The HttpFoundation Component

The HttpFoundation Component

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

Installation

$ composer require symfony/http-foundation

Note

If you install this component outside of a Symfony application, you must require the vendor/autoload.php file in your code to enable the class autoloading mechanism provided by Composer. Read this article for more details.

Request

The most common way to create a request is to base it on the current PHP global variables with createFromGlobals():

use Symfony\Component\HttpFoundation\Request;
$request = Request::createFromGlobals();

which is almost equivalent to the more verbose, but also more flexible, __construct() call:

$request = new Request(
    $_GET,
    $_POST,
    [],
    $_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);
files: equivalent of $_FILES;
server: equivalent of $_SERVER;
headers: mostly equivalent to a subset of $_SERVER (`$request->headers->get(‘User-Agent’)).

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 or Symfony\Component\HttpFoundation\InputBag if the data is coming from $_POST parameters;
query: Symfony\Component\HttpFoundation\InputBag;
cookies: Symfony\Component\HttpFoundation\InputBag;
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 their data:

all()

Returns the parameters.

keys()

Returns the parameter keys.

replace()

Replaces the current parameters by a new set.

add()

Adds parameters.

get()

Returns a parameter by name.

set()

Sets a parameter by name.

has()

Returns true if the parameter is defined.

remove()

Removes a parameter.

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

getAlpha()

Returns the alphabetic characters of the parameter value;

getAlnum()

Returns the alphabetic characters and digits of the parameter value;

getBoolean()

Returns the parameter value converted to boolean;

getDigits()

Returns the digits of the parameter value;

getInt()

Returns the parameter value converted to integer;

filter()

Filters the parameter by using the PHP filter_var function.

All getters take up to two 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', 'baz');
// returns 'baz'

When PHP imports the request query, it handles request parameters like foo[bar]=baz 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:

// the query string is '?foo[bar]=baz'
$request->query->get('foo');
// returns ['bar' => 'baz']
$request->query->get('foo[bar]');
// returns null
$request->query->get('foo')['bar'];
// returns 'baz'

Thanks to the public attributes property, you can store additional data in the request, 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.

Finally, the raw data sent with the request body can be accessed using getContent():

$content = $request->getContent();

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

If the request body is a JSON string, it can be accessed using toArray():

$data = $request->toArray();

New in version 5.2: The `toArray() method was introduced in Symfony 5.2.

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 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',
    ['name' => 'Fabien']
);

The 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 overrideGlobals():

$request->overrideGlobals();

Tip

You can also duplicate an existing request via duplicate() or change a bunch of parameters with a single call to initialize().

Accessing the Session

If you have a session attached to the request, you can access it via the getSession() method or the getSession() method; the hasPreviousSession() method tells you if the request contains a session which was started in one of the previous requests.

Processing HTTP Headers

Processing HTTP headers is not a trivial task because of the escaping and white space handling of their contents. Symfony provides a Symfony\Component\HttpFoundation\HeaderUtils class that abstracts this complexity and defines some methods for the most common tasks:

use Symfony\Component\HttpFoundation\HeaderUtils;
// Splits an HTTP header by one or more separators
HeaderUtils::split('da, en-gb;q=0.8', ',;');
// => [['da'], ['en-gb','q=0.8']]
// Combines an array of arrays into one associative array
HeaderUtils::combine([['foo', 'abc'], ['bar']]);
// => ['foo' => 'abc', 'bar' => true]
// Joins an associative array into a string for use in an HTTP header
HeaderUtils::toString(['foo' => 'abc', 'bar' => true, 'baz' => 'a b c'], ',');
// => 'foo=abc, bar, baz="a b c"'
// Encodes a string as a quoted string, if necessary
HeaderUtils::quote('foo "bar"');
// => '"foo \"bar\""'
// Decodes a quoted string
HeaderUtils::unquote('"foo \"bar\""');
// => 'foo "bar"'
// Parses a query string but maintains dots (PHP parse_str() replaces '.' by '_')
HeaderUtils::parseQuery('foo[bar.baz]=qux');
// => ['foo' => ['bar.baz' => 'qux']]

New in version 5.2: The `parseQuery() method was introduced in Symfony 5.2.

Accessing `Accept-*` Headers Data

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

getAcceptableContentTypes()

Returns the list of accepted content types ordered by descending quality.

getLanguages()

Returns the list of accepted languages ordered by descending quality.

getCharsets()

Returns the list of accepted charsets ordered by descending quality.

getEncodings()

Returns the list of accepted encodings ordered by descending quality.

