Symfony - Routing

• Routing maps request URI to a specific controller's method.
• Generally, routing checks the page segment against a set of constraints. If any constraint matches, then it returns a set of values. One of the main value is the controller.

Symfony Installation

• Follow the steps mentioned in this reference site - Symfony Installation

Annotations

• Annotation simplifies the configuration by declaring the configuration in the coding itself.
• Annotation is nothing but providing meta information about class, methods, and properties.
• Routing uses annotation extensively. Even though routing can be done without annotation, annotation simplifies routing to a large extent.
• Following is a sample annotation :

/** 
   * @Route(“/student/home”) 
*/ 
public function homeAction() { 
   // ... 
} 

Routing Concepts

• Consider the StudentController class.

namespace AppBundle\Controller;  

use Symfony\Bundle\FrameworkBundle\Controller\Controller; 
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route; 

class StudentController extends Controller { 
   /** 
      * @Route(“/student/home”) 
   */ 
   public function homeAction() { 
      // ... 
   }  
    
   /** 
      * @Route(“/student/about”) 
   */ 
   public function aboutAction() { 
   } 
}

• Here, the routing performs two steps.
• If you go to /student/home, the first route is matched then homeAction() is executed.
• Otherwise, If you go to /student/about, the second route is matched and then aboutAction() is executed.

Passing parameters to routes

• Consider the following example :

namespace AppBundle\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\Routing\Annotation\Route;

class TestController extends Controller{

    //  Demo route with parameters
    /**
     * @Route("/contact/{name}")
     */

     public function contactNameAction(string $name){
         return new Response("Name is : " . $name);
     }
}

• Here, if you go to /student/contact/Tom, the name "Tom" is the paramter passed via the route, so the first route is matched wherein "{name}" catches the incoming parameter then contactNameAction() is executed, which displays the name as a response.

@TODO: add references to examples which shows how to create a new route.