Posting news feeds in facebook

$config = array(
 'appId'  => 'yyyyyyyyyy',
 'secret' => 'xxxxxxxxxx',
 'cookie' => true,
 'domain' => true
);

$facebook_client = new Facebook($config);

//Grab the user's session
$session = $facebook_client->getSession();

/*If session does not exist, the user is not loggedin or hasn't added the app
so redirect them to the authorize page.*/
if(!$session){
 $text = "<script type=\"text/javascript\">\ntop.location.href = \"$oauth_url\";\n</script>";
 echo $text;
 exit;
}
$access_token = $access['access_token'];
$params = array('access_token' => $access_token);
try{
$me = $facebook_client->api('/me',$params);
$feed_params = array();
$feed_params['message'] = "Hello world";
$feed_params['link'] = "h开发者_Python百科ttp://apps.facebook.com/jagdish/";
$feed_params['name'] = "jag";
$feed_params['caption'] = "Trying to post from application";
$feed_params['description'] = "From jag";
$feed_params['access_token'] = $access_token;
$id = me['id'];
$result = $facebook->api('/me/feed/','post',$feed_params);
}
catch(FacebookApiException $e)
{
    error_log($e);
}

This is my code. When i executed it, got an exception saying

com.caucho.quercus.QuercusException: com.caucho.quercus.QuercusErrorException: /base/data/home/apps/fbookworkshop/version1.349114876107177725/index.php:49: Fatal Error: Method call 'api' is not allowed for a null value.

Where am i going wrong?

I guess you are mixing 3 (or more) tutorials together!!

Issues in your code:
The first issue:

$text = "<script type=\"text/javascript\">\ntop.location.href = \"$oauth_url\";\n</script>";

In this line:

1. Where did you set the $oauth_url?
2. Also no need for the \n

The second issue (mentioned by @fazo).

The third issue, NO NEED for the access_token all together if there's a valid session! so don't set it or use it in any of your requests as long as you are using /me.

The fourth issue:

$result = $facebook->api('/me/feed/','post',$feed_params);

Here you are using the code from another tutorial, since you are using $facebook var instead of $facebook_client

change

$access_token = $access['access_token'];

to

$access_token = $session['access_token'];

and tell us what happened

UPDATE:

looks like you can't use /me

https://github.com/facebook/php-sdk/issues/closed#issue/294