get extended access token

gistfile1.php

    /**
     * get extended access token
     *
	 * @param string $token token
	 *
	 * @return mixed
	 */
	public function get_extended_access_token($token)
	{

		$token_url = "https://graph.facebook.com/oauth/access_token?client_id=" . $this->config->config['facebook']['app_id'] . "&client_secret=" . $this->config->config['facebook']['secret'] . "&grant_type=fb_exchange_token&fb_exchange_token=" . $token;

		$curl = curl_init();
		curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
		curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, FALSE);
		curl_setopt($curl, CURLOPT_URL, $token_url);

		$contents = curl_exec($curl);
		$err      = curl_getinfo($curl, CURLINFO_HTTP_CODE);

		if ($err) {
			log_message('ERROR', print_r($err, 1));
		}
		curl_close($curl);

		$paramsfb = array();
		parse_str($contents, $paramsfb);

		return $paramsfb['access_token'];
	}