Callback function doesn't execute while sub on get/accepted shadow

[Abdallah24]

i am working on esp8266 connected to aws iot ,My project is to control lamp through esp8266 so after reading what should i do for getting the response from get/accepted shadow i have to send empty parenthesis on get shadow then receive from get/accepted shadow

the problem here that i don't receive any responses from get/accepted shadow
and callback function didnt called untill now also i tried to increase the size of mqtt packet but nothing happened

Here what i should receive on get/accepted shadow

{ "state": { "desired": { "Switch": 1, "power": "0" }, "delta": { "Switch": 1, "power": "0" } }, "metadata": { "desired": { "Switch": { "timestamp": 1563210303 }, "power": { "timestamp": 1563210303 } } }, "version": 6, "timestamp": 1563322772 }

Here is the code

`#include

include

include

include

//AWS

include "sha256.h"

include "Utils.h"

//WEBSockets

include

include

//MQTT PUBSUBCLIENT LIB

include

//AWS MQTT Websocket

include "Client.h"

include "AWSWebSocketClient.h"

include "CircularByteBuffer.h"

extern "C" {

include "user_interface.h"

}

//AWS IOT config, change these:

char wifi_ssid[] = "Hopa"; char wifi_password[] = "HopaInternet00"; char aws_endpoint[] = "xxxxxxxxxxxxxxxxxxx"; char aws_key[] = "xxxxxxxxxxxxxxxxxxxxx"; char aws_secret[] = "xxxxxxxxxxxxxxx"; char aws_region[] = "xxxxxxxxxxxxxxxxx"; const char aws_topic_sub = "$aws/things/esp/shadow/get/accepted"; const char aws_topic_pub = "$aws/things/esp/shadow/get"; int port = 443;

//MQTT config const int maxMQTTpackageSize = 1048; const int maxMQTTMessageHandlers = 1;

ESP8266WiFiMulti WiFiMulti;

AWSWebSocketClient awsWSclient(1000);

PubSubClient client(awsWSclient);

//# of connections long connection = 0;

//generate random mqtt clientID char generateClientID () { char cID = new char[23](); for (int i=0; i<22; i+=1) cID[i]=(char)random(1, 256); return cID; }

//count messages arrived int arrivedcount = 0;

//callback to handle mqtt messages 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(); }

//connects to websocket layer and mqtt layer bool connect () {

if (client.connected()) {    
    client.disconnect ();
}  
//delay is not necessary... it just help us to get a "trustful" heap space value
delay (1000);
Serial.print (millis ());
Serial.print (" - conn: ");
Serial.print (++connection);
Serial.print (" - (");
Serial.print (ESP.getFreeHeap ());
Serial.println (")");

//creating random client id
char* clientID = generateClientID ();

client.setServer(aws_endpoint, port);
if (client.connect(clientID)) {
  Serial.println("connected");     
  return true;
} else {
  Serial.print("failed, rc=");
  Serial.print(client.state());
  return false;
}

}

//subscribe to a mqtt topic void subscribe () { client.setCallback(callback); client.subscribe(aws_topic_sub); //subscript to a topic Serial.println("MQTT subscribed"); }

//send a message to a mqtt topic void sendmessage () { //send a message
char buf[100]; strcpy(buf, "{ }");
int rc = client.publish(aws_topic_pub, buf); }

void setup() { wifi_set_sleep_type(NONE_SLEEP_T); Serial.begin (115200); delay (2000); Serial.setDebugOutput(1);

//fill with ssid and wifi password
WiFiMulti.addAP(wifi_ssid, wifi_password);
Serial.println ("connecting to wifi");
while(WiFiMulti.run() != WL_CONNECTED) {
    delay(100);
    Serial.print (".");
}
Serial.println ("\nconnected");

//fill AWS parameters    
awsWSclient.setAWSRegion(aws_region);
awsWSclient.setAWSDomain(aws_endpoint);
awsWSclient.setAWSKeyID(aws_key);
awsWSclient.setAWSSecretKey(aws_secret);
awsWSclient.setUseSSL(true);

if (connect ()){

  subscribe ();
sendmessage ();

}

}

void loop() {

//keep the mqtt up and running if (awsWSclient.connected ()) {
delay(100);
client.loop (); delay(100); subscribe (); sendmessage ();

} else { //handle reconnection if (connect ()){ subscribe ();

}

}

}`

[stark526]

I also had this issue... I solved it by increasing the MQTT_MAX_PACKET_SIZE variable in the PubSubClient.h to 2048 (my shadow string size was too big).