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');

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.ymlparameters:    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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In case you use older approach, you can automate it with Rector.

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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...)).

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;}