zopieux / pycmarkgfm

Lightweight Python bindings to GitHub Flavored Markdown (GFM) library, with special support for task lists.

pycmarkgfm

Lightweight Python bindings to GitHub Flavored Markdown (GFM) library, cmark-gfm, with enhanced support for task lists.

Features

• By design, rendering is compliant with GitHub's, since this package wraps GitHub's own C parser and serializer.
• As opposed to most cmark-gfm bindings out there, this package supports parsing and toggling task lists.
• Compatibility: with Python 3.7 & newer, on Linux, MacOS and Windows.

Installation

This packages is available on PyPi along with precompiled wheels for most architectures.

$ pip install pycmarkgfm

Usage

import pycmarkgfm

# CommonMark (not GitHub flavored):
html = pycmarkgfm.markdown_to_html("Hello *world*")

# GitHub flavored Markdown:
html = pycmarkgfm.gfm_to_html("Hello ~world~")

Options

cmark and cmark-gfm come with a bunch of customization options (also known as flags) which are made available through the pycmarkgfm.options module. To use one or multiple options, use the options= argument with a mask (bitwise-or combination) of pycmarkgfm.options. Each option is documented.

text = "hello\n<img src='doge.png'>"

print(pycmarkgfm.markdown_to_html(text))
# <p>hello
# <!-- raw HTML omitted --></p>

from pycmarkgfm import options
print(pycmarkgfm.markdown_to_html(text, options=options.unsafe | options.hardbreaks))
# <p>hello<br />
# <img src='doge.png'></p>

Dealing with task lists

One of the distinctive features of this package is support for task lists. You can get the list of tasks with their checked state, and update that state before rendering:

import pycmarkgfm

md = """
- [ ] eggs
- [x] milk
"""

with pycmarkgfm.parse_gfm(md) as document: 
    eggs, milk = document.get_tasks()
    assert not eggs.checked
    assert milk.checked

    # Toggle! 
    eggs.checked = True
    print(document.to_commonmark())
    # - [x] eggs
    # - [x] milk

There is a convenience method to easily toggle a task state from the rendered HTML. The typical use-case is that your database stores the source GFM, renders it to HTML with gfm_to_html(), then you have some client Javascript snippet that is invoked when a checkbox is clicked. Thanks to the unique data-gfm-task HTML attribute, you can update the source GFM on the server:

import pycmarkgfm

md = """
- [ ] eggs
- [x] milk
"""

print(pycmarkgfm.gfm_to_html(md))
# <ul>
# <li data-gfm-task="2:1-2:10"><input type="checkbox" disabled="" /> eggs</li>
# <li data-gfm-task="3:1-3:10"><input type="checkbox" checked="" disabled="" /> milk</li>
# </ul>

# When user clicks a checkbox, get the parent 'data-gfm-task', then on the server, do:
new_md = pycmarkgfm.gfm_toggle_task_by_id(md, "2:1-2:10", checked=pycmarkgfm.TOGGLE)
print(new_md)
# - [x] eggs
# - [x] milk

You can also use checked=True/False instead of TOGGLE to force a particular state.

How is this package different from cmarkgfm?

cmarkgfm is similar to this package, in fact cmarkgfm's cffi build script is partially re-used in this project – in compliance with its MIT license.

As of October 2023, cmarkgfm is still a well-maintained project and I recommend using it if you don't need the extra features provided by pycmarkgfm, most notably the support for task lists.

License

GNU GPLv3.

The project includes components under a different copyright under the third_party directory.