source: binary-improvements/MapRendering/API/GetEntityListAbs.cs

using System;
using System.Collections.Generic;
using JetBrains.Annotations;
using Utf8Json;
using Webserver;
using Webserver.WebAPI;

namespace AllocsFixes.WebAPIs {
        [UsedImplicitly]
        internal abstract class GetEntityListAbs<T> : AbsWebAPI where T : EntityAlive {
                private static readonly byte[] jsonKeyId = JsonWriter.GetEncodedPropertyNameWithBeginObject ("id");
                private static readonly byte[] jsonKeyName = JsonWriter.GetEncodedPropertyNameWithPrefixValueSeparator ("name");
                private static readonly byte[] jsonKeyPosition = JsonWriter.GetEncodedPropertyNameWithPrefixValueSeparator ("position");

                private readonly List<T> entities = new List<T> ();
                private readonly Action<List<T>> getterMethod;
                

                protected GetEntityListAbs (Action<List<T>> _getterMethod) {
                        getterMethod = _getterMethod;
                }

                public override void HandleRequest (RequestContext _context) {
                        JsonWriter writer = new JsonWriter ();
                        writer.WriteBeginArray ();

                        getterMethod (entities);
                        for (int i = 0; i < entities.Count; i++) {
                                T entity = entities [i];
                                Vector3i position = new Vector3i (entity.GetPosition ());

                                if (i > 0) {
                                        writer.WriteValueSeparator ();
                                }
                                
                                writer.WriteRaw (jsonKeyId);
                                writer.WriteInt32 (entity.entityId);
                                
                                writer.WriteRaw (jsonKeyName);
                                if (!string.IsNullOrEmpty (entity.EntityName)) {
                                        writer.WriteString (entity.EntityName);
                                } else {
                                        writer.WriteString ($"entity class #{entity.entityClass}");
                                }
                                
                                writer.WriteRaw (jsonKeyPosition);
                                JsonCommons.WriteVector3I (ref writer, position);
                                
                                writer.WriteEndObject ();
                        }
                        
                        writer.WriteEndArray ();
                        WebUtils.WriteJsonData (_context.Response, ref writer);
                }
        }
}