CSharpProjekt/mqtt_task_pr3_solution.cs

using MQTTnet;
using MQTTnet.Client;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace MqttSensorApp
{
    // LÖSUNG Aufgabe 3: SensorData-Klasse implementieren
    public class SensorData
    {
        [JsonPropertyName("temperature")]
        public double Temperature { get; set; }
        
        [JsonPropertyName("humidity")]
        public double Humidity { get; set; }
        
        [JsonPropertyName("location")]
        public string Location { get; set; } = string.Empty;
    }

    public class Program
    {
        private static List<double> receivedTemperatures = new List<double>();
        
        public static async Task Main(string[] args)
        {
            Console.WriteLine("MQTT Sensor Data Processor gestartet...");
            
            // MQTT Client Setup (bereits implementiert)
            var factory = new MqttFactory();
            var client = factory.CreateMqttClient();
            
            // Event Handler für empfangene Nachrichten
            client.ApplicationMessageReceivedAsync += async e =>
            {
                var payload = System.Text.Encoding.UTF8.GetString(e.ApplicationMessage.Payload);
                await ProcessMessage(payload);
            };
            
            // Verbindungsoptionen
            var options = new MqttClientOptionsBuilder()
                .WithTcpServer("broker.hivemq.com", 1883)
                .WithClientId($"SensorClient_{Guid.NewGuid()}")
                .WithCleanSession()
                .Build();
            
            try
            {
                // Verbindung aufbauen
                await client.ConnectAsync(options);
                Console.WriteLine("Mit MQTT Broker verbunden");
                
                // Topic abonnieren
                await client.SubscribeAsync("sensor/data/room1");
                Console.WriteLine("Topic 'sensor/data/room1' abonniert");
                
                // Simulierte Sensordaten senden (für Testing)
                await SendTestData(client);
                
                // Programm laufen lassen
                Console.WriteLine("Drücken Sie eine Taste zum Beenden...");
                Console.ReadKey();
                
                // Verbindung trennen
                await client.DisconnectAsync();
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Fehler: {ex.Message}");
            }
        }
        
        private static async Task ProcessMessage(string jsonPayload)
        {
            try
            {
                Console.WriteLine($"Empfangen: {jsonPayload}");
                
                // LÖSUNG Aufgabe 3: Deserialisieren des JSON zu SensorData
                var sensorData = JsonSerializer.Deserialize<SensorData>(jsonPayload);
                
                if (sensorData != null)
                {
                    receivedTemperatures.Add(sensorData.Temperature);
                    
                    // LÖSUNG Aufgabe 2: Pattern Matching anwenden
                    var analysis = AnalyzeMessage(sensorData.Temperature);
                    Console.WriteLine($"Analyse: {analysis}");
                }
                
                // Alle 5 Nachrichten: Hohe Temperaturen anzeigen
                if (receivedTemperatures.Count % 5 == 0)
                {
                    var highTemps = FilterHighTemperatures(receivedTemperatures);
                    Console.WriteLine($"Hohe Temperaturen (>25°C): {string.Join(", ", highTemps.Select(t => $"{t:F1}°C"))}");
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Fehler beim Verarbeiten der Nachricht: {ex.Message}");
            }
        }
        
        // LÖSUNG Aufgabe 1: LINQ-Abfrage implementieren
        private static IEnumerable<double> FilterHighTemperatures(List<double> temperatures)
        {
            // LINQ Where-Klausel verwenden, um Temperaturen > 25°C zu filtern
            return temperatures.Where(temp => temp > 25.0);
        }
        
        // LÖSUNG Aufgabe 2: Pattern Matching implementieren
        private static string AnalyzeMessage(object value)
        {
            // Switch expression mit Pattern Matching
            return value switch
            {
                double temp when temp > 30.0 => "WARNUNG: Sehr hohe Temperatur!",
                double temp when temp >= 25.0 && temp <= 30.0 => "Hohe Temperatur",
                double temp when temp < 25.0 => "Normale Temperatur",
                string text => "Text-Nachricht erhalten",
                null => "Keine Daten",
                _ => "Unbekannter Datentyp"
            };
        }
        
        // Hilfsmethode: Testnachrichten senden
        private static async Task SendTestData(IMqttClient client)
        {
            var testData = new[]
            {
                new { temperature = 22.5, humidity = 65.0, location = "Room1" },
                new { temperature = 28.3, humidity = 58.2, location = "Room1" },
                new { temperature = 19.8, humidity = 72.1, location = "Room1" },
                new { temperature = 31.2, humidity = 45.3, location = "Room1" },
                new { temperature = 26.7, humidity = 62.8, location = "Room1" }
            };
            
            foreach (var data in testData)
            {
                var json = JsonSerializer.Serialize(data);
                var message = new MqttApplicationMessageBuilder()
                    .WithTopic("sensor/data/room1")
                    .WithPayload(json)
                    .Build();
                
                await client.PublishAsync(message);
                await Task.Delay(2000); // 2 Sekunden Pause
            }
        }
    }
}