minor fixes for api

Pilz.Net/Api/ApiServer.cs

@@ -27,6 +27,7 @@ public class ApiServer(string apiUrl) : IApiServer
     public virtual void Start()
     {
         Log.Info("Start listening");
+        httpListener.Prefixes.Add(ApiUrl + "/");
         httpListener.Start();
         Listen();
     }
@@ -44,21 +45,27 @@ public class ApiServer(string apiUrl) : IApiServer
 
         // Register each method
         foreach (var method in methods)
-            RegisterHandler(method.CreateDelegate(instance));
+            RegisterHandler(method.CreateDelegate(instance), false);
     }
 
     public virtual void RegisterHandler(Delegate handler)
+    {
+        RegisterHandler(handler, true);
+    }
+
+    public virtual void RegisterHandler(Delegate handler, bool throwOnError)
     {
         var method = handler.Method;
 
         // Sanity checks
         if (method.GetCustomAttribute<MessageHandlerAttribute>() is not MessageHandlerAttribute attribute
             || method.GetParameters().FirstOrDefault() is not ParameterInfo parameter
-            || !parameter.ParameterType.IsGenericType
-            || parameter.ParameterType.GenericTypeArguments.Length != 1
-            || !parameter.ParameterType.GenericTypeArguments[0].IsAssignableTo(typeof(ApiMessage))
             || !method.ReturnType.IsAssignableTo(typeof(ApiResult)))
+        {
+            if (throwOnError)
                 throw new NotSupportedException("The first parameter needs to be of type ApiMessage and must return an ApiResult object and the method must have the MessageHandlerAttribute.");
+            return;
+        }
 
         // Add handler
         var fullUrl = attribute.Route;
@@ -137,7 +144,7 @@ public class ApiServer(string apiUrl) : IApiServer
             Log.Info("Write response");
             context.Response.ContentType = "application/json";
             using StreamWriter output = new(context.Response.OutputStream);
-            output.Write(result);
+            output.Write(result.ResultJson);
         }
 
         Log.Debug("Finish response");

Pilz.Net/Api/IApiServer.cs

@@ -23,4 +23,6 @@ public interface IApiServer
     void RegisterHandler<T>(T instance) where T : class;
 
     void RegisterHandler(Delegate handler);
+
+    void RegisterHandler(Delegate handler, bool throwOnError);
 }