How to generate an s3 signed url in python

signurl.py

def generate_signed_url(mime, file_name, s3):
    """
    :param mime str: The file mime type.
    :param file_name str: The name of the file to be upload into s3.
    :param s3 Object: An object containing the bucket name and access keys to amazon.
    :return str: The signed url.
    """
    expires = int(time.time() + 10)
    amz_headers = 'x-amz-acl:private'

    request_to_sign = str("PUT\n\n{mime_type}\n{expires}\n{amz_headers}\n/{resource}".format(
        mime_type=mime, expires=expires, amz_headers=amz_headers, resource=s3.bucket + '/' + file_name))

    url = 'https://s3.amazonaws.com/{bucket}/{filename}'.format(
        filename=file_name, bucket=s3.bucket)

    signed = urllib.quote_plus(base64.encodestring(
        hmac.new(str(s3.secret_key), request_to_sign, sha).digest()).strip())

    return '{url}?AWSAccessKeyId={access_key}&Expires={expires}&Signature={signed}'.format(url=url, access_key=s3.access_key, expires=expires, signed=signed),
    #/blackhttpmagick