1-33

Symfony2 – Franz Jordán 2011
Congratulations! You've just created your first route and connected it to a controller. Now, when
you visit /blog/my-post, the showAction controller will be executed and the $slug variable
will be equal to my-post.
This is the goal of the Symfony2 router: to map the URL of a request to a controller. Along the
way, you'll learn all sorts of tricks that make mapping even the most complex URLs easy.
Routing: Under the Hood
When a request is made to your application, it contains an address to the exact "resource" that
the client is requesting. This address is called the URL, (or URI), and could
be /contact, /blog/read-me, or anything else. Take the following HTTP request for
example:
GET /blog/my-blog-post
The goal of the Symfony2 routing system is to parse this URL and determine which controller
should be executed. The whole process looks like this:
1. The request is handled by the Symfony2 front controller (e.g. app.php);
2. The Symfony2 core (i.e. Kernel) asks the router to inspect the request;
3. The router matches the incoming URL to a specific route and returns information about the
route, including the controller that should be executed;
4. The Symfony2 Kernel executes the controller, which ultimately returns a Response object.
56