Facebook publish_stream code ends up in a loop - php

Question

I have the following code which works fine as long as in a previous part of the application, the user accepts the applications request to publish_stream.
# The facebook library
require_once("/var/www/facebook-php-sdk-master/src/facebook.php");
# Create facebook object
$config = array();
$config['appId'] = 'appId_here';
$config['secret'] = 'secret_here';
$config['fileUpload'] = false; // optional
$facebook = new Facebook($config);
$user_id = $facebook->getUser();
if ($user_id) {
try {
$user_profile = $facebook->api('/me','GET');
#check permissions
$api_call = array(
'method' => 'users.hasAppPermission',
'uid' => $user_id,
'ext_perm' => 'publish_stream'
);
#set to true if true...
$can_offline = $facebook -> api( $api_call );
#is it true?
if( $can_offline ) {
$post = array(
'message' => 'post_a_message'
);
$facebook->api('/' . $_GET["id"] . '/feed', 'POST', $post);
} else {
// can't post message - don't have permission
}
} catch (FacebookApiException $e) {
error_log($e);
exit;
}
} else {
error_log("user not logged in");
exit;
}
To try to resolve this, I attempted to insert the following code into the else statement which currently in the code above only contains the comment // can't post message - don't have permission
The code I tried to insert into that else was this:
$loginUrl = $facebook->getLoginUrl( array( 'scope' => 'publish_stream' ) );
header("Location: ".$loginUrl);
That works as long as the user accepts to allow my app to publish_stream. However, if the user does not accept, my app will keep asking the user to accept publish_stream. How do I stop that loop from happening if the user decides not to accept?

Answer 1

As far as i remember, $facebook -> getLoginUrl can take parameter cancel_url, which contains the link, where user should be redirected if he doesn't give your app permissions.
So the code will be something like this
$login_url = $facebook -> getLoginUrl( array(
'scope' => 'publish_stream',
'cancel_url' => YOUR_LINK_HERE
));

Answer 2

Here is the working code : Please check it :
Page name : events.php
You can see $redirect_uri = https://localhost/facebook_page/events.php it is returning back to same page.
<?php
$facebook_appid = "your appid"; // Facebook appplication id
$facebook_secret = "your app secret"; // Facebook secret id
$redirect_uri = "https://localhost/facebook_page/events.php"; // return url to our application after facebook login ## should be SAME as in facebook application
$scope = "publish_stream"; // User permission for facebook
$profile_id = "profile_id";// Where do you want to post it(profile id - It is a number)
$code = $_REQUEST["code"]?$_REQUEST["code"]:"";
if(empty($code)) {
$_SESSION['state'] = rand(); // CSRF protection
$dialog_url = "https://www.facebook.com/dialog/oauth?client_id=". $facebook_appid . "&redirect_uri=" . urlencode($redirect_uri) . "&state=". $_SESSION['state'] . "&scope=".$scope;
header("location:".$dialog_url);
}
if($_SESSION['state'] && ($_SESSION['state'] == $_REQUEST['state'])) {
$token_url = "https://graph.facebook.com/oauth/access_token?". "client_id=" . $facebook_appid . "&redirect_uri=" . urlencode($redirect_uri). "&client_secret=" . $facebook_secret . "&code=" . $code;
$response = #file_get_contents($token_url);
$params = null;
parse_str($response, $params);
$access_token = $params['access_token'];
}
?>
<!-- Here you can use
message, picture, link, name, caption, description, source, place, tags
as input fields-->
<form enctype="multipart/form-data" method="POST" action="https://graph.facebook.com/<?php echo $profile_id;?>/feed?access_token=<?php echo $access_token; ?>">
<input type="text" name="message" value="test" />
<input type="submit" name="submit" value="Submit" />
</form>
You can post it using jquery also.

Answer 3

I use the following code to check if the user has allowed publishing permisions or not:
$permissions = $facebook->api('me/permissions');
if( array_key_exists('publish_stream', $permissions['data'][0]) ) {
//Continue with posting on users wall
} else {
//Continue without posting on users wall
}