Expanding Shortened URL's

Originally published on: Wed, 01 Jul 2009 01:38:18 +0000

Lately, I've read some complaints about URL shorteners ... sites that encode a URL into a shorter URL. The shortener web site keeps a record of the original URL and the smaller code that it has provided. All who navigate to the short URL are redirected to the original URL.

Unfortunately, as handy as these shorteners are, it's difficult to determine where one's browser might end up when clicking a link.

I wrote a small command-line C# program to accept a URL, retrieve the document, and display the final endpoint address. If the original URL had been redirected in any way, this displayed address would likely be different than the input address.

urlx.cs

// urlx.cs - Simple command-line utility to expand shortened URL's.
//
// License: MIT / X11
// Copyright (c) 2009 by James K. Lawless
// jimbo@radiks.net http://www.radiks.net/~jimbo
// http://www.mailsend-online.com
//
// Permission is hereby granted, free of charge, to any person
// obtaining a copy of this software and associated documentation
// files (the "Software"), to deal in the Software without
// restriction, including without limitation the rights to use,
// copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the
// Software is furnished to do so, subject to the following
// conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
// OTHER DEALINGS IN THE SOFTWARE.

using System ;
using System.IO ;
using System.Net;

namespace URLX
{
   public class URLX
   {
      public static void Main(string[] args)
      {
         if (args.Length == 1)
         {
            try
            {
               // Create a request to the passed URI.
               HttpWebRequest req =
                  (HttpWebRequest)WebRequest.Create (args[0]);
               req.AllowAutoRedirect=true;
               HttpWebResponse res =
                  (HttpWebResponse)req.GetResponse ();

               ServicePoint sp = req.ServicePoint;
               Console.WriteLine("End address is " + sp.Address.ToString());
            }
            catch(Exception e)
            {
               Console.WriteLine(e.Source);
               Console.WriteLine(e.Message);
            }
         }
         else
         {
            Console.WriteLine("Usage: urlx.exe url");
         }
      }
   }
}

As an example, the URL:

http://www.mailsend-online.com/blog?p=9

...is a link to my writeup on generating transparent, single-pixel GIF's for use in tracking the use of one's web site. By using the shortener service at http://bit.ly , and encoded redirector for my article URL becomes http://bit.ly/Rmncf .

To use my new urlx utility, I enter the following on the command-line:

urlx http://bit.ly/Rmncf

I see the output:

End address is http://www.mailsend-online.com/blog?p=9

NOTE: I've added a GUI to urlx in a separate article. Please see http://www.mailsend-online.com/blog/?p=20

You may download the source and .NET 2.0 EXE for urlx here:

http://www.mailsend-online.com/wp/urlx.zip

Unless otherwise noted, all code and text entries are Copyright Š2009 by James K. Lawless

Views expressed in this blog are those of the author and do not necessary reflect those of the author's employer. Views expressed in the comments are those of the responding individual.

Save to StumbleUpon
Digg it
Save to Reddit
Share on Facebook
Share on Twitter
More bookmarks

Previous post:	Generating Primes with XSLT
Next post:	A GUI for urlx

Jim Lawless' Blog

Expanding Shortened URL's

Follow me on Twitter

Recent Posts

Random Posts

Full List of Posts

Recent Posts from my Other Blog