Requests and Responses in PHP¶

So how do you interact with the "request" and create a "response" when using PHP? In reality, PHP abstracts you a bit from the whole process:

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$uri = $_SERVER['REQUEST_URI']; $foo = $_GET['foo']; header('Content-type: text/html'); echo 'The URI requested is: '.$uri; echo 'The value of the "foo" parameter is: '.$foo;

As strange as it sounds, this small application is in fact taking information from the HTTP request and using it to create an HTTP response. Instead of parsing the raw HTTP request message, PHP prepares superglobal variables such as $_SERVER and $_GET that contain all the information from the request. Similarly, instead of returning the HTTP-formatted text response, you can use the header() function to create response headers and simply print out the actual content that will be the content portion of the response message. PHP will create a true HTTP response and return it to the client:

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HTTP/1.1 200 OK Date: Sat, 03 Apr 2011 02:14:33 GMT Server: Apache/2.2.17 (Unix) Content-Type: text/html The URI requested is: /testing?foo=symfony The value of the "foo" parameter is: symfony

Requests and Responses in Symfony¶

 

Symfony provides an alternative to the raw PHP approach via two classes that allow you to interact with the HTTP request and response in an easier way. The Request class is a simple object-oriented representation of the HTTP request message. With it, you have all the request information at your fingertips:

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use Symfony\Component\HttpFoundation\Request; $request = Request::createFromGlobals(); // the URI being requested (e.g. /about) minus any query parameters $request->getPathInfo(); // retrieve GET and POST variables respectively $request->query->get('foo'); $request->request->get('bar', 'default value if bar does not exist'); // retrieve SERVER variables $request->server->get('HTTP_HOST'); // retrieves an instance of UploadedFile identified by foo $request->files->get('foo'); // retrieve a COOKIE value $request->cookies->get('PHPSESSID'); // retrieve an HTTP request header, with normalized, lowercase keys $request->headers->get('host'); $request->headers->get('content_type');$request->getMethod(); // GET, POST, PUT, DELETE, HEAD $request->getLanguages(); // an array of languages the client accepts As a bonus, the Request class does a lot of work in the background that you'll never need to worry about. For example, the isSecure() method checks the three different values in PHP that can indicate whether or not the user is connecting via a secured connection (i.e. HTTPS). As seen above, the $_GET and $_POST variables are accessible via the public query and request properties respectively. Each of these objects is a ParameterBag object, which has methods like get(), has(), all() and more. In fact, every public property used in the previous example is some instance of the ParameterBag. The Request class also has a public attributes property, which holds special data related to how the application works internally. For the Symfony2 framework, the attributes holds the values returned by the matched route, like _controller, id (if you have an {id} wildcard), and even the name of the matched route (_route). The attributes property exists entirely to be a place where you can prepare and store context-specific information about the request. ParameterBags and Request attributes