azure - 无法使用 MQTT 和 ESP8266 订阅 Azure 设备孪生

Question

过去一个月我一直在研究 Azure 设备双胞胎。主要目标是订阅三个设备双路径，以便所需属性的任何更改都会导致串行监视器上显示通知，并且解析所需属性并将其作为报告属性给出。我正在 NodeMCU 上运行代码，我面临的问题是设备连接到 IoTHub 并发布数据，但设备孪生中的任何更改都不会显示或解析。当 api-version=2016-11-14 添加到 MQTT 用户名时，设备孪生可以工作，一旦我在用户名中添加 api-version，它就会给出错误 failed rc=-1。我正在使用的代码如下所示

#include <ESP8266WiFi.h>
#include <PubSubClient.h>
#include <ArduinoJson.h>
#include <WiFiClientSecure.h>
const char mqtt_client[] = "test-device1";
const char mqtt_server[] = "HyperNet-IoTHub-Azure-Sphere.azure-devices.net";
const int mqtt_port = 8883;
const char mqtt_user[] = "HyperNet-IoTHub-Azure-Sphere.azure-devices.net/test-device1/api-version=2016-11-14";


void callback(char* topic, byte* payload, unsigned int length);

WiFiClientSecure WiFiclient;
PubSubClient client(WiFiclient);
void callback(char* topic, byte* payload, unsigned int length);
void parseDesiredProperties(byte* payload);

unsigned long previousMillis = 0;
long interval = 5000;
void reconnect();

void setup(){
  Serial.begin(9600);
  delay(250);
  client.setServer(mqtt_server, 8883);
  client.setCallback(callback);
  WiFi.disconnect();
  delay(100);
  WiFi.mode(WIFI_STA);
  Serial.println("Connecting To Wi-Fi: " + String(ssid));
  WiFi.begin(ssid,pass);
  while(WiFi.status() !=WL_CONNECTED){
    delay(500);
    Serial.print("..");
  }
  Serial.println(" ");
  Serial.println("Wi-Fi Connected");
}

void loop(){
  if(!client.connected()){
    reconnect();
  }
  unsigned long currentMillis = millis();
  if(currentMillis - previousMillis >= interval){
    previousMillis = currentMillis;
    float value1 = 12.3;
    float value2 = 13.6;
    String postData = "{\"testvalue1\":" + String(value1) + ",\"testvalue2\":" + String(value2) +"}";
    char postBuffer[postData.length()+1];
    postData.toCharArray(postBuffer, postData.length()+1);
    Serial.println(postBuffer);
    client.publish("devices/test-device1/messages/events/", postBuffer);
  }

  client.loop();

}

void reconnect(){
  WiFiclient.setInsecure();
  while(!client.connected()){
    Serial.println("Attempting MQTT Connection");
    if (client.connect(mqtt_client, mqtt_user, mqtt_pass)) {
      Serial.println("connected");
      client.subscribe("devices/test-device1/messages/devicebound/#");
      // subscribe to operation responses
      client.subscribe("$iothub/twin/res/#");
      // subscribe to desired property updates
      client.subscribe("$iothub/twin/PATCH/properties/desired/#");
    } 
    else {
     Serial.print("failed, rc=");
     Serial.print(client.state());
     Serial.println(" try again in 5 seconds");
     delay(5000);
    }  
  }
}

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("MQTT message arrived on topic: ");
  Serial.println(topic);
  if (String(topic).startsWith("$iothub/twin/PATCH/properties/desired")) {
    parseDesiredProperties(payload);  
  }   
}

void parseDesiredProperties(byte* payload) {

  JsonObject& root = jsonDesiredProperties.parseObject(payload);
  if(root.success()) {
    Serial.println("Parsed desired properties");
    int newMillis=root["reportInterval"];
    if(newMillis > 2999 && newMillis < 120001) {
      interval = newMillis;
      String postProperty = "{\"reportInterval\":" + String(newMillis) + "}";
      char postBuffer[postProperty.length()+1];
      postProperty.toCharArray(postBuffer, postProperty.length()+1);
      client.publish("$iothub/twin/PATCH/properties/reported/?$rid=1", postBuffer);
      Serial.print("Set new interval to: ");
      Serial.println(newMillis);
    }
   } 
   else {
    Serial.println("Could not parse desired properties");
   }
}

Answer 1

您发布的代码片段似乎不完整。例如，它缺少 jsonDesiredProperties 。您可能遗漏了其他一些东西，但缺少的一件重要的事情是证书指纹。 IoT 中心仅接受安全 MQTT 连接，为此，您需要包含 SHA1 指纹 Microsoft's CA cert .

您可以下载证书并将其放入文件中并使用 openssl 检索指纹:

openssl x509 -noout -fingerprint -sha1 -inform pem -in [certificate-file.crt]

您的设置方法可以包含指纹:

static const char *fingerprint PROGMEM = "D4 DE 20 D0 5E 66 FC 53 FE 1A 50 88 2C 78 DB 28 52 CA E4 74";

    void setup(){
          Serial.begin(9600);
          delay(250);
          WiFiclient.setFingerprint(fingerprint);
        
          client.setServer(mqtt_server, 8883);
          client.setCallback(callback);
          WiFi.disconnect();
          delay(100);
          WiFi.mode(WIFI_STA);
          Serial.println("Connecting To Wi-Fi");
          WiFi.begin("<REDACTED>","<REDACTED>");
          while(WiFi.status() !=WL_CONNECTED){
            delay(500);
            Serial.print("..");
          }
          Serial.println(" ");
          Serial.println("Wi-Fi Connected");
        }

我所做的另一个更改是您在 MQTT 用户名中包含的 API 版本。您可以使用 ?api-version=2018-06-30 而不是 api-version=2016-11-14。

我在我的 NodeMCU 上测试了这些更改，并且更新报告的孪生属性工作得很好!让我知道这是否适合您!