Click here to Skip to main content
Click here to Skip to main content

Tagged as

Go to top

Abbreviating URLs

, 3 May 2010
Rate this:
Please Sign up or sign in to vote.
Recently, I had a case where an ASP.NET page displayed the user's URL in a side column. This worked fine except that I found some users had very long URLs, which didn't look right. It occurred to me that I could simple truncate the visible URL while still keeping the underlying link the same. Howev

Recently, I had a case where an ASP.NET page displayed the user's URL in a side column. This worked fine except that I found some users had very long URLs, which didn't look right.

It occurred to me that I could simple truncate the visible URL while still keeping the underlying link the same. However, when I truncated the URL by trimming excess characters, I realized it could be done more intelligently.

For example, consider the URL http://www.domain.com/here/is/one/long/url/page.apsx. If I wanted to keep it within 40 characters, I could trim it to http://www.domain.com/here/is/one/long/u. The problem is that this abbreviation could be more informative. For example, is it a directory or a page? And, if it's a page, what kind? And what exactly does the "u" at the end stand for?

Wouldn't it be a little better if I instead abbreviated this URL to http://www.domain.com/.../url/page.apsx? We've lost a few characters due to the three dots that show information is missing. But we can still see the domain, and the page name and type.

The code is Listing 1 abbreviates a URL is this way. The UrlHelper class contains just a single, static method, LimitLength(). This method takes a URL string and a maximum length arguments, and attempts to abbreviate the URL so that it will fit within the specified number of characters as described above.

public class UrlHelper
{
  public static char[] Delimiters = { '/', '\\' };
  /// <span class="code-SummaryComment"><summary>
</span>  /// Attempts to intelligently short the length of a URL. No attempt is
  /// made to shorten less than 5 characters.
  /// <span class="code-SummaryComment"></summary>
</span>  /// <span class="code-SummaryComment"><param name="url">The URL to be tested</param>
</span>  /// <span class="code-SummaryComment"><param name="maxLength">The maximum length of the result string</param>
</span>  /// <span class="code-SummaryComment"><returns></returns>
</span>  public static string LimitLength(string url, int maxLength)
  {
    if (maxLength < 5)
      maxLength = 5;
    if (url.Length > maxLength)
    {
      // Remove protocol
      int i = url.IndexOfAny(new char[] { ':', '.' });
      if (i >= 0 && url[i] == ':')
        url = url.Remove(0, i + 1);
      // Remove leading delimiters
      i = 0;
      while (url.Length > 0 && (url[i] == Delimiters[0]
        || url[0] == Delimiters[1]))
        i++;
      if (i > 0)
        url = url.Remove(0, i);
      // Remove trailing delimiter
      if (url.Length > maxLength && (url.EndsWith("/") || url.EndsWith("\\")))
        url = url.Remove(url.Length - 1);
      // Remove path segments until url is short enough or no more segments:
      //
      // domain.com/abc/def/ghi/jkl.htm
      // domain.com/.../def/ghi/jkl.htm
      // domain.com/.../ghi/jkl.htm
      // domain.com/.../jkl.htm
      if (url.Length > maxLength)
      {
        i = url.IndexOfAny(Delimiters);
        if (i >= 0)
        {
          string first = url.Substring(0, i + 1);
          string last = url.Substring(i);
          bool trimmed = false;
          do
          {
            i = last.IndexOfAny(Delimiters, 1);
            if (i < 0 || i >= (last.Length - 1))
              break;
            last = last.Substring(i);
            trimmed = true;
          } while ((first.Length + 3 + last.Length) > maxLength);
          if (trimmed)
            url = String.Format("{0}...{1}", first, last);
        }
      }
    }
    return url;
  }
}
Listing 1: UrlHelper class.

If the specified maximum length is less than five, LimitLength() simply changes it to five as there is no point in attempting to shorten a URL to less than the length of the protocol (http://).

That's all there is to it. I hope some of you find this code helpful.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Share

About the Author

Jonathan Wood
Black Belt Coder
United States United States
Jonathan Wood has been a software developer for more years than he cares to admit. His current focus is on using C# and ASP.NET MVC to develop website applications, and C++ and MFC to develop desktop applications. His consulting company, SoftCircuits, is known for producing various commercial and shareware products.
 
Having an entrepreneurial spirit, Jonathan also has a number of other online businesses that he built from scratch such as Black Belt Coder, Trail Calendar and others. He also has expertise in designing brands (including graphics and logos) and search-engine optimization (SEO).
 
Jonathan is always willing to discuss consulting work or joint ventures with people looking to develop software or online businesses.
Follow on   Twitter

Comments and Discussions

 
-- There are no messages in this forum --
| Advertise | Privacy | Mobile
Web03 | 2.8.140916.1 | Last Updated 3 May 2010
Article Copyright 2010 by Jonathan Wood
Everything else Copyright © CodeProject, 1999-2014
Terms of Service
Layout: fixed | fluid