test.py

from urllib.request import BaseHandler
from urllib.request import Request

from urllib.response import addinfo
from urllib.response import addinfourl

import gzip

from typing import Union


# =====
class GzipHandler(BaseHandler):
    def http_request(self, request: Request) -> Request:
        request.add_header("Accept-Encoding", "gzip")
        return request

    def http_response(self, request: Request, response: addinfo) -> Union[addinfo, addinfourl]:  # pylint: disable=unused-argument
        if response.headers.get("Content-Encoding") == "gzip":
            gzip_file = gzip.GzipFile(fileobj=response, mode="r")
            new_response = addinfourl(gzip_file, response.headers, response.url, response.code)
            new_response.msg = response.msg
            return new_response
        return response

    https_request = http_request
    https_response = http_response