Uncaught OAuthException: Error validating application - php

Question

I am developing my first facebook app, which includes creating a new album and posting photos to the user wall. By learning through facebook documentation and few tutorial and came up this code, but I am getting following error with it.
Fatal error: Uncaught OAuthException: Error validating application. Thrown in /home/base_facebook.php on line 1106
Plus: I don’t know if it matters or not, but when I am printing out the
echo $facebook->getUser();
variable it giving me ‘0’ in return even though user (which in this case is myself) is logged in.
Kindly help me through this.
Code:
$config = array(
'appId' => '3663250024856',
'secret' => 'b14ac6d2b7dbdtyb259599b06983e881',
'fileUpload' => true,
'cookie' => true
);
$facebook = new Facebook($config);
echo "USER STATUS:".$facebook->getUser();
$facebook -> setFileUploadSupport(true);
$album_details = array('message' => 'Album desc', 'name' => 'Album name');
$create_album = $facebook -> api('/me/albums', 'post', $album_details);
$album_uid = $create_album['id'];
$photo_details = array('message' => 'Photo message');
$file = "temp/".$imageName;
$photo_details['image'] = '#' . realpath($file);
$upload_photo = $facebook -> api('/' . $album_uid . '/photos', 'post', $photo_details);

Answer 1

The best working solution I've found in the web. Add the below code at the top of your php page:
$app_id = "YOUR_APP_ID";
$app_secret = "YOUR_APP_SECRET";
$my_url = "YOUR_URL";
$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'];
}

Answer 2

Even though the user is logged in, the user needs to give permission to your app before you can make api calls.
Basically the flow for user authentication using facebook php sdk should be like this:
Detect whether the user is logged in and given permission to your app.
If he hasn't given permission, redirect him to the login and application permission page. After logging in and giving permission, he'll be redirected back again to your application page.
Otherwise, show the content of your app, make api calls,...
Here is a modified sample code from the php sdk's documentation page to handle authentication that should work if you just modify the appId, appSecret and redirect_uri:
<?php
require_once 'fb_php_sdk/facebook.php';
$appId = 'your_app_id';
$appSecret = 'your_app_secret';
// Create your Application instance (replace this with your appId and secret).
$facebook = new Facebook(
array(
'appId' => $appId,
'secret' => $appSecret,
'fileUpload' => true,
'cookie' => true
));
// Get User ID
$user = $facebook->getUser();
if ($user)
{
try {
// Proceed knowing you have a logged in user who's authenticated.
$user_profile = $facebook->api('/me');
} catch (FacebookApiException $e) {
error_log($e);
$user = null;
}
}
// Login or logout url will be needed depending on current user state.
if ($user)
{
$logoutUrl = $facebook->getLogoutUrl();
}
else
{
$loginUrl = $facebook->getLoginUrl(
array(
'canvas' => 1,
'fbconnect' => 0,
'scope' => '',//these are the extended permissions you will need for your app, add/remove according to your requirement
'redirect_uri' => 'http://apps.facebook.com/test_app_azk/',//this is the redirect uri where user will be redirected after allow,
));
}
if ($user)
{
//show the content of your app
//make api calls
var_dump($user_profile);
}
else
{
//redirect user to loginUrl
echo "<script>parent.location = '".$loginUrl."';</script>";
}
Hope this helps.

Answer 3

The problem might lie within the else statement. Instead of using else use if(!user). That should fix the issue.