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

use Symfony\Component\HttpFoundation\AcceptHeader;
$acceptHeader = AcceptHeader::fromString($request->headers->get('Accept'));
if ($acceptHeader->has('text/html')) {
    $item = $acceptHeader->get('text/html');
    $charset = $item->getAttribute('charset', 'utf-8');
    $quality = $item->getQuality();
}
// Accept header items are sorted by descending quality
$acceptHeaders = AcceptHeader::fromString($request->headers->get('Accept'))
    ->all();

The default values that can be optionally included in the Accept-* headers are also supported:

$acceptHeader = 'text/plain;q=0.5, text/html, text/*;q=0.8, */*;q=0.3';
$accept = AcceptHeader::fromString($acceptHeader);
$quality = $accept->get('text/xml')->getQuality(); // $quality = 0.8
$quality = $accept->get('application/xml')->getQuality(); // $quality = 0.3

Anonymizing IP Addresses

An increasingly common need for applications to comply with user protection regulations is to anonymize IP addresses before logging and storing them for analysis purposes. Use the anonymize() method from theSymfony\Component\HttpFoundation\IpUtils` to do that:

use Symfony\Component\HttpFoundation\IpUtils;
$ipv4 = '123.234.235.236';
$anonymousIpv4 = IpUtils::anonymize($ipv4);
// $anonymousIpv4 = '123.234.235.0'
$ipv6 = '2a01:198:603:10:396e:4789:8e99:890f';
$anonymousIpv6 = IpUtils::anonymize($ipv6);
// $anonymousIpv6 = '2a01:198:603:10::'

Accessing other Data

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

Overriding the Request

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 App\Http\SpecialRequest;
use Symfony\Component\HttpFoundation\Request;
Request::setFactory(function (
    array $query = [],
    array $request = [],
    array $attributes = [],
    array $cookies = [],
    array $files = [],
    array $server = [],
    $content = null
) {
    return new SpecialRequest(
        $query,
        $request,
        $attributes,
        $cookies,
        $files,
        $server,
        $content
    );
});
$request = Request::createFromGlobals();

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',
    Response::HTTP_OK,
    ['content-type' => 'text/html']
);

This 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 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 optionally call the prepare() method to fix any incompatibility with the HTTP specification (e.g. a wrong Content-Type header):

$response->prepare($request);

Sending the response to the client is done by calling the method send():

$response->send();

Setting Cookies

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

use Symfony\Component\HttpFoundation\Cookie;
$response->headers->setCookie(Cookie::create('foo', 'bar'));

The setCookie() method takes an instance of Symfony\Component\HttpFoundation\Cookie as an argument.

You can clear a cookie via the clearCookie() method.

In addition to the Cookie::create() method, you can create aCookieobject from a raw header value using [fromString()](https://github.com/symfony/symfony/blob/5.3/src/Symfony/Component/HttpFoundation/Cookie.php "Symfony\Component\HttpFoundation\Cookie::fromString()") method. You can also use thewith() methods to change some Cookie property (or to build the entire Cookie using a fluent interface). Each `with() method returns a new object with the modified property:

$cookie = Cookie::create('foo')
    ->withValue('bar')
    ->withExpires(strtotime('Fri, 20-May-2011 15:25:52 GMT'))
    ->withDomain('.example.com')
    ->withSecure(true);

New in version 5.1: The `with*() methods were introduced in Symfony 5.1.

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:

Note

The methods setExpires(), setLastModified() and setDate() accept any object that implements \DateTimeInterface, including immutable date objects.

The setCache() method can be used to set the most commonly used cache information in one method call:

$response->setCache([
    'must_revalidate'  => false,
    'no_cache'         => false,
    'no_store'         => false,
    'no_transform'     => false,
    'public'           => true,
    'private'          => false,
    'proxy_revalidate' => false,
    'max_age'          => 600,
    's_maxage'         => 600,
    'immutable'        => true,
    'last_modified'    => new \DateTime(),
    'etag'             => 'abcdef',
]);

New in version 5.1: The must_revalidate, no_cache, no_store, no_transform and proxy_revalidate directives were introduced in Symfony 5.1.

