A quick and dirty script to use online services to generate minified versions of js and css files next to the originals, such as for CDNJS.

minify.py

import os
import fnmatch
from urllib import urlopen, urlencode

services = {
    "css": "http://cssminifier.com/raw",
    "js": "http://javascript-minifier.com/raw"
}

for ext, url in services.items():
    files = [os.path.join(dirpath, f)
        for dirpath, dirnames, files in os.walk(".")
        for f in fnmatch.filter(files, '*.%s' % ext)]
    for path in files:
        if ".min." + ext in path: continue
        out_path = path[:-len(ext):] + "min." + ext
        with file(path) as f:
            raw = f.read()
        post = urlopen(url, urlencode({'input': raw}))
        with file(out_path, "w+") as f:
            f.write(post.read())
        print path, "->", out_path, map(os.path.getsize, [path, out_path])