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Boss lady

•Created by Boss lady on 6/11/2024 in #edge-networking

Establish a secure MQTT connection to a broker using TLS on an ESP32

@Middleware & OS Hello everyone, I have a code that I'm trying to use to establish a secure MQTT connection to a broker using TLS on an ESP32. However, I keep getting an undefined error when calling espClient.setCACert(test_root_ca). In order to fix this error, I need to generate a CA certificate using

openssl req -new -x509 -days 3650 -key ca.key -out ca.crt

openssl req -new -x509 -days 3650 -key ca.key -out ca.crt

and replace "YOUR_CA_CERTIFICATE_HERE" with the generated certificate. Can anyone help me with this issue? Thank you. Here's the code I'm using:

#include <WiFi.h>
#include <WiFiClientSecure.h>

const char* ssid = "your_SSID";
const char* password = "your_PASSWORD";
const char* mqtt_server = "broker.hivemq.com";

WiFiClientSecure espClient;
PubSubClient client(espClient);

void setup() {
  Serial.begin(115200);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }
  espClient.setCACert(test_root_ca);
  client.setServer(mqtt_server, 8883);
  client.setCallback(callback);
}

void callback(char* topic, byte* message, unsigned int length) {
  Serial.print("Message arrived on topic: ");
  Serial.print(topic);
  Serial.print(". Message: ");
  String messageTemp;
  for (int i = 0; i < length; i++) {
    messageTemp += (char)message[i];
  }
  Serial.println(messageTemp);
}

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

void reconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    if (client.connect("ESP32Client")) {
      Serial.println("connected");
      client.subscribe("test/topic");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

static const char test_root_ca[] PROGMEM = R"EOF(
-----BEGIN CERTIFICATE-----
YOUR_CA_CERTIFICATE_HERE
-----END CERTIFICATE-----
)EOF";

#include <WiFi.h>
#include <WiFiClientSecure.h>

const char* ssid = "your_SSID";
const char* password = "your_PASSWORD";
const char* mqtt_server = "broker.hivemq.com";

WiFiClientSecure espClient;
PubSubClient client(espClient);

void setup() {
  Serial.begin(115200);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }
  espClient.setCACert(test_root_ca);
  client.setServer(mqtt_server, 8883);
  client.setCallback(callback);
}

void callback(char* topic, byte* message, unsigned int length) {
  Serial.print("Message arrived on topic: ");
  Serial.print(topic);
  Serial.print(". Message: ");
  String messageTemp;
  for (int i = 0; i < length; i++) {
    messageTemp += (char)message[i];
  }
  Serial.println(messageTemp);
}

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

void reconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    if (client.connect("ESP32Client")) {
      Serial.println("connected");
      client.subscribe("test/topic");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

static const char test_root_ca[] PROGMEM = R"EOF(
-----BEGIN CERTIFICATE-----
YOUR_CA_CERTIFICATE_HERE
-----END CERTIFICATE-----
)EOF";

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