Enforcing user quota in Firebase

Question

What is the best way to enforce per-user quota on data stored in Firebase?

My users will be able to create documents with a unique id on the following path:

/documents/id/contents

The id will be uniquely generated using a transaction. The id will be reserved by using a verification rule ( contents.id == auth.id )

However how do I prevent a user from spamming the db (by randomly allocating ids to themselves)? Can I have a rule which counts the number of ids allocated to a user and rejects them if the count is too high?

Answer 1

There's currently no good way to do this.

In some cases you could fully enumerate the children that are allowed to exist (child1, child2, etc), and grant read / write for each one. This won't work for large numbers though or for ids you don't know beforehand.

We do have plans to built features to restrict the number of allowed children and to provide other features to enforce quotas on users.