The HttpFoundation Component

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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

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$ 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.

See also

This article explains how to use the HttpFoundation features as an independent component in any PHP application. In Symfony applications everything is already configured and ready to use. Read the Controller article to learn about how to use these features when creating controllers.

Request

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

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use Symfony\Component\HttpFoundation\Request;

$request = Request::createFromGlobals();

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

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$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 ParameterBag instance (or a subclass of), which is a data holder class:

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;
getEnum()
Returns the parameter value converted to a PHP enum;
getString()
Returns the parameter value as a string;
filter()
Filters the parameter by using the PHP filter_var function. If invalid values are found, a BadRequestHttpException is thrown. The FILTER_NULL_ON_FAILURE flag can be used to ignore invalid values.

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. The get() method doesn't support returning arrays, so you need to use the following code:

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

// don't use $request->query->get('foo'); use the following instead:
$request->query->all('foo');
// returns ['bar' => 'baz']

// if the requested parameter does not exist, an empty array is returned:
$request->query->all('qux');
// returns []

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

$request->query->all()['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 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():

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$data = $request->toArray();

If the request data could be $_POST data or a JSON string, you can use the getPayload() method which returns an instance of InputBag wrapping this data:

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$data = $request->getPayload();

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();

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 of the Request or RequestStack class; 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 HeaderUtils class that abstracts this complexity and defines some methods for the most common tasks:

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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']]

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();

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

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$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 the IpUtils to do that:

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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::'

Check If an IP Belongs to a CIDR Subnet

If you need to know if an IP address is included in a CIDR subnet, you can use the checkIp() method from IpUtils:

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use Symfony\Component\HttpFoundation\IpUtils;

$ipv4 = '192.168.1.56';
$CIDRv4 = '192.168.1.0/16';
$isIpInCIDRv4 = IpUtils::checkIp($ipv4, $CIDRv4);
// $isIpInCIDRv4 = true

$ipv6 = '2001:db8:abcd:1234::1';
$CIDRv6 = '2001:db8:abcd::/48';
$isIpInCIDRv6 = IpUtils::checkIp($ipv6, $CIDRv6);
// $isIpInCIDRv6 = true

Check if an IP Belongs to a Private Subnet

If you need to know if an IP address belongs to a private subnet, you can use the isPrivateIp() method from the IpUtils to do that:

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use Symfony\Component\HttpFoundation\IpUtils;

$ipv4 = '192.168.1.1';
$isPrivate = IpUtils::isPrivateIp($ipv4);
// $isPrivate = true

$ipv6 = '2a01:198:603:10:396e:4789:8e99:890f';
$isPrivate = IpUtils::isPrivateIp($ipv6);
// $isPrivate = false

Matching a Request Against a Set of Rules

The HttpFoundation component provides some matcher classes that allow you to check if a given request meets certain conditions (e.g. it comes from some IP address, it uses a certain HTTP method, etc.):

You can use them individually or combine them using the ChainRequestMatcher class:

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use Symfony\Component\HttpFoundation\ChainRequestMatcher;
use Symfony\Component\HttpFoundation\RequestMatcher\HostRequestMatcher;
use Symfony\Component\HttpFoundation\RequestMatcher\PathRequestMatcher;
use Symfony\Component\HttpFoundation\RequestMatcher\SchemeRequestMatcher;

// use only one criteria to match the request
$schemeMatcher = new SchemeRequestMatcher('https');
if ($schemeMatcher->matches($request)) {
    // ...
}

// use a set of criteria to match the request
$matcher = new ChainRequestMatcher([
    new HostRequestMatcher('example.com'),
    new PathRequestMatcher('/admin'),
]);

if ($matcher->matches($request)) {
    // ...
}

7.1

The HeaderRequestMatcher and QueryParameterRequestMatcher were introduced in Symfony 7.1.

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 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 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:

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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:

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$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:

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$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):

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$response->prepare($request);

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

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$response->send();

The send() method takes an optional flush argument. If set to false, functions like fastcgi_finish_request() or litespeed_finish_request() are not called. This is useful when debugging your application to see which exceptions are thrown in listeners of the TerminateEvent. You can learn more about it in the dedicated section about Kernel events.

