How To: Post On Facebook Page As Page Not As Admin User Using PHP-SDK

Posting as Admin is easy but posting as Page requires more work from your side. To post as Page we need the following permissions:

• publish_stream
• manage_pages

Using the page object

UPDATE: Facebook has extended their page object and now you can retrieve the page access_token directly from the page. The code below uses the latest methods.
UPDATE #2: the below example was broken because for some reason if the admin didn’t grant the app the manage_pages permission, the /$page_id?fields=access_token call is returning the page id instead of an error. And hence, a permission check was added as a work around and a bug was reported.

We need the manage_pages permission to get the page access token so we can post on its behalf. And this is how we do it:

<?php
// This code is just a snippet of the example.php script 
// from the PHP-SDK <https://github.com/facebook/facebook-php-sdk/blob/master/examples/example.php>
require '../src/facebook.php';

// Create our Application instance (replace this with your appId and secret).
$facebook = new Facebook(array(
  'appId'  => 'app_id',
  'secret' => 'app_secret',
));

// Get User ID
$user = $facebook->getUser();

if ($user) {
  try {
	$page_id = 'page_id';
	$page_info = $facebook->api("/$page_id?fields=access_token");
	if( !empty($page_info['access_token']) ) {
		$args = array(
			'access_token'  => $page_info['access_token'],
			'message'       => "I'm a Page!"
		);
		$post_id = $facebook->api("/$page_id/feed","post",$args);
	} else {
		$permissions = $facebook->api("/me/permissions");
		if( !array_key_exists('publish_stream', $permissions['data'][0]) || 
			!array_key_exists('manage_pages', $permissions['data'][0])) {
			// We don't have one of the permissions
			// Alert the admin or ask for the permission!
			header( "Location: " . $facebook->getLoginUrl(array("scope" => "publish_stream, manage_pages")) );
		}

	}
  } 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('scope'=>'manage_pages,publish_stream'));
}

// ... rest of your code
?>

And the result:

Posting as Page

Using the Javascript-SDK

Achieving the same with only client-side technology:

function postToPage() {
	var page_id = '195234433832970';
	FB.api('/' + page_id, {fields: 'access_token'}, function(resp) {
		if(resp.access_token) {
			FB.api('/' + page_id + '/feed',
				'post',
				{ message: "I'm a Page!", access_token: resp.access_token }
				,function(response) {
					console.log(response);
			});
		}
	});
}

Using /me/accounts connection

If you are building some sort of a CMS where the admin wants to select one of the pages to update its status, then using the /me/accounts is better you can list the pages and save their access_token in one API call.

$page_id = "XXXXXXXXX";
$page_access_token = "";
$result = $facebook->api("/me/accounts");
foreach($result["data"] as $page) {
    if($page["id"] == $page_id) {
        $page_access_token = $page["access_token"];
        break;
    }
}
if( !empty($page_access_token) ) {
	$args = array(
		'access_token'  => $page_access_token,
		'message'       => "I'm a Page!"
	);
	$post_id = $facebook->api("/$page_id/feed","post",$args);
	// sucess...
} else {
	// couldn't find the page!
}

Always communicate with your page fans as Page not as Admin, fans do know (and trust) your page (product) but not necessary you!