Prevent multiple login CakePHP3

Question

I have finished the CakePHP3 Blog tutorial. Now I want to prevent users from multiple login on same computer. I mean, after having logged in, the user has to log out in order to access the log in action again. How can I do that?

Answer 1

Had the exact same issue here's how I fixed it. In your AppController, add this to your initialize function:

$this->loadComponent('Auth', [
        'authenticate' => [
            'Form' => [
                'fields' => [
                    'username' => 'username',
                    'password' => 'password'
                ]
            ]
        ],
        'loginAction' => [
            'controller' => 'Users',
            'action' => 'login'
        ],
    ]);

This basically forces the user to log-in before anything else.

And in the controller that handles the login I added this:

if($this->Auth->user()){
        $this->Flash->error(__('You are already logged in!'));
        return $this->redirect(['controller' => 'index']);
    }

This checks if there is already a user logged in and, if so, is redirected to the home page.