xmodule/assets: edx-platform XBlock resources
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This folder exists to contain resources (i.e., static assets) for the XBlocks
defined in edx-platform.
Concepts
********
We would like edx-platform XBlock resources to match the standard XBlock
resource strategy as much as possible, because:
* it'll make it easier to extract the XBlocks into their own packages
eventually, and
* it makes it easier to reason about the system as a whole when
internally-defined and externally-defined blocks play by the same rules.
Due to the legacy of the XModule system, we're not quite there yet.
However, we are proactively working towards a system where:
* Python is not involved in the generation of static assets.
* We minimze conditionals that differentiate between "older" (aka "XModule-style")
XBlocks and newer (aka "pure") XBlocks.
* Each XBlock's assets are contained within their own folder as much as
possible. See ``./vertical`` as an example.
Themable Sass (.scss)
*********************
Formerly, built-in XBlock CSS for ``student_view``, ``author_view``, and
``public_view`` was compiled from the various
``./<ClassName>BlockDisplay.scss`` modules, and ``studio_view`` CSS was
compiled from the various ``./<ClassName>BlockEditor.scss`` modules.
As of November 2024, all that built-in XBlock Sass was been permanently
compiled into CSS, stored at ``../static/css-builtin-blocks/``.
The theme-overridable Sass variables are injected into CSS variables via
``../../common/static/sass/_builtin-block-variables.scss``.
JavaScript (.js)
****************
Currently, edx-platform XBlock JS is defined both here in `xmodule/assets`_ and outside in `xmodule/js`_. Different JS resources are processed differently:
* For many older blocks, their JS is:
* bundled using a `webpack.builtinblocks.config.js`_,
* which is included into `webpack.common.config.js`_,
* allowing it to be included into XBlock fragments using ``add_webpack_js_to_fragment`` from `builtin_assets.py`_.
Example blocks using this setup:
* `ProblemBlock`_
* `HtmlBlock`_
* `AnnotatableBlock`_
* For other "purer" blocks, the JS is used as a standard XBlock fragment. Example blocks:
* `VerticalBlock`_
* `LibraryContentBlock`_
As part of an `active build refactoring`_, we will soon consolidate all edx-platform XBlock JS here in `xmodule/assets`_.
.. _xmodule/assets: https://github.com/openedx/edx-platform/tree/master/xmodule/assets
.. _xmodule/js: https://github.com/openedx/edx-platform/tree/master/xmodule/js
.. _ProblemBlock: https://github.com/openedx/edx-platform/blob/master/xmodule/capa_block.py
.. _HtmlBlock: https://github.com/openedx/edx-platform/blob/master/xmodule/html_block.py
.. _AnnotatableBlock: https://github.com/openedx/edx-platform/blob/master/xmodule/annotatable_block.py
.. _VerticalBlock: https://github.com/openedx/edx-platform/blob/master/xmodule/vertical_block.py
.. _LibraryContentBlock: https://github.com/openedx/edx-platform/blob/master/xmodule/library_content_block.py
.. _active build refactoring: https://github.com/openedx/edx-platform/issues/31624
.. _builtin_assets.py: https://github.com/openedx/edx-platform/tree/master/xmodule/util/builtin_assets.py
.. _static_content.py: https://github.com/openedx/edx-platform/blob/master/xmodule/static_content.py
.. _library_source_block/style.css: https://github.com/openedx/edx-platform/blob/master/xmodule/assets/library_source_block/style.css
.. _webpack.builtinblocks.config.js: https://github.com/openedx/edx-platform/blob/master/webpack.builtinblocks.config.js
.. _webpack.common.config.js: https://github.com/openedx/edx-platform/blob/master/webpack.common.config.js
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