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.. index::
   single: HTTP
   single: HttpFoundation
   single: Components; HttpFoundation

The HttpFoundation Component

The HttpFoundation component defines an object-oriented layer for the HTTP specification.

In PHP, the request is represented by some global variables ($_GET, $_POST, $_FILES, $_COOKIE, $_SESSION, ...) and the response is generated by some functions (echo, header, setcookie, ...).

The Symfony2 HttpFoundation component replaces these default PHP global variables and functions by an object-oriented layer.

Installation

You can install the component in 2 different ways:

Request

The most common way to create a request is to base it on the current PHP global variables with :method:`Symfony\\Component\\HttpFoundation\\Request::createFromGlobals`:

use Symfony\Component\HttpFoundation\Request;

$request = Request::createFromGlobals();

which is almost equivalent to the more verbose, but also more flexible, :method:`Symfony\\Component\\HttpFoundation\\Request::__construct` call:

$request = new Request(
    $_GET,
    $_POST,
    array(),
    $_COOKIE,
    $_FILES,
    $_SERVER
);

Accessing Request Data

A Request object holds information about the client request. This information can be accessed via several public properties:

  • request: equivalent of $_POST;
  • query: equivalent of $_GET ($request->query->get('name'));
  • cookies: equivalent of $_COOKIE;
  • attributes: no equivalent - used by your app to store other data (see :ref:`below <component-foundation-attributes>`);
  • files: equivalent of $_FILES;
  • server: equivalent of $_SERVER;
  • headers: mostly equivalent to a sub-set of $_SERVER ($request->headers->get('User-Agent')).

Each property is a :class:`Symfony\\Component\\HttpFoundation\\ParameterBag` instance (or a sub-class of), which is a data holder class:

All :class:`Symfony\\Component\\HttpFoundation\\ParameterBag` instances have methods to retrieve and update its data:

The :class:`Symfony\\Component\\HttpFoundation\\ParameterBag` instance also has some methods to filter the input values:

All getters takes up to three arguments: the first one is the parameter name and the second one is the default value to return if the parameter does not exist:

// the query string is '?foo=bar'

$request->query->get('foo');
// returns bar

$request->query->get('bar');
// returns null

$request->query->get('bar', 'bar');
// returns 'bar'

When PHP imports the request query, it handles request parameters like foo[bar]=bar in a special way as it creates an array. So you can get the foo parameter and you will get back an array with a bar element. But sometimes, you might want to get the value for the "original" parameter name: foo[bar]. This is possible with all the ParameterBag getters like :method:`Symfony\\Component\\HttpFoundation\\Request::get` via the third argument:

// the query string is '?foo[bar]=bar'

$request->query->get('foo');
// returns array('bar' => 'bar')

$request->query->get('foo[bar]');
// returns null

$request->query->get('foo[bar]', null, true);
// returns 'bar'

Thanks to the public attributes property, you can store additional data in the request, which is also an instance of :class:`Symfony\\Component\\HttpFoundation\\ParameterBag`. This is mostly used to attach information that belongs to the Request and that needs to be accessed from many different points in your application. For information on how this is used in the Symfony2 framework, see :ref:`the Symfony2 book <book-fundamentals-attributes>`.

Finally, the raw data sent with the request body can be accessed using :method:`Symfony\\Component\\HttpFoundation\\Request::getContent()`:

$content = $request->getContent();

For instance, this may be useful to process a JSON string sent to the application by a remote service using the HTTP POST method.

Identifying a Request

In your application, you need a way to identify a request; most of the time, this is done via the "path info" of the request, which can be accessed via the :method:`Symfony\\Component\\HttpFoundation\\Request::getPathInfo` method:

// for a request to http://example.com/blog/index.php/post/hello-world
// the path info is "/post/hello-world"
$request->getPathInfo();

Simulating a Request

Instead of creating a request based on the PHP globals, you can also simulate a request:

$request = Request::create(
    '/hello-world',
    'GET',
    array('name' => 'Fabien')
);

The :method:`Symfony\\Component\\HttpFoundation\\Request::create` method creates a request based on a URI, a method and some parameters (the query parameters or the request ones depending on the HTTP method); and of course, you can also override all other variables as well (by default, Symfony creates sensible defaults for all the PHP global variables).

