispatchLoop',
  13. function (Event $event, $dispatcher) {
  14. $action = $dispatcher->getActionName();
  15. // Remove extension
  16. $action = preg_replace('/\.php$/', '', $action);
  17. // Override action
  18. $dispatcher->setActionName($action);
  19. }
  20. );
  21. $dispatcher = new MvcDispatcher();
  22. $dispatcher->setEventsManager($eventsManager);
  23. return $dispatcher;
  24. }
  25. );

Inject model instances

In this example, the developer wants to inspect the parameters that an action will receive in order to dynamically inject model instances.

The controller looks like:

  1. <?php
  2. use Phalcon\Mvc\Controller;
  3. class PostsController extends Controller
  4. {
  5. /**
  6. * Shows posts
  7. *
  8. * @param \Posts $post
  9. */
  10. public function showAction(Posts $post)
  11. {
  12. $this->view->post = $post;
  13. }
  14. }

Method showAction receives an instance of the model \Posts, the developer could inspect this before dispatch the action preparing the parameter accordingly:

  1. <?php
  2. use \Exception;
  3. use Phalcon\Mvc\Model;
  4. use Phalcon\Mvc\Dispatcher as MvcDispatcher;
  5. use Phalcon\Events\Event;
  6. use Phalcon\Events\Manager as EventsManager;
  7. use \ReflectionMethod;
  8. $di->set(
  9. 'dispatcher',
  10. function () {
  11. // Create an EventsManager
  12. $eventsManager = new EventsManager();
  13. $eventsManager->attach(
  14. 'dispatch:beforeDispatchLoop',
  15. function (Event $event, $dispatcher) {
  16. // Possible controller class name
  17. $controllerName = $dispatcher->getControllerClass();
  18. // Possible method name
  19. $actionName = $dispatcher->getActiveMethod();
  20. try {
  21. // Get the reflection for the method to be executed
  22. $reflection = new ReflectionMethod($controllerName, $actionName);
  23. $parameters = $reflection->getParameters();
  24. // Check parameters
  25. foreach ($parameters as $parameter) {
  26. // Get the expected model name
  27. $className = $parameter->getClass()->name;
  28. // Check if the parameter expects a model instance
  29. if (is_subclass_of($className, Model::class)) {
  30. $model = $className::findFirstById($dispatcher->getParams()[0]);
  31. // Override the parameters by the model instance
  32. $dispatcher->setParams([$model]);
  33. }
  34. }
  35. } catch (Exception $e) {
  36. // An exception has occurred, maybe the class or action does not exist?
  37. }
  38. }
  39. );
  40. $dispatcher = new MvcDispatcher();
  41. $dispatcher->setEventsManager($eventsManager);
  42. return $dispatcher;
  43. }
  44. );

The above example has been simplified. A developer can improve it to inject any kind of dependency or model in actions before be executed.

From 3.1.x onwards the dispatcher also comes with an option to handle this internally for all models passed into a controller action by using Phalcon\Mvc\Model\Binder.

  1. use Phalcon\Mvc\Dispatcher;
  2. use Phalcon\Mvc\Model\Binder;
  3. $dispatcher = new Dispatcher();
  4. $dispatcher->setModelBinder(new Binder());
  5. return $dispatcher;
Since the Binder object is using internally Reflection Api which can be heavy, there is ability to set cache. This can be done by using second argument in setModelBinder() which can also accept service name or just by passing cache instance to Binder constructor.

It also introduces a new interface Phalcon\Mvc\Model\Binder\BindableInterface which allows you to define the controllers associated models to allow models binding in base controllers.

For example, you have a base CrudController which your PostsController extends from. Your CrudController looks something like this:

  1. use Phalcon\Mvc\Controller;
  2. use Phalcon\Mvc\Model;
  3. class CrudController extends Controller
  4. {
  5. /**
  6. * Show action
  7. *
  8. * @param Model $model
  9. */
  10. public function showAction(Model $model)
  11. {
  12. $this->view->model = $model;
  13. }
  14. }

In your PostsController you need to define which model the controller is associated with. This is done by implementing the Phalcon\Mvc\Model\Binder\BindableInterface which will add the getModelName() method from which you can return the model name. It can return string with just one model name or associative array where key is parameter name.

