Examples to get shorten or decode target url using bit.ly.

bitly.lib.php

<?php 
	define('LOGIN', 'xxxxx');
	define('API_KEY', 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx');
	define('END_POINT', 'http://api.bit.ly/v3');
	
	function getShortUrl($longUrl)
	{
		$query = http_build_query(
			array(
				'login' => LOGIN,
				'apiKey' => API_KEY,
				'longUrl' => $longUrl,
				'format' => 'txt'
				#'domain' => 'j.mp' 
			)
		);
		return file_get_contents(sprintf('%s/%s?%s', END_POINT, 'shorten', $query));
	}
	
	function getLongUrl($shortUrl)
	{
		$query = http_build_query(
			array(
				'login' => LOGIN,
				'apiKey' => API_KEY,
				'shortUrl' => $shortUrl,
				'format' => 'txt'
			)
		);
		return file_get_contents(sprintf('%s/%s?%s', END_POINT, 'expand', $query));
	}