Performing a redirect using string map

Both absolute and relative paths in a Location header are allowed. (See the Wikipedia article). So it should work fine either way.

I believe you can use HTTP::redirect and just specify the new host without the protocol. I think you could process the string a little more quickly with an explicit string replace instead of string map, too, and save the system from having to search the string for a pattern because you know it's always going to be the first 31 characters of the string.

So instead, you could do something like this:

if { [HTTP::path] starts_with {/shop/wedding-registry/product/} } {
    set uri [string replace [HTTP::uri] 0 30 {/shop/registry/wedding/product/}]
    HTTP::redirect "//$uri"
}

I imagine it would be even faster to use a Rewrite profile, but if you're already processing iRules, it might be more discoverable to keep the logic all together here.

Edit: As noted in the docs for HTTP::redirect, it does give you a 302 response code, so if you want 301, you'd have to use HTTP::respond instead.

Just to make the reference convenient, here's the HTTP module documentation page.