Keyvan Nayyeri

In my opinion the Nth rule of simplicity would be the simplicity of the internet URLs.  One of things that I always attend to on any new web application is this and for me it's very important to have a site with simple and readable URLs.

If we go back and forth and recall the history of the web, can believe that we've been moving forward in simplicity of the URLs in the time.  Coming from the days of long URLs with many folders included and long queries to days with shorter URLs that try to rewrite all public URLs from queries to simplify them.

There are many parameters of simplicity for URLs such as the length, exclusion of queries, exclusion of page extensions and ...  In this post I want to outline some parameters that make your URLs simpler and talk about implementing them for ASP.NET sites in general.  I use some of these methods on my site to simplify URLs.

Make URLs Shorter

The most obvious way to simplify a URL is making it shorter.  We're passed the days with long URLs and long queries.  There are some techniques that help you to make your URLs shorter.  As site developers, you're able to choose a good strategy for designing your URLs to make them as short as possible.  Some of the next items can also be techniques to make URLs shorter but I'd prefer to talk about them separately.

One common problem with many ASP.NET sites and web applications is the fact that they use unnecessary items in the URLs that should be eliminated.  For example, as many ASP.NET blogging tools are inspired from original .Text engine, they use year, month and day numbers in the post permalinks which is unnecessary and just makes them longer.  This is the default behavior in .Text, Community Server and Subtext while new BlogEngine doesn't use this pattern.  You have to avoid such unnecessary usages of URL items.

On the other hand, the readability of URLs and being SEO friendly shouldn't become victims of shorter URLs.  You can simply use an identifier rather than a page name or item name to make it shorter but this isn't recommended at all.

A very good example of a very bad design for URLs is DotNetNuke!!  Taking a look at DotNetNuke URLs, you suddenly notice that not only URLs aren't readable but also they're long in many pages on many sites.

However, in general, making URLs shorter is something left to you and your strategies in the application that you write but is something easy to handle if you consider it from the first stages.

Use Subdomains

One common way to simplify URLs is using subdomains.  You can easily move a part of URL to a subdomain.  This has some benefits:

• With subdomains you can categorize your site URLs and choose different subdomains for each category.  For example, you can move blogs application to its own subdomain and forum application to its own and so on.
• This makes your URLs more readable and easier to remember.  With subdomains, URLs are readable and normally people can remember them easier.
• Beside other benefits, using subdomains, you can have shorter URLs.

The implementation of subdomains in ASP.NET is easy and there are some options available for you as ready to go components or you can write your own code.

Rewrite Queries

Queries should be avoided in public URLs as much as possible.  Queries make a URL hard to read and remember and sometimes can make it longer.  With rewriting queries you get two benefits:

• This improves the readability of your codes and makes them easy to remember.
• Rewriting queries improves your SEO very much. 

While these are two positive points about queries, note that rewriting queries can make your URLs shorter or longer.  There is no general rule about this and it depends on your case but however it worth it and you always should rewrite your queries.

One famous open source component for URL rewriting in ASP.NET is UrlRewriter.NET that lets you rewrite URLs based on regular expressions easily.

Eliminate Some Characters

Sometimes some special characters appear in URLs that can be eliminated and aren't human readable and beautiful and just make URLs longer.

For example, you may simply use encoding techniques to replace "C#" with "C_2300_" in your URLs.  That "_2300_" is something that should be eliminated to simplify the URL and make it shorter.

As a general guideline, I'd prefer to escape any non-alphanumeric character (except dash) in URLs and this can be simply done with string manipulation methods in .NET.  For consistency, I also would prefer to lower case all my URLs before making them public.

Remove "WWW" From URLs

Having "WWW" prefix at the start of the URLs makes them longer and in some cases can break down the popularity of your pages by providing two different URLs.  But by removing this part of the URL, not only you have shorter URLs, but also have single links on your site and of course, in my opinion your URLs are beautiful in this case.

I had talked about this in good details before and outlined the negative and positive points of having or not having "WWW" in URLs.  I also gave a simple solution to remove "WWW" with an ASP.NET HttpModule.  Note that you can achieve this by using an ISAPI filter as well.  I talk about them in the next section.

Remove Default Pages From URLs

Default pages are the other parameter that make URLs long.  In ASP.NET technically it's not possible to exclude default pages from URLs in IIS 6.0 (and earlier) unless there is a default page physically located at the path or you have access to an ISAPI filter.  However, I've experienced that in many cases default pages can be dropped at the end of URLs without any ISAPI filter because there is a default page physically located.

Default pages have another drawback and that is they may break down your link popularity by providing two different access points to same page so for professional websites this should be a big concern.

The good news is this can be achieved in IIS 7.0 easier but you can do this in preceding versions by an ISAPI filter.  Before I get off to military service training, there were some discussions about common IIS ISAPI filters here and there about ISAPI_Rewrite and Ionic's ISAPI Rewrite Filter.  The first one is commercial and requires you to buy a license but the second one is open source and free and I use it on my VPS to simplify my URLs on this site.  For both filters, you can use patterns like this to remove default pages and redirect them permanently to new URLs:

RewriteRule (.*)/default.htm$ $1/ [I,RP]
RewriteRule (.*)/default.aspx$ $1/ [I,RP]
RewriteRule (.*)/index.htm$ $1/ [I,RP]
RewriteRule (.*)/index.html$ $1/ [I,RP]

All in all, this isn't easy to achieve to IIS 6.0 or 5.0 because needs you to install an ISAPI filter on the server and this may be impossible for you if you're hosted on a shared environment.

Drop Page Extensions

The last way of simplifying URLs that I can remember is dropping page extensions that makes URLs shorter and has an extra benefit that can help you to have technology independent URLs.  It means that if you suddenly decide to change the technology of your website then you don't need to redirect all old URLs and just have to put new pages in the same location.

Unfortunately like removing default pages, dropping page extensions isn't easy to achieve in IIS 5.0 or 6.0 and again you need to use an ISAPI filter but however I would recommend it for any professional website.