This PR introduces some backend python + REST APIs for storing static
asset files along with an XBlock in a content library. It also updates
the new runtime to be able to load such static asset files.
Example use cases:
* Store an image file with an HTML block and then use the image inline
in the HTML block.
* Store a PDF file with an HTML block and provide a link in the HTML for
the learner to download the PDF.
* Store .srt files or even video .mp4 files that belong to a video
XBlock.
Within the bundle, these static asset files are stored in a "static/"
subfolder of the folder that contains the OLX file. Extending an
existing LMS/Studio convention, a static asset file such as "image.png"
is referenced within the OLX as "/static/image.png" and the URL will be
rewritten by the runtime.
This commit introduces the changes needed for XBlocks in Blockstore to save
their user state into CSM. Before this commit, all student state for Blockstore
blocks was ephemeral (in-process dict store).
Notes:
* The main risk factor of this PR is that it adds non-course keys to the
course_id field in CSM. If any code (like analytics?) reads course keys
directly out of CSM and doesn't have graceful handling for key types it
doesn't recognize, it could cause an issue. With the included changes to
opaque-keys, calling CourseKey.from_string(...) on these values will raise
InvalidKeyError since they're not CourseKeys. (But calling
LearningContextKey.from_string(...) will work for both course and library
keys.)
* This commit introduces a slight regression for the Studio view of XBlocks in
Blockstore content libraries: their state is now lost from request to request.
I have a follow up PR to give them a proper studio-appropriate state store,
but I want to review it separately so it doesn't hold up this PR and we can
test this PR on its own.
https://github.com/edx/edx-platform/pull/20645
This introduces:
* A new XBlock runtime that can read and write XBlocks that are persisted using
Blockstore instead of Modulestore. The new runtime is currently isolated so
that it can be tested without risk to the current courseware/runtime.
* Content Libraries v2, which store XBlocks in Blockstore not modulestore
* An API Client for Blockstore
* "Learning Context" plugin API. A learning context is a more abstract concept
than a course; it's a collection of XBlocks that serves some learning purpose.
