add some default types to de-duplicate similar implmentations

Pilz.Net/Api/Server/BaseChildItemHandler.cs

@@ -0,0 +1,52 @@
+using Pilz.Extensions.Reflection;
+using Pilz.Net.Data;
+using Pilz.Net.Extensions;
+using System.Diagnostics;
+
+namespace Pilz.Net.Api.Server;
+
+public abstract class BaseChildItemHandler<TEntity, TParent, TUpdateMsg>(IApiServer server)
+    : BaseHandler<TEntity, TUpdateMsg>(server)
+    where TEntity : IDataObject
+    where TParent : IDataObject
+    where TUpdateMsg : ApiMessage
+{
+    protected virtual bool RegisterGetAll => true;
+    protected virtual bool RegisterPost => true;
+
+    public override void Initialize(IApiServer server)
+    {
+        base.Initialize(server);
+        var t = GetType();
+        if (RegisterGetAll)
+            server.RegisterHandler(t.GetMethod(nameof(GetAll))!.CreateDelegate(this), new(Route, "GET"), Debugger.IsAttached);
+        if (RegisterPost)
+            server.RegisterHandler(t.GetMethod(nameof(Post))!.CreateDelegate(this), new(Route, "POST"), Debugger.IsAttached);
+    }
+
+    public virtual ApiResult GetAll(int parent)
+    {
+        IQueryable<TEntity> list;
+
+        if (parent != 0 && server.Manager.Find(parent, out TParent? parentEntity))
+            list = GetChilds(parentEntity).AsQueryable();
+        else
+            list = server.Manager.Get<TEntity>();
+
+        return list.ToList().Select(ToClient).ToItemsResult();
+    }
+
+    public virtual ApiResult Post(int parent, TUpdateMsg msg)
+    {
+        if (!server.Manager.Find(parent, out TParent? parentEntity))
+            return ApiResult.NotFound();
+        var entity = CreateNewEntity();
+        if (UpdateEntity(entity, msg) is ApiResult result)
+            return result;
+        GetChilds(parentEntity).Add(entity);
+        server.Manager.Save(parentEntity, true);
+        return ToClient(entity).ToItemResult();
+    }
+
+    public abstract IList<TEntity> GetChilds(TParent parent);
+}