Problem statement
When sending an invitation link, a Client stores an expiration date for the invitation and generates a GUID as an ID for it. That GUID is passed in the query string of the invitation link. When the user clicks the link to sign up, we need Auth0 to read that GUID from the query string and make an API call back to the client to determine whether the link is still valid (unexpired). If that API call returns false, we want to skip the account creation. We don’t want the account created in that case.
We either need a good suggestion on achieving this, or functionality added to allow the pre-user registration Action to see the query string, which it is not able to do today.
Solution
Unfortunately, the event.request.query property is not available in the pre-user registration Action. It’s available in the post-Login Action only.
As a workaround, you could create and host a proxy application that will handle your logic before sending a user to Auth0 for account registration.