md-to-html2 0.2

Convert Markdown to HTML using Jinja2 templates

Convert Markdown to HTML using Jinja2 templates

This converts a markdown file to a full HTML file by using a template. The default templates are:

1. simple: A simple one column layout using Bootstrap, with support for math (using MathJax), syntax highlighting, and automatic light/dark theme switching. (See a demo here.)

2. revealjs: A RevealJS presentation. (See a demo here.)

3. A LightGallery slideshow. (See a demo here.) (This script can also resize your original images and create thumbnails / web versions for your slideshow. See the demo for instructions.)

Installation

• Using pip: If you use pip, then install by:

    pip install md-to-html2
  

  ( Note the extra 2; the name md-to-html was already used on PyPi 🙄.)

• Without using pip: If you don't use pip, you can install this directly by doing the following:

  • Clone the repository https://codeberg.org/gi1242/md-to-html.git

  • Create a symlink to src/md-to-html from somewhere in your PATH.

  • Install the required dependencies: python, python-frontmatter, python-jinja, python-markdown, python-pyxdg.

  • Optionally install the optional dependencies: python-pillow (for resizing images), python-pygments (for syntax highlighting output).

Usage

Simple one file use case

Just run md-to-html file.md to produce file.html. (Optionally choose template / set options in the YAML front matter.)

More complicated multi-file use case

To build more complicated sites, this will do two things for you:

1. Recurse directories and create HTML files (either in the same location, or in a specified destination directory preserving the hierarchy).

2. Recurse through the destination directory, and purge all HTML files that don't correspond to markdown source files. (You can set exclude / preserve lists.)

To build a website, you may need a few other things. This script doesn't do them because there are other tools that do them excellently. For example:

1. Copying static files, or uploading to your web server. I use rsync for this. (You can configure this script to run rsync or any external command on successful completion using the exec option in config files.)

2. Automatically watch files and compile HTML when the source is changed. I configured my editor (Neovim) to do this automatically every time a source file is changed (instructions [[examples/livereload/index.html|here]]).

3. Automatically reload the HTML preview when the HTML is compiled. I use a livereload server (instructions [[examples/livereload/index.html|here]]).

Command line options

usage: md-to-html [-h] [-c CONFIG] [-d] [-f] [-F] [-n] [-q] [-R] [-r] [-s]
                  [-p PREVIEW] [-t THREADS] [-u] [-v]
                  [files ...]

Convert markdown files to HTML using Jinja2 templates

positional arguments:
  files                 Markdown (or YAML config) files

options:
  -h, --help            show this help message and exit
  -c CONFIG, --config CONFIG
                        Config file (YAML)
  -d, --delete-extra    Delete extra html files
  -f, --force           Render whether or not source is newer
  -F, --force-resize    Resize images whether or not source is newer
  -n, --no-exec         Show extra html files
  -q, --quiet           Suppress info messages
  -R, --no-recurse      Recurse subdirectories for *.md files
  -r, --resize-images   Resize images for slideshows
  -s, --show-extra      Show extra html files
  -p PREVIEW, --preview PREVIEW
                        Launch preview for output file (no output is
                        generated)
  -t THREADS, --threads THREADS
                        Number of threads. Use 0 (default) to let the system
                        decide automatically.
  -u, --update          Only render if source is newer
  -v, --verbose         Show debug messages

Configuration (from YAML config files)

The following directories are searched for configuration.

1. The directory this script was installed in
2. /etc/xdg/md-to-html
3. ~/.config/md-to-html
4. The directory of the input file.

Global options should be in a config.yaml file. The default (hardcoded) options are:

:::yaml
enable_mathjax: true
enable_codehilite: true
enable_jinja: false
jinja_header: |
  {%- import 'lightgallery.j2' as LightGallery -%}
template: simple
encoding: utf-8
absolute_links: False
update: False
exclude_dirs: [
  '.git'
  '__pycache__'
  'templates'
  'reveal.js'
]
exclude_files: []
protect_dirs: [
  'reveal.js'
]
protect_files: []

• base_dir: Base of the source directory hierarchy. Source file outside this directory will raise an exception. (Default ..) It is treated as a relative path from the file it was defined in, so that base_dir: . works as expected.
• dst_dir : All output goes in this directory, preserving the directory hierarchy up to base_dir. That is base_dir/path/file.md becomes dst_dir/path/file.html. It is treated as a relative path from the file it was defined in.
• exclude_files / exlcude_dirs: List of glob patterns of source files / directories to ignore when recursing through directories. (Values are appended to existing values; to clear the list use !!reset as the first entry.)
• protect_files / protect_dirs: List of glob patterns of destination files / directories to protect from deletion. When -d is used, all HTML files in the destination directory that do not correspond to source markdown files are deleted. protect_files / protect_dirs can be used to protect some of these files from deletion. (Values are appended to existing values; to clear the list use !!reset as the first entry.)
• sources: List of source files / directories to convert to HTML / recurse into.
• update: Only compile source if it is newer than the target HTML (overridden by -u / -f on command line)
• exec: Commands to run if all files are processed without error (must be defined in a YAML config file specified with -c) Useful to start rsync to transfer static files. Multiple commands can be given if separated by newlines. All commands are passed through a shell, and run in base_dir.

