Problem whit reconnect when wifif is off at start

[fjonshon]

hello, i have a problem, im using a esp8266, Everithing works perfect, but when the esp8266 start and dont have internet at the start, then if a few moments later it get internet, the client.conected function keep showing that is disconnected, but i can send mqtt messages, i need to use this function, is there any bug or i am missing something?

[zvone141]

Can you post your code?

[fjonshon]

This is the code, as i said it works perfect when the wifi is reset, but only if the wifi was On at the startup of the esp8266, when i get to this part of the code client.connected() shows that the esp8266 is not connected, but is connected because is publishing messages.
if(!client.connected())
{
// Attempt to connect
if (client.connect(CON_CLIENT_ID, _User, _Password, CON_TOPIC, 0, false, CON_OFFLINE))
{
Resuscripcion();
Wifi_Status();
}
else
{
Serial.print("failed, rc="); Serial.println(client.state());
}
}

[rvt]

try to disconnected then re-connect. You must assume that wifi is not always available and take appropriate action.

[mdeanda]

i have a similar problem, in my case i disable wifi after its been running for awhile:

/*
 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 <WiFi.h>
#include <PubSubClient.h>

// Update these with values suitable for your network.

const char* ssid = "ssid";
const char* password = "ssidpssword";
const char* mqtt_server = "mqtt.local";

WiFiClient espClient;
PubSubClient client(espClient);
long lastMsg = 0;
char msg[50];
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.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 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 an 1 was received as first character
  if ((char)payload[0] == '1') {
    digitalWrite(BUILTIN_LED, 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)
  } else {
    digitalWrite(BUILTIN_LED, 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...");
    // Create a random client ID
    String clientId = "ESP8266Client-";
    clientId += String(random(0xffff), HEX);
    // Attempt to connect
    if (client.connect(clientId.c_str())) {
      Serial.println("connected");
      // Once connected, publish an announcement...
      client.publish("outTopic", "hello world");
      // ... and resubscribe
      client.subscribe("inTopic");
    } 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() {
  pinMode(BUILTIN_LED, OUTPUT);     // Initialize the BUILTIN_LED pin as an output
  Serial.begin(115200);
  setup_wifi();
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
}

void loop() {

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

  long now = millis();
  if (now - lastMsg > 2000) {
    lastMsg = now;
    ++value;
    snprintf (msg, 50, "hello world #%ld", value);
    Serial.print("Publish message: ");
    Serial.println(msg);
    client.publish("outTopic", msg);
  }
}

my output looks like this:

Publish message: hello world #115
Publish message: hello world #116
Publish message: hello world #117
Publish message: hello world #118
Publish message: hello world #119
Publish message: hello world #120
Publish message: hello world #121
Publish message: hello world #122
Attempting MQTT connection...

it just seems to stall at that last message. which happens shortly after i disable/enable wifi on my router

[mdeanda]

i forgot to add, in my other terminal where i receive the messages i get up to #119 only but i'm ok with the lost messages w/o warning for now.

i'm also running this on an esp32 board, not ESP8266 as the example mentions

[rvt]

@mdeanda you also need to disconnected the pubsubclient client after wifi was disconnected. Then after the wifi connectes again you do a connect. The disconnect of pubsubclient was important for me to get stable re-connects.

[scaider]

Hi! I try to use this the same program code on d1mini esp8266, and I see that function callback(...) does not work properly. On cloudmqtt not work! On local server I receive one message from 10 published! I read in internet that this bug appeared from ver 2.2. I use ver 2.7. What I doing wrong or this problem really exist?thx.