Facebook PHP SDK - How to get access token?

Question

I'm trying to post on user's Facebook wall from my app. The user granted the permissions to the app to post on his wall, and I have userid in db. I need to send the post automatically, without the user logging in again.

My code is:

try{
    require_once(dirname(__FILE__) . '\lib\facebook-php\src\facebook.php' );
}
catch(Exception $o){
        print_r($o);
}
$config = array(
    'appId' => '123456',
    'secret' => '454544',
    'allowSignedRequest' => false // optional but should be set to false for non-canvas apps
);

$facebook = new Facebook($config);
$user_id = $facebook->getUser();
$user_id = '123456';

if($user_id) {

    // We have a user ID, so probably a logged in user.
    // If not, we'll get an exception, which we handle below.
    try {

        $ret_obj = $facebook->api('/me/feed', 'POST',
            array(
                'access_token' => $facebook->getAccessToken(),
                'link' => 'www.example.com',
                'message' => 'Posting with the PHP SDK!'
            ));
        echo '<pre>Post ID: ' . $ret_obj['id'] . '</pre>';

        // Give the user a logout link
        echo '<br /><a href="' . $facebook->getLogoutUrl() . '">logout</a>';
    } catch(FacebookApiException $e) {
        // If the user is logged out, you can have a
        // user ID even though the access token is invalid.
        // In this case, we'll get an exception, so we'll
        // just ask the user to login again here.
        var_dump($e);
        $login_url = $facebook->getLoginUrl( array(
            'scope' => 'publish_stream'
        ));
        echo 'Please <a href="' . $login_url . '">login.</a>';
        error_log($e->getType());
        error_log($e->getMessage());
    }
} else {

    // No user, so print a link for the user to login
    // To post to a user's wall, we need publish_stream permission
    // We'll use the current URL as the redirect_uri, so we don't
    // need to specify it here.
    $login_url = $facebook->getLoginUrl( array( 'scope' => 'publish_stream' ) );
    echo 'Please <a href="' . $login_url . '">login.</a>';

}

This throws An active access token must be used to query information about the current user. error and asks for login. After I click login, the post is sucesfully posted.

How can I get the access token with userid without the user logging in?

Answer 1

This happens when the active access token is not available while calling the API end point /me

There are two solutions to get rig of this

• use the userid instead of /me

• set the access-token prior sending the api call

For the first you can make the call as

ret_obj = $facebook->api('/'.$user_id.'/feed', 'POST',
            array(
                'link' => 'www.example.com',
                'message' => 'Posting with the PHP SDK!'
            ));

You dont need to send 'access_token' => $facebook->getAccessToken(),

The Second option is to do as

$access_token =  $facebook->getAccessToken();
$facebook->setAccessToken($access_token);
ret_obj = $facebook->api('/me/feed', 'POST',
                array(
                    'link' => 'www.example.com',
                    'message' => 'Posting with the PHP SDK!'
                ));

NOTE: publish_stream scope must be send while doing the login

Deprecation Notice :publish_stream was replaced by publish_actions, check the facebook doc for permission