Facebook PHP SDK - 如何获取访问令牌？

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

Answer 2

you have to get permission . Check it out here

https://developers.facebook.com/docs/reference/login/