  1. use Phalcon\Mvc\Model\Binder\BindableInterface;
  2. use Models\Posts;
  3. class PostsController extends CrudController implements BindableInterface
  4. {
  5. public static function getModelName()
  6. {
  7. return Posts::class;
  8. }
  9. }

By declaring the model associated with the PostsController the binder can check the controller for the getModelName() method before passing the defined model into the parent show action.

If your project structure does not use any parent controller you can of course still bind the model directly into the controller action:

  1. use Phalcon\Mvc\Controller;
  2. use Models\Posts;
  3. class PostsController extends Controller
  4. {
  5. /**
  6. * Shows posts
  7. *
  8. * @param Posts $post
  9. */
  10. public function showAction(Posts $post)
  11. {
  12. $this->view->post = $post;
  13. }
  14. }
Currently the binder will only use the models primary key to perform a findFirst() on. An example route for the above would be /posts/show/{1}

Handling Not-Found Exceptions

Using the EventsManager it’s possible to insert a hook point before the dispatcher throws an exception when the controller/action combination wasn’t found:

  1. <?php
  2. use Exception;
  3. use Phalcon\Dispatcher;
  4. use Phalcon\Mvc\Dispatcher as MvcDispatcher;
  5. use Phalcon\Events\Event;
  6. use Phalcon\Events\Manager as EventsManager;
  7. use Phalcon\Mvc\Dispatcher\Exception as DispatchException;
  8. $di->setShared(
  9. 'dispatcher',
  10. function () {
  11. // Create an EventsManager
  12. $eventsManager = new EventsManager();
  13. // Attach a listener
  14. $eventsManager->attach(
  15. 'dispatch:beforeException',
  16. function (Event $event, $dispatcher, Exception $exception) {
  17. // Handle 404 exceptions
  18. if ($exception instanceof DispatchException) {
  19. $dispatcher->forward(
  20. [
  21. 'controller' => 'index',
  22. 'action' => 'show404',
  23. ]
  24. );
  25. return false;
  26. }
  27. // Alternative way, controller or action doesn't exist
  28. switch ($exception->getCode()) {
  29. case Dispatcher::EXCEPTION_HANDLER_NOT_FOUND:
  30. case Dispatcher::EXCEPTION_ACTION_NOT_FOUND:
  31. $dispatcher->forward(
  32. [
  33. 'controller' => 'index',
  34. 'action' => 'show404',
  35. ]
  36. );
  37. return false;
  38. }
  39. }
  40. );
  41. $dispatcher = new MvcDispatcher();
  42. // Bind the EventsManager to the dispatcher
  43. $dispatcher->setEventsManager($eventsManager);
  44. return $dispatcher;
  45. }
  46. );

Of course, this method can be moved onto independent plugin classes, allowing more than one class take actions when an exception is produced in the dispatch loop:

  1. <?php
  2. use Exception;
  3. use Phalcon\Events\Event;
  4. use Phalcon\Mvc\Dispatcher;
  5. use Phalcon\Mvc\Dispatcher\Exception as DispatchException;
  6. class ExceptionsPlugin
  7. {
  8. public function beforeException(Event $event, Dispatcher $dispatcher, Exception $exception)
  9. {
  10. // Default error action
  11. $action = 'show503';
  12. // Handle 404 exceptions
  13. if ($exception instanceof DispatchException) {
  14. $action = 'show404';
  15. }
  16. $dispatcher->forward(
  17. [
  18. 'controller' => 'index',
  19. 'action' => $action,
  20. ]
  21. );
  22. return false;
  23. }
  24. }
Only exceptions produced by the dispatcher and exceptions produced in the executed action are notified in the beforeException events. Exceptions produced in listeners or controller events are redirected to the latest try/catch.

Implementing your own Dispatcher

The Phalcon\Mvc\DispatcherInterface interface must be implemented to create your own dispatcher replacing the one provided by Phalcon.