How to rewrite URL as subdomain in asp.net without actually creating a subdomain on server

asp.net, c#-4.0, iis-7.5, subdomain, url-rewriting

Solution

EDIT following our comments:

To access `http://foo.com/xyzPage.aspx?barvalue=yehaa` using `http://yehaa.foo.com/`, you have to use the following rule:

<rules>
    <rule name="Rewrite subdomains">
        <match url="^/?$" />
        <conditions>
            <add input="{HTTP_HOST}" pattern="^(.+)\.foo\.com$" />
        </conditions>
        <action type="Rewrite" url="http://foo.com?barvalue={C:1}" />
    </rule>
</rules>

It matches every url ending or not with a `/` and using something before `foo.com` and then rewrites it to `http://foo.com?barvalue={C:1}` where `{C:1}` is whatever value was entered before `foo.com`.

If you want to prevent people from accessing directly to `http://foo.com?barvalue={C:1}`, you can use the rule below.

You could use the Rewrite module for IIS by adding the following rule in your `web.config` file:

<rewrite>
    <rules>
        <rule name="Redirect to Subdomains" stopProcessing="true">
            <match url="^xyzPage.aspx$" />
            <conditions>
                <add input="{QUERY_STRING}" pattern="^barvalue=(.+)$" />
            </conditions>
            <action type="Redirect" url="http://{C:1}.{HTTP_HOST}" appendQueryString="false" />
        </rule>
    </rules>
</rewrite>

It checks if the url matches exactly `xyzPage.aspx` (nothing before or after). It checks if the querystring contains the `barvalue` parameter (and only this one) and if its value is not empty. If those 2 conditions are ok, it triggers the `Redirect` to `http://barvalue.original.host`.

Your question specify `Rewrite`, so if this is really what you want to do, change the action `type="Redirect"` to `type="Rewrite"`.

Important: you may need the Application Request Routing module installed and setup with the proxy mode enabled to `Rewrite` to a different domain.

Problem

I hope this isn't the first time i'm asking this question on SO. I've URLs in my website and which are using `query string` values For example: http://foo.com/xyzPage.aspx?barvalue=yehaa to http://yehaa.foo.com/ Please suggest how it can be accomplished without actually creating subdomains on server .. I've IIS 7.5 installed on server machine and using Asp.net 4.0. Many thanks

Original source