irule pool selection

Hello Team,

I am looking for an irule for the following scenario.

if the uri is starting with /app traffic should go to pool app_server pool. but should change the path to default document root ("/). i tried couple of irules all are passing the uri to server.

vip : http://192.168.0.10/app/test.html server : http://172.0.139.12/ttest.html

I want to strip "/app" in server side request