symfony An error has occurred: Notice: Undefined property: ::$container

Question

I working on a web socket app using ratchet and symfony 2.8 to connect to database and changing value in a certain column if someone connect to the server but I get error in this line

    $sql = $this->container->get('database_connection');

the full error message

An error has occurred: Notice: Undefined property: check\roomsBundle\Sockets\Chat::$container

my injection in the services.yml code

services:
     database_connection:
         class: check\roomsBundle\Sockets\Chat
         arguments: ["@service_container"] 

my Chat.php code

<?php
namespace check\roomsBundle\Sockets;
use tuto\testBundle\Entity\Users;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Symfony\Component\HttpFoundation\Request;

use Ratchet\MessageComponentInterface;
use Ratchet\ConnectionInterface;
use Symfony\Component\DependencyInjection\ContainerInterface;

class Chat implements MessageComponentInterface  {


    protected $clients;
    //protected $db;
    public function __construct() {
        $this->clients = new \SplObjectStorage;
    }

    public function onOpen(ConnectionInterface $conn) {
        $this->clients->attach($conn);

        echo "New connection! ({$conn->resourceId})\n";

        $sql = $this->container->get('database_connection');
        $users = $sql->query("UPDATE user SET ONoff= '1' WHERE UserId='2'");


    }
}

Answer 1

Ok so there's a few things that you'll need to fix in order to solve your problem.

services:
     database_connection:
         class: check\roomsBundle\Sockets\Chat
         arguments: ["@service_container"] 

What this is doing is when it calls the constructor it's going to pass in the service container, however using the constructor to pass in your container isn't favorable, but rather instead you should implement the Symfony\Component\DependencyInjection\ContainerAwareInterface interface and then implement the method setContainer and optional a getContainer method.

/**
 * @param ContainerInterface|NULL $container
 */
public function setContainer(
    ContainerInterface $container = NULL
)
{
    $this->container = $container;
    return $this;
}

/**
 * @return ContainerInterface
 */
protected function getContainer()
{
    return $this->container;
}

And then after that update your service to call this method when initializing it.

services:
     chat_service: # renamed because this is your chat service, not your database connection
         class: check\roomsBundle\Sockets\Chat
         calls:
             - [setContainer, ["@service_container"]]

Answer 2

Your service is fine you just need little changes in your chat.php class

use Symfony\Component\DependencyInjection\ContainerInterface as Container;

class Chat implements MessageComponentInterface  {

protected $clients;
private $container;
//protected $db;
public function __construct(Container $container) {
    $this->clients = new \SplObjectStorage;
    $this->container = $container;
}

Now u can use $this->container

Updated

Try to inject entity manager

services:
  database_connection:
    class: check\roomsBundle\Sockets\Chat
    arguments: 
        - @doctrine.orm.default_entity_manager

in chat.php do like this

use Doctrine\ORM\EntityManager;
class Chat implements MessageComponentInterface  {

   protected $clients;
   protected $em;
   public function __construct(EntityManager $em) {
       $this->clients = new \SplObjectStorage;
       $this->em = $em;
   }
$this->em->getRepository('yorrepo')->updateFuntion();

Now try to call from some repo to update

Answer 3

Injecting the service container is generally considered as a bad idea.

you should consider to inject database_connection service .

There are few ways to do that. Have a look at Types of Injection.

services:
     chat_service:
         class: check\roomsBundle\Sockets\Chat
         arguments: ["@database_connection"]

your class

protected $connection;

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

Even if you want to go ahead with injecting the service container, the above link has relavent documentation that will help you to solve the issue you are facing.