changing URI path

The stream profile/filter only operates against the payload. So if you've added an HTTP profile to the VIP, and want to modify the path in the URI (part of the headers--not the payload), you should use nmenant's example of HTTP::path.

If you need to rewrite the request and/or response payload, I'd suggest adding a blank stream profile to the VIP and an iRule to configure the stream filter. Here is an example of replacing a string in the response content:

http://devcentral.f5.com/wiki/default.aspx/iRules/stream__expression

when HTTP_RESPONSE {
    Disable the stream filter by default
   STREAM::disable
    Check if response type is text
   if {[HTTP::header value Content-Type] contains "text"}{
       Replace IE with Apache, Windows with Linux
      STREAM::expression "@IE@Apache@ @Windows@Linux@"
       Enable the stream filter for this response only
      STREAM::enable
   }
}

You can find more information on the stream profile and related STREAM:: commands on AskF5 and the iRules wiki:

SOL8115: Overview of the Stream profile:

https://support.f5.com/kb/en-us/solutions/public/8000/100/sol8115.html?sr=636220

iRules STREAM wiki page:

http://devcentral.f5.com/wiki/default.aspx/iRules/stream

Aaron