code: public function completeLogin($extrainputs = array()) {
  		$facebook = $this->getFacebookObject();
  		
  		// we are not sure about $_GET contains all correct data
  		// as in this model data are posted with $extrainputs
  		// ideally it would be good if facebook lib accept data not only from _GET but also from any array
  		$old_GET = $_GET;
  		$_GET = $extrainputs;
  		
  		$helper = $facebook->getRedirectLoginHelper();
  
  		// don't catch exceptions. it will be done in the model or controller
  		$accessToken = $helper->getAccessToken();
  		
  		$_GET = $old_GET;
  		
  		if (! isset($accessToken)) {
  			if ($helper->getError()) {
  				throw new \Exception($helper->getError().' '.
  					$helper->getErrorCode().' '.
  					$helper->getErrorReason().' '.
  					$helper->getErrorDescription());
      			} else {
      				throw new \Exception('Unknown error from Facebook');
      			}
    		}
  
    		$this->accesstoken = $accessToken;
    		
    		return $this->getUserProfile();
  	}
docs: Completes social login. Is caled after redirect from facebook auth page
  
  @param array $extrainputs List of POST/GET arguments names