Internals¶

Looks like you want to understand how Symfony2 works and how to extend it. That makes me very happy! This section is an in-depth explanation of the Symfony2 internals.

Note

You need to read this section only if you want to understand how Symfony2 works behind the scene, or if you want to extend Symfony2.

Overview¶

The Symfony2 code is made of several independent layers. Each layer is built on top of the previous one.

Tip

Autoloading is not managed by the framework directly; it’s done independently with the help of the Symfony\Component\ClassLoader\UniversalClassLoader class and the src/autoload.php file. Read the dedicated chapter for more information.

`HttpFoundation` Component¶

The deepest level is the :namespace:`Symfony\\Component\\HttpFoundation` component. HttpFoundation provides the main objects needed to deal with HTTP. It is an Object-Oriented abstraction of some native PHP functions and variables:

The Symfony\Component\HttpFoundation\Request class abstracts the main PHP global variables like $_GET, $_POST, $_COOKIE, $_FILES, and $_SERVER;
The Symfony\Component\HttpFoundation\Response class abstracts some PHP functions like header(), setcookie(), and echo;
The Symfony\Component\HttpFoundation\Session class and Symfony\Component\HttpFoundation\SessionStorage\SessionStorageInterface interface abstract session management session_*() functions.

`HttpKernel` Component¶

On top of HttpFoundation is the :namespace:`Symfony\\Component\\HttpKernel` component. HttpKernel handles the dynamic part of HTTP; it is a thin wrapper on top of the Request and Response classes to standardize the way requests are handled. It also provides extension points and tools that makes it the ideal starting point to create a Web framework without too much overhead.

It also optionally adds configurability and extensibility, thanks to the Dependency Injection component and a powerful plugin system (bundles).

`FrameworkBundle` Bundle¶

The :namespace:`Symfony\\Bundle\\FrameworkBundle` bundle is the bundle that ties the main components and libraries together to make a lightweight and fast MVC framework. It comes with a sensible default configuration and conventions to ease the learning curve.

Kernel¶

The Symfony\Component\HttpKernel\HttpKernel class is the central class of Symfony2 and is responsible for handling client requests. Its main goal is to “convert” a Symfony\Component\HttpFoundation\Request object to a Symfony\Component\HttpFoundation\Response object.

Every Symfony2 Kernel implements Symfony\Component\HttpKernel\HttpKernelInterface:

function handle(Request $request, $type = self::MASTER_REQUEST, $catch = true)

Controllers¶

To convert a Request to a Response, the Kernel relies on a “Controller”. A Controller can be any valid PHP callable.

The Kernel delegates the selection of what Controller should be executed to an implementation of Symfony\Component\HttpKernel\Controller\ControllerResolverInterface:

public function getController(Request $request);

public function getArguments(Request $request, $controller);

The :method:`Symfony\\Component\\HttpKernel\\Controller\\ControllerResolverInterface::getController` method returns the Controller (a PHP callable) associated with the given Request. The default implementation (Symfony\Component\HttpKernel\Controller\ControllerResolver) looks for a _controller request attribute that represents the controller name (a “class::method” string, like Bundle\BlogBundle\PostController:indexAction).

Tip

The default implementation uses the Symfony\Bundle\FrameworkBundle\EventListener\RouterListener to define the _controller Request attribute (see kernel.request Event).

The :method:`Symfony\\Component\\HttpKernel\\Controller\\ControllerResolverInterface::getArguments` method returns an array of arguments to pass to the Controller callable. The default implementation automatically resolves the method arguments, based on the Request attributes.

Handling Requests¶

The handle() method takes a Request and always returns a Response. To convert the Request, handle() relies on the Resolver and an ordered chain of Event notifications (see the next section for more information about each Event):

Before doing anything else, the kernel.request event is notified – if one of the listeners returns a Response, it jumps to step 8 directly;
The Resolver is called to determine the Controller to execute;
Listeners of the kernel.controller event can now manipulate the Controller callable the way they want (change it, wrap it, ...);
The Kernel checks that the Controller is actually a valid PHP callable;
The Resolver is called to determine the arguments to pass to the Controller;
The Kernel calls the Controller;
If the Controller does not return a Response, listeners of the kernel.view event can convert the Controller return value to a Response;
Listeners of the kernel.response event can manipulate the Response (content and headers);
The Response is returned.

