FacebookRepository4.php

<?php

/* ... */

	/**
	* Gets Facebook login URL
	*
	* @param array $scope
	* @return string
	**/
	public function getLoginUrl( $scope = [] )
	{
		$redirect_url = $this->createLoginResultUrl();
		$helper = $this->fb->getRedirectLoginHelper();

		return $helper->getLoginUrl( $redirect_url, $scope );
	}

	/**
	* Creates resolving URL for Facebook login redirects
	*
	* @return string
	**/
	protected function createLoginResultUrl()
	{
		return url('api/facebook-token') . '/result';
	}
	
	/**
	* Parses Facebook redirect and returns access token
	*
	* @return string|null
	**/
	public function parseLoginResult()
	{
		$redirect_url = $this->createLoginResultUrl();
		$helper = $this->fb->getRedirectLoginHelper();

		if ( ! $accessToken = $helper->getAccessToken( $redirect_url ) )
		{
			return null;
		}

		$oAuth2Client = $this->fb->getOAuth2Client();
		$longLivedAccessToken = $oAuth2Client->getLongLivedAccessToken( $accessToken );

		return is_string($longLivedAccessToken) ? (string)$longLivedAccessToken : $longLivedAccessToken->getValue();
	}