Creating a new page - whether it's an HTML page or a JSON endpoint - is a two-step process:
- Create a controller: A controller is the PHP function you write that
builds the page. You take the incoming request information and use it to
create a Symfony
Responseobject, which can hold HTML content, a JSON string or even a binary file like an image or PDF; - Create a route: A route is the URL (e.g.
/about) to your page and points to a controller.
Screencast
Do you prefer video tutorials? Check out the Harmonious Development with Symfony screencast series.
.. seealso::
Symfony *embraces* the HTTP Request-Response lifecycle. To find out more,
see :doc:`/introduction/http_fundamentals`.
Tip
Before continuing, make sure you've read the :doc:`Setup </setup>` article and can access your new Symfony app in the browser.
Suppose you want to create a page - /lucky/number - that generates a lucky (well,
random) number and prints it. To do that, create a "Controller" class and a
"controller" method inside of it:
<?php
// src/Controller/LuckyController.php
namespace App\Controller;
use Symfony\Component\HttpFoundation\Response;
class LuckyController
{
public function number(): Response
{
$number = random_int(0, 100);
return new Response(
'<html><body>Lucky number: '.$number.'</body></html>'
);
}
}
Now you need to associate this controller function with a public URL (e.g. /lucky/number)
so that the number() method is called when a user browses to it. This association
is defined with the #[Route] attribute (in PHP, attributes are used to add
metadata to code):
// src/Controller/LuckyController.php
// ...
+ use Symfony\Component\Routing\Attribute\Route;
class LuckyController
{
+ #[Route('/lucky/number')]
public function number(): Response
{
// this looks exactly the same
}
}That's it! If you are using :doc:`the Symfony web server </setup/symfony_server>`, try it out by going to: http://localhost:8000/lucky/number
Tip
Symfony recommends defining routes as attributes to have the controller code and its route configuration at the same location. However, if you prefer, you can :doc:`define routes in separate files </routing>` using YAML, XML and PHP formats.
If you see a lucky number being printed back to you, congratulations! But before you run off to play the lottery, check out how this works. Remember the two steps to create a page?
- Create a controller and a method: This is a function where you build the page and ultimately
return a
Responseobject. You'll learn more about :doc:`controllers </controller>` in their own section, including how to return JSON responses; - Create a route: In
config/routes.yaml, the route defines the URL to your page (path) and whatcontrollerto call. You'll learn more about :doc:`routing </routing>` in its own section, including how to make variable URLs.
Your project already has a powerful debugging tool inside: the bin/console command.
Try running it:
$ php bin/console
You should see a list of commands that can give you debugging information, help generate code, generate database migrations and a lot more. As you install more packages, you'll see more commands.
To get a list of all of the routes in your system, use the debug:router command:
$ php bin/console debug:router
You should see your app_lucky_number route in the list:
---------------- ------- ------- ----- --------------
Name Method Scheme Host Path
---------------- ------- ------- ----- --------------
app_lucky_number ANY ANY ANY /lucky/number
---------------- ------- ------- ----- --------------
You will also see debugging routes besides app_lucky_number -- more on
the debugging routes in the next section.
You'll learn about many more commands as you continue!
Tip
If your shell is supported, you can also set up console completion support.
This autocompletes commands and other input when using bin/console.
See :ref:`the Console document <console-completion-setup>` for more
information on how to set up completion.
One of Symfony's amazing features is the Web Debug Toolbar: a bar that displays
a huge amount of debugging information along the bottom of your page while
developing. This is all included out of the box using a :ref:`Symfony pack <symfony-packs>`
called symfony/profiler-pack.
You will see a dark bar along the bottom of the page. You'll learn more about all the information it holds along the way, but feel free to experiment: hover over and click the different icons to get information about routing, performance, logging and more.
If you're returning HTML from your controller, you'll probably want to render a template. Fortunately, Symfony comes with Twig: a templating language that's minimal, powerful and actually quite fun.
Install the twig package with:
$ composer require twig
Make sure that LuckyController extends Symfony's base
:class:`Symfony\\Bundle\\FrameworkBundle\\Controller\\AbstractController` class:
// src/Controller/LuckyController.php
// ...
+ use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
- class LuckyController
+ class LuckyController extends AbstractController
{
// ...
}Now, use the handy render() method to render a template. Pass it a number
variable so you can use it in Twig:
// src/Controller/LuckyController.php
namespace App\Controller;
use Symfony\Component\HttpFoundation\Response;
// ...
class LuckyController extends AbstractController
{
#[Route('/lucky/number')]
public function number(): Response
{
$number = random_int(0, 100);
return $this->render('lucky/number.html.twig', [
'number' => $number,
]);
}
}
Template files live in the templates/ directory, which was created for you automatically
when you installed Twig. Create a new templates/lucky directory with a new
number.html.twig file inside:
{# templates/lucky/number.html.twig #}
<h1>Your lucky number is {{ number }}</h1>
The {{ number }} syntax is used to print variables in Twig. Refresh your browser
to get your new lucky number!
http://localhost:8000/lucky/number
Now you may wonder where the Web Debug Toolbar has gone: that's because there is
no </body> tag in the current template. You can add the body element yourself,
or extend base.html.twig, which contains all default HTML elements.
In the :doc:`templates </templates>` article, you'll learn all about Twig: how to loop, render other templates and leverage its powerful layout inheritance system.
Great news! You've already worked inside the most important directories in your project:
config/- Contains... configuration!. You will configure routes, :doc:`services </service_container>` and packages.
src/- All your PHP code lives here.
templates/- All your Twig templates live here.
Most of the time, you'll be working in src/, templates/ or config/.
As you keep reading, you'll learn what can be done inside each of these.
So what about the other directories in the project?
bin/- The famous
bin/consolefile lives here (and other, less important executable files). var/- This is where automatically-created files are stored, like cache files
(
var/cache/) and logs (var/log/). vendor/- Third-party (i.e. "vendor") libraries live here! These are downloaded via the Composer package manager.
public/- This is the document root for your project: you put any publicly accessible files here.
And when you install new packages, new directories will be created automatically when needed.
Congrats! You're already starting to master Symfony and learn a whole new way of building beautiful, functional, fast and maintainable applications.
OK, time to finish mastering the fundamentals by reading these articles:
Then, learn about other important topics like the :doc:`service container </service_container>`, the :doc:`form system </forms>`, using :doc:`Doctrine </doctrine>` (if you need to query a database) and more!
Have fun!
.. toctree::
:maxdepth: 1
:glob:
introduction/*