If an Exception is thrown during processing, the kernel.exception is notified and listeners are given a chance to convert the Exception to a Response. If that works, the kernel.response event is notified; if not, the Exception is re-thrown.

If you don’t want Exceptions to be caught (for embedded requests for instance), disable the kernel.exception event by passing false as the third argument to the handle() method.

Internal Requests¶

At any time during the handling of a request (the ‘master’ one), a sub-request can be handled. You can pass the request type to the handle() method (its second argument):

HttpKernelInterface::MASTER_REQUEST;
HttpKernelInterface::SUB_REQUEST.

The type is passed to all events and listeners can act accordingly (some processing must only occur on the master request).

Events¶

Each event thrown by the Kernel is a subclass of Symfony\Component\HttpKernel\Event\KernelEvent. This means that each event has access to the same basic information:

getRequestType() - returns the type of the request (HttpKernelInterface::MASTER_REQUEST or HttpKernelInterface::SUB_REQUEST);
getKernel() - returns the Kernel handling the request;
getRequest() - returns the current Request being handled.

`getRequestType()`¶

The getRequestType() method allows listeners to know the type of the request. For instance, if a listener must only be active for master requests, add the following code at the beginning of your listener method:

use Symfony\Component\HttpKernel\HttpKernelInterface;

if (HttpKernelInterface::MASTER_REQUEST !== $event->getRequestType()) {
    // return immediately
    return;
}

Tip

If you are not yet familiar with the Symfony2 Event Dispatcher, read the Events section first.

`kernel.request` Event¶

Event Class: Symfony\Component\HttpKernel\Event\GetResponseEvent

The goal of this event is to either return a Response object immediately or setup variables so that a Controller can be called after the event. Any listener can return a Response object via the setResponse() method on the event. In this case, all other listeners won’t be called.

This event is used by FrameworkBundle to populate the _controller Request attribute, via the Symfony\Bundle\FrameworkBundle\EventListener\RouterListener. RequestListener uses a Symfony\Component\Routing\RouterInterface object to match the Request and determine the Controller name (stored in the _controller Request attribute).

`kernel.controller` Event¶

Event Class: Symfony\Component\HttpKernel\Event\FilterControllerEvent

This event is not used by FrameworkBundle, but can be an entry point used to modify the controller that should be executed:

use Symfony\Component\HttpKernel\Event\FilterControllerEvent;

public function onKernelController(FilterControllerEvent $event)
{
    $controller = $event->getController();
    // ...

    // the controller can be changed to any PHP callable
    $event->setController($controller);
}

`kernel.view` Event¶

Event Class: Symfony\Component\HttpKernel\Event\GetResponseForControllerResultEvent

This event is not used by FrameworkBundle, but it can be used to implement a view sub-system. This event is called only if the Controller does not return a Response object. The purpose of the event is to allow some other return value to be converted into a Response.

The value returned by the Controller is accessible via the getControllerResult method:

use Symfony\Component\HttpKernel\Event\GetResponseForControllerResultEvent;
use Symfony\Component\HttpFoundation\Response;

public function onKernelView(GetResponseForControllerResultEvent $event)
{
    $val = $event->getReturnValue();
    $response = new Response();
    // some how customize the Response from the return value

    $event->setResponse($response);
}

`kernel.response` Event¶

Event Class: Symfony\Component\HttpKernel\Event\FilterResponseEvent

The purpose of this event is to allow other systems to modify or replace the Response object after its creation:

public function onKernelResponse(FilterResponseEvent $event)
{
    $response = $event->getResponse();
    // .. modify the response object
}

The FrameworkBundle registers several listeners:

Symfony\Component\HttpKernel\EventListener\ProfilerListener: collects data for the current request;
Symfony\Bundle\WebProfilerBundle\EventListener\WebDebugToolbarListener: injects the Web Debug Toolbar;
Symfony\Component\HttpKernel\EventListener\ResponseListener: fixes the Response Content-Type based on the request format;
Symfony\Component\HttpKernel\EventListener\EsiListener: adds a Surrogate-Control HTTP header when the Response needs to be parsed for ESI tags.

