Fix OPTIONS responses: Remove all HEAD methods as they return errors. Do not advertise writable method for class/id/properties path if property is read only (i.e. protected prop). Collections do not have PUT, PATCH, DELETE (delete is accepted but always returns 400 code).

def audit_html_files(db, cl, nodeid, newvalues):
    if 'type' in newvalues and newvalues['type'] == 'text/html':
        newvalues['type'] = 'text/plain'
    

def init(db):
    db.file.audit('set', audit_html_files)
    db.file.audit('create', audit_html_files)