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

use Symfony\Component\HttpFoundation\RedirectResponse;
$response = new RedirectResponse('http://example.com/');

Streaming a Response

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 () {
    var_dump('Hello World');
    flush();
    sleep(2);
    var_dump('Hello World');
    flush();
});
$response->send();

Note

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

Additionally, PHP isn’t the only layer that can buffer output. Your web server might also buffer based on its configuration. Some servers, such as nginx, let you disable buffering at the config level or by adding a special HTTP header in the response:

// disables FastCGI buffering in nginx only for this response
$response->headers->set('X-Accel-Buffering', 'no');

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 straightforward, using non-ASCII filenames is more involved. The makeDisposition() abstracts the hard work behind a simple API:

use Symfony\Component\HttpFoundation\HeaderUtils;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpFoundation\ResponseHeaderBag;
$fileContent = ...; // the generated file content
$response = new Response($fileContent);
$disposition = HeaderUtils::makeDisposition(
    HeaderUtils::DISPOSITION_ATTACHMENT,
    'foo.pdf'
);
$response->headers->set('Content-Disposition', $disposition);

Alternatively, if you are serving a static file, you can use a 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 trustXSendfileTypeHeader() if it should:

BinaryFileResponse::trustXSendfileTypeHeader();

Note

The BinaryFileResponse will only handle X-Sendfile if the particular header is present. For Apache, this is not the default case.

To add the header use the mod_headers Apache module and add the following to the Apache configuration:

<IfModule mod_xsendfile.c>
  # This is already present somewhere...
  XSendFile on
  XSendFilePath ...some path...
  # This needs to be added:
  <IfModule mod_headers.c>
    RequestHeader set X-Sendfile-Type X-Sendfile
  </IfModule>
</IfModule>

With the BinaryFileResponse, 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'
);

It is possible to delete the file after the response is sent with the deleteFileAfterSend() method. Please note that this will not work when the X-Sendfile header is set.

If the size of the served file is unknown (e.g. because it’s being generated on the fly, or because a PHP stream filter is registered on it, etc.), you can pass a Stream instance to BinaryFileResponse. This will disable Range and Content-Length handling, switching to chunked encoding instead:

use Symfony\Component\HttpFoundation\BinaryFileResponse;
use Symfony\Component\HttpFoundation\File\Stream;
$stream = new Stream('path/to/stream');
$response = new BinaryFileResponse($stream);

Note

If you just created the file during this same request, the file may be sent without any content. This may be due to cached file stats that return zero for the size of the file. To fix this issue, call `clearstatcache(true, $file) with the path to the binary file.

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([
    'data' => 123,
]));
$response->headers->set('Content-Type', 'application/json');

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

use Symfony\Component\HttpFoundation\JsonResponse;
// if you know the data to send when creating the response
$response = new JsonResponse(['data' => 123]);
// if you don't know the data to send or if you want to customize the encoding options
$response = new JsonResponse();
// ...
// configure any custom encoding options (if needed, it must be called before "setData()")
//$response->setEncodingOptions(JsonResponse::DEFAULT_ENCODING_OPTIONS | \JSON_PRESERVE_ZERO_FRACTION);
$response->setData(['data' => 123]);
// if the data to send is already encoded in JSON
$response = JsonResponse::fromJsonString('{ "data": 123 }');

The JsonResponse class sets the Content-Type header to application/json and encodes your data to JSON when needed.

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: Session Management.

Safe Content Preference

Some web sites have a “safe” mode to assist those who don’t want to be exposed to content to which they might object. The RFC 8674 specification defines a way for user agents to ask for safe content to a server.

The specification does not define what content might be considered objectionable, so the concept of “safe” is not precisely defined. Rather, the term is interpreted by the server and within the scope of each web site that chooses to act upon this information.

Symfony offers two methods to interact with this preference:

New in version 5.1: The preferSafeContent() andsetContentSafe() methods were introduced in Symfony 5.1.

The following example shows how to detect if the user agent prefers “safe” content:

if ($request->preferSafeContent()) {
    $response = new Response($alternativeContent);
    // this informs the user we respected their preferences
    $response->setContentSafe();
    return $response;
}

Learn More

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.

HttpFoundation

The HttpFoundation Component

The HttpFoundation Component

Installation

Request

Accessing Request Data

Identifying a Request

Simulating a Request

Accessing the Session

Processing HTTP Headers

Accessing Accept-* Headers Data

Anonymizing IP Addresses

Accessing other Data

Overriding the Request

Response

Sending the Response

Setting Cookies

Managing the HTTP Cache

Redirecting the User

Streaming a Response

Serving Files

Creating a JSON Response

JSONP Callback

Session

Safe Content Preference

Learn More

Accessing `Accept-*` Headers Data