telegram-bot/Core/Controllers/Telegram.cs

using BotFramework.Abstractions.UpdateProvider;
using BotFramework.Config;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Newtonsoft.Json;
using System.IO;
using System.Threading.Tasks;
using Telegram.Bot;
using Telegram.Bot.Types;

namespace Kruzya.TelegramBot.Core.Controllers
{
    public class Telegram : Controller
    {
        private const string SecretTokenHeader = "X-Telegram-Bot-Api-Secret-Token";

        private readonly ILogger<Telegram> _logger;
        private readonly ITelegramBotClient _client;
        private readonly IUpdateTarget _updateTarget;
        private readonly string _secretToken;

        public Telegram(ILogger<Telegram> logger, ITelegramBotClient client, IUpdateTarget updateTarget, IOptions<BotConfig> config)
        {
            _logger = logger;
            _client = client;
            _updateTarget = updateTarget;

            _secretToken = config.Value.Webhook.SecretToken;
            if (string.IsNullOrEmpty(_secretToken))
            {
                _secretToken = null;
            }
        }

        [HttpPost]
        public async IActionResult Index()
        {
            if (_secretToken != null && !Request.Headers.ContainsKey(SecretTokenHeader))
            {
                _logger.LogWarning("Someone tried push update without secret key in headers");
                return BadRequest();
            }

            var ok = (_secretToken == null || Request.Headers[SecretTokenHeader] == _secretToken);
            if (!ok)
            {
                _logger.LogWarning("Someone tried push update with wrong secret key in headers");
                return BadRequest();
            }

            var body = await (new StreamReader(Request.Body)).ReadToEndAsync();
            LaunchHandle(JsonConvert.DeserializeObject<Update>(body));
            return Ok();
        }

        private void LaunchHandle(Update? update)
        {
            try
            {
                if (update == null)
                {
                    throw new System.Exception("Invalid request body");
                }

                _updateTarget.Push(update);
            }
            catch (System.Exception e)
            {
                _logger.LogError($"Error occured when handling a new update: {e}");
            }
        }
    }
}