jinja-assets-compressor
A Jinja2 extension to compile and/or compress your assets.
Installing
pip install jac
For LESS and CSS support, install less:
npm install -g less
For COFFEE support, install coffee-script:
npm install -g coffee-script
For Sass and SCSS support, install sass:
gem install sass
JavaScript minification is built-in using the Python rJsmin package.
When installing on Mac OS X set this shell variable, because jac dependencies contain C code:
export CFLAGS=-Qunused-arguments
Usage
To use it, you just have to put your css or js inside a compress tag.
{% compress 'css' %}
<style type="text/sass">
sass stuff
</style>
<link rel="stylesheet" type="text/sass" href="file.sass">
{% endcompress %}
{% compress 'js' %}
<script type="text/coffeescript">
coffee stuff
</script>
<script type="text/coffeescript" src="file.coffee"></script>
{% endcompress %}
Configuring Jinja
You just have to create an environment with jac on it and configure output dir, static prefix and say where it can find your sources.
import jinja2
from jac import CompressorExtension
env = jinja2.Environment(extensions=[CompressorExtension])
env.compressor_output_dir = './static/dist'
env.compressor_static_prefix = '/static'
env.compressor_source_dirs = './static_files'
After that just use template = env.from_string(html); template.render() to get it done.
Configuring Flask
Where you configure your app, just do this:
from jac.contrib.flask import JAC
app = Flask(__name__)
app.config['COMPRESSOR_DEBUG'] = app.config.get('DEBUG')
app.config['COMPRESSOR_OUTPUT_DIR'] = './static/dist'
app.config['COMPRESSOR_STATIC_PREFIX'] = '/static'
jac = JAC(app)
And you are done.
Offline Compression
JAC supports compressing static assets offline, then deploying to a production server. Here is a command to compress your static assets if using Flask:
python -m jac.contrib.flask my_flask_module:create_app
Replace my_flask_module with the correct import path to find your Flask app.
Custom Compressors
The compressor_classes template env variable tells jac which compressor to use for each mimetype. The default value for compressor_classes is:
{
'text/css': LessCompressor,
'text/coffeescript': CoffeeScriptCompressor,
'text/less': LessCompressor,
'text/javascript': JavaScriptCompressor,
'text/sass': SassCompressor,
'text/scss': SassCompressor,
}
To use an alternate compressor class, provide a class with a compile class method accepting arg text and kwargs mimetype, cwd, uri_cwd, and debug. For example, to use libsass-python for SASS files instead of the built-in SassCompressor, create your custom compressor class:
import sass
class CustomSassCompressor(object):
"""Custom compressor for text/sass mimetype.
Uses libsass-python for compression.
"""
@classmethod
def compile(cls, text, cwd=None, **kwargs):
include_paths = []
if cwd:
include_paths += [cwd]
return sass.compile(string=text, include_paths=include_paths)
Then tell jac to use your custom compressor for text/sass mimetypes:
env.compressor_classes['text/sass'] = CustomSassCompressor
The equivalent for Flask is:
jac.set_compressor('text/sass', CustomSassCompressor)
To only customize the path of a compressor which forks a subprocess for the compile step (LessCompressor, CoffeeScriptCompressor, and SassCompressor), just extend the compressor class and overwrite the binary class attribute:
from jac.compressors import SassCompressor
class CustomSassCompressor(SassCompressor):
"""Custom SASS compressor using Compass binary instead of libsass for text/sass mimetype.
Uses the faster libsass wrapper sassc for SASS compression.
https://github.com/sass/sassc
"""
binary = '/usr/bin/sassc'
# Tell Flask to use our custom SASS compressor
jac.set_compressor('text/sass', CustomSassCompressor)
Running Tests
virtualenv venv . venv/bin/activate pip install -r requirements_tests.txt make coverage make lint
Or use tox to run with multiple python versions:
pip install tox tox
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