add validation for configured URL

CustomChatAddOns/Data/Ping.cs

@@ -16,7 +16,7 @@ namespace Kruzya.TelegramBot.CustomChatAddOns.Data
         [JsonProperty("confirmation")]
         public string Confirmation { get; set; } = Guid.NewGuid().ToString();
 
-        public Ping From(Message message) => new() {
+        public static Ping From(Message message) => new() {
             ChatId = message.Chat.Id,
             UserId = message.From!.Id
         };

CustomChatAddOns/Handler/Config.cs

@@ -3,8 +3,12 @@ using Kruzya.TelegramBot.Core.Data;
 using Kruzya.TelegramBot.Core.Extensions;
 using Kruzya.TelegramBot.Core.Handler;
 using Kruzya.TelegramBot.Core.Service;
+using Kruzya.TelegramBot.CustomChatAddOns.Data;
 using Kruzya.TelegramBot.CustomChatAddOns.Options;
+using Kruzya.TelegramBot.CustomChatAddOns.Service;
+using System.Net.NetworkInformation;
 using Telegram.Bot.Types.Enums;
+using Ping = Kruzya.TelegramBot.CustomChatAddOns.Data.Ping;
 
 namespace Kruzya.TelegramBot.CustomChatAddOns.Handler
 {
@@ -12,12 +16,13 @@ namespace Kruzya.TelegramBot.CustomChatAddOns.Handler
     {
         private readonly CustomChatHandler _option;
         private readonly UserService _userService;
+        private readonly InteropService _interopService;
 
-        public Config(CustomChatHandler option, UserService userService, CoreContext db) : base(db)
+        public Config(CustomChatHandler option, UserService userService, InteropService interopService, CoreContext db) : base(db)
         {
             _option = option;
             _userService = userService;
-            
+            _interopService = interopService;
         }
 
         private bool IsAllowedChatType(ChatType chatType)
@@ -49,7 +54,22 @@ namespace Kruzya.TelegramBot.CustomChatAddOns.Handler
                 return;
             }
 
-            // TODO: perform a "ping" request to endpoint. "Ping" should contain chat id and user id who performs this action.
+            try
+            {
+                var ping = Ping.From(Message!);
+                var pong = await _interopService.PostMessage<Ping, Pong>(endpoint.ToString(), ping);
+                if (pong.Confirmation != ping.Confirmation)
+                {
+                    throw new Exception("Invalid response");
+                }
+            }
+            // catch (HttpRequestException e)
+            catch (Exception e)
+            {
+                await Reply($"Sorry, this URL cannot be set as chat webhook: {e.Message}");
+                return;
+            }
+
             await _option.SetValueAsync(Chat.Id, endpoint.ToString());
             await Reply("Done, configured");
         }

CustomChatAddOns/Service/InteropService.cs

@@ -0,0 +1,41 @@
+using Newtonsoft.Json;
+using Newtonsoft.Json.Serialization;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Http.Json;
+using System.Text;
+using System.Threading.Tasks;
+using Telegram.Bot.Types;
+
+namespace Kruzya.TelegramBot.CustomChatAddOns.Service
+{
+    public class InteropService
+    {
+        private readonly JsonSerializerSettings _serializerSettings;
+        private readonly HttpClient _client;
+
+        public InteropService(ISerializationBinder serializationBinder, HttpClient client)
+        {
+            _serializerSettings = new()
+            {
+                TypeNameHandling = TypeNameHandling.Objects,
+                SerializationBinder = serializationBinder
+            };
+
+            _client = client;
+        }
+
+        public async Task<TOut> PostMessage<TIn, TOut>(string endpoint, TIn message)
+        {
+            var serializedMessage = JsonConvert.SerializeObject(message, _serializerSettings);
+            var httpContent = new StringContent(serializedMessage, Encoding.UTF8, "application/json");
+
+            var response = await (await _client.PostAsync(endpoint, httpContent))
+                .EnsureSuccessStatusCode()
+                .Content.ReadAsStringAsync();
+
+            return JsonConvert.DeserializeObject<TOut>(response, _serializerSettings)!;
+        }
+    }
+}