Capturing a Value in a Cookie using URL Rewrite for IIS7 - iis-7

Question

I need to write a URL Rewrite rule for my IIS 7.5 website that captures a value in a particular cookie, and then uses that value to construct a URL. For instance, the incoming requests looks like this:
GET http://myserver.com/test.aspx HTTP/1.1
Accept: text/html, application/xhtml+xml, */*
Accept-Language: en-US
User-Agent: Mozilla/5.0
Host: myserver.com
Cookie: foo=bar; bat=bar
I'd like to route them to this (based on the "foo" cookie value):
http://myserver.com/bar/test.aspx
fter reviewing the documentation and searching for examples, I'm stumped! Thanks for your help.

Answer 1

Answering my own question, here's a working example. The pattern may need additional work depending on what characters require supporting, but the following rule will will use the discovered cookie value and route to the discovered server--and the server can be specified by IPv4 address or by name (alphanumeric-and-period).
<rule name="Route Base On Cookie" stopProcessing="true">
<match url="^(.*)" />
<conditions>
<add input="{HTTP_COOKIE}" pattern="foo=(.*?);" />
</conditions>
<action type="Rewrite" url="http://{C:1}/{R:0}" />
</rule>

Answer 2

#Geoffrey To make your code support returning any cookie value, I'd recommend this pattern:
<add input="{HTTP_COOKIE}" pattern="foo=(.*?);" />
As a reminder, the {HTTP_COOKIE} value looks like this for example:
Cookie: foo=myexamplevalue; expires=Wed, 03-May-2014 22:31:08 GMT; path=/; HttpOnly\r\n

Answer 3

The following rule will use the discovered cookie value and route to the discovered path:
<rule name="Route Base On Cookie" stopProcessing="true">
<match url=".*" />
<conditions>
<add input="{HTTP_COOKIE}" pattern="^(.+; )?foo=([^;]*)(;.+)?$" />
</conditions>
<action type="Rewrite" url="https://{HTTP_HOST}/{C:2}/{R:0}" />
</rule>
The pattern supports several cookies and doesn't depend on the order of foo in cookie (when it is the last, browser doesn't append ';'):
both foo=bar; bat=bar and bat=bar; foo=bar work fine.
It works correctly when you have another cookie with the same substring such as barfoo.
{C:2} corresponds to the second capture in cookie, i.e. value of foo in pattern="...";
{R:0} corresponds to whole url in <match url="...">. IIS uses path part only without host name, i.e. /test.aspx.
NB. It may be not secure to use value from cookie in path as is. Possibly you should match against the list of expected values (bar|bar2|bar3|bar4).