`kernel.exception` Event¶

Event Class: Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent

FrameworkBundle registers an Symfony\Component\HttpKernel\EventListener\ExceptionListener that forwards the Request to a given Controller (the value of the exception_listener.controller parameter – must be in the class::method notation).

A listener on this event can create and set a Response object, create and set a new Exception object, or do nothing:

use Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent;
use Symfony\Component\HttpFoundation\Response;

public function onKernelException(GetResponseForExceptionEvent $event)
{
    $exception = $event->getException();
    $response = new Response();
    // setup the Response object based on the caught exception
    $event->setResponse($response);

    // you can alternatively set a new Exception
    // $exception = new \Exception('Some special exception');
    // $event->setException($exception);
}

The Event Dispatcher¶

Objected Oriented code has gone a long way to ensuring code extensibility. By creating classes that have well defined responsibilities, your code becomes more flexible and a developer can extend them with subclasses to modify their behaviors. But if he wants to share his changes with other developers who have also made their own subclasses, code inheritance is moot.

Consider the real-world example where you want to provide a plugin system for your project. A plugin should be able to add methods, or do something before or after a method is executed, without interfering with other plugins. This is not an easy problem to solve with single inheritance, and multiple inheritance (were it possible with PHP) has its own drawbacks.

The Symfony2 Event Dispatcher implements the Observer pattern in a simple and effective way to make all these things possible and to make your projects truly extensible.

Take a simple example from the Symfony2 HttpKernel component. Once a Response object has been created, it may be useful to allow other elements in the system to modify it (e.g. add some cache headers) before it’s actually used. To make this possible, the Symfony2 kernel throws an event - kernel.response. Here’s how it works:

A listener (PHP object) tells a central dispatcher object that it wants to listen to the kernel.response event;
At some point, the Symfony2 kernel tells the dispatcher object to dispatch the kernel.response event, passing with it an Event object that has access to the Response object;
The dispatcher notifies (i.e. calls a method on) all listeners of the kernel.response event, allowing each of them to make modifications to the Response object.

Events¶

When an event is dispatched, it’s identified by a unique name (e.g. kernel.response), which any number of listeners might be listening to. An Symfony\Component\EventDispatcher\Event instance is also created and passed to all of the listeners. As you’ll see later, the Event object itself often contains data about the event being dispatched.

Naming Conventions¶

The unique event name can be any string, but optionally follows a few simple naming conventions:

use only lowercase letters, numbers, dots (.), and underscores (_);
prefix names with a namespace followed by a dot (e.g. kernel.);
end names with a verb that indicates what action is being taken (e.g. request).

Here are some examples of good event names:

kernel.response
form.pre_set_data

Event Names and Event Objects¶

When the dispatcher notifies listeners, it passes an actual Event object to those listeners. The base Event class is very simple: it contains a method for stopping event propagation, but not much else.

Often times, data about a specific event needs to be passed along with the Event object so that the listeners have needed information. In the case of the kernel.response event, the Event object that’s created and passed to each listener is actually of type Symfony\Component\HttpKernel\Event\FilterResponseEvent, a subclass of the base Event object. This class contains methods such as getResponse and setResponse, allowing listeners to get or even replace the Response object.

The moral of the story is this: when creating a listener to an event, the Event object that’s passed to the listener may be a special subclass that has additional methods for retrieving information from and responding to the event.

The Dispatcher¶

The dispatcher is the central object of the event dispatcher system. In general, a single dispatcher is created, which maintains a registry of listeners. When an event is dispatched via the dispatcher, it notifies all listeners registered with that event.

use Symfony\Component\EventDispatcher\EventDispatcher;

$dispatcher = new EventDispatcher();

Connecting Listeners¶

To take advantage of an existing event, you need to connect a listener to the dispatcher so that it can be notified when the event is dispatched. A call to the dispatcher addListener() method associates any valid PHP callable to an event:

$listener = new AcmeListener();
$dispatcher->addListener('foo.action', array($listener, 'onFooAction'));

The addListener() method takes up to three arguments:

The event name (string) that this listener wants to listen to;
A PHP callable that will be notified when an event is thrown that it listens to;
An optional priority integer (higher equals more important) that determines when a listener is triggered versus other listeners (defaults to 0). If two listeners have the same priority, they are executed in the order that they were added to the dispatcher.

