Arduino网络编程实战-Ethernet篇-MQTT客户端

MQTT客户端

Arduino Ethernet Shield V1 允许 Arduino 板连接到互联网。它基于 Wiznet W5100ethernet 芯片（数据表）。 Wiznet W5100 提供支持 TCP 和 UDP 的网络 (IP) 堆栈。它最多支持四个同时套接字连接。

本次实例将演示如何实现一个简单的MQTT客户端。

1、硬件准备

Arduino Mega 2560
Arduino Ethernet Shield
路由器（推荐可以上网、开启DHCP）
网线一条
电脑一台

2、软件准备

Arduino IDE
网络调试软件（推荐使用通信猫)
支持库：https://github.com/knolleary/pubsubclient
Nodejs
Nodejs MQTT支持库：mosca ,mqtt

3、代码实现

1）Arduino的MQTT客户端实现

#include <SPI.h>
#include <Ethernet.h>
#include <PubSubClient.h>

#define USE\_STATIC 0
byte mac[] = {
  0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED
};
#if USE\_STATIC
IPAddress ip(192, 168, 0, 177);
#endif

void callback(char\* topic, byte\* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  for (int i=0;i<length;i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();
}

EthernetClient ethClient;
PubSubClient client(ethClient);
IPAddress serverIP(192, 168, 0, 100);

void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    // Attempt to connect
    if (client.connect("arduinoClient")) {
      Serial.println("connected");
      // Once connected, publish an announcement...
      client.publish("/public/TEST/window","hello world");
      // ... and resubscribe
      client.subscribe("/public/TEST/#");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}

void setup() {
  
   Serial.begin(115200);
   Serial.println("Ethernet MQTT Client Example");
   
#if USE\_STATIC
   Ethernet.begin(mac,ip);
#else
  Ethernet.begin(mac);
#endif

   if (Ethernet.hardwareStatus() == EthernetNoHardware) {
    Serial.println("Ethernet shield was not found. Sorry, can't run without hardware. :(");
    while (true) {
      delay(1); 
    }
  }
  if (Ethernet.linkStatus() == LinkOFF) {
    Serial.println("Ethernet cable is not connected.");
    while(true){
      delay(1);  
    }
  }

  Serial.print("IP:");
  Serial.println(Ethernet.localIP());
  Serial.print("Subnet Mask:");
  Serial.println(Ethernet.subnetMask());
  Serial.print("Gateway:");
  Serial.println(Ethernet.gatewayIP());
  Serial.print("DNS Server:");
  Serial.println(Ethernet.dnsServerIP());

  client.setServer(serverIP, 1886);
  client.setCallback(callback);
}

void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();
}

** 2）Nodejs的MQTT服务器实现**

var mosca = require('mosca');

var MqttServer = new mosca.Server({
    port: 1886
});
MqttServer.on('clientConnected', function(client) {
    //监听连接
    console.log('client connected', client.id);
});
/\*\*
 \* 监听题消息
 \*\*/
MqttServer.on('published', function(packet, client) {
    // 发布主题消息
    var topic = packet.topic;
    console.log(packet);
    switch (topic) {
        case 'test':
            console.log('message-publish', packet.payload.toString());
            break;
        case 'other':
            console.log('message-123', packet.payload.toString());
            break;
    }
});

MqttServer.on('ready', function() {
    console.log('mqtt is running...');
});