Rules to redirect based on URL

If the URI path is /User1, /User2 or /User3 (with nothing following), and you are using BIG-IP version 11.4 or higher, you can accomplish this using Local Traffic Policies:

• SOL15085: Overview of the Local Traffic Policies feature

If you are using a version before 11.4, you can use HTTP Classes:

• SOL15085: Overview of the Local Traffic Policies feature

If, instead, the URI path is, e.g., /User1/... (where ... is any arbitrary path) and you want to send everything after the /User1/ part to the server, then you'll need an iRule. Something like this:

when HTTP_REQUEST {
    switch -glob [HTTP::uri] {
        "/User1" -
        "/User1/*" { 
            HTTP::uri [substr [HTTP::uri] 6]
            node 192.168.1.1:80
        }
        
        "/User2" -
        "/User2/*" {
            HTTP::uri [substr [HTTP::uri] 6]
            node 192.168.2.1:80
        }
        
        "/User3" -
        "/User3/*" {
            HTTP::uri [substr [HTTP::uri] 6]
            node 192.168.3.1:80
        }
    }
}

This can be made more efficient, readable and configurable with the use of a datagroup.

... and in fact, I think I have a bit of a bug there with the non-glob matches, so here is a variant that uses a data group :).

create ltm pool pool-user1-context members add { 192.168.1.1:80 { } }
create ltm pool pool-user2-context members add { 192.168.2.1:80 { } }
create ltm pool pool-user3-context members add { 192.168.3.1:80 { } }

create ltm data-group internal dg-user-server type string records add { \
   User1 { data pool-user1-context } \
   User2 { data pool-user2-context } \
   User3 { data pool-user3-context } \
}

create ltm rule context-to-server {
when RULE_INIT {
    set static::uc_user_server_dg dg-user-server
}


when HTTP_REQUEST {
    set context [getfield [HTTP::uri] / 2]
    set swpool [class lookup $context $static::uc_user_server_dg]
    
    if { $swpool ne "" } {
        set nuri [substring [HTTP::uri] [string length "/$context"]]
        if { $nuri eq "" } {
            HTTP::uri /
        } else {
            HTTP::uri $nuri
        }
        
        pool $swpool
    }
}
}

It makes sense to define a default pool for the Virtual Server to which this rule would be applied.