Configuration (from YAML front matter)

All metadata, including the template name, can also be specified as YAML front matter surrounded by ---:

---
template: simple
encoding: utf-8
enable_jinja: true
---
Markdown content starts here.

Markdown Syntax and Extensions

We use python-markdown to render the HTML, with the following extensions enabled:

• Extra: A compilation of various Python-Markdown extensions that (mostly) imitates PHP Markdown Extra. The supported extensions include: Abbreviations, Attribute Lists, Definition Lists, Fenced Code Blocks, Footnotes, Tables, Markdown in HTML.

• Sane Lists: The Sane Lists extension alters the behavior of the Markdown List syntax to be less surprising.

• SmartyPants: The SmartyPants extension converts ASCII dashes, quotes and ellipses to their HTML entity equivalents.

• Table of Contents: The Table of Contents extension generates a Table of Contents from a Markdown document and adds it into the resulting HTML document. (Use it either in templates via {{toc}} or in markdown after setting enable_jinja: true.)

• Strikethrough: Produce strike through text using ~~text~~

• CodeHilite: The CodeHilite extension adds code/syntax highlighting to standard Python-Markdown code blocks using Pygments. (Disable it with enable_codehilite: false)

• Wiki Links: To use [[link.html|label]] syntax (and provide warnings if the link is to a local find and isn't found.

• Math: Render math using MathJax

• Jinja2 expressions if enable_jinja is true (default is false).

MathJax Macros and options

A few MathJax options and LaTex macros are defined in the simple.j2 template. To add your own macros or change the mathjax configuration, you have a few options:

1. For new macros in one document use this at the start of the file:

    $
      \newcommand{\mymacro}{expansion}
      ...
    $
   

2. For per document configuration changes use the mathjax_config YAML metadata.

    :::yaml
    ---
    mathjax_config: |
      MathJax.tex.tags = 'ams'
      MathJax.tex.macros = {
        ...MathJax.tex.macros,
        sign: '\\operatorname{sign}',
        abs: [ '#1\\lvert#2#1\\rvert', 2, '' ]
      }
    ---
   

   The contents of mathjax_config are treated as JavaScript and included right after the MathJax configuration object is defined. You can, for instance, also define (or undefine) macros using MathJax.tex.macros. (If you put this in config.yaml, then it will be used for all files in that directory.)

3. For more global settings, you can extend the template and override the mathjax block (look at tests/templates/custom.j2 for an example).

WikiLinks

Use [[file.html|label]] to generate a link to file.html with label label. To use the file name as the label, just use [[file.html]]

• Link to files which don't exist produce a warning.
• [[/absolute/path]] links to base_url/absolute/path.
• If absolute_links is set, then all wiki-links are converted to absolute links using base_url/absolute/path.

Using Jinja2 commands in the markdown file.

By default Jinja2 expressions are only available in templates, and not in the markdown file. If you want to use them, set enable_jinja=true in either the metadata or global configuration options. For example:

:::markdown
---
title: Document tile
author: Author
template: simple
enable_jinja: true
user_flag: true
---

# {{title}}

*{{author}}, 2023-10-06*

You can use Jinja2 expressions: 1 + 1 = {{1 + 1}}.

{% if user_flag %}
You can set conditionals in metadata
{% else %}
and render content based on the values.
{% endif %}

Note: enable_jinja=false by default so invalid Jinja2 expressions don't surprise users.

Templates

A file is converted to HTML using a Jinja2 template. Templates should be in the templates subdirectory of one of the configuration folders, and should have a .j2 extension. A bare bones example of a template is:

:::jhtml
<!DOCTYPE html>
<html>
  <head><title>{{title}}</title></head>
  <body>{{content}}</body>
</html>

All YAML metadata and global options are accessible as template variables. The following additional variables are defined while processing:

• uses_math: True if math was detected when rendering the file
• uses_codehilite: True if syntax highlighted code was detected when rendering the file
• toc: HTML table of contents obtained from the file
• title: Contents of the first <h1> element, if not previously set.
• content: Document content after conversion from Markdown to HTML

Template specific options

There are various template specific options that can be set from YAML front matter (or config files).For instance, to add a style sheet, you can use

end_head: <link href="..." rel="stylesheet" integrity="..." crossorigin="anonymous">

These are only documented in the source 😄

Live Previews

You can have the web browser automatically reload the HTML preview every time you make a change. Two ways of doing this are described in examples/livereload/index.md

---

Copyright 2023, Gautam Iyer. MIT Licence.