single: Create your First Page in Symfony
Creating a new page - whether it's an HTML page or a JSON endpoint - is a simple two-step process:
- Create a route: A route is the URL (e.g.
/about
) to your page and points to a controller; - 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
Response
object, which can hold HTML content, a JSON string or even a binary file like an image or PDF.
Do you prefer video tutorials? Check out the Joyful Development with Symfony screencast series from KnpUniversity.
Symfony embraces the HTTP Request-Response lifecycle. To find out more, see /introduction/http_fundamentals
.
single: Page creation; Example
Tip
Before continuing, make sure you've read the 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:
// src/Controller/LuckyController.php
namespace App\Controller;
use Symfony\Component\HttpFoundation\Response;
class LuckyController
{
public function number()
{
$number = mt_rand(0, 100);
return new Response(
'<html><body>Lucky number: '.$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 executed when a user browses to it. This association is defined by creating a route in the config/routes.yaml
file:
# config/routes.yaml
# the "app_lucky_number" route name is not important yet
app_lucky_number:
path: /lucky/number
controller: App\Controller\LuckyController::number
That's it! If you are using Symfony web server, try it out by going to:
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 creating a page?
- Create a route: In
config/routes.yaml
, the route defines the URL to your page (
path
) and whatcontroller
to call. You'll learn more aboutrouting </routing>
in its own section, including how to make variable URLs;
- Create a route: In
- Create a controller: This is a function where you build the page and ultimately return a
Response
object. You'll learn more aboutcontrollers </controller>
in their own section, including how to return JSON responses.
Instead of defining your route in YAML, Symfony also allows you to use annotation routes. To do this, install the annotations package:
$ composer require annotations
You can now add your route directly above the controller:
// src/Controller/LuckyController.php
// ...
+ use Symfony\Component\Routing\Annotation\Route;
class LuckyController
{
+ /**
+ * @Route("/lucky/number")
+ */
public function number()
{
// this looks exactly the same
}
}
That's it! The page - http://localhost:8000/lucky/number
will work exactly like before! Annotations are the recommended way to configure routes.
You may not have noticed, but when you ran composer require annotations
, two special things happened, both thanks to a powerful Composer plugin called Flex </setup/flex>
.
First, annotations
isn't a real package name: it's an alias (i.e. shortcut) that Flex resolves to sensio/framework-extra-bundle
.
Second, after this package was downloaded, Flex executed a recipe, which is a set of automated instructions that tell Symfony how to integrate an external package. Flex recipes exist for many packages (see symfony.sh) and have the ability to do a lot, like adding configuration files, creating directories, updating .gitignore
and adding new config to your .env
file. Flex automates the installation of packages so you can get back to coding.
You can learn more about Flex by reading "/setup/flex
". But that's not necessary: Flex works automatically in the background when you add packages.
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 one route so far:
Name | Method | Scheme | Host | Path |
---|---|---|---|---|
|
|
|
|
|
You'll learn about many more commands as you continue!
One of Symfony's killer features is the Web Debug Toolbar: a bar that displays a huge amount of debugging information along the bottom of your page while developing.
To use the web debug toolbar, just install it:
$ composer require --dev profiler
As soon as this finishes, refresh your page. You should see a black 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.
The profiler
package is also a great example of Flex! After downloading the package, the recipe created several configuration files so that the web debug toolbar worked instantly.
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 easy, powerful and actually quite fun.
First, install Twig:
$ composer require twig
Second, make sure that LuckyController
extends Symfony's base Symfony\\Bundle\\FrameworkBundle\\Controller\\Controller
class:
// src/Controller/LuckyController.php
// ...
+ use Symfony\Bundle\FrameworkBundle\Controller\Controller;
- class LuckyController
+ class LuckyController extends Controller
{
// ...
}
Now, use the handy render()
function to render a template. Pass it a number
variable so you can use it in Twig:
// src/Controller/LuckyController.php
// ...
class LuckyController extends Controller
{
/**
* @Route("/lucky/number")
*/
public function number()
{
$number = mt_rand(0, 100);
return $this->render('lucky/number.html.twig', array(
'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!
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 /templating
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 of course!. You will configure routes,
services </service_container>
and packages.src/
All your PHP code lives here.
Most of the time, you'll be working in src/
(PHP files) 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/console
file 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 apps.
Ok, time to finish mastering the fundamentals by reading these articles:
/routing
/controller
/templating
Then, learn about other important topics like the service container </service_container>
, the form system </forms>
, using Doctrine </doctrine>
(if you need to query a database) and more!
Have fun!
routing
introduction/*