Request

Your Slim app’s routes and middleware are given a PSR 7 request object that represents the current HTTP request received by your web server. The request object implements the PSR 7 ServerRequestInterface with which you can inspect and manipulate the HTTP request method, headers, and body.

How to get the Request object

The PSR 7 request object is injected into your Slim application routes as the first argument to the route callback like this:

<?php
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Message\ResponseInterface;

$app = new \Slim\App;
$app->get('/foo', function (ServerRequestInterface $request, ResponseInterface $response) {
    // Use the PSR 7 $request object

    return $response;
});
$app->run();
Figure 1: Inject PSR 7 request into application route callback.

The PSR 7 request object is injected into your Slim application middleware as the first argument of the middleware callable like this:

<?php
use Psr\Http\Message\ServerRequestInterface;
use Psr\Http\Message\ResponseInterface;

$app = new \Slim\App;
$app->add(function (ServerRequestInterface $request, ResponseInterface $response, callable $next) {
    // Use the PSR 7 $request object

    return $next($request, $response);
});
// Define app routes...
$app->run();
Figure 2: Inject PSR 7 request into application middleware.

The Request Method

Every HTTP request has a method that is typically one of:

  • GET
  • POST
  • PUT
  • DELETE
  • HEAD
  • PATCH
  • OPTIONS

You can inspect the HTTP request’s method with the Request object method appropriately named getMethod().

$method = $request->getMethod();

Because this is a common task, Slim’s built-in PSR 7 implementation also provides these proprietary methods that return true or false.

  • $request->isGet()
  • $request->isPost()
  • $request->isPut()
  • $request->isDelete()
  • $request->isHead()
  • $request->isPatch()
  • $request->isOptions()

It is possible to fake or override the HTTP request method. This is useful if, for example, you need to mimic a PUT request using a traditional web browser that only supports GET or POST requests.

There are two ways to override the HTTP request method. You can include a _METHOD parameter in a POST request’s body. The HTTP request must use the application/x-www-form-urlencoded content type.

POST /path HTTP/1.1
Host: example.com
Content-type: application/x-www-form-urlencoded
Content-length: 22

data=value&_METHOD=PUT
Figure 3: Override HTTP method with _METHOD parameter.

You can also override the HTTP request method with a custom X-Http-Method-Override HTTP request header. This works with any HTTP request content type.

POST /path HTTP/1.1
Host: example.com
Content-type: application/json
Content-length: 16
X-Http-Method-Override: PUT

{"data":"value"}
Figure 4: Override HTTP method with X-Http-Method-Override header.

You can fetch the original (non-overridden) HTTP method with the PSR 7 Request object’s method named getOriginalMethod().

The Request URI

Every HTTP request has a URI that identifies the requested application resource. The HTTP request URI has several parts:

  • Scheme (e.g. http or https)
  • Host (e.g. example.com)
  • Port (e.g. 80 or 443)
  • Path (e.g. /users/1)
  • Query string (e.g. sort=created&dir=asc)

You can fetch the PSR 7 Request object’s URI object with its getUri() method:

$uri = $request->getUri();

The PSR 7 Request object’s URI is itself an object that provides the following methods to inspect the HTTP request’s URL parts:

  • getScheme()
  • getAuthority()
  • getUserInfo()
  • getHost()
  • getPort()
  • getPath()
  • getBasePath()
  • getQuery() (returns the full query string, e.g. a=1&b=2)
  • getFragment()
  • getBaseUrl()

You can get the query parameters as an associative array on the Request object using getQueryParams().

You can also get a single query parameter value, with optional default value if the parameter is missing, using getQueryParam($key, $default = null).

Base Path
If your Slim application's front-controller lives in a physical subdirectory beneath your document root directory, you can fetch the HTTP request's physical base path (relative to the document root) with the Uri object's getBasePath() method. This will be an empty string if the Slim application is installed in the document root's top-most directory.

The Request Headers

Every HTTP request has headers. These are metadata that describe the HTTP request but are not visible in the request’s body. Slim’s PSR 7 Request object provides several methods to inspect its headers.

Get All Headers

You can fetch all HTTP request headers as an associative array with the PSR 7 Request object’s getHeaders() method. The resultant associative array’s keys are the header names and its values are themselves a numeric array of string values for their respective header name.

$headers = $request->getHeaders();
foreach ($headers as $name => $values) {
    echo $name . ": " . implode(", ", $values);
}
Figure 5: Fetch and iterate all HTTP request headers as an associative array.

Get One Header

You can get a single header’s value(s) with the PSR 7 Request object’s getHeader($name) method. This returns an array of values for the given header name. Remember, a single HTTP header may have more than one value!

$headerValueArray = $request->getHeader('Accept');
Figure 6: Get values for a specific HTTP header.

You may also fetch a comma-separated string with all values for a given header with the PSR 7 Request object’s getHeaderLine($name) method. Unlike the getHeader($name) method, this method returns a comma-separated string.

$headerValueString = $request->getHeaderLine('Accept');
Figure 7: Get single header's values as comma-separated string.

Detect Header

You can test for the presence of a header with the PSR 7 Request object’s hasHeader($name) method.

if ($request->hasHeader('Accept')) {
    // Do something
}
Figure 8: Detect presence of a specific HTTP request header.

The Request Body

Every HTTP request has a body. If you are building a Slim application that consumes JSON or XML data, you can use the PSR 7 Request object’s getParsedBody() method to parse the HTTP request body into a native PHP format. Slim can parse JSON, XML, and URL-encoded data out of the box.

