2. Tagging App structure

2. Tagging App structure#

Status#

Partially accepted, partially obsolete (see note under “ObjectTag”).

Context#

We want the openedx_tagging app to be useful in different Django projects outside of just openedx-learning and edx-platform.

Decisions#

The openedx_tagging data structures and code will stand alone with no dependencies on other Open edX projects.

Classes which require dependencies on other Open edX projects should be defined within a tagging module inside those projects.

Taxonomy#

The openedx_tagging module defines openedx_tagging.models.Taxonomy, whose data and functionality are self-contained to the openedx_tagging app. However in Studio, we need to be able to limit access to some Taxonomy by organization, using the same “course creator” access which limits course creation for an organization to a defined set of users.

So in edx-platform, we will create the openedx.core.djangoapps.content_tagging app, to contain the models and logic for linking Organization owners to Taxonomies. Here, we can subclass Taxonomy as needed, preferably using proxy models. The APIs are responsible for ensuring that any Taxonomy instances are cast to the appropriate subclass.

ObjectTag#

Similarly, the openedx_tagging module defines openedx_tagging.models.ObjectTag, also self-contained to the openedx_tagging app.

But to tag content in the LMS/Studio, we need to enforce object_id as a CourseKey or UsageKey type. So to do this, we subclass ObjectTag, and use this class when creating content object tags. Once the object_id is set, it is not editable, and so this key validation need not happen again.

Note 2026-04-02: In 2024, we simplified this, and ObjectTags are no longer subclassable. Instead, Django rules permissions hooks allow openedx-platform to extend the can_change_object_tag permission rule as needed.

Rejected Alternatives#

Embed in edx-platform#

Embedding the logic in edx-platform would provide the content tagging logic specifically required for the MVP.

However, we plan to extend tagging to other object types (e.g. People) and contexts (e.g. Marketing), and so a generic, standalone library is preferable in the log run.

Changelog#

2026-04-02:

  • Added “Status”

  • Updated references to module paths