Mqtt_server 未连接到端口 8884

Question

there is a problem I am facing that when I tried to connect server on port 8884 it gives me error Attempting MQTT connection…failed, rc = -4 try again in 5 seconds but the connection is successfully built on port 8883 I don't understand the reason behind this kindly help me to to over come this problem. I am totally new with mqtt protocol and try to figure out how to make web based system to automate farm using esp32 or esp8266,HiveMQ server and Django for backend development also give me some suggestions how to do complete this task

The code I am using provided by the HiveMQ community

#include <ESP8266WiFi.h>
#include <PubSubClient.h>
#include <time.h>
#include <TZ.h>
#include <FS.h>
#include <LittleFS.h>
#include <CertStoreBearSSL.h>

// Update these with values suitable for your network.
const char* ssid = "******";
const char* password = "******";
const char* mqtt_server = "*******";

// A single, global CertStore which can be used by all connections.
// Needs to stay live the entire time any of the WiFiClientBearSSLs
// are present.
BearSSL::CertStore certStore;

WiFiClientSecure espClient;
PubSubClient * client;
unsigned long lastMsg = 0;
#define MSG_BUFFER_SIZE (500)
char msg[MSG_BUFFER_SIZE];
int value = 0;

void setup_wifi() {
  delay(10);
  // We start by connecting to a WiFi network
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  randomSeed(micros());

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}


void setDateTime() {
  // You can use your own timezone, but the exact time is not used at all.
  // Only the date is needed for validating the certificates.
  configTime(TZ_Europe_Berlin, "pool.ntp.org", "time.nist.gov");

  Serial.print("Waiting for NTP time sync: ");
  time_t now = time(nullptr);
  while (now < 8 * 3600 * 2) {
    delay(100);
    Serial.print(".");
    now = time(nullptr);
  }
  Serial.println();

  struct tm timeinfo;
  gmtime_r(&now, &timeinfo);
  Serial.printf("%s %s", tzname[0], asctime(&timeinfo));
}


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();

  // Switch on the LED if the first character is present
  if ((char)payload[0] != NULL) {
    digitalWrite(LED_BUILTIN, LOW); // Turn the LED on (Note that LOW is the voltage level
    // but actually the LED is on; this is because
    // it is active low on the ESP-01)
    delay(500);
    digitalWrite(LED_BUILTIN, HIGH); // Turn the LED off by making the voltage HIGH
  } else {
    digitalWrite(LED_BUILTIN, HIGH); // Turn the LED off by making the voltage HIGH
  }
}


void reconnect() {
  // Loop until we’re reconnected
  while (!client->connected()) {
    Serial.print("Attempting MQTT connection…");
    String clientId = "ESP8266Client - MyClient";
    // Attempt to connect
    // Insert your password
    if (client->connect(clientId.c_str(), "Hassan", "******")) {
      Serial.println("connected");
      // Once connected, publish an announcement…
      client->publish("testTopic", "hello world");
      // … and resubscribe
      client->subscribe("testTopic");
    } 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() {
  delay(500);
  // When opening the Serial Monitor, select 9600 Baud
  Serial.begin(9600);
  delay(500);

  LittleFS.begin();
  setup_wifi();
  setDateTime();

  pinMode(LED_BUILTIN, OUTPUT); // Initialize the LED_BUILTIN pin as an output

  // you can use the insecure mode, when you want to avoid the certificates
  //espclient->setInsecure();

  int numCerts = certStore.initCertStore(LittleFS, PSTR("/certs.idx"), PSTR("/certs.ar"));
  Serial.printf("Number of CA certs read: %d\n", numCerts);
  if (numCerts == 0) {
    Serial.printf("No certs found. Did you run certs-from-mozilla.py and upload the LittleFS directory before running?\n");
    return; // Can't connect to anything w/o certs!
  }

  BearSSL::WiFiClientSecure *bear = new BearSSL::WiFiClientSecure();
  // Integrate the cert store with this connection
  bear->setCertStore(&certStore);

  client = new PubSubClient(*bear);

  client->setServer(mqtt_server, 8884);
  client->setCallback(callback);
}

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

  unsigned long now = millis();
  if (now - lastMsg > 2000) {
    lastMsg = now;
    ++value;
    snprintf (msg, MSG_BUFFER_SIZE, "hello world #%ld", value);
    Serial.print("Publish message: ");
    Serial.println(msg);
    client->publish("testTopic", msg);
  }
}

Answer 1

As mentioned in the comments.

The PubSubClient does NOT support MQTT over Websockets.