Merge branch 'feature/antiflood' into dev

Core/Service/IAntiFlood.cs

@@ -0,0 +1,9 @@
+using Telegram.Bot.Types;
+
+namespace Kruzya.TelegramBot.Core.Service;
+
+public interface IAntiFlood
+{
+    public bool IsUserFlooding(Chat chat, User user);
+    public void RecordAction(Chat chat, User user);
+}

Core/Service/MemoryAntiFloodService.cs

@@ -0,0 +1,63 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using Microsoft.Extensions.Configuration;
+using Telegram.Bot.Types;
+
+namespace Kruzya.TelegramBot.Core.Service;
+
+public class MemoryAntiFloodService : IAntiFlood
+{
+    private IDictionary<string, IList<DateTime>> _floodUsers;
+    private IDictionary<string, DateTime> _bannedUsers;
+    private int _floodStartsAfter = 3;
+    private TimeSpan _banningTimeSpan; 
+
+    public MemoryAntiFloodService(IConfiguration configuration)
+    {
+        _floodUsers = new Dictionary<string, IList<DateTime>>();
+        _bannedUsers = new Dictionary<string, DateTime>();
+        _floodStartsAfter = configuration.GetValue<int>("FloodActions");
+        _banningTimeSpan = TimeSpan.FromMinutes(configuration.GetValue<double>("FloodBanTime"));
+    }
+
+    public bool IsUserFlooding(Chat chat, User user)
+    {
+        var dictKey = DictKey(chat, user);
+        if (_bannedUsers.TryGetValue(dictKey, out var expirationTime))
+        {
+            if (DateTime.UtcNow <= expirationTime)
+            {
+                expirationTime = DateTime.MinValue;
+                _bannedUsers.Remove(dictKey);
+            }
+        }
+
+        return (DateTime.UtcNow >= expirationTime);
+    }
+
+    public void RecordAction(Chat chat, User user)
+    {
+        var dictKey = DictKey(chat, user);
+        if (!_floodUsers.TryGetValue(dictKey, out var actionTimeList))
+        {
+            actionTimeList = new List<DateTime>();
+        }
+
+        actionTimeList.Add(DateTime.UtcNow);
+        actionTimeList = actionTimeList.Where(e => e.Subtract(_banningTimeSpan) <= DateTime.UtcNow).ToList();
+        _floodUsers[dictKey] = actionTimeList;
+
+        if (actionTimeList.Count > _floodStartsAfter)
+        {
+            actionTimeList.Clear();
+            _bannedUsers[dictKey] = DateTime.UtcNow.Add(_banningTimeSpan);
+        }
+    }
+
+    private string DictKey(Chat chat, User user)
+    {
+        return $"{chat.Id}-{user.Id}";
+    }
+}

Core/Startup.cs

@@ -43,6 +43,7 @@ namespace Kruzya.TelegramBot.Core
             services.AddSingleton<ICacheStorage<long, User>, MemoryCache<long, User>>();
 
             services.AddSingleton<UserService>();
+            services.AddSingleton<IAntiFlood, MemoryAntiFloodService>();
 
             // Trigger module handlers.
             _core.Modules.ConfigureServices(services);