A simple Facebook social reader app. This can be improved a lot

sreader.php

<?php

$app_id = "xxxxxxx"; //facebook app id
$redirect_url = "xxxxxx"; //url to redirct after getting the token, should be in the same domain of the canvas url
$app_secret = "xxxxxxx"; //facebook app secret

session_start();

$code = $_REQUEST['code'];

if(empty($code))
{

$outh_url = "https://www.facebook.com/dialog/oauth?client_id=" . $app_id . "&redirect_uri=" . urlencode($redirect_url) . "&scope=publish_actions";
header('Location:' . $outh_url);
}


$token_url = "https://graph.facebook.com/oauth/access_token?client_id=" . $app_id . "&redirect_uri=" . urlencode($redirect_url) . "&client_secret=" . $app_secret . "&code=" . $code;

$response = file_get_contents($token_url);
parse_str($response, $params);
$acctoken = $params['access_token'];


//echo $acctoken;
//echo "/n" . $toktok;

$data = array('access_token' => $acctoken , 'article' => URL);

$curl = curl_init();
curl_setopt($curl, CURLOPT_URL,"https://graph.facebook.com/me/NAMESPACE_OF_APP:publish");
curl_setopt($curl, CURLOPT_POST, 1);
curl_setopt($curl, CURLOPT_POSTFIELDS, $data);
curl_exec ($curl);
curl_close ($curl);


?>