Codeigniter, Facebook SDK, PHP: Using Facebook SDK to get user FB id, like gate and/or check login status

gistfile1

/*
	BE SURE TO INCLUDE THE FACEBOOK SDK FILES, DROP THE FOLLOWING FILES INTO THE 'third_party' FOLDER IN CODEIGNITER:
		base_facebook.php
		facebook.php
		fb_ca_chain_bundle.crt
*/


// ============= MODEL FILE (facebook_api_model.php)

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class Facebook_api_model extends CI_Model
{
	
	// --------------------------------  GET USERS FACEBOOK ID, CHECK LOGGED IN STATUS AND LIKE GATE
	function call_facebook()
	{
		/*===================== FACEBOOK API STUFF STARTS ====================*/
		
		// INCLUDE FACEBOOK SDK
		require 'application/third_party/facebook.php';
	
		// THE BELOW LINES ARE USED TO CREATE THE $auth_url VAR - THIS VARIABLE IS RESPONSIBLE FOR REDIRECTION IF YOU ARE NOT SIGNED IN
		$app_id = '414815291884674';
		// $canvas_page = "http://www.facebook.com/pages/Proximity/160329604032006?sk=app_414815291884674";
		$canvas_page = "http://www.facebook.com/kenco/?sk=app_YOUR APP ID";
		//$canvas_page = "http://fb.kraft-hosting.net/kenco/uken/adoration";
		$auth_url = "http://www.facebook.com/dialog/oauth?client_id=" . $app_id . "&redirect_uri=" . urlencode($canvas_page);
		
		// INIT FACEBOOK OBJECT WITH APP KEYS
		$facebook = new Facebook(array(
		  'appId'  => 'YOUR APP ID HERE',
		  'secret' => 'YOUR APP SECRET'
		));
		
		// BELOW LINE GETS USER ID AND STORES TO VAR
		$user = $facebook->getUser();
		
		// STORE USER FACEBOOK ID IN SESSION REGARDLESS OF WHETHER OR NOT PAGE IS LIKED
		if(isset($user)){
			$this->session->set_userdata('fb_id', $user);
		}else{
			$this->session->set_userdata('fb_id', '');
		}
		
		// BELOW LINE GETS THE SIGNED REQUEST TO FIND OUT IF A USER HAS LIKED THE PAGE OR NOT
		$signed_request = $facebook->getSignedRequest();
		
		// REDIRECT IF USER VAR IS EMPTY/NOT SIGNED IN
		if($user == '' || $user == NULL || $user == 'NULL')
		{
			if($user == '0' || $user == 0)
			{
				
				echo '<script type="text/javascript">window.parent.location = "'.$auth_url.'"</script>';
				exit;
				
			}
			// BECAUSE FACEBOOK APPS ARE IN IFRAMES YOU NEED TO DO A PARENT WINDOW REDIRECT USING JAVASCRIPT
			echo '<script type="text/javascript">window.parent.location = "'.$auth_url.'"</script>';
			exit;
			//header("Location: ".$auth_url);
		}
		
		// GET LIKE STATUS
		$likeStatus = empty($signed_request["page"]["liked"]) ? false : (bool)$signed_request["page"]["liked"];
		
		return $likeStatus;
		
		/*===================== FACEBOOK API STUFF ENDS ====================*/
	}


// --------------------------------  LIKE GATE ONLY
	function like_gate()
	{
		/*===================== FACEBOOK API STUFF STARTS ====================*/
		
		// INCLUDE FACEBOOK SDK
		require 'application/third_party/facebook.php';
		
		// INIT FACEBOOK OBJECT WITH APP KEYS
		$facebook = new Facebook(array(
		  'appId'  => '258007694310745',
		  'secret' => '67736210f55f2c355fee0025e1715ef0'
		));
		
		// BELOW LINE GETS THE SIGNED REQUEST TO FIND OUT IF A USER HAS LIKED THE PAGE OR NOT
		$signed_request = $facebook->getSignedRequest();
		
		// GET LIKE STATUS
		$likeStatus = empty($signed_request["page"]["liked"]) ? false : (bool)$signed_request["page"]["liked"];
		
		return $likeStatus;
		
		/*===================== FACEBOOK API STUFF ENDS ====================*/
	}

}	

/* End of file facebook_api_model.php */
/* Location: ./application/models/facebook_api_model.php */








// ============= CONTROLLER FILE (like_gate.php)

// THIS VERSION WILL ALSO CHECK IF YOU ARE LOGGED IN, WILL GET THE USERS FACEBOOK ID AND WILL REDIRECT IF YOU ARE NOT BEFIRE LIKE GATING
$this->likeStatus = $this->facebook_api_model->call_facebook(); 
if($this->likeStatus){
	$data['main_content'] = 'liked_view';
}else{
	$data['main_content'] = 'not_liked_view';
}


// THIS IS PURELY FOR LIKE GATING
$this->likeStatus = $this->facebook_api_model->like_gate();
if($this->likeStatus){
	$data['main_content'] = 'liked_view';
}else{
	$data['main_content'] = 'not_liked_view';
}

/* End of file like_gate.php */
/* Location: ./application/controllers/like_gate.php */