Question

I was developing Facebook Based Authentication for one of my app, earlier time i was using following code From Nettuts Tutorial

but when graph api 3.0 came out i can add this same code for my new web app, how can i generate a login as the about link?

i am using following code, but dont know how to do session in it?

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Answer 1

Using the Facebook PHP SDK, you need to redirect to Facebook’s OAuth dialog, and then use the returning request to authenticate your user.

Facebook have the following sample on http://developers.facebook.com/docs/authentication/:

<?php

$app_id = "YOUR_APP_ID";
$app_secret = "YOUR_APP_SECRET";
$my_url = "YOUR_URL";

session_start();
$code = $_REQUEST["code"];

if(empty($code)) {
  $_SESSION['state'] = md5(uniqid(rand(), TRUE)); //CSRF protection
  $dialog_url = "http://www.facebook.com/dialog/oauth?client_id=" 
    . $app_id . "&redirect_uri=" . urlencode($my_url) . "&state="
    . $_SESSION['state'];

  echo("<script> top.location.href='" . $dialog_url . "'</script>");
}

if($_REQUEST['state'] == $_SESSION['state']) {
  $token_url = "https://graph.facebook.com/oauth/access_token?"
    . "client_id=" . $app_id . "&redirect_uri=" . urlencode($my_url)
    . "&client_secret=" . $app_secret . "&code=" . $code;

  $response = @file_get_contents($token_url);
  $params = null;
  parse_str($response, $params);

  $graph_url = "https://graph.facebook.com/me?access_token=" 
    . $params['access_token'];

  $user = json_decode(file_get_contents($graph_url));
  echo("Hello " . $user->name);
}
else {
  echo("The state does not match. You may be a victim of CSRF.");
}