# problem with example.com
def head_url(url):
    """Perform HEAD, may throw socket errors"""

    import httplib, urlparse

    def _head(url):
        """Returns a http response object"""

        host, path = urlparse.urlparse(url)[1:3]

        connection = httplib.HTTPConnection(host)
        connection.request("HEAD", path)
        return connection.getresponse()

    # redirection limit, default of 10
    redirect = 10

    # Perform HEAD
    resp = _head(url)

    # check for redirection
    while (resp.status >= 300) and (resp.status <= 399):
        # tick the redirect
        redirect -= 1

        # if redirect is 0, we tried :-(
        if redirect == 0:
            # we hit our redirection limit, raise exception
            raise IOError, (0, "Hit redirection limit")

        # Perform HEAD
        url = resp.getheader('location')
        resp = _head(url)

    if resp.status >= 200 and resp.status <= 299:
        # horray!  We found what we were looking for.
        return (resp.status, url, resp.reason)

    else:
        # Status unsure, might be, 404, 500, 401, 403, raise error
        # with actual status code.
        print "ERROR", (resp.status, url, resp.reason)
        raise IOError, (resp.status, url, resp.reason)