example.py

import re

css_source = """
@import url("../something.css");
@import url(../something.css);
@import url(/some/url.css);

body {
  background-image: url("images/file.png");
  background-image: url('images/file.png');
  background-image: url(../data/images/file.png);
  background-image: url(//python-cssembed.googlecode.com/git/cssembed/tests/data/file.png);
  background-image: url(http://python-cssembed.googlecode.com/git/cssembed/tests/data/file.png);
  background-image: url(https://python-cssembed.googlecode.com/git/cssembed/tests/data/file.png);
  background-image: url("http://python-cssembed.googlecode.com/git/cssembed/tests/data/file.png");
  background-image: url('https://python-cssembed.googlecode.com/git/cssembed/tests/data/file.png');
  background-image: url(missing.gif);
  background-image: url(../data/images/missing.gif);
  background-image: url(images/file1.png), url(images/file2.png);
  background-image: url(images/file1.png), url(images/file2.png)
  background-image: url(images/file.png)
}
"""

PATTERN=r'[\s:,]*url\(([^\(\)]*)\)[;,\s]?'

def find_all_urls(source, pattern=PATTERN):
  for match in re.finditer(pattern, source, re.MULTILINE | re.IGNORECASE):
    s = match.span()
    #print dir(match)
    print [unquote(s) for s in match.groups()]
    #print source[s[0]:s[1]]

def unquote(s):
  quote_chars = '\"\''
  if s[0] in quote_chars and s[-1] in quote_chars:
    return s[1:-1]
  else:
    return s


if __name__ == '__main__':
  find_all_urls(css_source)