Using capture groups in regexp replace


I need to replace url like this:

I’m doing it now with 2 separate rules:

  1. regexp replace “^/some/prefix” with “”
  2. append “/secret-suffix”

What I’d do if groups were supported is:
Regex: "^/some/prefix/(.+)$"
Substitution: “/$1/secret-suffix”

Is it possible?
I read vcl-regular-expression-cheat-sheet guide but it’s talking about pure VCL, not sure how to use it in UI based config.
Seems like I could use something like if(req.url ~ "^/some/prefix(/.+)$", "some suffix", "") in UI as constant Set mode (instead of Regex), but it looks overcomplicated.


You can use \1, \2, etc. for groups in your regular expression in the UI.

So you were close with $1:

Regex: ^/some/prefix/(.+)$
Substitution: /\1/secret-suffix