mqtt-client: dart example added

mqtt-client/README.md

@@ -177,3 +177,34 @@ Example source code is located at [./browser/](./browser/)
 You may run the example [in your browser from GitHub Pages](https://flespi-software.github.io/examples/mqtt-client/browser/example.html) or open the example.html file from your local file system.
 
 This example uses the [browser-version of the mqtt.js](https://github.com/mqttjs/MQTT.js#browser) library.
+
+## dart
+
+Example source code is located at [./dart/](./dart/)
+
+### Setup and Run
+
+1. **Navigate to the Dart project directory**:
+```sh
+cd dart
+```
+
+2. **Ensure you have Dart SDK installed, then initialize the project**:
+```sh
+dart pub get
+```
+
+3. **Set the Flespi token environment variable**:
+On Linux/macOS:
+```sh
+export FlespiToken=your_flespi_token
+```
+On Windows:
+```cmd
+set FlespiToken=your_flespi_token
+```
+
+4. **Run the Dart script**:
+```sh
+dart run lib/example.dart
+```

mqtt-client/dart/.gitignore

@@ -0,0 +1,4 @@
+.dart_tool/
+.packages
+.pub/
+build/

mqtt-client/dart/README.md

@@ -0,0 +1,3 @@
+# lua MQTT Client example
+
+Please [refer here](../#dart) for complete README

mqtt-client/dart/lib/example.dart

@@ -0,0 +1,79 @@
+import 'package:mqtt5_client/mqtt5_client.dart';
+import 'package:mqtt5_client/mqtt5_server_client.dart';
+import 'dart:async';
+import 'dart:io';
+import 'package:typed_data/typed_data.dart';
+
+void main() async {
+  // Retrieve Flespi token from environment variable
+  final flespiToken = Platform.environment['FlespiToken'];
+  if (flespiToken == null || flespiToken.isEmpty) {
+    print('Flespi token is not set in the environment variables.');
+    return;
+  }
+
+  // Create an MQTT client instance
+  print('mqtt client created, connecting...');
+  final client = MqttServerClient.withPort('wss://mqtt.flespi.io', '', 443);
+
+  // Configure the client for WebSocket
+  client.useWebSocket = true;
+  client.websocketProtocolString = ['mqtt'];
+
+  // Set the client identifier
+  client.clientIdentifier = 'dart_mqtt_client';
+
+  // Set the username with the Flespi token (no password in this example)
+  final connMessage = MqttConnectMessage()
+      .withClientIdentifier('dart_mqtt_client')
+      .authenticateAs(flespiToken, '');
+
+  client.connectionMessage = connMessage;
+
+  // Connect to the MQTT broker
+  try {
+    await client.connect();
+  } on Exception catch (e) {
+    print('Connection failed: $e');
+    client.disconnect();
+    return;
+  }
+
+  // Check if we are connected
+  if (client.connectionStatus?.state == MqttConnectionState.connected) {
+    print('connected, subscribing to "test" topic...');
+  } else {
+    print('Connection failed: ${client.connectionStatus}');
+    return;
+  }
+
+  // Subscribe to the "test" topic
+  const topic = 'test';
+  client.subscribe(topic, MqttQos.atMostOnce);
+  print('subscribed to "test" topic, publishing message...');
+
+  // Handle incoming messages
+  client.updates?.listen((List<MqttReceivedMessage<MqttMessage>> c) {
+    final MqttPublishMessage message = c[0].payload as MqttPublishMessage;
+    final Uint8Buffer? payloadBuffer = message.payload.message;
+
+    if (payloadBuffer != null) {
+      final payload = String.fromCharCodes(payloadBuffer);
+      print('received message in topic "test": "$payload"');
+    } else {
+      print('Received null payload from topic: "${c[0].topic}"');
+    }
+  });
+
+  // Publish a message to the "test" topic
+  final builder = MqttPayloadBuilder();
+  builder.addString('hello from flespi mqtt client example script!');
+  client.publishMessage(topic, MqttQos.atMostOnce, builder.payload!);
+
+  // Keep the connection alive
+  await Future.delayed(Duration(seconds: 5));  // Give some time to receive the message
+
+  print('disconnecting...');
+  client.disconnect();
+  print('disconnected');
+}

mqtt-client/dart/pubspec.yaml

@@ -0,0 +1,14 @@
+name: example
+description: A sample Dart application demonstrating MQTT client functionality.
+version: 1.0.0
+
+environment:
+  sdk: '>=2.12.0 <3.0.0'
+
+dependencies:
+  mqtt_client: ^9.6.1
+  mqtt5_client: ^4.2.5
+
+dev_dependencies:
+  lints: ^3.0.0
+  test: ^1.24.0