Note

A PHP callable is a PHP variable that can be used by the call_user_func() function and returns true when passed to the is_callable() function. It can be a \Closure instance, a string representing a function, or an array representing an object method or a class method.

So far, you’ve seen how PHP objects can be registered as listeners. You can also register PHP Closures as event listeners:

use Symfony\Component\EventDispatcher\Event;

$dispatcher->addListener('foo.action', function (Event $event) {
    // will be executed when the foo.action event is dispatched
});

Once a listener is registered with the dispatcher, it waits until the event is notified. In the above example, when the foo.action event is dispatched, the dispatcher calls the AcmeListener::onFooAction method and passes the Event object as the single argument:

use Symfony\Component\EventDispatcher\Event;

class AcmeListener
{
    // ...

    public function onFooAction(Event $event)
    {
        // do something
    }
}

Tip

If you use the Symfony2 MVC framework, listeners can be registered via your configuration. As an added bonus, the listener objects are instantiated only when needed.

In many cases, a special Event subclass that’s specific to the given event is passed to the listener. This gives the listener access to special information about the event. Check the documentation or implementation of each event to determine the exact Symfony\Component\EventDispatcher\Event instance that’s being passed. For example, the kernel.event event passes an instance of Symfony\Component\HttpKernel\Event\FilterResponseEvent:

use Symfony\Component\HttpKernel\Event\FilterResponseEvent

public function onKernelResponse(FilterResponseEvent $event)
{
    $response = $event->getResponse();
    $request = $event->getRequest();

    // ...
}

Creating and Dispatching an Event¶

In addition to registering listeners with existing events, you can create and throw your own events. This is useful when creating third-party libraries and also when you want to keep different components of your own system flexible and decoupled.

The Static `Events` Class¶

Suppose you want to create a new Event - store.order - that is dispatched each time an order is created inside your application. To keep things organized, start by creating a StoreEvents class inside your application that serves to define and document your event:

namespace Acme\StoreBundle;

final class StoreEvents
{
    /**
     * The store.order event is thrown each time an order is created
     * in the system.
     *
     * The event listener receives an Acme\StoreBundle\Event\FilterOrderEvent
     * instance.
     *
     * @var string
     */
    const onStoreOrder = 'store.order';
}

Notice that this class doesn’t actually do anything. The purpose of the StoreEvents class is just to be a location where information about common events can be centralized. Notice also that a special FilterOrderEvent class will be passed to each listener of this event.

Creating an Event object¶

Later, when you dispatch this new event, you’ll create an Event instance and pass it to the dispatcher. The dispatcher then passes this same instance to each of the listeners of the event. If you don’t need to pass any information to your listeners, you can use the default Symfony\Component\EventDispatcher\Event class. Most of the time, however, you will need to pass information about the event to each listener. To accomplish this, you’ll create a new class that extends Symfony\Component\EventDispatcher\Event.

In this example, each listener will need access to some pretend Order object. Create an Event class that makes this possible:

namespace Acme\StoreBundle\Event;

use Symfony\Component\EventDispatcher\Event;
use Acme\StoreBundle\Order;

class FilterOrderEvent extends Event
{
    protected $order;

    public function __construct(Order $order)
    {
        $this->order = $order;
    }

    public function getOrder()
    {
        return $this->order;
    }
}

Each listener now has access to the Order object via the getOrder method.

Dispatch the Event¶

The :method:`Symfony\\Component\\EventDispatcher\\EventDispatcher::dispatch` method notifies all listeners of the given event. It takes two arguments: the name of the event to dispatch and the Event instance to pass to each listener of that event:

use Acme\StoreBundle\StoreEvents;
use Acme\StoreBundle\Order;
use Acme\StoreBundle\Event\FilterOrderEvent;

// the order is somehow created or retrieved
$order = new Order();
// ...

