Google has a new URL shortening API. This API works much like bit.ly and others, with one notable exception: it has an API!

Like most Google API’s this one is REST based so you can access it in any language rather easily. For this tutorial I will demonstrate this in C#.

Why use the Google for URL Shortening?

Google is growing rapidly and I think it’s fair to say they will be around for quite a long time. Whatever service you choose to shorten your URL’s is up to you, but I would suggest something with longevity. And having a clever moniker such as goo.gl is nice too!

Getting to know the Google Url Shortner API

To use the API you do not require an API key, but by using an API key you get increased limits to the amount of times you can call the API and you get statistics through Google analytics.

The API can do the following:

* Can shorten URL’s
* Can take a shortened URL and expand it back to the long URL
* Can give you Analytics info
* Can give you user history

This article will only cover the first 2 of those, but the code shown here could easily be applied to cover the last two if you like.

Making a Short URL with Google

To shorten a long URL you need to do an HTTP POST with a JSON payload that includes the long URL. Google will then give you back a JSON object that has the short URL in it.

Getting the Long Url from the Short

To lookup the long url you need to send an HTTP GET with the short url as a parameter, and then Google Shortner API will return a JSON reply with the long URL.

C# Google Shortner Classes

This is the main class that send the responses and gets the replies from the Google Shortner API.

GoogleUrlShortner.cs
?
using System.IO;
using System.Net;
using System.Runtime.Serialization.Json;
using System.Text;

namespace Jarloo
{
public class GoogleUrlShortner
{
public static GoogleUrlReply Shorten(string longUrl, string apiKey=”")
{
string data = “{\”longUrl\”:\”" + longUrl + “\”}”;
string gUrl = “https://www.googleapis.com/urlshortener/v1/url”;

if (!string.IsNullOrEmpty(apiKey)) gUrl += “?key=” + apiKey;

string response = Post(gUrl, data);
return FromJSON(response);
}

public static GoogleUrlReply Expand(string shortUrl, string apiKey=”")
{
string gUrl = “https://www.googleapis.com/urlshortener/v1/url?shortUrl=” + shortUrl;

if (!string.IsNullOrEmpty(apiKey)) gUrl += “&key=” + apiKey;

string response = Get(gUrl);
return FromJSON(response);
}

public static string Get(string url)
{
using (WebClient web = new WebClient())
{
return web.DownloadString(url);
}
}

private static string Post(string url, string data)
{
WebRequest request = WebRequest.Create(url);
request.Method = “POST”;
request.ContentType = “application/json”;

byte[] byteData = Encoding.UTF8.GetBytes(data);

request.ContentLength = byteData.Length;

using (Stream s = request.GetRequestStream())
{
s.Write(byteData, 0, byteData.Length);
s.Close();
}

string replyData;

using (HttpWebResponse response = (HttpWebResponse) request.GetResponse())
{
using (Stream dataStream = response.GetResponseStream())
{
using (StreamReader reader = new StreamReader(dataStream))
{
replyData = reader.ReadToEnd();
}
}
}

return replyData;
}

private static T FromJSON(string input)
{
MemoryStream stream = new MemoryStream();

try
{
DataContractJsonSerializer jsSerializer = new DataContractJsonSerializer(typeof (T));
stream = new MemoryStream(Encoding.UTF8.GetBytes(input));
T obj = (T) jsSerializer.ReadObject(stream);

return obj;
}
finally
{
stream.Close();
stream.Dispose();
}
}
}
}

The GoogleUrlReply class is the deserialized representation of Google’s reply.

GoogleUrlReply.cs
?
namespace Jarloo
{
public class GoogleUrlReply
{
public string kind { get; set; }

//is the short URL
public string id { get; set; }

//is the long URL to which it expands.
//longUrl may not be present in the response, for example, if status is “REMOVED”.
public string longUrl { get; set; }

//is “OK” for most URLs.
//If Google believes that the URL is fishy,
//status may be something else, such as “MALWARE”.
public string status { get; set; }
}
}

read more

Try it

http://goo.gl/