source: binary-improvements2/MarkersMod/src/Markers.cs@ 401

using System.Collections.Generic;
using System.Net;
using AllocsFixes.JSON;
using Webserver;
using Webserver.WebAPI;

namespace Examples {
        public class Markers : AbsRestApi {
                private const int numRandomMarkers = 5;

                private readonly Dictionary<string, (int, int)> markers = new Dictionary<string, (int, int)> ();

                private static readonly JsonArray emptyResult = new JsonArray ();
                
                public Markers () {
                        GameRandom random = GameRandomManager.Instance.CreateGameRandom ();
                        
                        for (int i = 0; i < numRandomMarkers; i++) {
                                int lat = random.RandomRange (-1000, 1001);
                                int lng = random.RandomRange (-1000, 1001);

                                markers.Add (WebUtils.GenerateGuid (), (lat, lng));
                        }
                }

                protected override void HandleRestGet (RequestContext _context) {
                        string id = _context.RequestPath;
                        
                        if (string.IsNullOrEmpty (id)) {
                                JsonArray result = new JsonArray ();

                                foreach ((string markerId, (int, int) coordinates) in markers) {
                                        JsonObject marker = new JsonObject ();
                                        marker.Add ("id", new JsonString (markerId));
                                        marker.Add ("lat", new JsonNumber (coordinates.Item1));
                                        marker.Add ("lng", new JsonNumber (coordinates.Item2));
                                        result.Add (marker);
                                }
                                
                                SendEnvelopedResult (_context, result);
                                return;
                        }

                        if (!markers.TryGetValue (id, out (int, int) location)) {
                                SendEnvelopedResult (_context, emptyResult, HttpStatusCode.NotFound);
                                return;
                        }

                        {
                                JsonArray result = new JsonArray ();
                                JsonObject marker = new JsonObject ();
                                marker.Add ("id", new JsonString (id));
                                marker.Add ("lat", new JsonNumber (location.Item1));
                                marker.Add ("lng", new JsonNumber (location.Item2));
                                result.Add (marker);
                                SendEnvelopedResult (_context, result);
                        }
                }

                protected override void HandleRestPost (RequestContext _context, JsonNode _jsonBody) {
                        if (!(_jsonBody is JsonObject bodyObject)) {
                                SendEnvelopedResult (_context, null, HttpStatusCode.BadRequest, _jsonBody, "BODY_NOT_OBJECT");
                                return;
                        }

                        if (!TryGetJsonField (bodyObject, "lat", out int lat)) {
                                SendEnvelopedResult (_context, null, HttpStatusCode.BadRequest, _jsonBody, "NO_OR_INVALID_LAT");
                                return;
                        }

                        if (!TryGetJsonField (bodyObject, "lng", out int lng)) {
                                SendEnvelopedResult (_context, null, HttpStatusCode.BadRequest, _jsonBody, "NO_OR_INVALID_LNG");
                                return;
                        }

                        string newId = WebUtils.GenerateGuid ();
                        markers.Add (newId, (lat, lng));

                        JsonString result = new JsonString (newId);
                        SendEnvelopedResult (_context, result, HttpStatusCode.Created);
                }

                protected override void HandleRestPut (RequestContext _context, JsonNode _jsonBody) {
                        if (!(_jsonBody is JsonObject bodyObject)) {
                                SendEnvelopedResult (_context, null, HttpStatusCode.BadRequest, _jsonBody, "BODY_NOT_OBJECT");
                                return;
                        }

                        if (!TryGetJsonField (bodyObject, "lat", out int lat)) {
                                SendEnvelopedResult (_context, null, HttpStatusCode.BadRequest, _jsonBody, "NO_OR_INVALID_LAT");
                                return;
                        }

                        if (!TryGetJsonField (bodyObject, "lng", out int lng)) {
                                SendEnvelopedResult (_context, null, HttpStatusCode.BadRequest, _jsonBody, "NO_OR_INVALID_LNG");
                                return;
                        }

                        string id = _context.RequestPath;

                        if (!markers.TryGetValue (id, out _)) {
                                SendEnvelopedResult (_context, null, HttpStatusCode.NotFound, _jsonBody, "ID_NOT_FOUND");
                                return;
                        }
                        
                        markers [id] = (lat, lng);

                        JsonObject result = new JsonObject ();
                        result.Add ("id", new JsonString (id));
                        result.Add ("lat", new JsonNumber (lat));
                        result.Add ("lng", new JsonNumber (lng));
                        SendEnvelopedResult (_context, result);
                }

                protected override void HandleRestDelete (RequestContext _context) {
                        string id = _context.RequestPath;

                        SendEnvelopedResult (_context, null, markers.Remove (id) ? HttpStatusCode.NoContent : HttpStatusCode.NotFound);
                }
        }
}