How do I read from parameters.yml in a controller in symfony2?

The Clean Way - 2018+, Symfony 3.4+

Since 2017 and Symfony 3.3 + 3.4 there is much cleaner way - easy to setup and use.

Instead of using container and service/parameter locator anti-pattern, you can pass parameters to class via it's constructor. Don't worry, it's not time-demanding work, but rather setup once & forget approach.

How to set it up in 2 steps?

1. app/config/services.yml

# config.yml

# config.yml
parameters:
    api_pass: 'secret_password'
    api_user: 'my_name'

services:
    _defaults:
        autowire: true
        bind:
            $apiPass: '%api_pass%'
            $apiUser: '%api_user%'

    App\:
        resource: ..

2. Any Controller

<?php declare(strict_types=1);

final class ApiController extends SymfonyController
{
    /**
     * @var string 
     */
    private $apiPass;

    /**
     * @var string
     */
    private $apiUser;

    public function __construct(string $apiPass, string $apiUser)
    {
        $this->apiPass = $apiPass;
        $this->apiUser = $apiUser;
    }

    public function registerAction(): void
    {
        var_dump($this->apiPass); // "secret_password"
        var_dump($this->apiUser); // "my_name"
    }
}

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This is called constructor injection over services locator approach.

To read more about this, check my post How to Get Parameter in Symfony Controller the Clean Way.

(It's tested and I keep it updated for new Symfony major version (5, 6...)).

In Symfony 4, you can use the ParameterBagInterface:

use Symfony\Component\DependencyInjection\ParameterBag\ParameterBagInterface;

class MessageGenerator
{
    private $params;

    public function __construct(ParameterBagInterface $params)
    {
        $this->params = $params;
    }

    public function someMethod()
    {
        $parameterValue = $this->params->get('parameter_name');
        // ...
    }
}

and in app/config/services.yaml:

parameters:
    locale: 'en'
    dir: '%kernel.project_dir%'

It works for me in both controller and form classes. More details can be found in the Symfony blog.

I send you an example with swiftmailer:

parameters.yml

recipients: [email1, email2, email3]

services:

your_service_name:
        class: your_namespace
        arguments: ["%recipients%"]

the class of the service:

protected $recipients;

public function __construct($recipients)
{
    $this->recipients = $recipients;
}

In Symfony 2.6 and older versions, to get a parameter in a controller - you should get the container first, and then - the needed parameter.

$this->container->getParameter('api_user');

This documentation chapter explains it.

While $this->get() method in a controller will load a service (doc)

In Symfony 2.7 and newer versions, to get a parameter in a controller you can use the following:

$this->getParameter('api_user');