Consuming URL Shortening Services

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Overview

Another article of our series that talks about accessing URL shortening services programmatically.

This article is talking about is.gd shortening service, how you can use it, and how to access it via your C#/VB.NET application.

Introduction

Is.gd is one of the most popular shortening services ever in the web because of its simple interface and its easy-to-use API.

When you visit service website, http://is.gd, you can see that nothing easier from is.gd, just push your long URL into the text box and click the shortening button.

API

is.gd provides you a very simple easy-to-use API. This API contains only one function that's used for shortening URLs. Another good thing is that this function doesn't require any kind of authentication for users. Therefore, you need just to spam it with your long URL (as you did with the website.)

This glorious function is called http://is.gd/api.php, it accepts only a single argument, longurl, which can be set to the long URL you need to shorten. When you call the function, it simply returns the shortened URL as plain text (no more overhead.)

Now, let's try this function. We'll try to shorten the URL http://JustLikeAMagic.com with our function. First, connect the arguments, http://is.gd/api.php?longurl=http://JustLikeAMagic.com. Now copy this address and paste it into your favorite browser. If everything was OK, you should see the short URL after clicking in the browser toolbar.

Now, let's do it in C# and VB.NET. Check the following function that tries to shorten long URLs via the id.gd API:

C#
string Shorten(string url)
{
url = Uri.EscapeUriString(url);
string reqUri = String.Format(@"http://is.gd/api.php?longurl={0}", url);

HttpWebRequest req = (HttpWebRequest)WebRequest.Create(reqUri);
req.Timeout = 5000;

try
{
using (System.IO.StreamReader reader =
new System.IO.StreamReader(req.GetResponse().GetResponseStream()))
{
return reader.ReadLine();
}
}
catch (WebException ex)
{
return ex.Message;
}
}

VB.NET

Function Shorten(ByVal url As String) As String

url = Uri.EscapeUriString(url)
Dim reqUri As String = _
String.Format("http://is.gd/api.php?longurl={0}", url)
Dim req As WebRequest = WebRequest.Create(reqUri)
req.Timeout = 5000

Try
Dim reader As System.IO.StreamReader = _
New System.IO.StreamReader(req.GetResponse().GetResponseStream())

Dim retValue As String = reader.ReadLine()
reader.Dispose()

Return retValue
Catch ex As WebException
Return ex.Message
End Try

End Function

Notice that we have used the function System.Net.Uri.EscapeUriString() to eliminate unacceptable characters from the URL by encoding them.

Notice too that we have included our code in a Try-Catch block so we can catch exceptions before they blow up our application.

What's next

Consider reading other articles in this series here.