exact steps. fail. if someone want to take this internally that’s fine, i won’t be submitting a support ticket as it’s always an uphill battle to get anything other than a canned answer, no desire to waste energy on begging for escalation. implemented in workers instead, moved on.
Turns out this is only available on Business+. The documentation needs to be much clearer here, it would also help if they bubble up in the UX rather than Code: undefined. Turns out this only mentioned in page linked three steps away and only somewhat closely related https://developers.cloudflare.com/firewall/cf-firewall-language/values#case-sensitivity-and-regular-expressions-in-values.
Also, for feedback, whilst I understand the reserving of regex for business+, given how computationally expensive a bad regex can be, there should at least be a simple string_replace transform function for Pro plans…
You have got to be kidding me. I have been banging my head against the wall trying to get this to work - literally to the point of just copying the code in the docs. Why can’t Cloudflare make this sort of thing crystal clear? Thank you @matt53 for posting the follow up.