MQTT esp8266 client.subscribe（）无效

1 回答

• 0

  实际上，您的代码仅在循环内移动而您正在调用客户端 . subscribe（）在reconnect（）函数内 . 因此，如果您的ESP8266在一次点击中连接到MQTT Broker，那么您的Reconnect（）将不会被调用 .

  这是代码

  #include <ESP8266WiFi.h>
  #include <WiFiClient.h>
  #include <MySQL_Connection.h>
  #include <MySQL_Cursor.h>
  #include <PubSubClient.h>
  IPAddress server_addr(***, , ,); // IP of the MySQL server
  char user[] = "root"; // MySQL user login username
  char password[] = ""; // MySQL user login password
  char ssid[] = "***"; // your SSID
  char pass[] = "*****"; // your SSID Password
  const char mqtt_server = "192.168.0.109";
  
  long lastMsg = 0;
  char msg[50];
  int value = 0;
  WiFiClient espClient;
  MySQL_Connection conn((Client *)&espClient);
  
  PubSubClient client(espClient);
  
  void setup() {
  Serial.begin(115200);
  WiFi.begin(ssid, pass); // initializing the WIFI library
  
  while ( WiFi.status() != WL_CONNECTED ) { // while loop to write dots     during connecting
  delay ( 500 );
  Serial.print ( "." );
  }
  
  // print out information about the WIFI connection
  Serial.println ( "" );
  Serial.print ( "Connected to " );
  
  Serial.println ( ssid );
  Serial.print ( "IP address: " );
  Serial.println ( WiFi.localIP() );
  
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
  connectmqtt();  
  }
  
  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();
  
  }
  
  void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
  Serial.print("Attempting MQTT connection...");
  // Attempt to connect
  if (client.connect("ESP8266Client")) {
  Serial.println("connected");
  // Once connected, publish an announcement...
  client.publish("outTopic", "SAAIL");
  // ... and resubscribe
  
    client.subscribe("say");
  
  } else {
    Serial.print("failed, rc=");
    Serial.print(client.state());
    Serial.println(" try again in 5 seconds");
    // Wait 5 seconds before retrying
    delay(5000);
  }
  
  }
  } 
  
  
  void loop() {
  
  if (!client.connected()) {
  reconnect();
  }
  client.loop();
  delay(1000);
  long now = millis();
  if (now - lastMsg > 2000) {
  lastMsg = now;
  
  int newTemp = sht1x.readTemperatureC();
  int newHum = sht1x.readHumidity();
  Serial.print("temp:");
  Serial.print(newTemp);
  char INSERT_SQL[] = "INSERT INTO test.users (humidity,temp) VALUES (%d, %d );";
  char query[255];
  sprintf(query, INSERT_SQL, newHum, newTemp);
  Serial.println("Recording data.");
  conn.connect(server_addr, 3306, user, password);
  // Initiate the query class instance
  MySQL_Cursor *cur_mem = new MySQL_Cursor(&conn);
  // Execute the query
  cur_mem->execute(query);
  // Note: since there are no results, we do not need to read any data
  // Deleting the cursor also frees up memory used
  delete cur_mem;
  conn.close();
  
  }
  
  }
  
  void connectmqtt()
  {
    client.connect("ESP8266Client");
    {
        Serial.println("connected");
        // Once connected, publish an announcement...
  
        // ... and resubscribe
        client.subscribe("say");
         client.publish("outTopic", "SAAIL");
  
         if (!client.connected()) 
    {
      reconnect();
    }
  }
  
  }
  

  回复于 2024-04-29T21:03:01+08:00