Introduction

This ticket originated from the desire to handle courseware access better in the mobile API. The mobile API uses has_access for permission checks, which currently returns a boolean: True if access is granted and False otherwise. However, this gives no information about the reason for denied access (although the implementation of has_access does have this information, it just doesn't return it). Therefore, we would like to change the return type of has_access into something that can provide specific information in the case access is denied. We have designed the following 2 classes, AccessResponse and AccessError, that can hold this extra information without requiring changes to most of the existing calls to has_access.

AccessResponse

AccessResponse is the class created to be the new return type of has_access. It holds detailed information about the results of a has_access request.

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• Methods:
  • __nonzero__: override this so truth value testing/bool() works as it did for has_access before. Most calls to has_access use it in this context (if has_access...) so they should not change. 
  • to_json: for mobile API use it later on

AccessError

AccessError is a class used by AccessResponse to hold the error details. Different subclasses of AccessError represent specific types of errors, because these different types may need various amounts of additional information. For example, a milestone error could contain exactly which pre-req course is missing. Some types of errors may not need additional fields. 

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• error_code: "course_not_started"

Implementation Plan

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