Using URL Rewrite to change part of URL - iis

Question

I'm trying to use an URL Rewrite on an IIS 8.0 to rewrite existing URL:s on a developer machine. The reason for this is that I don't want to change existing (old) code.
What I'm trying to achieve is to change the following code in the response stream:
Foo Page
into:
Foo Page
But when I'm trying, I end up with:
Foo Page
And as you all know, this is not a very satisfying result.
So - how do I do this rewrite proper to achieve what I'm trying to do?
I know there are better ways of doing this, using application variables etc., but it's an old solution and I don't want to mess too much with the application itself. I want to keep the changes to a minimum. At least to begin with.
The rules I tried look like this:
<system.webServer>
<rewrite>
<outboundRules>
<rule name="foo.com" enabled="true">
<match filterByTags="A, Area, Base, Form, Frame, Head, IFrame, Img, Input, Link, Script" pattern="foo.com" />
<action type="Rewrite" value="foo.localhost" />
</rule>
</outboundRules>
</rewrite>
</system.webServer>
I guess there is some regex magic I should be using.

Answer 1

Your rule needs to be changed to:
<rule name="foo.com" enabled="true">
<match filterByTags="A, Area, Base, Form, Frame, Head, IFrame, Img, Input, Link, Script" pattern="^(.*)foo.com(.*)$" />
<action type="Rewrite" value="{R:1}foo.localhost{R:2}" />
</rule>
In the pattern, ^(.*) will match anything (0 or more characters) from the beginning before foo.com and (.*)$ anything after foo.com until the end.
You can then use the back references in the action, where {R:1} will take the value matching (.*) before foo.com and {R:2} the value matching (.*) after foo.com