URL Rewriting in ASP.NET

There are cases when you need to optimize the links so that they are better indexed by search engines (for SEO purposes and not only). Suppose when you need to rewrite links that include the characters "?", "&" And "=" in a more readable form.

For example, you want to remake a link of the following form:
www.domain.com/default.aspx?category=Title&entry=Name

In this, more understandable:
www.domain.com/Title/Name
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There are several ways to achieve Url Rewriting in ASP.NET.

1. You can take advantage of what standard ASP.NET 2.0 gives you, that is, use the urlMappings element. Add the following lines to the Web.config file:

< system.web >
< urlMappings enabled = "true" >
< add url = "~ / Home.aspx" mappedUrl = "~ / Default.aspx? tab = home" />
</ urlMappings >
</ system.web > * This code was highlighted with Source Code Highlighter .

This method is simple and convenient, but here all links will be " hardcoded ". Using this method your opportunities will be limited. You cannot dynamically rewrite links.


2. There is also an Open Source module called UrlRewritingNet.UrlRewrite . UrlRewritingNet is essentially a set of DLL files. To work with them, you need to copy them to the / Bin / directory of your project.

Next, add the following lines to your project's Web.config file:

< configuration >
< configSections >
< section name = "urlrewritingnet" requirePermission = "false" type = "UrlRewritingNet.Configuration.UrlRewriteSection, UrlRewritingNet.UrlRewriter" />
</ configSections >
< configuration >

< system.web >
< httpModules >
< add name = "UrlRewriteModule" type = "UrlRewritingNet.Web.UrlRewriteModule, UrlRewritingNet.UrlRewriter" />
</ httpModules >
</ system.web > * This code was highlighted with Source Code Highlighter .

and finally the link rewrite rules themselves:

< urlrewritingnet rewriteOnlyVirtualUrls = "true" contextItemsPrefix = "QueryString" defaultPage = "default.aspx" xmlns = " www.urlrewriting.net/schemas/config/2006/07 " >
< rewrites >
< add name = "Rule1" virtualUrl = "^ ~ /(.*)/ Detail (. *) & # 60 ; / strong > .aspx" rewriteUrlParameter = "ExcludeFromClientQueryString" destinationUrl = "~ / Default.aspx? language = $ 1 & id = $ 2 "ignoreCase =" true " />
.
.
.
</ rewrites >
</ urlrewritingnet > This is where the source code was highlighted.

As you can see from the example, UrlRewritingNet allows you to dynamically rewrite links using regular expressions.

It is convenient to use UrlRewritingNet in cases when you do not have dedicated hosting (that is, when you do not have the ability to rewrite URLs at the server level).

You can read more about all the features of UrlRewritingNet here , and download the module itself here .

3. And the most, in my opinion, the correct way to rewrite the URL will be according to the means of the ISAPI Rewrite filter. This is a module for IIS that accepts standard rules written for Apache .htaccess mod_rewrite . It must be installed as an ISAPI Filter through IIS on the site itself.

An example .htaccess file for rewriting links:

RewriteEngine on
RewriteRule ^/(.*)/(.*)/(.*).aspx /Default.aspx?Title=$1&Description=$2&Topic=$3

In this example, we want to refer to the following link:
www.domain.com/Default.aspx?Title=A&Description=B&Topic=C

Through this, more readable and short:
www.domain.com/A/B/C.aspx

And so, for example, you can overcome the devouring of traffic from your site by blocking the display of pictures from other sites that are physically on your site:

RewriteEngine on
RewriteCond %{HTTP:Host}#%{HTTP:Referer} ^([^#]+)#(?!http://\1).+
RewriteRule .*\.(?:gif|jpg|png) /block.gif [NC]

ISAPI Rewrite rewrites URLs at the IIS level. Here your possibilities are almost unlimited. The capabilities of ISAPI Rewrite are not limited to rewriting links.

About ISAPI Rewrite filter is written in more detail here , and you can download the free module here . The difference between the free and paid versions is that in the free version all the rules are saved in one file and valid for all sites under IIS. In the paid version of the same rules can be written for specific sites.

Useful articles on this topic:
- URL Mapping in ASP.NET 2.0
- Tip / Trick: Url Rewriting with ASP.NET
- A Complete URL Rewriting Solution for ASP.NET 2.0
- URL Rewriting in ASP.NET

PS
This is my first more or less serious post on Habré, so do not judge strictly.
I will be glad to any amendments in the Russian language and not only. :)