Facebook PHP SDK Extracting Access Token - php

Question

Every time I run this script it gives me a different access token. I thought the access token was unique to a user.. Also why is this script so unreliable, fails half the time.
My Facebook Access Token Page
Here is the code:
<?php
require 'lib/facebook.php';
require_once('C:\inetpub\storeboard.com\linkedin\extract_data.php');
$facebook = new Facebook(array(
'appId' => FACEBOOK_APPID,
'secret' => FACEBOOK_APP_SECRET
));
$user = $facebook->getUser();
if ($user) {
try {
// Proceed knowing you have a logged in user who's authenticated.
$user_profile = $facebook->api('/me');
} catch (FacebookApiException $e) {
echo '<pre>'.htmlspecialchars(print_r($e, true)).'</pre>';
$user = null;
}
}
$access_token = $facebook->getAccessToken();
if (isset($access_token)) {
echo $access_token;
//header( 'Location: http://www.'.APP_ROOT_DOMAIN.'/facebook/save_token.asp?nToken='.$access_token);
}
?>
Have I cut out code that is required from the original: http://developers.facebook.com/blog/post/534/
or am I missing something.
require_once('C:\inetpub\storeboard.com\linkedin\extract_data.php');
This line of code just extracts the APPID and APPSECRET from the database.
I am a complete beginner when it comes to PHP, so any help would be greatly appreciated.
Many Thanks!

Answer 1

You don't need to play with the token to get simple authentication:
After you get facebook api instance:
$facebook = new Facebook(array(
'appId' => FACEBOOK_APPID,
'secret' => FACEBOOK_APP_SECRET
));
If you are using me API - get the user profile:
$user_profile = $facebook->api('/me');
then obtain email from it:
$email = $user_profile['email'];
At this point you check if the email is valid in your database - if yes start the user session and you are good to go.