Django: Highlighting with ReST using Pygments

In my last post I wrote about code highlighting in HTML formatted text, but since I’m now using reStructuredText for markup things, I want to share how I added synthax highlighting for this.

Within your project directory (the same that contains the settings.py) create a file called rst_directive.py and fill it with the following code:

# -*- coding: utf-8 -*-
"""
    The Pygments reStructuredText directive
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

    This fragment is a Docutils_ 0.5 directive that renders source code
    (to HTML only, currently) via Pygments.

    To use it, adjust the options below and copy the code into a module
    that you import on initialization.  The code then automatically
    registers a ``sourcecode`` directive that you can use instead of
    normal code blocks like this::

        .. sourcecode:: python

            My code goes here.

    If you want to have different code styles, e.g. one with line numbers
    and one without, add formatters with their names in the VARIANTS dict
    below.  You can invoke them instead of the DEFAULT one by using a
    directive option::

        .. sourcecode:: python
            :linenos:

            My code goes here.

    Look at the `directive documentation`_ to get all the gory details.

    .. _Docutils: http://docutils.sf.net/
    .. _directive documentation:
       http://docutils.sourceforge.net/docs/howto/rst-directives.html

    :copyright: Copyright 2006-2009 by the Pygments team, see AUTHORS.
    :license: BSD, see LICENSE for details.
"""

# Options
# ~~~~~~~

# Set to True if you want inline CSS styles instead of classes
INLINESTYLES = False

from pygments.formatters import HtmlFormatter

# The default formatter
DEFAULT = HtmlFormatter(noclasses=INLINESTYLES)

# Add name -> formatter pairs for every variant you want to use
VARIANTS = {
    # 'linenos': HtmlFormatter(noclasses=INLINESTYLES, linenos=True),
}


from docutils import nodes
from docutils.parsers.rst import directives, Directive

from pygments import highlight
from pygments.lexers import get_lexer_by_name, TextLexer

class Pygments(Directive):
    """ Source code syntax hightlighting.
    """
    required_arguments = 1
    optional_arguments = 0
    final_argument_whitespace = True
    option_spec = dict([(key, directives.flag) for key in VARIANTS])
    has_content = True

    def run(self):
        self.assert_has_content()
        try:
            lexer = get_lexer_by_name(self.arguments[0])
        except ValueError:
            # no lexer found - use the text one instead of an exception
            lexer = TextLexer()
        # take an arbitrary option if more than one is given
        formatter = self.options and VARIANTS[self.options.keys()[0]] or DEFAULT
        parsed = highlight(u'\n'.join(self.content), lexer, formatter)
        return [nodes.raw('', parsed, format='html')]

directives.register_directive('sourcecode', Pygments)

Open the file __init__.py in the same directory and add the following line:

import rst_directive

Furthermore you might want to create a CSS file containing all the style definitions in your static media directory. The following python script will do the job:

# Call it this way:
# python gen_css.py pygments.css
import sys

from pygments.formatters import HtmlFormatter

f = open(sys.argv[1], 'w')

# You can change style and the html class here:
f.write(HtmlFormatter(style='colorful').get_style_defs('.highlight'))

f.close()

Now you can highlight code using the sourcecode directive:

*Hello World!* in Python is so easy:

.. sourcecode:: python

    print 'Hello World!'

That’s it! If you have any questions, leave a comment.