MessagesController.cs

namespace LuisBot
{
    using System;
    using System.Diagnostics;
    using System.Net;
    using System.Net.Http;
    using System.Threading.Tasks;
    using System.Web.Configuration;
    using System.Web.Http;
    using Dialogs;
    using Microsoft.Bot.Builder.Dialogs;
    using Microsoft.Bot.Connector;
    using System.Net.Http.Headers;
    using System.Xml.Linq;

    [BotAuthentication]
    public class MessagesController : ApiController
    {
        string ApiKey = "e2e6074acad9425999d89ba796c85275";
        string targetLang = "en";

        /// <summary>
        /// POST: api/Messages
        /// Receive a message from a user and reply to it
        /// </summary>
        public async Task<HttpResponseMessage> Post([FromBody]Activity activity)
        {
            if (activity.Type == ActivityTypes.Message)
            {
              //  if (IsSpellCorrectionEnabled)
               // {
                    try
                    {
                        //  activity.Text = await this.spellService.GetCorrectedTextAsync(activity.Text);
                        ConnectorClient connector = new ConnectorClient(new Uri(activity.ServiceUrl));

                        var input = activity.Text;
                     
                        Task.Run(async () =>
                        {
                            var accessToken = await GetAuthenticationToken(ApiKey);
                            var output = await TranslateText(input, targetLang, accessToken);
                            Console.WriteLine(output);
                            activity.Text = output;
                            await Conversation.SendAsync(activity, () => new RootLuisDialog());
                            // Activity reply = activity.CreateReply($"Your text translation to English is => '{output}'");
                            //  await connector.Conversations.ReplyToActivityAsync(reply);

                        }).Wait();
                    }
                    catch (Exception ex)
                    {
                        Trace.TraceError(ex.ToString());
                    }
               // }

                //await Conversation.SendAsync(activity, () => new RootLuisDialog());
            }
            else
            {
                this.HandleSystemMessage(activity);
            }

            var response = Request.CreateResponse(HttpStatusCode.OK);
            return response;
        }

        static async Task<string> TranslateText(string inputText, string language, string accessToken)
        {
            string url = "http://api.microsofttranslator.com/v2/Http.svc/Translate";
            string query = $"?text={System.Net.WebUtility.UrlEncode(inputText)}&to={language}&contentType=text/plain";

            using (var client = new HttpClient())
            {
                client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
                var response = await client.GetAsync(url + query);
                var result = await response.Content.ReadAsStringAsync();

                if (!response.IsSuccessStatusCode)
                    return "Hata: " + result;

                var translatedText = XElement.Parse(result).Value;
                return translatedText;
            }
        }

        static async Task<string> GetAuthenticationToken(string key)
        {
            string endpoint = "https://api.cognitive.microsoft.com/sts/v1.0/issueToken";

            using (var client = new HttpClient())
            {
                client.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", key);
                var response = await client.PostAsync(endpoint, null);
                var token = await response.Content.ReadAsStringAsync();
                return token;
            }
        }

        private Activity HandleSystemMessage(Activity message)
        {
            if (message.Type == ActivityTypes.DeleteUserData)
            {
                // Implement user deletion here
                // If we handle user deletion, return a real message
            }
            else if (message.Type == ActivityTypes.ConversationUpdate)
            {
                // Handle conversation state changes, like members being added and removed
                // Use Activity.MembersAdded and Activity.MembersRemoved and Activity.Action for info
                // Not available in all channels
            }
            else if (message.Type == ActivityTypes.ContactRelationUpdate)
            {
                // Handle add/remove from contact lists
                // Activity.From + Activity.Action represent what happened
            }
            else if (message.Type == ActivityTypes.Typing)
            {
                // Handle knowing tha the user is typing
            }
            else if (message.Type == ActivityTypes.Ping)
            {
            }

            return null;
        }
    }
}