[Tagging] Taxonomies for Org API #74

Story

"As a content author, I want to see all the taxonomies available for use with my course, block, or library, so that I can tag my content."

Description

Implement a Python and a REST API that allows retrieving the full list of taxonomies given a certain block/context.
This API will be used to fetch the taxonomies relevant to creating/editing content on Studio.

Note: this API should be marked as “unstable” for the MVP.

Completion criteria

Build on/subclass the "taxonomy REST API view" added by #73, and implement this REST API endpoint:

/api/content_tagging/v1/taxonomy?org=<org>&enabled=True|False&page_size=<size>&page=1

• Returns a paginated list of Taxonomy metadata (including their pks), with the same fields and serializers as the "oel_tagging taxonomy list view".
• Always returns the system-defined and instance-wide Taxonomies (subject to the enabled parameter)
• org parameter: (optional) Organization short name
  • Limits the returned taxonomies to the ones that are "owned by" the requested .
• (optional) enabled parameter: bool (same behavior as [Tagging] Taxonomy view/management APIs #73)
  • If omitted, then returns both enabled and disabled Taxonomies.
  • If True, then returns only enabled Taxonomies
  • If False, then returns only disabled Taxonomies
• Paginate this data, with a default MAX_PAGE_SIZE = 100, to allow most people to retrieve all of their taxonomies in one hit.
  People with more taxonomies will need to know where to go to get their next page of data, and so this endpoint should support that too.

Note: it's ok to adjust the openedx.features.content_tagging.rules to meet the behavioral requirements noted below.

Automated testing must cover common paths in behavioral specification.

Pagination

You're welcome to rename the pagination parameters and data specified here to whatever is the standard recommended by DRF Pagination or Django Pagination.

For your tests, feel free to set a more reasonable MAX_PAGE_SIZE to test the next page behavior.

Behavioral specifications

Suppose the Open edX instance has these taxonomies:

• system-defined taxonomies: st1 (enabled), st2 (disabled)
• 1 instance-wide taxonomy: t1 (enabled), t2 (disabled)
• 2 taxonomies owned by organization A: tA1 (enabled), tA2 (disabled)
• 2 taxonomies owned by organization B: tB1 (enabled), tB2 (disabled)
• 2 taxonomies owned by both organizations A & B: tC1 (enabled), tC2 (disabled)

and the following users:

• userA: ordinary, non-staff user

• userS: global staff user

• Anyone can view an enabled taxonomy or its tags

• Only superusers or global staff can view a disabled taxonomy or its tags.

• Only superusers or global staff can assign orgs to a taxonomy.
  These assigned "orgs" will be used to filter which taxonomies returned when the org parameter is provided for the list view, but don't affect taxonomy/tag permissions.

• No users can add/edit/delete a system-defined taxonomy.

• Only superusers or global staff can add/edit/delete a taxonomy (so long as it isn't system-defined)

• Only superusers can add/edit/delete tags on a taxonomy (where allow_free_text=False)

• No users can add/edit/delete tags on a free text taxonomy.

/api/content_tagging/v1/taxonomy/ -- returns all taxonomies the user is allowed to view.

• When userA requests ^, they receive taxonomy metadata for these taxonomies: s1, t1, tA1, tB1, tC1
• When userS requests ^ they receive taxonomy metadata for these taxonomies: s1, s2, t1, t2, tA1, tA2, tB1, tB2, tC1, tC2

/api/content_tagging/v1/taxonomy/context/?enabled=True -- returns enabled taxonomies the user is allowed to view.

• When userA or userS requests ^, they receive taxonomy metadata for these taxonomies: s1, t1, tA1, tB1, tC1

/api/content_tagging/v1/taxonomy/context/?enabled=False -- returns disabled taxonomies the user is allowed to view.

• When userA requests ^, they receive no taxonomy metadata at all
• When userS requests ^ they receive taxonomy metadata for these taxonomies: s2, t2, tA2, tB2, tC2

/api/content_tagging/v1/taxonomy/?org=A -- returns taxonomies the user is allowed to view which are configured for use with content owned by org A

• When userA requests ^, they receive taxonomy metadata for these taxonomies: s1, t1, tA1, tA2, tC1, tC2
• When userS requests ^ they receive taxonomy metadata for these taxonomies: s1, s2, t1, t2, tA1, tA2, tC1, tC2

/api/content_tagging/v1/taxonomy/?org=B -- returns taxonomies the user is allowed to view which are configured for use with content owned by org B

• When userA requests ^, they receive taxonomy metadata for these taxonomies: s1, t1, tB1, tB2, tC1, tC2
• When userS requests ^ they receive taxonomy metadata for these taxonomies: s1, s2, t1, t2, tB1, tB2, tC1, tC2

/api/content_tagging/v1/taxonomy/?org=A&enabled=True -- returns enabled taxonomies the user is allowed to view which are configured for use with content owned by org A

• When userA requests ^, they receive taxonomy metadata for these taxonomies: s1, t1, tA1, tC1
• When userS requests ^ they receive taxonomy metadata for these taxonomies: s1, t1, tA1, tC1

/api/content_tagging/v1/taxonomy/?org=A&enabled=False -- returns disabled taxonomies the user is allowed to view which are configured for use with content owned by org A (No explicit use case exists for this combination, but it's included here for completeness.)

• When userA requests ^, they receive no taxonomy metadata at all
• When userS requests ^ they receive taxonomy metadata for these taxonomies: s2, t2, tA2, tC2

/api/content_tagging/v1/taxonomy/?org=X -- returns taxonomies the user is allowed to view which are configured for use with content owned by org X.
But there are no taxonomies configured for use with org X -- org X may not even exist -- and so only returns:

• When userA requests ^, they receive taxonomy metadata for these taxonomies: s1, t1
• When userS requests ^ they receive taxonomy metadata for these taxonomies: s1, s2, t1, t2

/api/content_tagging/v1/taxonomy/?page_size=2&page=3 -- returns "page 3 of the taxonomies the user is allowed to view.
Since we've specified page_size=2, we'd see the following returned taxonomies here:

• When userA requests ^, they receive taxonomy metadata for these taxonomies: tC1
• When userS requests ^ they receive taxonomy metadata for these taxonomies: tA1, tA2 (with next url providing page=4)

Documentation updates & improvements criteria

• API endpoint and its parameters should be well-documented

Relevant PRs/repositories

• Most of these changes are relevant to Content Tagging, cf: feat: adds Content Tagging openedx-platform#32661
  Code that is content- or org-specific should build on this change.
• But there may be some generic tagging changes that are useful beyond content tagging. They should go in: https://github.com/openedx/openedx-learning/