【发布时间】：2017-11-29 09:12:40
【问题描述】：
我想在 IBM Watson IOT 上使用 ESP8266 订阅“iot-2/evt/status/fmt/json”主题。连接已建立，但它再次断开连接。因此，将 MQTT 客户端重新连接到……并订阅 iot-2 / cmd / + / fmt / + OK。这个循环继续。为什么连接断开？
我的 ESP8266 代码如下。
我使用的是 ESP8266-12E NodeMCU，我为发布者创建了一个 Android 应用。
/*
Basic ESP8266 MQTT example
This sketch demonstrates the capabilities of the pubsub library in combination
with the ESP8266 board/library.
It connects to an MQTT server then:
- publishes "hello world" to the topic "outTopic" every two seconds
- subscribes to the topic "inTopic", printing out any messages
it receives. NB - it assumes the received payloads are strings not binary
- If the first character of the topic "inTopic" is an 1, switch ON the ESP Led,
else switch it off
It will reconnect to the server if the connection is lost using a blocking
reconnect function. See the 'mqtt_reconnect_nonblocking' example for how to
achieve the same result without blocking the main loop.
To install the ESP8266 board, (using Arduino 1.6.4+):
- Add the following 3rd party board manager under "File -> Preferences -> Additional Boards Manager URLs":
http://arduino.esp8266.com/stable/package_esp8266com_index.json
- Open the "Tools -> Board -> Board Manager" and click install for the ESP8266"
- Select your ESP8266 in "Tools -> Board"
*/
#include <ESP8266WiFi.h>
#include <ESP8266WiFiMulti.h>
//#include <ESP8266HTTPClient.h>
#include <SPI.h>
#include <ArduinoJson.h>
#include <PubSubClient.h>
// Update these with values suitable for your network.
//ZYxel
#define ssid "......."
#define password ".................."
//GES ARGE
#define ssid2 "..............." // WiFi SSID
#define password2 "............." // WiFi password
#define spi_ss_pin SS
#define ORG "............"
#define DEVICE_TYPE "........."
#define DEVICE_ID "..........."
#define TOKEN "................"
//-------- Customise the above values --------
char server[] = ORG ".messaging.internetofthings.ibmcloud.com";
int mqttPort=1883;
const char topic[] = "iot-2/cmd/status/fmt/json"; //"iot-2/cmd/status/fmt/json";
char authMethod[] = "use-token-auth";
char token[] = TOKEN;
char clientId[] = "d:" ORG ":" DEVICE_TYPE ":" DEVICE_ID;
WiFiClient wifiClient;
void callback(char* topic, byte* payload, unsigned int payloadLength) ;
PubSubClient client(server, 1883, callback, wifiClient);
void setup() {
Serial.begin(115200);
Serial.println();
wifiConnect();
mqttConnect();
}
void loop() {
if (!client.loop()) {
mqttConnect();
}
}
void wifiConnect() {
Serial.print("Connecting to "); Serial.print(ssid);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.print("nWiFi connected, IP address: "); Serial.println(WiFi.localIP());
}
void mqttConnect() {
if (!client.connected()) {
Serial.print("Reconnecting MQTT client to "); Serial.println(server);
while (!client.connect(clientId, authMethod, token)) {
Serial.print(".");
delay(500);
}
initManagedDevice();
Serial.println();
}
}
void initManagedDevice() {
if (client.subscribe(topic)) {
Serial.println("subscribe to cmd OK");
} else {
Serial.println("subscribe to cmd FAILED");
}
}
void callback(char* topic, byte* payload, unsigned int payloadLength) {
Serial.print("callback invoked for topic: "); Serial.println(topic);
for (int i = 0; i < payloadLength; i++) {
Serial.print((char)payload[i]);
}
}
【问题讨论】：
标签： mqtt publish-subscribe esp8266 watson-iot