// create the FilterOrderEvent and dispatch it
$event = new FilterOrderEvent($order);
$dispatcher->dispatch(StoreEvents::onStoreOrder, $event);

Notice that the special FilterOrderEvent object is created and passed to the dispatch method. Now, any listener to the store.order event will receive the FilterOrderEvent and have access to the Order object via the getOrder method:

// some listener class that's been registered for onStoreOrder
use Acme\StoreBundle\Event\FilterOrderEvent;

public function onStoreOrder(FilterOrderEvent $event)
{
    $order = $event->getOrder();
    // do something to or with the order
}

Passing along the Event Dispatcher Object¶

If you have a look at the EventDispatcher class, you will notice that the class does not act as a Singleton (there is no getInstance() static method). That is intentional, as you might want to have several concurrent event dispatchers in a single PHP request. But it also means that you need a way to pass the dispatcher to the objects that need to connect or notify events.

The best practice is to inject the event dispatcher object into your objects, aka dependency injection.

You can use constructor injection:

class Foo
{
    protected $dispatcher = null;

    public function __construct(EventDispatcher $dispatcher)
    {
        $this->dispatcher = $dispatcher;
    }
}

Or setter injection:

class Foo
{
    protected $dispatcher = null;

    public function setEventDispatcher(EventDispatcher $dispatcher)
    {
        $this->dispatcher = $dispatcher;
    }
}

Choosing between the two is really a matter of taste. Many tend to prefer the constructor injection as the objects are fully initialized at construction time. But when you have a long list of dependencies, using setter injection can be the way to go, especially for optional dependencies.

Tip

If you use dependency injection like we did in the two examples above, you can then use the Symfony2 Dependency Injection component to elegantly manage the injection of the event_dispatcher service for these objects.

# src/Acme/HelloBundle/Resources/config/services.yml
services:
    foo_service:
        class: Acme/HelloBundle/Foo/FooService
        arguments: [@event_dispatcher]

Using Event Subscribers¶

The most common way to listen to an event is to register an event listener with the dispatcher. This listener can listen to one or more events and is notified each time those events are dispatched.

Another way to listen to events is via an event subscriber. An event subscriber is a PHP class that’s able to tell the dispatcher exactly which events it should subscribe to. It implements the Symfony\Component\EventDispatcher\EventSubscriberInterface interface, which requires a single static method called getSubscribedEvents. Take the following example of a subscriber that subscribes to the kernel.response and store.order events:

namespace Acme\StoreBundle\Event;

use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\HttpKernel\Event\FilterResponseEvent;

class StoreSubscriber implements EventSubscriberInterface
{
    static public function getSubscribedEvents()
    {
        return array(
            'kernel.response' => 'onKernelResponse',
            'store.order'     => 'onStoreOrder',
        );
    }

    public function onKernelResponse(FilterResponseEvent $event)
    {
        // ...
    }

    public function onStoreOrder(FilterOrderEvent $event)
    {
        // ...
    }
}

This is very similar to a listener class, except that the class itself can tell the dispatcher which events it should listen to. To register a subscriber with the dispatcher, use the :method:`Symfony\\Component\\EventDispatcher\\EventDispatcher::addSubscriber` method:

use Acme\StoreBundle\Event\StoreSubscriber;

$subscriber = new StoreSubscriber();
$dispatcher->addSubscriber($subscriber);

The dispatcher will automatically register the subscriber for each event returned by the getSubscribedEvents method. This method returns an array indexed by event names and whose values are either the method name to call or an array composed of the method name to call and a priority.

Tip

If you use the Symfony2 MVC framework, subscribers can be registered via your configuration. As an added bonus, the subscriber objects are instantiated only when needed.