Based on such a request, you can override the PHP global variables via :method:`Symfony\\Component\\HttpFoundation\\Request::overrideGlobals`:

$request->overrideGlobals();

Tip

You can also duplicate an existing request via :method:`Symfony\\Component\\HttpFoundation\\Request::duplicate` or change a bunch of parameters with a single call to :method:`Symfony\\Component\\HttpFoundation\\Request::initialize`.

Accessing the Session

If you have a session attached to the request, you can access it via the :method:`Symfony\\Component\\HttpFoundation\\Request::getSession` method; the :method:`Symfony\\Component\\HttpFoundation\\Request::hasPreviousSession` method tells you if the request contains a session which was started in one of the previous requests.

Accessing Accept-* Headers Data

You can easily access basic data extracted from Accept-* headers by using the following methods:

If you need to get full access to parsed data from Accept, Accept-Language, Accept-Charset or Accept-Encoding, you can use :class:`Symfony\\Component\\HttpFoundation\\AcceptHeader` utility class:

use Symfony\Component\HttpFoundation\AcceptHeader;

$accept = AcceptHeader::fromString($request->headers->get('Accept'));
if ($accept->has('text/html')) {
    $item = $accept->get('text/html');
    $charset = $item->getAttribute('charset', 'utf-8');
    $quality = $item->getQuality();
}

// Accept header items are sorted by descending quality
$accepts = AcceptHeader::fromString($request->headers->get('Accept'))
    ->all();

Accessing other Data

The Request class has many other methods that you can use to access the request information. Have a look at :class:`the Request API <Symfony\\Component\\HttpFoundation\\Request>` for more information about them.

Overriding the Request

.. versionadded:: 2.4
    The :method:`Symfony\\Component\\HttpFoundation\\Request::setFactory`
    method was introduced in Symfony 2.4.

The Request class should not be overridden as it is a data object that represents an HTTP message. But when moving from a legacy system, adding methods or changing some default behavior might help. In that case, register a PHP callable that is able to create an instance of your Request class:

use Symfony\Component\HttpFoundation\Request;

Request::setFactory(function (
    array $query = array(),
    array $request = array(),
    array $attributes = array(),
    array $cookies = array(),
    array $files = array(),
    array $server = array(),
    $content = null
) {
    return SpecialRequest::create(
        $query,
        $request,
        $attributes,
        $cookies,
        $files,
        $server,
        $content
    );
});

$request = Request::createFromGlobals();

Response

A :class:`Symfony\\Component\\HttpFoundation\\Response` object holds all the information that needs to be sent back to the client from a given request. The constructor takes up to three arguments: the response content, the status code, and an array of HTTP headers:

use Symfony\Component\HttpFoundation\Response;

$response = new Response(
    'Content',
    Response::HTTP_OK,
    array('content-type' => 'text/html')
);

.. versionadded:: 2.4
    Support for HTTP status code constants was introduced in Symfony 2.4.

These information can also be manipulated after the Response object creation:

$response->setContent('Hello World');

// the headers public attribute is a ResponseHeaderBag
$response->headers->set('Content-Type', 'text/plain');

$response->setStatusCode(Response::HTTP_NOT_FOUND);

When setting the Content-Type of the Response, you can set the charset, but it is better to set it via the :method:`Symfony\\Component\\HttpFoundation\\Response::setCharset` method:

$response->setCharset('ISO-8859-1');

Note that by default, Symfony assumes that your Responses are encoded in UTF-8.

Sending the Response

Before sending the Response, you can ensure that it is compliant with the HTTP specification by calling the :method:`Symfony\\Component\\HttpFoundation\\Response::prepare` method:

$response->prepare($request);

Sending the response to the client is then as simple as calling :method:`Symfony\\Component\\HttpFoundation\\Response::send`:

$response->send();

Setting Cookies

The response cookies can be manipulated through the headers public attribute:

use Symfony\Component\HttpFoundation\Cookie;

$response->headers->setCookie(new Cookie('foo', 'bar'));

The :method:`Symfony\\Component\\HttpFoundation\\ResponseHeaderBag::setCookie` method takes an instance of :class:`Symfony\\Component\\HttpFoundation\\Cookie` as an argument.

You can clear a cookie via the :method:`Symfony\\Component\\HttpFoundation\\ResponseHeaderBag::clearCookie` method.

