For local files urllib.py doesn't return the MIME
  headers that the documentation says it does:

  http://www.python.org/doc/current/lib/module-
  urllib.html#l2h-2187 states that "When the method is
  local-file, returned headers will include a Date
  representing the file's last-modified time, a Content-
  Length giving file size, and a Content-Type containing
  a guess at the file's type"

  But in Python 2.1 the only header that gets returned
  is the Content-Type:

  >>> import urllib
  >>> f = urllib.urlopen("gurk.txt")
  >>> f.info().headers
  ['Content-Type: text/plain\n']