Stopping Event Flow/Propagation¶

In some cases, it may make sense for a listener to prevent any other listeners from being called. In other words, the listener needs to be able to tell the dispatcher to stop all propagation of the event to future listeners (i.e. to not notify any more listeners). This can be accomplished from inside a listener via the :method:`Symfony\\Component\\EventDispatcher\\Event::stopPropagation` method:

use Acme\StoreBundle\Event\FilterOrderEvent;

public function onStoreOrder(FilterOrderEvent $event)
{
    // ...

    $event->stopPropagation();
}

Now, any listeners to store.order that have not yet been called will not be called.

Profiler¶

When enabled, the Symfony2 profiler collects useful information about each request made to your application and store them for later analysis. Use the profiler in the development environment to help you to debug your code and enhance performance; use it in the production environment to explore problems after the fact.

You rarely have to deal with the profiler directly as Symfony2 provides visualizer tools like the Web Debug Toolbar and the Web Profiler. If you use the Symfony2 Standard Edition, the profiler, the web debug toolbar, and the web profiler are all already configured with sensible settings.

Note

The profiler collects information for all requests (simple requests, redirects, exceptions, Ajax requests, ESI requests; and for all HTTP methods and all formats). It means that for a single URL, you can have several associated profiling data (one per external request/response pair).

Visualizing Profiling Data¶

Analyzing Profiling data with the Web Profiler¶

The Web Profiler is a visualization tool for profiling data that you can use in development to debug your code and enhance performance; but it can also be used to explore problems that occur in production. It exposes all information collected by the profiler in a web interface.

Accessing the Profiling information¶

You don’t need to use the default visualizer to access the profiling information. But how can you retrieve profiling information for a specific request after the fact? When the profiler stores data about a Request, it also associates a token with it; this token is available in the X-Debug-Token HTTP header of the Response:

$profile = $container->get('profiler')->loadProfileFromResponse($response);

$profile = $container->get('profiler')->loadProfile($token);

Tip

When the profiler is enabled but not the web debug toolbar, or when you want to get the token for an Ajax request, use a tool like Firebug to get the value of the X-Debug-Token HTTP header.

Use the find() method to access tokens based on some criteria:

// get the latest 10 tokens
$tokens = $container->get('profiler')->find('', '', 10);

// get the latest 10 tokens for all URL containing /admin/
$tokens = $container->get('profiler')->find('', '/admin/', 10);

// get the latest 10 tokens for local requests
$tokens = $container->get('profiler')->find('127.0.0.1', '', 10);

If you want to manipulate profiling data on a different machine than the one where the information were generated, use the export() and import() methods:

// on the production machine
$profile = $container->get('profiler')->loadProfile($token);
$data = $profiler->export($profile);

// on the development machine
$profiler->import($data);

Configuration¶

The default Symfony2 configuration comes with sensible settings for the profiler, the web debug toolbar, and the web profiler. Here is for instance the configuration for the development environment:

YAML

# load the profiler
framework:
    profiler: { only_exceptions: false }

# enable the web profiler
web_profiler:
    toolbar: true
    intercept_redirects: true
    verbose: true

XML

<!-- xmlns:webprofiler="http://symfony.com/schema/dic/webprofiler" -->
<!-- xsi:schemaLocation="http://symfony.com/schema/dic/webprofiler http://symfony.com/schema/dic/webprofiler/webprofiler-1.0.xsd"> -->

<!-- load the profiler -->
<framework:config>
    <framework:profiler only-exceptions="false" />
</framework:config>

<!-- enable the web profiler -->
<webprofiler:config
    toolbar="true"
    intercept-redirects="true"
    verbose="true"
/>

PHP

// load the profiler
$container->loadFromExtension('framework', array(
    'profiler' => array('only-exceptions' => false),
));

// enable the web profiler
$container->loadFromExtension('web_profiler', array(
    'toolbar' => true,
    'intercept-redirects' => true,
    'verbose' => true,
));

When only-exceptions is set to true, the profiler only collects data when an exception is thrown by the application.

When intercept-redirects is set to true, the web profiler intercepts the redirects and gives you the opportunity to look at the collected data before following the redirect.

When verbose is set to true, the Web Debug Toolbar displays a lot of information. Setting verbose to false hides some secondary information to make the toolbar shorter.