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(Cookie::create('foo', 'bar'));

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

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

In addition to the Cookie::create() method, you can create a Cookie object from a raw header value using fromString() method. You can also use the with*() 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:

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

It is possible to define partitioned cookies, also known as CHIPS, by using the withPartitioned() method:

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$cookie = Cookie::create('foo')
    ->withValue('bar')
    ->withPartitioned();

// you can also set the partitioned argument to true when using the `create()` factory method
$cookie = Cookie::create('name', 'value', partitioned: true);

Managing the HTTP Cache

The 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:

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$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,
    'stale_if_error'   => 86400,
    'stale_while_revalidate' => 60,
    'immutable'        => true,
    'last_modified'    => new \DateTime(),
    'etag'             => 'abcdef',
]);

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 (): void {
    var_dump('Hello World');
    flush();
    sleep(2);
    var_dump('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. Some servers, such as nginx, let you disable buffering at the config level or by adding a special HTTP header in the response:

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

Streaming a JSON Response

The StreamedJsonResponse allows to stream large JSON responses using PHP generators to keep the used resources low.

The class constructor expects an array which represents the JSON structure and includes the list of contents to stream. In addition to PHP generators, which are recommended to minimize memory usage, it also supports any kind of PHP Traversable containing JSON serializable data:

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use Symfony\Component\HttpFoundation\StreamedJsonResponse;

// any method or function returning a PHP Generator
function loadArticles(): \Generator {
    yield ['title' => 'Article 1'];
    yield ['title' => 'Article 2'];
    yield ['title' => 'Article 3'];
};

$response = new StreamedJsonResponse(
    // JSON structure with generators in which will be streamed as a list
    [
        '_embedded' => [
            'articles' => loadArticles(),
        ],
    ],
);

When loading data via Doctrine, you can use the toIterable() method to fetch results row by row and minimize resources consumption. See the Doctrine Batch processing documentation for more:

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public function __invoke(): Response
{
    return new StreamedJsonResponse(
        [
            '_embedded' => [
                'articles' => $this->loadArticles(),
            ],
        ],
    );
}

public function loadArticles(): \Generator
{
    // get the $entityManager somehow (e.g. via constructor injection)
    $entityManager = ...

    $queryBuilder = $entityManager->createQueryBuilder();
    $queryBuilder->from(Article::class, 'article');
    $queryBuilder->select('article.id')
        ->addSelect('article.title')
        ->addSelect('article.description');

    return $queryBuilder->getQuery()->toIterable();
}

If you return a lot of data, consider calling the flush function after some specific item count to send the contents to the browser:

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public function loadArticles(): \Generator
{
    // ...

    $count = 0;
    foreach ($queryBuilder->getQuery()->toIterable() as $article) {
        yield $article;

        if (0 === ++$count % 100) {
            flush();
        }
    }
}

Alternatively, you can also pass any iterable to StreamedJsonResponse, including generators:

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public function loadArticles(): \Generator
{
    yield ['title' => 'Article 1'];
    yield ['title' => 'Article 2'];
    yield ['title' => 'Article 3'];
}

public function __invoke(): Response
{
    // ...

    return new StreamedJsonResponse(loadArticles());
}

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\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 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();

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:

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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.

Alternatively, BinaryFileResponse supports instances of \SplTempFileObject. This is useful when you want to serve a file that has been created in memory and that will be automatically deleted after the response is sent:

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use Symfony\Component\HttpFoundation\BinaryFileResponse;

$file = new \SplTempFileObject();
$file->fwrite('Hello World');
$file->rewind();

$response = new BinaryFileResponse($file);

7.1

The support for \SplTempFileObject in BinaryFileResponse was introduced in Symfony 7.1.

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);

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 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 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.

Danger

To avoid XSSI JSON Hijacking, you should pass an associative array as the outermost 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.

Warning

The JsonResponse constructor exhibits non-standard JSON encoding behavior and will treat null as an empty object if passed as a constructor argument, despite null being a valid JSON top-level value.

This behavior cannot be changed without backwards-compatibility concerns, but it's possible to call setData and pass the value there to opt-out of the behavior.

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});

Session

The session information is in its own document: Sessions.

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:

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

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

    return $response;

Generating Relative and Absolute URLs

Generating absolute and relative URLs for a given path is a common need in some applications. In Twig templates you can use the absolute_url() and relative_path() functions to do that.

The UrlHelper class provides the same functionality for PHP code via the getAbsoluteUrl() and getRelativePath() methods. You can inject this as a service anywhere in your application:

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// src/Normalizer/UserApiNormalizer.php
namespace App\Normalizer;

use Symfony\Component\HttpFoundation\UrlHelper;

class UserApiNormalizer
{
    public function __construct(
        private UrlHelper $urlHelper,
    ) {
    }

    public function normalize($user): array
    {
        return [
            'avatar' => $this->urlHelper->getAbsoluteUrl($user->avatar()->path()),
        ];
    }
}

Learn More

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