django-static-class-minifier 0.1.3

Precompress Django static files with class names shortening.

Django Static class minifier

Description

The class minifier package shortens the class name in the DOM to single character and reduces the file size. more about the algorithm in the upcoming blog post.

End result :

Installation

$ pip install django-static-class-minifier

(you may want to write this in your requirements.txt)

In settings.py -

In Installed apps -

INSTALLED_APPS = [
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'static_compressor', #installed app
'.....'
]

In Middleware -

MIDDLEWARE = [
'django.middleware.security.SecurityMiddleware',
'django.contrib.sessions.middleware.SessionMiddleware',
'django.middleware.common.CommonMiddleware',
'django.middleware.csrf.CsrfViewMiddleware',
'static_compressor.middleware.MinifyClassMiddleware', # Add this line, right after csrf middleware.
'django.contrib.auth.middleware.AuthenticationMiddleware',

Make sure, you have set up path of static files and static root directory.

STATICFILES_DIRS = (
os.path.join(BASE_DIR, 'static'),
)

STATIC_ROOT = os.path.join(BASE_DIR, 'all_staticfiles')

Update the static files storage:

STATICFILES_STORAGE = 'static_compressor.staticfiles_storage.CompressedStaticFilesStorage'

Run the below command and make sure static_root folder is deleted before running the command.

$ python manage.py collectstatic_compress

When you run $ python manage.py collectstatic_compress it will have an additional post-processing pass to compress your static files and it creates data.json file which contains classes from all included css files and js files.

The class selectors which js files consider and change -

querySelector('.flex-box');
querySelectorAll('.flex-boxes');
classList.contains('active');
classList.add('active);
classList.remove('active');
classList.toggle('active');

If your adding classes to the DOM based on http response or a common function which appends class to the dom, then consider excluding those files. Right now that's the limitation of this project. In the future, There might be a syntax to consider those classes.

Make sure that your web server is configured to serve precompressed static files:

• If using nginx:
  • Setup ngx_http_gzip_static_module to serve gzip (.gz) precompressed files.
  • Out of tree module ngx_brotli is required to serve Brotli (.br) precompressed files.
• Caddy will serve .gz and .br without additional configuration.

Also, as Brotli is not supported by all browsers you should make sure that your reverse proxy/CDN honor the Vary header, and your web server set it to Vary: Accept-Encoding.

Available Storages

• static_compress.CompressedStaticFilesStorage: Generate .br and .gz from your static files
• static_compress.CompressedManifestStaticFilesStorage: Like ManifestStaticFilesStorage, but also generate compressed files for the hashed files
• static_compress.CompressedCachedStaticFilesStorage: Like CachedStaticFilesStorage, but also generate compressed files for the hashed files You can also add support to your own backend by applying static_compressor.staticfiles_storage.CompressMixin to your class. By default it will only compress files ending with .js, .css and .svg. This is controlled by the settings below.

Settings

django-static-class-minifier settings and their default values:

EXCLUDE_STATIC_JS_FILES = [''] # exclude js libraries from classnames minifier
EXCLUDE_STATIC_CSS_FILES = ['']
EXCLUDE_STATIC_SVG_FILES = ['']
EXCLUDE_STATIC_DIRECTORY = ['']
EXCLUDE_URL_MINIFICATION = ['']
EXCLUDED_CLASSNAMES_FROM_MINIFYING = ['']
MINIFY_CLASS_HTML = False # Change it to True in production environment
# By default, the admin files classes won't be minified.
STATIC_CLASSES_FILE_NAME = 'data.json' # It should be an json file

# Incase, Inside your app if there is static directory then include it in STATIC_INCLUDE_DIRS

STATIC_INCLUDE_DIRS = (
    os.path.join(BASE_DIR, 'faq/static'), # Example : Let the app name be faq
)

STATIC_COMPRESS_FILE_EXTS = ['js', 'css', 'svg']
STATIC_COMPRESS_METHODS = ['gz', 'br']
STATIC_COMPRESS_KEEP_ORIGINAL = True
STATIC_COMPRESS_MIN_SIZE_KB = 30

Default values types and description -

Settings	Type	Description
EXCLUDE_STATIC_JS_FILES	Array	These js files will be excluded from classnames shortening, In other words the class names won't be changed.
EXCLUDE_STATIC_CSS_FILES	Array	Same as above but for css files.
EXCLUDE_STATIC_SVG_FILES	Array	Same as above but for svg files
EXCLUDE_STATIC_DIRECTORY	Array	The directory name in the array will be excluded from class names shortening.
EXCLUDE_URL_MINIFICATION	Array	The URL in the array will exclude from shortening of class names.
EXCLUDED_CLASSNAMES_FROM_MINIFYING	Array	The words in an array won't be shortened.
MINIFY_CLASS_HTML	Boolean	If its True it minifies class names in the HTML. Make sure there is JSON file or it will throws an error.
STATIC_CLASSES_FILE_NAME	String	The JSON file name. By default its data.json
STATIC_INCLUDE_DIRS	Tuple	Includes static directory inside the app.

Resources

In case, If you want to Internal style or Internal load script in the HTML. Then consider using Django Inline Static package.

File size reduction

Original file - 100k style.css
compressed class minifier file - 70k style.css (30% reduction in file size)
(Note - reduction of the file depends on the number of class selectors used and the length of the class name.)
After brotli and Gzip compression - 40k style.css.gz (60% reduction in file size, in total), 35k style.css.br (65% reduction in file size) 

Credits

I have merged the code with django-static-compress package to enable gzip and brotli compression. In case, if you just use brotli and gzip compression without using class minifier. You can use django-static-compress The author of django-static-compress Manatsawin Hanmongkolchai

Licence

Licensed under the MIT License

Happy coding! :)