Google URL Shortener PHP Class

Google has had a URL shortening domain for quite a while now but it wasn't until recently that Google exposed the URL shortening API to the public.  I took a few minutes to review their API and created a very basic GoogleUrlApi class that will shorten long URLs and expand shortened URLs.


The PHP
The class itself is quite compact and the code should be easy to read:

// Declare the class
class GoogleUrlApi {

// Constructor
function GoogleURLAPI($key,$apiURL = 'https://www.googleapis.com/urlshortener/v1/url') {
// Keep the API Url
$this->apiURL = $apiURL.'?key='.$key;
}

// Shorten a URL
function shorten($url) {
// Send information along
$response = $this->send($url);
// Return the result
return isset($response['id']) ? $response['id'] : false;
}

// Expand a URL
function expand($url) {
// Send information along
$response = $this->send($url,false);
// Return the result
return isset($response['longUrl']) ? $response['longUrl'] : false;
}

// Send information to Google
function send($url,$shorten = true) {
// Create cURL
$ch = curl_init();
// If we're shortening a URL...
if($shorten) {
curl_setopt($ch,CURLOPT_URL,$this->apiURL);
curl_setopt($ch,CURLOPT_POST,1);
curl_setopt($ch,CURLOPT_POSTFIELDS,json_encode(array("longUrl"=>$url)));
curl_setopt($ch,CURLOPT_HTTPHEADER,array("Content-Type: application/json"));
}
else {
curl_setopt($ch,CURLOPT_URL,$this->apiURL.'&shortUrl='.$url);
}
curl_setopt($ch,CURLOPT_RETURNTRANSFER,1);
// Execute the post
$result = curl_exec($ch);
// Close the connection
curl_close($ch);
// Return the result
return json_decode($result,true);
}
}
The constructor requires your Google API key.  A second argument may be provided to the URL of the Google API.  As the API is currently in version 1, changing this URL would be more harmful than useful.  The class features two main methods:  shorten and expand.  Each method takes the long or short URL, contacts Google, and returns its counterpart.  If no counterpart is found, or the Google URL Shortener API is down, a result of false is returned, so please be sure to use your own error handling.

Now let's create an instance of GoogleUrlApi to shorten and then expand a URL:

// Create instance with key
$key = 'xhjkhzkhfuh38934hfsdajkjaf';
$googer = new GoogleURLAPI($key);

// Test: Shorten a URL
$shortDWName = $googer->shorten("https://davidwalsh.name");
echo $shortDWName; // returns http://goo.gl/i002

// Test: Expand a URL
$longDWName = $googer->expand($shortDWName);
echo $longDWName; // returns https://davidwalsh.name
The shorten() and expand() methods return their counterparts, as expected.  Quite painless, no?

The Google URL Shortener API provides much more than what my class provides, including user URL listing and usage tracking.  My class provides only the basics;  I'm assuming that 90%+ care only about getting the URL shortened so I've catered to that audience.  I had also thought about adding a caching mechanism to the class but since most everyone has their own method of caching information, I thought it best to leave that out.  Hopefully this class has some use for you all!