Markdown XBlock

Based on the HTML XBlock by OpenCraft

Introduction

This XBlock allows course authors to create and edit course content in Markdown and displays it as HTML.

Installation

You may install the markdown-xblock using its setup.py, or if you prefer to use pip, run:

pip install markdown-xblock

If you prefer to install directly from Git, run:

pip install git+https://github.com/citynetwork/markdown-xblock.git

You may specify the -e flag if you intend to develop on the repo.

The minimum supported Python version is 3.8.

To enable this block, add "markdown" to the course's advanced module list. The option Markdown will appear in the advanced components.

Once you've added a new Markdown component to your course, you can also add custom CSS classes to the component by selecting EDIT/Settings and adding to the classes list (Note: use double quotes " "). Example:

["custom-css-class-1", "custom-css-class-2"]

The Markdown block uses markdown2 to translate the content into HTML, by default the following extras are included:

"code-friendly"
"fenced-code-blocks"
"footnotes"
"tables"
"use-file-vars"

Configuration

It is possible to configure more extras, by adding to the extras list under "markdown" key in XBLOCK_SETTINGS at /edx/etc/{studio|lms}.yml

By default, the safe_mode for markdown2 library is enabled and set to replace, which means that writing inline HTML is not allowed and if written, all tags will be replaced with [HTML_REMOVED]. You can also set safe_mode to escape, which only replaces <, > and & with <, > and &. To disable safe mode altogether and allow inline HTML, you'll need to set safe_mode to False or None in XBLOCK_SETTINGS. Please note that setting safe_mode to the empty string ('') also disables safe mode.

Example:

XBLOCK_SETTINGS:
    markdown:
        extras:
            - code-friendly
            - fenced-code-blocks
            - footnotes
            - header-ids
            - metadata
            - pyshell
            - smarty-pants
            - strike
            - target-blank-links
            - use-file-vars
            - wiki-tables
            - tag-friendly
        safe_mode: replace

Usage notes

Images

To include images in your markdown content, use the standard Markdown inline image syntax. Your course images will normally live in the static/images directory, relative to the root of your course, so you would include an image like this:

![alt text for example image](/static/images/example.png)

The XBlock will then mangle your image reference into a static asset reference.

Links

If Markdown XBlock content contains links to another course, and your platform is configured with the XBlock's safe mode enabled, a link like

[link text](https://example.com/courses/course-v1:Org+Class+Version/about)

will, when rendered, turn its + characters into whitespace. That isn't actually wrong, because both + and the %20 escape sequence in URLs are meant to represent whitespace, yet Open edX uses the + character to mean something other than whitespace, and that's a bit of a problem.

To preserve Open edX course URL references, please explicitly encode the + character as %2B, like so:

[link text](https://example.com/courses/course-v1:Org%2BClass%2BVersion/about)

Development

If you'd like to develop on this repo or test it in devstack, clone this repo to your devstack's ~/workspace/src, ssh into the appropriate docker container (make lms-shell and/or make studio-shell), run pip install -e /edx/src/markdown-xblock, and restart the service(s).

Running tests

The testing framework is built on tox. After installing tox, you can run tox from your Git checkout of this repository.

To throw away and rebuild the testing environment, run:

$ tox -r

For running PEP-8 checks only:

$ tox -e flake8