If you enable the web profiler, you also need to mount the profiler routes:

YAML

_profiler:
    resource: @WebProfilerBundle/Resources/config/routing/profiler.xml
    prefix:   /_profiler

XML

<import resource="@WebProfilerBundle/Resources/config/routing/profiler.xml" prefix="/_profiler" />

PHP

$collection->addCollection($loader->import("@WebProfilerBundle/Resources/config/routing/profiler.xml"), '/_profiler');

As the profiler adds some overhead, you might want to enable it only under certain circumstances in the production environment. The only-exceptions settings limits profiling to 500 pages, but what if you want to get information when the client IP comes from a specific address, or for a limited portion of the website? You can use a request matcher:

YAML

# enables the profiler only for request coming for the 192.168.0.0 network
framework:
    profiler:
        matcher: { ip: 192.168.0.0/24 }

# enables the profiler only for the /admin URLs
framework:
    profiler:
        matcher: { path: "^/admin/" }

# combine rules
framework:
    profiler:
        matcher: { ip: 192.168.0.0/24, path: "^/admin/" }

# use a custom matcher instance defined in the "custom_matcher" service
framework:
    profiler:
        matcher: { service: custom_matcher }

XML

<!-- enables the profiler only for request coming for the 192.168.0.0 network -->
<framework:config>
    <framework:profiler>
        <framework:matcher ip="192.168.0.0/24" />
    </framework:profiler>
</framework:config>

<!-- enables the profiler only for the /admin URLs -->
<framework:config>
    <framework:profiler>
        <framework:matcher path="^/admin/" />
    </framework:profiler>
</framework:config>

<!-- combine rules -->
<framework:config>
    <framework:profiler>
        <framework:matcher ip="192.168.0.0/24" path="^/admin/" />
    </framework:profiler>
</framework:config>

<!-- use a custom matcher instance defined in the "custom_matcher" service -->
<framework:config>
    <framework:profiler>
        <framework:matcher service="custom_matcher" />
    </framework:profiler>
</framework:config>

PHP

// enables the profiler only for request coming for the 192.168.0.0 network
$container->loadFromExtension('framework', array(
    'profiler' => array(
        'matcher' => array('ip' => '192.168.0.0/24'),
    ),
));

// enables the profiler only for the /admin URLs
$container->loadFromExtension('framework', array(
    'profiler' => array(
        'matcher' => array('path' => '^/admin/'),
    ),
));

// combine rules
$container->loadFromExtension('framework', array(
    'profiler' => array(
        'matcher' => array('ip' => '192.168.0.0/24', 'path' => '^/admin/'),
    ),
));

# use a custom matcher instance defined in the "custom_matcher" service
$container->loadFromExtension('framework', array(
    'profiler' => array(
        'matcher' => array('service' => 'custom_matcher'),
    ),
));

Internals¶

Overview¶

HttpFoundation Component¶

HttpKernel Component¶

FrameworkBundle Bundle¶

Kernel¶

Controllers¶

Handling Requests¶

Internal Requests¶

Events¶

getRequestType()¶

kernel.request Event¶

kernel.controller Event¶

kernel.view Event¶

kernel.response Event¶

kernel.exception Event¶

The Event Dispatcher¶

Events¶

Naming Conventions¶

Event Names and Event Objects¶

The Dispatcher¶

Connecting Listeners¶

Creating and Dispatching an Event¶

The Static Events Class¶

Creating an Event object¶

Dispatch the Event¶

Passing along the Event Dispatcher Object¶

Using Event Subscribers¶

Stopping Event Flow/Propagation¶

Profiler¶

Visualizing Profiling Data¶

Using the Web Debug Toolbar¶

Analyzing Profiling data with the Web Profiler¶

Accessing the Profiling information¶

Configuration¶

Learn more from the Cookbook¶

`HttpFoundation` Component¶

`HttpKernel` Component¶

`FrameworkBundle` Bundle¶

`getRequestType()`¶

`kernel.request` Event¶

`kernel.controller` Event¶

`kernel.view` Event¶

`kernel.response` Event¶

`kernel.exception` Event¶

The Static `Events` Class¶