$parsedBody = $request->getParsedBody();
Figure 9: Parse HTTP request body into native PHP format
  • JSON requests are converted into associative arrays with json_decode($input, true).
  • XML requests are converted into a SimpleXMLElement with simplexml_load_string($input).
  • URL-encoded requests are converted into a PHP array with parse_str($input).

For URL-encoded requests, you can also get a single parameter value, with optional default value if the parameter is missing, using getParsedBodyParam($key, $default = null).

Technically speaking, Slim’s PSR 7 Request object represents the HTTP request body as an instance of \Psr\Http\Message\StreamInterface. You can get the HTTP request body StreamInterface instance with the PSR 7 Request object’s getBody() method. The getBody() method is preferable if the incoming HTTP request size is unknown or too large for available memory.

$body = $request->getBody();
Figure 10: Get HTTP request body

The resultant \Psr\Http\Message\StreamInterface instance provides the following methods to read and iterate its underlying PHP resource.

  • getSize()
  • tell()
  • eof()
  • isSeekable()
  • seek()
  • rewind()
  • isWritable()
  • write($string)
  • isReadable()
  • read($length)
  • getContents()
  • getMetadata($key = null)

Reparsing the body

When calling getParsedBody on the Request object multiple times, the body is only parsed once, even if the Request body is modified in the meantime.

To ensure the body is reparsed, the Request object’s method reparseBody can be used.

Uploaded Files

The file uploads in $_FILES are available from the Request object’s getUploadedFiles() method. This returns an array keyed by the name of the <input> element.

$files = $request->getUploadedFiles();
Figure 11: Get uploaded files

Each object in the $files array is a instance of \Psr\Http\Message\UploadedFileInterface and supports the following methods:

  • getStream()
  • moveTo($targetPath)
  • getSize()
  • getError()
  • getClientFilename()
  • getClientMediaType()

See the cookbook on how to upload files using a POST form.

Request Helpers

Slim’s PSR 7 Request implementation provides these additional proprietary methods to help you further inspect the HTTP request.

Detect XHR requests

You can detect XHR requests with the Request object’s isXhr() method. This method detects the presence of the X-Requested-With HTTP request header and ensures its value is XMLHttpRequest.

POST /path HTTP/1.1
Host: example.com
Content-type: application/x-www-form-urlencoded
Content-length: 7
X-Requested-With: XMLHttpRequest

foo=bar
Figure 13: Example XHR request.
if ($request->isXhr()) {
    // Do something
}

Content Type

You can fetch the HTTP request content type with the Request object’s getContentType() method. This returns the Content-Type header’s full value as provided by the HTTP client.

$contentType = $request->getContentType();

Media Type

You may not want the complete Content-Type header. What if, instead, you only want the media type? You can fetch the HTTP request media type with the Request object’s getMediaType() method.

$mediaType = $request->getMediaType();

You can fetch the appended media type parameters as an associative array with the Request object’s getMediaTypeParams() method.

$mediaParams = $request->getMediaTypeParams();

Character Set

One of the most common media type parameters is the HTTP request character set. The Request object provides a dedicated method to retrieve this media type parameter.

$charset = $request->getContentCharset();

Content Length

You can fetch the HTTP request content length with the Request object’s getContentLength() method.

$length = $request->getContentLength();

Request Parameter

To fetch single request parameter value, use methods: getParam(), getQueryParam(), getParsedBodyParam(), getCookieParam(), getServerParam(), counterparts of PSR-7’s plural form get*Params() methods.

For example, to get a single Server Parameter:

$foo = $request->getServerParam('HTTP_NOT_EXIST', 'default_value_here');

Route Object

Sometimes in middleware you require the parameter of your route.

In this example we are checking first that the user is logged in and second that the user has permissions to view the particular video they are attempting to view.

    $app->get('/course/{id}', Video::class.":watch")->add(Permission::class)->add(Auth::class);

    //.. In the Permission Class's Invoke
    /** @var $route \Slim\Route */
    $route = $request->getAttribute('route');
    $courseId = $route->getArgument('id');

Media Type Parsers

Slim looks as the request’s media type and if it recognises it, will parse it into structured data available via $request->getParsedBody(). This is usually an array, but is an object for XML media types.

The following media types are recognised and parsed:

  • application/x-www-form-urlencoded
  • application/json
  • application/xml & text/xml

If you want Slim to parse content from a different media type then you need to either parse the raw body yourself or register a new media parser. Media parsers are simply callables that accept an $input string and return a parsed object or array.

Register a new media parser in an application or route middleware. Note that you must register the parser before you try to access the parsed body for the first time.

For example, to automatically parse JSON that is sent with a text/javascript content type, you register a media type parser in middleware like this:

// Add the middleware
$app->add(function ($request, $response, $next) {
    // add media parser
    $request->registerMediaTypeParser(
        "text/javascript",
        function ($input) {
            return json_decode($input, true);
        }
    );

    return $next($request, $response);
});

Attributes

With PSR-7 it is possible to inject objects/values into the request object for further processing. In your applications middleware often need to pass along information to your route closure and the way to do is it is to add it to the request object via an attribute.

Example, Setting a value on your request object.

$app->add(function ($request, $response, $next) {
    $request = $request->withAttribute('session', $_SESSION); //add the session storage to your request as [READ-ONLY]
    return $next($request, $response);
});

Example, how to retrieve the value.

$app->get('/test', function ($request, $response, $args) {
    $session = $request->getAttribute('session'); //get the session from the request

    return $response->write('Yay, ' . $session['name']);
});

The request object also has bulk functions as well. $request->getAttributes() and $request->withAttributes()