..versionadded::2.4

The ``request_stack`` service was introduced in version 2.4.

Almost all Symfony2 built-in services behave in the same way: a single

instance is created by the container which it returns whenever you get it or

when it is injected into another service. There is one exception in a standard

Symfony2 application: the ``request`` service.

If you try to inject the ``request`` into a service, you will probably receive

a

:class:`Symfony\\Component\\DependencyInjection\\Exception\\ScopeWideningInjectionException`

exception. That's because the ``request`` can **change** during the life-time

of a container (when a sub-request is created for instance).

As of Symfony 2.4, instead of injecting the ``request`` service, you should

inject the ``request_stack`` service instead and access the Request by calling

the ``getCurrentRequest()`` method. For earlier versions, or if you want to

understand this problem better, refer to the cookbook article

:doc:`/cookbook/service_container/scopes`.

the ``getCurrentRequest()`` method:

namespace Acme\HelloBundle\Newsletter;

use Symfony\Component\HttpFoundation\RequestStack;

class NewsletterManager

{

protected $requestStack;

public function __construct(RequestStack $requestStack)

{

$this->requestStack = $requestStack;

}

public function anyMethod()

{

$request = $this->requestStack->getCurrentRequest();

// ... do something with the request

}

// ...

}

Now, just inject the ``request_stack``, which behaves like any normal service:

..configuration-block::

..code-block::yaml

..code-block::xml

..code-block::php

..tip::