Paho Python 客户端版本 1.6.1 和 MQTTv5 ResponseTopic

Question

I am using the mosquitto broker with the mqtt vcpkg C++ client.
I can use the v5 properties to publish messages with a reply topic.
When I tried with the Paho Python client, I had no reply topic in the message received on the C++ side.
I followed some guidelines here for the python side:

from paho.mqtt.properties import Properties
from paho.mqtt.packettypes import PacketTypes
from paho.mqtt.client import Client

properties=Properties(PacketTypes.PUBLISH)
properties.ResponseTopic="myreplies"
client = Client(client_id = "client_1",protocol=5)
client.connect("localhost",properties=properties)
publisher.publish(topic = "acquisition/FifoServerParams", payload = "message")

but when the C++ client receives the message in the handler

client->set_v5_publish_handler(
            [&](mqtt::optional<async_client_t::packet_id_t>, mqtt::publish_options, mqtt::buffer topicName, mqtt::buffer contents, mqtt::v5::properties props)

gots an empty props value.

Answer 1

As mentioned in the comments, you need to pass the properties to the publish function not connect

from paho.mqtt.properties import Properties
from paho.mqtt.packettypes import PacketTypes
from paho.mqtt.client import Client

properties=Properties(PacketTypes.PUBLISH)
properties.ResponseTopic="myreplies"
client = Client(client_id = "client_1",protocol=5)
client.connect("localhost")
publisher.publish(topic = "acquisition/FifoServerParams", payload = "message", properties = properties)