mqtt

问题 Please help, I need to use mqtt protocol in lambda function to send some data to a broker. I use simple code to test it : mqtt = require('mqtt'); var client = mqtt.connect('mqtt://test.mosquitto.org'); client.on('connect', function () { client.subscribe('presence'); client.publish('presence', 'Hello mqtt'); }); client.on('message', function (topic, message) { // message is Buffer console.log(message.toString()); client.end(); }); But I get an error "Cannot find module 'mqtt'", how can I

问题 The question is already posted, Mqtt How a client can get to know that another client is connected or not and How to Find Connected MQTT Client Details In my case, if client X is already subscribed in a channel A, client Y can't subcribe to the channel A, until X unsubcribes. I can only have one client subscribed in the channel Can I also use the idea of retained messages and LWT? If yes, I don't know exactly from where should I start. It would be good to start with a simple example to see

问题 Azure has implemented MQTT protocol in its IoTHub so I'm trying to use mosquitto to send messages from my pc. I'm creating azure devices using Device Explorer. In the beginning I generated SAS token from there, but it hasn't the "&skn=" part, so I tried to generate a new SAS using compatible event hub from visual studio. After that i tried to use mosquitto broker to send an MQTT message to my IoTHub using parameters in the CONNECT packet as explained here: https://azure.microsoft.com/en-us

问题 I've been trying to use https://www.npmjs.com/package/mqtt to simulate a large number of publishes and found that the queue does not hold more than 65535 messages at a time. (If I try to send more, the remaining are discarded) Is there a reason for this and are there any workarounds? 回答1: Because that is the maximum number of packet ids allowed in the MQTT spec Packet ids are a 16bit number (max 65535) and must be unique for all inflight messages. SUBSCRIBE, UNSUBSCRIBE, and PUBLISH (in cases

问题 I connect to my mosquitto broker with client.connect("192.168.1.1",1883,60) to establish the connection, and the server expects traffic every 60 seconds. The paho documentation refers to a PINGREQ/PINGACK message which I would like to use to keep the connection alive. Can't find any examples of this - how to do this in python (2.7)? 回答1: The short answer is you don't The pings are handled by the MQTT Client network loop. You need to start this after connecting. There are 3 ways to run the

问题 I am using Paho Android Service for MQTT over web sockets. https://www.hivemq.com/blog/mqtt-client-library-enyclopedia-paho-android-service My question is how do I set the Broker WSS URI which has a query parameter in it. For example: wss://test.amazon.com:80/mqtt?query1=value&query2=value Edit If we add the complete URL, the PAHO client library throws following exception: MqttException (0) - java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.String

问题 I'm trying to store my MQTT data in SQLITE database on raspberry. What am I doing wrong to get the error below? CODE: import paho.mqtt.client as mqtt from store_Sensor_Data_to_DB import sensor_Data_Handler # MQTT Settings MQTT_Broker = "tcp://localhost:1883" MQTT_Port = 1883 Keep_Alive_Interval = 45 MQTT_Topic = "kuca/primanje/kanta01/r" #Subscribe to all Sensors at Base Topic def on_connect(mosq, obj, rc): self.subscribe(MQTT_Topic, 0) #Save Data into DB Table def on_message(mosq, obj, msg):

问题 I am trying to use TLS for communicating over mqtt. I have ubuntu installed in my system. For using TLS, I have created certificates using the below link: http://www.embedded101.com/Blogs/PaoloPatierno/entryid/366/mqtt-over-ssl-tls-with-the-m2mqtt-library-and-the-mosquitto-broker I am able to create certificates. But when I give value to bind_address property in the mosquitto_m2mqtt.conf file and start mosquitto using the command mosquitto -c mosquitto_m2mqtt.conf , I get error as given in

问题 Rookie here. I have a simple python code that's supposed to subscribe to a topic and publish JSON payload to the same topic using MQTT protocol. But for some reason, I am unable to load the payload as JSON! What am I doing wrong here? # -*- coding: utf-8 -*- import paho.mqtt.client as mqtt import json mqtt_broker = '192.168.1.111' mqtt_topic_one = 'mqtt_topic/tops_one' mqtt_topic_two = 'mqtt_topic/tops_two' json_data_1 = '''{ "this_json": "info", "data": { "multi_keyval": { "1": "1", "5": "5"

问题 I can successfully connect to AWS IoT using MQTT over Websockets. But when publishing or subscribing, the connection is terminated. I figure it must be a policy/permissions-based issue with AWS, but I am confident that I have the correct permissions. Here is my setup: I have a lambda function which creates a signed url using STS assumeRole (permissions in policy will be tighter but I have allowed access to all iot functions on all resources for testing): const config = require('./config');