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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, $_FILE, $_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 many different ways:

Use the official Git repository (https://github.com/symfony/HttpFoundation);
Install it via Composer</components/using_components> (symfony/http-foundation on Packagist).

Request

The most common way to create request is to base it on the current PHP global variables with 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, 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 below<component-foundation-attributes>)
files: equivalent of $_FILE;
server: equivalent of $_SERVER;
headers: mostly equivalent to a sub-set of $_SERVER ($request->headers->get('Content-Type')).

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

request: Symfony\\Component\\HttpFoundation\\ParameterBag;
query: Symfony\\Component\\HttpFoundation\\ParameterBag;
cookies: Symfony\\Component\\HttpFoundation\\ParameterBag;
attributes: Symfony\\Component\\HttpFoundation\\ParameterBag;
files: Symfony\\Component\\HttpFoundation\\FileBag;
server: Symfony\\Component\\HttpFoundation\\ServerBag;
headers: Symfony\\Component\\HttpFoundation\\HeaderBag.

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

Symfony\\Component\\HttpFoundation\\ParameterBag::all: Returns the parameters;
Symfony\\Component\\HttpFoundation\\ParameterBag::keys: Returns the parameter keys;
Symfony\\Component\\HttpFoundation\\ParameterBag::replace: Replaces the current parameters by a new set;
Symfony\\Component\\HttpFoundation\\ParameterBag::add: Adds parameters;
Symfony\\Component\\HttpFoundation\\ParameterBag::get: Returns a parameter by name;
Symfony\\Component\\HttpFoundation\\ParameterBag::set: Sets a parameter by name;
Symfony\\Component\\HttpFoundation\\ParameterBag::has: Returns true if the parameter is defined;
Symfony\\Component\\HttpFoundation\\ParameterBag::remove: Removes a parameter.

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

Symfony\\Component\\HttpFoundation\\ParameterBag::getAlpha: Returns the alphabetic characters of the parameter value;
Symfony\\Component\\HttpFoundation\\ParameterBag::getAlnum: Returns the alphabetic characters and digits of the parameter value;
Symfony\\Component\\HttpFoundation\\ParameterBag::getDigits: Returns the digits of the parameter value;
Symfony\\Component\\HttpFoundation\\ParameterBag::getInt: Returns the parameter value converted to integer;
Symfony\\Component\\HttpFoundation\\ParameterBag::filter: Filters the parameter by using the PHP filter_var() function.

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 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'

Finally, you can also store additional data in the request, thanks to the public attributes property, which is also an instance of 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 read more<book-fundamentals-attributes>.

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 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 Symfony\\Component\\HttpFoundation\\Request::create method creates a request based on a path info, a method and some parameters (the query parameters or the request ones depending on the HTTP method); and of course, you an 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 Symfony\\Component\\HttpFoundation\\Request::overrideGlobals:

$request->overrideGlobals();

Tip

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

Accessing the Session

If you have a session attached to the Request, you can access it via the Symfony\\Component\\HttpFoundation\\Request::getSession method; the 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:

Symfony\\Component\\HttpFoundation\\Request::getAcceptableContentTypes: returns the list of accepted content types ordered by descending quality;
Symfony\\Component\\HttpFoundation\\Request::getLanguages: returns the list of accepted languages ordered by descending quality;
Symfony\\Component\\HttpFoundation\\Request::getCharsets: returns the list of accepted charsets ordered by descending quality;

Accessing other Data

The Request class has many other methods that you can use to access the request information. Have a look at the API for more information about them.

Response

A 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',
    200,
    array('content-type' => 'text/html')
);

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(404);

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

$response->prepare($request);

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

$response->send();

Setting Cookies

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

use Symfony\Component\HttpFoundation\Cookie;

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

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

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

Managing the HTTP Cache

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

Symfony\\Component\\HttpFoundation\\Response::setPublic;
Symfony\\Component\\HttpFoundation\\Response::setPrivate;
Symfony\\Component\\HttpFoundation\\Response::expire;
Symfony\\Component\\HttpFoundation\\Response::setExpires;
Symfony\\Component\\HttpFoundation\\Response::setMaxAge;
Symfony\\Component\\HttpFoundation\\Response::setSharedMaxAge;
Symfony\\Component\\HttpFoundation\\Response::setTtl;
Symfony\\Component\\HttpFoundation\\Response::setClientTtl;
Symfony\\Component\\HttpFoundation\\Response::setLastModified;
Symfony\\Component\\HttpFoundation\\Response::setEtag;
Symfony\\Component\\HttpFoundation\\Response::setVary;

The 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 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 remove the actual response content.

Redirecting the User

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

use Symfony\Component\HttpFoundation\RedirectResponse;

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

Streaming a Response

2.1 Support for streamed responses was added in Symfony 2.1.

The 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 bufferring. So if ob_start() has been called before or php.ini option output_buffering is not disabled (which is on some installations by default), you have to call ob_flush() before flush().

But not only php can buffer output. Your web-server can also do it. Even more, if you use fastcgi, buffering can't be disabled at all.

Downloading Files

2.1 The makeDisposition method was added in Symfony 2.1.

When uploading 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 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);

Creating a JSON Response

Any type of response can be created via the 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');

2.1 The Symfony\\Component\\HttpFoundation\\JsonResponse class was added in Symfony 2.1.

There is also a helpful 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. 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: /components/http_foundation/sessions.

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introduction.rst

introduction.rst

The HttpFoundation Component

Installation

Request

Accessing Request Data

Identifying a Request

Simulating a Request

Accessing the Session

Accessing Accept-* Headers Data

Accessing other Data

Response

Sending the Response

Setting Cookies

Managing the HTTP Cache

Redirecting the User

Streaming a Response

Downloading Files

Creating a JSON Response

Session

Files

introduction.rst

Latest commit

History

introduction.rst

File metadata and controls

The HttpFoundation Component

Installation

Request

Accessing Request Data

Identifying a Request

Simulating a Request

Accessing the Session

Accessing Accept-* Headers Data

Accessing other Data

Response

Sending the Response

Setting Cookies

Managing the HTTP Cache

Redirecting the User

Streaming a Response

Downloading Files

Creating a JSON Response

Session