Background
I am working on a React app for event participation management using the CiviCRM ajax API. There is a little more to this that isn't relevant.
Each user has access to their own API key, but no CiviCRM or CMS account. I have used the civitest_civicrm_alterAPIPermissions hook to expose/restrict various entities. I have given each user the "access AJAX API" permission.
Issue
Before I go looking through the code, I had a question about an issue I am having:
Users with CMS accounts and the exact same permissions (i.e. no "access CiviCRM" and cannot log into CMS) can access the API fine, but those without get the error "ERROR: No CMS user associated with given api-key"
The error is pretty self explanatory, but I was curious if there was a way to work around it that is built into CiviCRM.
Setup
Joomla 3.8
CiviCRM 4.7.22