Automatically follow a twitter user on post save

autofollow.php

<?php

$Twitter_Auto_Follow = new Twitter_Auto_Follow();

class Twitter_Auto_Follow {
	
	static $TwitterAPIExchange;

	public function __construct() {
	
		/* Include Twitter API Class */
		include_once( WO_PATH . 'includes/twitter-api-php-master/TwitterAPIExchange.php');
		
		self::define_static_variables();
		self::load_hooks();
		
	}

	public static function define_static_variables() {
		
		/* @devinboundnow */
		self::$TwitterAPIExchange = new TwitterAPIExchange( array(
			'oauth_access_token' => '2462503164-2jKjIj2lmIirUEqgrcXi3rtXKLFWqh3dIwi----',
			'oauth_access_token_secret' => 'xv1sA45pzWz95EIy6cyISZ3119H1gL9Ac5C01n1L----',
			'consumer_key' => '4YuaL3c1BGl89SiPRv7h5----',
			'consumer_secret' => 'uLtFdSUS9jLaZHRrU8t5KW34gOyh7fFvOnx5GrQCwKnFH6----'
		));
	}
	
	public static function load_hooks() {
	
		add_action( 'save_post' , array( __CLASS__ , 'follow_user' ) , 12 );

	}
	
	public static function follow_user( $post_id ) {
		
		global $post;
		
		if ( !isset($post) || $post->post_type != 'job_listing' ) {
			return;
		}

		$twitter_username = ( get_post_meta( $post->ID , '_company_twitter' , true ) ) ? get_post_meta( $post->ID , '_company_twitter' , true ) : null;
		$followed = ( get_post_meta( $post->ID , '_twitter_followed' , true ) ) ? get_post_meta( $post->ID , '_twitter_followed' , true ) : null;

		if ( !$twitter_username || $followed ) {
			return;
		}
				
		$url = 'https://api.twitter.com/1.1/friendships/create.json';
		$postfields = array('screen_name' => $twitter_username );
		$requestMethod = 'POST';
		$twitter_username = str_replace('@','',$twitter_username);
		
		$response = self::$TwitterAPIExchange->setPostfields( $postfields )
						->buildOauth($url, $requestMethod)
						->performRequest();
		
	
		update_post_meta( $post->ID , '_twitter_followed' , true );
	}
	
}