Lessn More integration for WP

sd_lessn.php

<?php
/*
	Plugin Name: Lessn Shortlinks
	Description: Integrates WP's shortlink functionality with the <a href="http://lessnmore.net/">Lessn More</a> URL shortener. <em>Hasn't been tested with vanilla Lessn, but the API should be compatible.</em> (Edit the file manually to configure)
	Version: 1.0
	Author: Matt Wiebe
	Author URI: http://somadesign.ca/
*/

/**
 * SD_Lessn class: integrates WP's shortlink functionality with the Lessn More
 * URL shortener.
 * 
 * @uses Lessn More @link http://lessnmore.net/
 * @author Matt Wiebe
 * @license GPL 2
 * 
 **/

class SD_Lessn {
	
	const API_KEY = 'apikey'; // your Lessn API key
	const LESSN_API_BASE = 'http://shorturl.com/-/'; // the API base for your Lessn install
	const META_KEY = '_lessnd_url';
	
	private $allowed_types = array('post');
	
	function __construct() {
		add_action('publish_post', array($this, 'get_lessnd_url'), 10, 1 );
		add_filter('get_shortlink', array($this, 'get_shortlink'), 10, 3 );
	}
	
	public function add_post_type( $post_type = '' ) {
		if ( $post_type )
			$this->allowed_types = array_merge( $this->allowed_types, (array) $post_type );
	}
	
	public function get_lessnd_url( $post_id ) {
		if ( 'publish' !== get_post_status($post_id) )
			return false;
		
		if ( ! in_array( get_post_type($post_id), $this->allowed_types ) )
			return false;
		
		if ( $url = get_post_meta( $post_id, self::META_KEY, true) )
			return $url;
		
		$params = array(
			'api' => self::API_KEY,
			'url' => get_permalink($post_id)
		);
		$api_url = add_query_arg($params, self::LESSN_API_BASE);
		
		$get = wp_remote_get($api_url);
		
		if ( is_wp_error($get) )
			return false;
		
		$lessnd_url = wp_remote_retrieve_body($get);
		
		if ( $lessnd_url ) {
			update_post_meta( $post_id, self::META_KEY, $lessnd_url );
			return $lessnd_url;
		}
		return false;
	}
	
	/**
	 * @param int $id A post or blog id.  Default is 0, which means the current post or blog.
	 * @param string $contex Whether the id is a 'blog' id, 'post' id, or 'media' id.  If 'post', the post_type of the post is consulted.  If 'query', the current query is consulted to determine the id and context. Default is 'post'.
	 */
	
	public function get_shortlink( $shortlink, $id, $context ) {
		
		if ( 'query' == $context ) {
			global $wp_query;
			if ( is_singular() ) {
				$context = 'post';
				$id = $wp_query->get_queried_object_id();
			}
		}
		
		if ( 'post' !== $context )
			return $shortlink;

		// Try Lessn'd url.
		if ( $try_lessn = $this->get_lessnd_url($id) )
			return $try_lessn;
//		do_action('elog', $shortlink);
		return $shortlink;
	}
}

$sd_lessn = new SD_Lessn;

// uncomment line below to add support for the "page" post_type
// $sd_lessn->add_post_type('page');