phparchitect-2019-08

http://www.phparch.com \ August 2019 \ 9

Symfony 4: A New Way to Develop Applications

As you can see in Figure 10, with

this one single command, Symfony

flex installs and fully configures Twig

templating. If we want to remove it the

only thing we need is to write in console

composer remove twig and all files and

configuration are removed automati-

cally. Awesome, right?

In Listing 3, I rewrote the controller

a little bit as I wanted to get access to

helper methods. Please notice I extend

AbstractController, not the Controller

class. Controller class is deprecated. The

main thing here is that you don’t have

any more direct access to $container, as

that is useless, so if you try $contain-

er->get('my_service') it won’t work.

Be sure to check the AbstractController

class to see what it does.

I am sure you’ll want to have profiler while you are devel-

oping your apps—just run composer require profiler. It is

automatically added and configured for your test and devel-

opment environment.

Our Hello World controller looks like Listing 4.

With routing:

index:

path: /{name}

controller: App\Controller\DefaultController::index

And template:

{% extends 'base.html.twig' %}

{% block body %}Hello {{ name }}{% endblock %}

Symfony 4 automates configuration so you can keep coding
features and reduce the time that you are spending inside
YAML files configuring your application. This is achieved
with providing the great error messages that we already saw,
but the main thing here is autowiring.

Autowiring And Configuration

Although Symfony 3 introduced Autowiring^19 , it is not some

new Symfony 4 thing. But, in combination with Symfony Flex,

it got better.

Autowiring allows you to manage services in the container

with minimal configuration. It reads the type hints on your

constructor (or other methods) and automatically passes

the correct services to each method. Symfony’s autowiring is

designed to be predictable: if it is not absolutely clear which

dependency should be passed, you’ll see an actionable excep-

tion.

19 Autowiring: https://phpa.me/symfony-autowiring

Some developers don’t use it because of all the magic that is

happening during autowiring. However, just like most impres-

sive magic tricks, there is no magic at all, and it is quite simple.

In the past, we needed to define everything manually when

we were creating services. First, we needed to create a class,

and then we defined that class as service in our configuration

file (services.yml, for example). All services have a unique ID

(name) and class that matches that service, previously defined.

Figure 10

Listing 3

1. <?php


2. 
   


3. namespace App\Controller;


4. 
   


5. use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;


6. 
   


7. class DefaultController extends AbstractController


8. {


9. public function index()


10. {


11. return $this->render('index.html.twig');


12. }


13. }

Listing 4

1. <?php


2. 
   


3. namespace App\Controller;


4. 
   


5. use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;


6. 
   


7. class DefaultController extends AbstractController


8. {


9. public function index($name)


10. {


11. return $this->render('index.html.twig', [


12. 'name' => $name


13. ]);


14. }


15. }