self._make_opener()

    def _make_opener(self):

        mgr = urllib.request.HTTPPasswordMgrWithDefaultRealm()

        mgr.add_password(None, self._uri, self.user, self.passwd)

        handler = urllib.request.HTTPBasicAuthHandler(mgr)

        self.opener = urllib.request.build_opener(handler)

    def _request(self, url, body=None, headers=None,

                 method=None, noformat=False,

                 empty_response_ok=False):

        _headers = {"Content-type": "application/json",

                    "Accept": "application/json"}

        if self.user and self.passwd:

            authstring = ascii_str(base64.b64encode(safe_bytes("%s:%s" % (self.user, self.passwd))))

            _headers["Authorization"] = "Basic %s" % authstring

        if headers:

            _headers.update(headers)

        log.debug("Sent to crowd at %s:\nHeaders: %s\nBody:\n%s", url, _headers, body)

        req = urllib.request.Request(url, body, _headers)

        if method:

            req.get_method = lambda: method

        global msg

        try:

            rdoc = self.opener.open(req)

            if not msg and empty_response_ok:

                rval = {}

                rval["status"] = True

                rval["error"] = "Response body was empty"

            elif not noformat:

                rval = ext_json.loads(msg)

                rval["status"] = True

            else:

                rval = "".join(rdoc.readlines())

        except Exception as e:

            if not noformat:

                rval = {"status": False,

                        "body": body,

            else:

                rval = None

        return rval

    def user_auth(self, username, password):

        """Authenticate a user against crowd. Returns brief information about

        the user."""

        url = ("%s/rest/usermanagement/%s/authentication?username=%s"

               % (self._uri, self._version, urllib.parse.quote(username)))

        body = ascii_bytes(ext_json.dumps({"value": password}))

        return self._request(url, body)

    def user_groups(self, username):

        """Retrieve a list of groups to which this user belongs."""

        url = ("%s/rest/usermanagement/%s/user/group/nested?username=%s"

               % (self._uri, self._version, urllib.parse.quote(username)))

        return self._request(url)

class KallitheaAuthPlugin(auth_modules.KallitheaExternalAuthPlugin):

    def __init__(self):

        self._protocol_values = ["http", "https"]

    @hybrid_property