How it works

In your templates, all HTML code between the tags {% compress js/css %} and {% endcompress %} is parsed and searched for CSS or JS. These styles and scripts are subsequently processed with optional, configurable compilers and filters.

The default filter for CSS rewrites paths to static files to be absolute. Both Javascript and CSS files are by default concatenated and minified.

As the final step the template tag outputs a <script> or <link> tag pointing to the optimized file. Alternatively it can also inline the resulting content into the original template directly.

Since the file name is dependent on the content, these files can be given a far future expiration date without worrying about stale browser caches.

For increased performance, the concatenation and compressing process can also be run once manually outside of the request/response cycle by using the Django management command manage.py compress.

Configurability & Extensibility

Django Compressor is highly configurable and extensible. The HTML parsing is done using lxml or if it’s not available Python’s built-in HTMLParser by default. As an alternative Django Compressor provides a BeautifulSoup and a html5lib based parser, as well as an abstract base class that makes it easy to write a custom parser.

Django Compressor also comes with built-in support for YUI CSS and JS compressor, yUglify CSS and JS compressor, Google’s Closure Compiler, a Python port of Douglas Crockford’s JSmin, a Python port of the YUI CSS Compressor csscompressor and a filter to convert (some) images into data URIs.

If your setup requires a different compressor or other post-processing tool it will be fairly easy to implement a custom filter. Simply extend from one of the available base classes.

More documentation about the usage and settings of Django Compressor can be found on django-compressor.readthedocs.org.

The source code for Django Compressor can be found and contributed to on github.com/django-compressor/django-compressor. There you can also file tickets.

The in-development version of Django Compressor can be installed with pip install git+https://github.com/django-compressor/django-compressor.git