Creating a Controller

Being Lazy with the Maker Bundle

To generate controllers effortlessly, we can use the symfony/maker-bundle package, which has been installed as part of the webapp package.

The maker bundle helps you generate a lot of different classes. We will use it all the time in this book. Each "generator" is defined in a command and all commands are part of the make command namespace.

The Symfony Console built-in list command lists all commands available under a given namespace; use it to discover all generators provided by the maker bundle:

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$ symfony console list make

Choosing a Configuration Format

Before creating the first controller of the project, we need to decide on the configuration formats we want to use. Symfony supports YAML, XML, PHP, and PHP attributes out of the box.

For configuration related to packages, YAML is the best choice. This is the format used in the config/ directory. Often, when you install a new package, that package's recipe will add a new file ending in .yaml to that directory.

For configuration related to PHP code, attributes are a better choice as they are defined next to the code. Let me explain with an example. When a request comes in, some configuration needs to tell Symfony that the request path should be handled by a specific controller (a PHP class). When using YAML, XML or PHP configuration formats, two files are involved (the configuration file and the PHP controller file). When using attributes, the configuration is done directly in the controller class.

You might wonder how you can guess the package name you need to install for a feature? Most of the time, you don't need to know. In many cases, Symfony contains the package to install in its error messages. Running symfony console make:message without the messenger package for instance would have ended with an exception containing a hint about installing the right package.

Generating a Controller

Create your first Controller via the make:controller command:

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$ symfony console make:controller ConferenceController

The command creates a ConferenceController class under the src/Controller/ directory. The generated class consists of some boilerplate code ready to be fine-tuned:

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namespace App\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\Routing\Attribute\Route;

class ConferenceController extends AbstractController
{
    #[Route('/conference', name: 'app_conference')]
    public function index(): Response
    {
        return $this->render('conference/index.html.twig', [
            'controller_name' => 'ConferenceController',
        ]);
    }
}

The #[Route('/conference', name: 'app_conference')] attribute is what makes the index() method a controller (the configuration is next to the code that it configures).

When you hit /conference in a browser, the controller is executed and a response is returned.

Tweak the route to make it match the homepage:

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--- a/src/Controller/ConferenceController.php
+++ b/src/Controller/ConferenceController.php
@@ -8,7 +8,7 @@ use Symfony\Component\Routing\Attribute\Route;

 class ConferenceController extends AbstractController
 {
-    #[Route('/conference', name: 'app_conference')]
+    #[Route('/', name: 'homepage')]
     public function index(): Response
     {
         return $this->render('conference/index.html.twig', [

The route name will be useful when we want to reference the homepage in the code. Instead of hard-coding the / path, we will use the route name.

Instead of the default rendered page, let's return a simple HTML one:

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--- a/src/Controller/ConferenceController.php
+++ b/src/Controller/ConferenceController.php
@@ -11,8 +11,13 @@ class ConferenceController extends AbstractController
     #[Route('/', name: 'homepage')]
     public function index(): Response
     {
-        return $this->render('conference/index.html.twig', [
-            'controller_name' => 'ConferenceController',
-        ]);
+        return new Response(<<<EOF
+            <html>
+                <body>
+                    <img src="/images/under-construction.gif" />
+                </body>
+            </html>
+            EOF
+        );
     }
 }

Refresh the browser:

The main responsibility of a controller is to return an HTTP Response for the request.

As the rest of the chapter is about code that we won't keep, let's commit our changes now:

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$ git add .
$ git commit -m'Add the index controller'

Adding an Easter Egg

To demonstrate how a response can leverage information from the request, let's add a small Easter egg. Whenever the homepage contains a query string like ?hello=Fabien, let's add some text to greet the person:

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--- a/src/Controller/ConferenceController.php
+++ b/src/Controller/ConferenceController.php
@@ -3,17 +3,24 @@
 namespace App\Controller;

 use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\Routing\Attribute\Route;

 class ConferenceController extends AbstractController
 {
     #[Route('/', name: 'homepage')]
-    public function index(): Response
+    public function index(Request $request): Response
     {
+        $greet = '';
+        if ($name = $request->query->get('hello')) {
+            $greet = sprintf('<h1>Hello %s!</h1>', htmlspecialchars($name));
+        }
+
         return new Response(<<<EOF
             <html>
                 <body>
+                    $greet
                     <img src="/images/under-construction.gif" />
                 </body>
             </html>

Symfony exposes the request data through a Request object. When Symfony sees a controller argument with this type-hint, it automatically knows to pass it to you. We can use it to get the name item from the query string and add an <h1> title.

Try hitting / then /?hello=Fabien in a browser to see the difference.

We could also have made the name part of the URL:

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--- a/src/Controller/ConferenceController.php
+++ b/src/Controller/ConferenceController.php
@@ -9,11 +9,11 @@ use Symfony\Component\Routing\Attribute\Route;

 class ConferenceController extends AbstractController
 {
-    #[Route('/', name: 'homepage')]
-    public function index(Request $request): Response
+    #[Route('/hello/{name}', name: 'homepage')]
+    public function index(string $name = ''): Response
     {
         $greet = '';
-        if ($name = $request->query->get('hello')) {
+        if ($name) {
             $greet = sprintf('<h1>Hello %s!</h1>', htmlspecialchars($name));
         }

The {name} part of the route is a dynamic route parameter - it works like a wildcard. You can now hit /hello then /hello/Fabien in a browser to get the same results as before. You can get the value of the {name} parameter by adding a controller argument with the same name. So, $name.

Revert the changes we have just made:

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$ git checkout src/Controller/ConferenceController.php

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$ git reset HEAD src/Controller/ConferenceController.php
$ git checkout src/Controller/ConferenceController.php

Debugging Variables

A great debug helper is the Symfony dump() function. It is always available and allows you to dump complex variables in a nice and interactive format.

Temporarily change src/Controller/ConferenceController.php to dump the Request object:

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--- a/src/Controller/ConferenceController.php
+++ b/src/Controller/ConferenceController.php
@@ -3,14 +3,17 @@
 namespace App\Controller;

 use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\Routing\Attribute\Route;

 class ConferenceController extends AbstractController
 {
     #[Route('/', name: 'homepage')]
-    public function index(): Response
+    public function index(Request $request): Response
     {
+        dump($request);
+
         return new Response(<<<EOF
             <html>
                 <body>

When refreshing the page, notice the new "target" icon in the toolbar; it lets you inspect the dump. Click on it to access a full page where navigating is made simpler:

Revert the changes we have just made:

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$ git checkout src/Controller/ConferenceController.php

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$ git reset HEAD src/Controller/ConferenceController.php
$ git checkout src/Controller/ConferenceController.php