/**
* Authenticates the current viewer of the app, prompting them to login and
* grant permissions if necessary. For more information, check the
* 'https://developers.facebook.com/docs/authentication/'
*
* @return app access token if login is successful
*/
public static function login($redirect)
{
$app_id = AppInfo::appID();
$app_secret = AppInfo::appSecret();
$home = AppInfo::getHome();
// Scope defines what permissions that we are asking the user to grant.
// In this example, we are asking for the ability to publish stories
// about using the app, access to what the user likes, and to be able
// to use their pictures. You should rewrite this scope with whatever
// permissions your app needs.
// See https://developers.facebook.com/docs/reference/api/permissions/
// for a full list of permissions
$scope = 'user_likes,user_photos,user_photo_video_tags';
session_start();
$code = $_REQUEST["code"];
// If we don't have a code returned from Facebook, the first step is to get
// that code
if (empty($code)) {
// CSRF protection - for more information, look at 'Security Considerations'
// at 'https://developers.facebook.com/docs/authentication/'
$state = md5(uniqid(rand(), TRUE));
setcookie(AppInfo::appID() . '-fb-app', $state, $expires = 0, $path = "", $domain = "", $secure = "", $httponly = true);
// Now form the login URL that you will use to authorize your app
$authorize_url = "https://www.facebook.com/dialog/oauth?client_id={$app_id}" . "&redirect_uri={$home}&state=" . $state . "&scope={$scope}";
// Now we redirect the user to the login page
echo "<script> top.location.href='" . $authorize_url . "'</script>";
return false;
// Once we have that code, we can now request an access-token. We check to
// ensure that the state has remained the same.
} else {
if ($_REQUEST['state'] === $_COOKIE[AppInfo::appID() . '-fb-app']) {
$ch = curl_init("https://graph.facebook.com/oauth/access_token");
curl_setopt($ch, CURLOPT_POSTFIELDS, "client_id={$app_id}&redirect_uri={$home}&client_secret={$app_secret}" . "&code={$code}&scope={$scope}");
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$response = curl_exec($ch);
// Once we get a response, we then parse it to extract the access token
parse_str($response, $params);
$token = $params['access_token'];
return $token;
// In the event that the two states do not match, we return false to signify
// that something has gone wrong during authentication
} else {
echo "States do not match. CSRF?";
return false;
}
}
}
// Fetch the basic info of the app that they are using
$app_id = AppInfo::appID();
$app_info = FBUtils::fetchFromFBGraph("{$app_id}?access_token={$token}");
// This fetches some things that you like . 'limit=*" only returns * values.
// To see the format of the data you are retrieving, use the "Graph API
// Explorer" which is at https://developers.facebook.com/tools/explorer/
$likes = array_values(idx(FBUtils::fetchFromFBGraph("me/likes?access_token={$token}&limit=4"), 'data'));
// This fetches 4 of your friends.
$friends = array_values(idx(FBUtils::fetchFromFBGraph("me/friends?access_token={$token}&limit=4"), 'data'));
// And this returns 16 of your photos.
$photos = array_values(idx($raw = FBUtils::fetchFromFBGraph("me/photos?access_token={$token}&limit=16"), 'data'));
// Here is an example of a FQL call that fetches all of your friends that are
// using this app
$app_using_friends = FBUtils::fql("SELECT uid, name, is_app_user, pic_square FROM user WHERE uid in (SELECT uid2 FROM friend WHERE uid1 = me()) AND is_app_user = 1", $token);
// This formats our home URL so that we can pass it as a web request
$encoded_home = urlencode(AppInfo::getHome());
$redirect_url = $encoded_home . 'close.php';
// These two URL's are links to dialogs that you will be able to use to share
// your app with others. Look under the documentation for dialogs at
// developers.facebook.com for more information
$send_url = "https://www.facebook.com/dialog/send?redirect_uri={$redirect_url}&display=popup&app_id={$app_id}&link={$encoded_home}";
$post_to_wall_url = "https://www.facebook.com/dialog/feed?redirect_uri={$redirect_url}&display=popup&app_id={$app_id}";
} else {
// Stop running if we did not get a valid response from logging in
exit("Invalid credentials");
}
?>
<!-- This following code is responsible for rendering the HTML -->
<!-- content on the page. Here we use the information generated -->
<!-- in the above requests to display content that is personal -->