telegram-bot/modules/UrlLimitations/UserJoinHandler.cs

using System;
using BotFramework;
using BotFramework.Attributes;
using BotFramework.Setup;
using Kruzya.TelegramBot.Core.Cache;
using Telegram.Bot.Types.Enums;

namespace Kruzya.TelegramBot.UrlLimitations
{
    public class UserJoinHandler : BotEventHandler
    {
        protected MemoryCache<ChatMember, UInt16> ChatMembersCache;
        
        public UserJoinHandler(MemoryCache<ChatMember, UInt16> chatMembersCache)
        {
            ChatMembersCache = chatMembersCache;
        }
        
        [Message(MessageType.ChatMembersAdded, InChat.Public)]
        public void OnChatMembersAdded()
        {
            ChatMembersCache.SetValue(ChatMember.From(Chat.Id, From.Id), 0);
        }
    }
}