Irule to redirect traffic based on path and uri

Why don't you use LTM policies, essentially F5 created these to make http parsing easy and not to need to code an irule... take a look its pretty self explanatory

Your question is a bit vague, but this might push you in the right direction.

when HTTP_REQUEST { 

    Set a variable to control if a pool has been chosen or not. 
    set chosen 0

    switch [string tolower [HTTP::uri]] { 
        "/bla/blabla.gif" { set chosen 1; pool pool-frontend }
    }

    Check if the switch has chosen a pool
    if { $chosen != 1 } {

        if { [HTTP::path] starts_with "/bla" } { 
            pool pool-frontend2
        } else {
            pool default_pool
        }
    }
}

Please note that I have not tested the rule myself.

/Patrik

Why not use the switch function for it all. I believe the switch command uses the first match so you could do:

when HTTP_REQUEST { 
  switch [string tolower [HTTP::uri]] { 
            "/bla/blabla.gif" { pool pool-frontend }
            "/bla*" {pool pool-frontend2}
            default {pool default}
        }
}