python - 在烧瓶资产（网络资产）中编写自定义过滤器

Question

将 Flask 与烧瓶资产（来自 webassets）一起使用，我按照文档为 css 压缩器编写了自己的自定义过滤器。它似乎不起作用：

from csscompressor import compress
from flask_assets import Bundle
from webassets.filter import Filter, register_filter

class NoopFilter(Filter):
    name = 'csscompressor'
    print("noopfilter")

    def output(self, _in, out, **kwargs):
        print("output")

    def input(self, _in, out, **kwargs):
        print("input")

register_filter(NoopFilter)

bundles = {
    'home_css': Bundle(
        'css/main.css',
        'css/forms.css',
        output='gen/home.css',
        filters='csscompressor'
    )

该类在启动时被调用两次，过滤器是通过它的名字找到的，但input()似乎output()永远不会被调用。创建了 css 文件，但显然没有任何压缩。这个事情谁有经验？

Answer 1

显然，这是一个缓存问题。更改过滤器名称使其工作。希望这可以帮助人们将头发拉出几 kB。

Answer 2

使用 csscompressor 包压缩 CSS 的示例（pip install csscompressor）

from csscompressor import compress
from flask_assets import Bundle
from webassets.filter import Filter, register_filter

class NoopFilter(Filter):
    name = 'css_compress'

    def output(self, _in, out, **kwargs):
        css = compress(_in.read())
        out.write(css)

    def input(self, _in, out, **kwargs):
        css = compress(_in.read())
        out.write(css)


register_filter(NoopFilter)


bundles = {
    'app_css': Bundle(
        'css/responsive.css',
        'css/ads.css',
         filters='css_compress',
         output='all/app.css'
    ),