Symfony Services Cookbook

Overview

Services should be used to provide business logic for controllers.

Controllers should follow a 5-10-20 rule. 5 variables, 10 actions, and 20 lines of code at a maximum for each controller. Push as much business logic to services to conform to this rule.

Class locations

Business logic classes should be outside the Entity directory, but still within the bundle. Something like {project_root}\src\AppBundle\Utils\.

Creating a service (example)

1. Create a business logic class
2. Define the service in services.yml
3. Use the service in a controller.

Business logic class

Defines a utility method, slugify():

// src/AppBundle/Utils/Slugger.php
namespace AppBundle\Utils;

class Slugger
{
    public function slugify($string)
    {
        return preg_replace(
            '/[^a-z0-9]/', '-', strtolower(trim(strip_tags($string)))
        );
    }
}

Define a service for the class

The naming convention traditionally is the path to the class, e.g. app.utils.slugger, but brevity is the preferred convention, so use the shortest name possible (in this case app.slugger).

# app/config/services.yml
services:
    # keep your service names short
    app.slugger:
        class: AppBundle\Utils\Slugger

Using the service

Services are accessed (in a controller for example) with the get() routine:

$slug = $this->get('app.slugger')->slugify($post->getTitle());