Managing the HTTP Cache

The :class:`Symfony\\Component\\HttpFoundation\\Response` class has a rich set of methods to manipulate the HTTP headers related to the cache:

The :method:`Symfony\\Component\\HttpFoundation\\Response::setCache` method can be used to set the most commonly used cache information in one method call:

$response->setCache(array(
    'etag'          => 'abcdef',
    'last_modified' => new \DateTime(),
    'max_age'       => 600,
    's_maxage'      => 600,
    'private'       => false,
    'public'        => true,
));

To check if the Response validators (ETag, Last-Modified) match a conditional value specified in the client Request, use the :method:`Symfony\\Component\\HttpFoundation\\Response::isNotModified` method:

if ($response->isNotModified($request)) {
    $response->send();
}

If the Response is not modified, it sets the status code to 304 and removes the actual response content.

Redirecting the User

To redirect the client to another URL, you can use the :class:`Symfony\\Component\\HttpFoundation\\RedirectResponse` class:

use Symfony\Component\HttpFoundation\RedirectResponse;

$response = new RedirectResponse('http://example.com/');

Streaming a Response

The :class:`Symfony\\Component\\HttpFoundation\\StreamedResponse` class allows you to stream the Response back to the client. The response content is represented by a PHP callable instead of a string:

use Symfony\Component\HttpFoundation\StreamedResponse;

$response = new StreamedResponse();
$response->setCallback(function () {
    echo 'Hello World';
    flush();
    sleep(2);
    echo 'Hello World';
    flush();
});
$response->send();

Note

The flush() function does not flush buffering. If ob_start() has been called before or the output_buffering php.ini option is enabled, you must call ob_flush() before flush().

Additionally, PHP isn't the only layer that can buffer output. Your web server might also buffer based on its configuration. Even more, if you use fastcgi, buffering can't be disabled at all.

Serving Files

When sending a file, you must add a Content-Disposition header to your response. While creating this header for basic file downloads is easy, using non-ASCII filenames is more involving. The :method:`Symfony\\Component\\HttpFoundation\\Response::makeDisposition` abstracts the hard work behind a simple API:

use Symfony\Component\HttpFoundation\ResponseHeaderBag;

$d = $response->headers->makeDisposition(
    ResponseHeaderBag::DISPOSITION_ATTACHMENT,
    'foo.pdf'
);

$response->headers->set('Content-Disposition', $d);

Alternatively, if you are serving a static file, you can use a :class:`Symfony\\Component\\HttpFoundation\\BinaryFileResponse`:

use Symfony\Component\HttpFoundation\BinaryFileResponse;

$file = 'path/to/file.txt';
$response = new BinaryFileResponse($file);

The BinaryFileResponse will automatically handle Range and If-Range headers from the request. It also supports X-Sendfile (see for Nginx and Apache). To make use of it, you need to determine whether or not the X-Sendfile-Type header should be trusted and call :method:`Symfony\\Component\\HttpFoundation\\BinaryFileResponse::trustXSendfileTypeHeader` if it should:

BinaryFileResponse::trustXSendfileTypeHeader();

You can still set the Content-Type of the sent file, or change its Content-Disposition:

$response->headers->set('Content-Type', 'text/plain');
$response->setContentDisposition(
    ResponseHeaderBag::DISPOSITION_ATTACHMENT,
    'filename.txt'
);

Creating a JSON Response

Any type of response can be created via the :class:`Symfony\\Component\\HttpFoundation\\Response` class by setting the right content and headers. A JSON response might look like this:

use Symfony\Component\HttpFoundation\Response;

$response = new Response();
$response->setContent(json_encode(array(
    'data' => 123,
)));
$response->headers->set('Content-Type', 'application/json');

There is also a helpful :class:`Symfony\\Component\\HttpFoundation\\JsonResponse` class, which can make this even easier:

use Symfony\Component\HttpFoundation\JsonResponse;

$response = new JsonResponse();
$response->setData(array(
    'data' => 123
));

This encodes your array of data to JSON and sets the Content-Type header to application/json.

Caution!

To avoid XSSI JSON Hijacking, you should pass an associative array as the outer-most array to JsonResponse and not an indexed array so that the final result is an object (e.g. {"object": "not inside an array"}) instead of an array (e.g. [{"object": "inside an array"}]). Read the OWASP guidelines for more information.

Only methods that respond to GET requests are vulnerable to XSSI 'JSON Hijacking'. Methods responding to POST requests only remain unaffected.

JSONP Callback

If you're using JSONP, you can set the callback function that the data should be passed to:

$response->setCallback('handleResponse');

In this case, the Content-Type header will be text/javascript and the response content will look like this:

handleResponse({'data': 123});

Session

The session information is in its own document: :doc:`/components/http_foundation/sessions`.