如何向运行中的HiveMQ Broker发送MQTT消息（如Hello World）？

Got it, let's break down how you can send a "Hello World" message to your running HiveMQ Broker. Since the mbed example is tied to its specific embedded environment, we'll use more accessible tools that work with your local setup:

1. Use the Mosquitto Command-Line Tools (Easiest Option) #

Mosquitto provides lightweight, easy-to-use MQTT client tools that are perfect for quick testing.

• First, install the mosquitto-clients package:
  • On Ubuntu/Debian: Run sudo apt install mosquitto-clients
  • On Windows/macOS: Download the full Mosquitto package from its official distribution channel
• To send your "Hello World" message, open a terminal and run:

  mosquitto_pub -h localhost -p 1883 -t "test/my-topic" -m "Hello World"
  

  Let's break down the parameters:
  • -h localhost: Points to your local HiveMQ Broker (since it's running on your machine)
  • -p 1883: Uses the port your Broker is listening on (matches your startup log)
  • -t "test/my-topic": The MQTT topic to publish to (you can name this anything you want)
  • -m "Hello World": The actual message content
• To verify the message was received, open another terminal and subscribe to the same topic:

  mosquitto_sub -h localhost -p 1883 -t "test/my-topic"
  

  You'll see "Hello World" pop up right away.

2. Use Putty (Raw Mode, For Low-Level Testing) #

Putty doesn't have a built-in MQTT client, but you can use its Raw mode to connect directly to the Broker's TCP port and manually send MQTT packets. Note: This requires understanding basic MQTT binary packet structure.

• Open Putty, select the Raw connection type. Enter localhost as the Host Name and 1883 as the Port, then click "Open".
• First, you need to send a CONNECT packet to establish a connection with the Broker. Paste this hex string (ensure your tool supports hex input—you might need a Putty plugin or use Netcat instead for easier sending):

  10 17 00 04 4D 51 54 54 04 02 00 3C 00 05 74 65 73 74 31
  

  This is a basic MQTT 3.1.1 connect packet with client ID "test1", keep-alive set to 60 seconds.
• Once you receive a CONNACK response (hex 20 02 00 00 means connection success), send the PUBLISH packet for your message:

  30 0D 00 08 74 65 73 74 2F 74 6F 70 69 63 48 65 6C 6C 6F 20 57 6F 72 6C 64
  

  This publishes "Hello World" to the topic "test/topic" with QoS 0.

If hex input feels too clunky, use Netcat instead (most systems have it pre-installed):

# Send connect packet
echo -n -e '\x10\x17\x00\x04MQTT\x04\x02\x00\x3C\x00\x05test1' | nc localhost 1883
# Send publish packet
echo -n -e '\x30\x0D\x00\x08test/topicHello World' | nc localhost 1883

3. Write a Simple Python Script (Flexible & Customizable) #

If you want more control or want to integrate this into code, use the Paho MQTT Python library:

• Install the library first:

  pip install paho-mqtt
  

• Create a script (e.g., mqtt_publish.py) with this code:

  import paho.mqtt.client as mqtt
  
  # Callback that runs when we connect to the Broker
  def on_connect(client, userdata, flags, rc):
      print(f"Connected successfully (result code: {rc})")
      # Publish the "Hello World" message
      client.publish(
          topic="test/my-topic",
          payload="Hello World",
          qos=0,
          retain=False
      )
      # Disconnect after sending the message
      client.disconnect()
  
  # Create an MQTT client instance
  client = mqtt.Client(client_id="python_test_client")
  # Attach the connect callback
  client.on_connect = on_connect
  
  # Connect to the local HiveMQ Broker
  client.connect(host="localhost", port=1883, keepalive=60)
  
  # Start the client loop to handle connection and message sending
  client.loop_forever()
  

• Run the script with python mqtt_publish.py—it will connect, send the message, then disconnect automatically.

内容的提问来源于stack exchange，提问作者Nephilim