iRule for URL persistence

I have a environment , can't use insert client ip in the http head , but the device(is not the end client ) in front of f5 coult insert the client ip in the url in the follow format ,:

 

http://test.big-ip.com/ebv/rbv&clientIP=192.168.1.5?svk

 

 

Does the follow irules "

 

when HTTP_REQUEST {

 

set session_id [getfield [HTTP::uri] "/" 11]

 

if {$session_id ne ""} {

 

persist uie $session_id 1800

 

}

 

}

 

 

"

 

work ?

 

Does anyone have similar environment with me? Or can provide me any iRule sample to do this?

 

 

thanks !