The HttpFoundation Component

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 ParameterBag instance (or a sub-class of), which is a data holder class:

• request: ParameterBag;
• query: ParameterBag;
• cookies: ParameterBag;
• attributes: ParameterBag;
• files: FileBag;
• server: ServerBag;
• headers: HeaderBag.

All 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 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:

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// 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:

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// 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 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():

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$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 getPathInfo() method:

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// 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:

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$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():

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$request->overrideGlobals();

Accessing the Session

If you have a session attached to the request, you can access it via the getSession() method; the 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 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 AcceptHeader utility class:

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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();

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:

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use AppBundle\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();

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):

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$response->prepare($request);

Sending the response to the client is then as simple as calling send():

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$response->send();

Setting Cookies

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

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use Symfony\Component\HttpFoundation\Cookie;

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

The setCookie() method takes an instance of Cookie as an argument.

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

Note you can create a Cookie object from a raw header value using fromString().

Managing the HTTP Cache

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

• setPublic()
• setPrivate()
• expire()
• setExpires()
• setMaxAge()
• setSharedMaxAge()
• setTtl()
• setClientTtl()
• setLastModified()
• setEtag()
• setVary()

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

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

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

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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 RedirectResponse class:

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use Symfony\Component\HttpFoundation\RedirectResponse;

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

Streaming a Response

The 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:

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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();

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// 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:

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use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpFoundation\ResponseHeaderBag;

$fileContent = ...; // the generated file content
$response = new Response($fileContent);

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

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

Alternatively, if you are serving a static file, you can use a BinaryFileResponse:

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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:

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BinaryFileResponse::trustXSendfileTypeHeader();

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<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:

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// ...
$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:

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use Symfony\Component\HttpFoundation\BinaryFileResponse;
use Symfony\Component\HttpFoundation\File\Stream;

$stream  = new Stream('path/to/stream');
$response = new BinaryFileResponse($stream);

Creating a JSON Response

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

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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 JsonResponse class, which can make this even easier:

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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 when creating the response
$response = new JsonResponse();
// ...
$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.

JSONP Callback

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

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$response->setCallback('handleResponse');

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

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handleResponse({'data': 123});