implement message subscribing and worker

dotnet/AipsWorker/Utilities/LoadingDotEnv.cs

@@ -0,0 +1,24 @@
+using DotNetEnv;
+
+namespace AipsWorker.Utilities;
+
+public static class LoadingDotEnv
+{
+    public static bool TryLoad()
+    {
+        string? dir = Directory.GetCurrentDirectory();
+
+        while (dir != null && !File.Exists(Path.Combine(dir, ".env")))
+        {
+            dir = Directory.GetParent(dir)?.FullName;
+        }
+
+        if (dir != null)
+        {
+            Env.Load(Path.Combine(dir, ".env"));
+            return true;
+        }
+
+        return false;
+    }
+}

dotnet/AipsWorker/Utilities/SubscribeMethodUtility.cs

@@ -0,0 +1,48 @@
+using System.Reflection;
+using AipsCore.Application.Abstract.MessageBroking;
+
+namespace AipsWorker.Utilities;
+
+public class SubscribeMethodUtility
+{
+    private readonly IMessageSubscriber _subscriber;
+
+    public SubscribeMethodUtility(IMessageSubscriber subscriber)
+    {
+        _subscriber = subscriber;
+    }
+    
+    public async Task SubscribeToMessageTypeAsync(
+        Type messageType,
+        object targetInstance,
+        MethodInfo handlerMethod)
+    {
+        var subscribeMethod = GetGenericSubscribeMethod(messageType);
+        var handlerDelegate = CreateHandlerDelegate(messageType, targetInstance, handlerMethod);
+
+        var task = (Task)subscribeMethod.Invoke(
+            _subscriber,
+            new object[] { handlerDelegate })!;
+
+        await task;
+    }
+    
+    private MethodInfo GetGenericSubscribeMethod(Type messageType)
+    {
+        var method = typeof(IMessageSubscriber)
+            .GetMethod(nameof(IMessageSubscriber.SubscribeAsync))!;
+
+        return method.MakeGenericMethod(messageType);
+    }
+    
+    private Delegate CreateHandlerDelegate(
+        Type messageType,
+        object targetInstance,
+        MethodInfo handlerMethod)
+    {
+        var delegateType = typeof(Func<,,>)
+            .MakeGenericType(messageType, typeof(CancellationToken), typeof(Task));
+
+        return Delegate.CreateDelegate(delegateType, targetInstance, handlerMethod);
+    }
+}