Flask-Minify

flask_minify

Flask extension to parse and minify html, javascript, css and less.

Install:

With pip

• pip install Flask-Minify

for better performance (almost two times) you can use the optional go dependency [only Linux supported]

• pip install Flask-Minify[go]

With setup-tools

• git clone https://github.com/mrf345/flask_minify.git
• cd flask_minify
• python setup.py install

Setup:

In this example the extension will minify every HTML request, unless it's explicitly bypassed.

from flask import Flask
from flask_minify import Minify

app = Flask(__name__)
Minify(app=app, html=True, js=True, cssless=True)

Another approach is using decorators, you can set the extension to be passive so will only minify the decorated routes

from flask import Flask
from flask_minify import Minify, decorators as minify_decorators

app = Flask(__name__)
Minify(app=app, passive=True)

@app.route('/')
@minify_decorators.minify(html=True, js=True, cssless=True)
def example():
  return '<h1>Example...</h1>'

Options:

Option	type	Description
app	object	Flask app instance to be passed (default: None)
html	bool	minify HTML (default: True)
js	bool	minify JavaScript output (default: True)
cssless	bool	minify CSS or Less. (default: True)
fail_safe	bool	avoid raising error while minifying (default: True)
bypass	list	endpoints to bypass minifying for, supports Regex (default: [])
bypass_caching	list	endpoints to bypass caching for, supports Regex (default: [])
caching_limit	int	limit the number of cached response variations (default: 2).
passive	bool	disable active minifying, to use decorators instead (default: False)
static	bool	enable minifying static files css, less and js (default: True)
script_types	list	script types to limit js minification to (default: [])
parsers	dict	parsers to handle minifying specific tags, mainly for advanced customization (default: {})
go	bool	prefer go minifier, if optional go dependency is installed (default: True)

- bypass and bypass_caching

endpoint in this context is the name of the function decorated with @app.route so in the following example the endpoint will be root:

@app.route('/root/<id>')
def root(id):
    return id

both options can handle regex patterns as input so for example, if you want to bypass all routes on a certain blueprint you can just pass the pattern as such:

Minify(app, bypass=['blueprint_name.*'])

- caching_limit

if the option is set to 0, we'll not cache any response, so if you want to disable caching just do that.

- script_types

when using the option include '' (empty string) in the list to include script blocks which are missing the type attribute.

- parsers

allows passing tag specific options to the module responsible for the minification, as well as replacing the default parser with another included option or your own custom one.

In the following example will replace the default style (handles CSS) parser rcssmin with lesscpy:

from flask_minify import Minify, parsers as minify_parsers

parsers = {'style': minify_parsers.Lesscpy}

Minify(app=app, parsers=parsers)

you can override the default parser runtime options as well, as shown in the following example:

from flask_minify import Minify, parsers as minify_parsers

class CustomCssParser(minify_parsers.Lesscpy):
    runtime_options = {
        **minify_parsers.Lesscpy.runtime_options,
        "xminify": False,
    }

parsers = {'style': CustomCssParser}

Minify(app=app, parsers=parsers)

the default parsers are set to {"html": Html, "script": Jsmin, "style": Rcssmin} check out the code for more insight.

Development:

• Tests: make test
• Style check: make lint
• Format code: make format

Breaking changes

0.44

Introduced more performant parsers that will be enabled by default, if you're running Linux and the optional Go dependency is installed tdewolff-minify. You can disable that behavior using minify(go=False).

0.40

Due to a future deprecation in Flask 2.3, the extension is no longer going to fallback to Flask._app_ctx_stack, it will raise an exception instead (flask_minify.exceptions.MissingApp)

0.33

introduces a breaking change to the expected output, in this release lesscpy will be replaced by cssmin as the default css minifier so no more less compiling by default. in case you don't want that, follow this example.