remapping issue

The

string map

substitutes every instance of / for /xxxxx. Thus, if the path-uri were /, it would change the path-uri to /xxxxx. If the path-uri were /foo/bar, it would change the path-uri to /xxxxxfoo/xxxxxbar. I believe what you are attempting to do is insert a path element at the start of any submitted path-uri, so that:

• if the user-agent requests http://link.domain.com/, the server sees /xxxxx/ as the request path-uri;
• if the user-agent requests http://link.domain.com/foo/bar, the server sees /xxxxx/foo/bar as the request path-uri;
• if the user-agent requests http://link.domain.com/images/logo.png, the server sees /xxxxx/images/logo.png as the request path-uri.

Is that correct? If so, then you should be able to simply do this:

when HTTP_REQUEST {
    HTTP::uri "/xxxxx[HTTP::uri]"
}

If you are using BIG-IP 11.4 or higher, you could also use a Local Traffic Policy:

ltm policy expand-path {
    controls { forwarding }
    requires { http }
    rules {
        rule01 {
            actions {
                0 {
                    http-uri
                    replace
                    path /xxxxx[HTTP::uri]
                }
            }
            ordinal 2
        }
    }
    strategy first-match
}