def render_POST(self, request):
        send_cors(request)
        err = require_args(request, ("medium", "address", "room_id", "sender",))
        if err:
            return json.dumps(err)
        medium = request.args["medium"][0]
        address = request.args["address"][0]
        roomId = request.args["room_id"][0]
        sender = request.args["sender"][0]

        globalAssocStore = GlobalAssociationStore(self.sydent)
        mxid = globalAssocStore.getMxid(medium, address)
        if mxid:
            request.setResponseCode(400)
            return json.dumps({
                "errcode": "THREEPID_IN_USE",
                "error": "Binding already known",
                "mxid": mxid,
            })

        if medium != "email":
            request.setResponseCode(400)
            return json.dumps({
                "errcode": "M_UNRECOGNIZED",
                "error": "Didn't understand medium '%s'" % (medium,),
            })

        token = self._randomString(128)

        tokenStore = JoinTokenStore(self.sydent)

        ephemeralPrivateKey = nacl.signing.SigningKey.generate()
        ephemeralPublicKey = ephemeralPrivateKey.verify_key

        ephemeralPrivateKeyBase64 = encode_base64(ephemeralPrivateKey.encode(), True)
        ephemeralPublicKeyBase64 = encode_base64(ephemeralPublicKey.encode(), True)

        tokenStore.storeEphemeralPublicKey(ephemeralPublicKeyBase64)
        tokenStore.storeToken(medium, address, roomId, sender, token)

        substitutions = {}
        for key, values in request.args.items():
            if len(values) == 1 and type(values[0]) == str:
                substitutions[key] = values[0]
        substitutions["token"] = token

        required = [
            'sender_display_name',
            'token',
            'room_name',
            'bracketed_room_name',
            'room_avatar_url',
            'sender_display_name',
            'guest_user_id',
            'guest_access_token',
        ]
        for k in required:
            substitutions.setdefault(k, '')

        substitutions["ephemeral_private_key"] = ephemeralPrivateKeyBase64
        if substitutions["room_name"] != '':
            substitutions["bracketed_room_name"] = substitutions["room_name"] % "(%s)"

        subject_header = Header(self.sydent.cfg.get('email', 'email.invite.subject', raw=True) % substitutions, 'utf8')
        substitutions["subject_header_value"] = subject_header.encode()

        sendEmail(self.sydent, "email.invite_template", address, substitutions)

        pubKey = self.sydent.keyring.ed25519.verify_key
        pubKeyBase64 = encode_base64(pubKey.encode())

        baseUrl = "%s/_matrix/identity/api/v1" % (self.sydent.cfg.get('http', 'client_http_base'),)

        keysToReturn = []
        keysToReturn.append({
            "public_key": pubKeyBase64,
            "key_validity_url": baseUrl + "/pubkey/isvalid",
        })
        keysToReturn.append({
            "public_key": ephemeralPublicKeyBase64,
            "key_validity_url": baseUrl + "/pubkey/ephemeral/isvalid",
        })

        resp = {
            "token": token,
            "public_key": pubKeyBase64,
            "public_keys": keysToReturn,
            "display_name": self.redact(address),
        }

        return json.dumps(resp)
dataset/ETHPy150Open matrix-org/sydent/sydent/http/servlets/store_invite_servlet.py/StoreInviteServlet.render_POST/swapped operands of `%`