title: Authenticate Facebook users in Cakephp 3x
body: <p>I have used PHP SDK-4 for Facebook login in CakePHP 3 (beta version) which works fine.<br>Now, I'm in need to fetch user data based on FB login and authenticate users. Am trying with Cake's Auth component. Initially, while trying to Auth users,</p>
  
  <blockquote>
    <p>$this->Auth->setUser($user)</p>
  </blockquote>
  
  <p>Got <pre>Error: Session was already started</pre> as we require session_start() for Facebook login.<br> 1- Tried with <a href="https://stackoverflow.com/questions/24194112/facebook-php-sdk-exception-error">enter link description here</a>, and sessions [session_write_close()] etc..still it did not work.<br> Could I get some shot on best way to authenticate users with Facebook login in site?</p>