How to properly write Regex validation in Firestore Security Rules

Question

I'm trying to validate submitted data against Regex expressions in Firestore Security Rules. I've read through the documentation, but I'm still unsure how to write them.

I read through the Regex documentation here https://firebase.google.com/docs/reference/security/database/regex , but it doesn't really show how to use it in Firestore. I tried using an 'allow validate' rule and copy/pasted a regex expression from the docs, but I'm getting all kinds of errors.

Here's what I tried:

Do I need to put it in a format like this? (From the docs) allow create: if !("ranking" in request.resource.data)? If so, how do I use a regex expression with it?

Answer 1

It looks like you're trying to start a regex with /. That's not going to work - it's not like perl. Slash starts a path object. Might want to check the API documentation on this. You should just be passing a plain string to matches() that contains the regex to match.

https://firebase.google.com/docs/reference/rules/rules.String#matches