How to set dynamically specific LG file to initiate conversations in Bot Composer

Question

I created a bot project using bot composer with multiple language generation files. I created a one custom action to identify which language bot should initiate conversation/chat which will be called before greeting dialog/before welcome message.

I had deployed bot to Wats App channel with default language as English(en-US) (Bot Composer -->Project Settings--> Bot Languages-->English).

Even thought bot is deployed to Azure web app in English language, but If custom action dialog result returns Italian ("it-it") language, bot should show greeting response with "it-it" lg file response only.

How do I achieve this kind of functionality in Bot Composer?

Ex: Custom Action Output : en-Us

Bot: Hi, Welcome to Multi Lingual Bot

Ex: Custom Action Output(Italy) : it-it

Bot: Ciao, benvenuto in Multi Lingual Bot

Answer 1

Solution: Create your own Middleware Component in Bot Composer Project. I had provided steps to follow how to create middleware with partial coding.

Code:

 public class LanguageDetectionMiddleware : IMiddleware
{
   public async Task OnTurnAsync(ITurnContext turnContext, CancellationToken cancellationToken = default)
    {
      //Step1: Fetch Channel Data  

      // Step2: Fetch Coutry Code and Number : Since I am using wats app channel, I will get phone number of any user with country code and number.

       string channelLocale = await FetchLocaleFromChannelMobileNumber(Channeldata);  

     //Step4 : Assign turn activity locale to ChannelLocale.
      
      turnContext.Activity.Locale = channelLocale; 

     //save the language to user state.
      await this.userstate.SaveChangesAsync(turnContext, false, cancellationToken);

    } 
}

Code changes to be done in Startup.cs File:

  //step5: Add middleware in startup.cs file adapter
       .Use(s.GetService<LanguageDetectionMiddleware>());

     // step6: Add Language Middle to Configure Services
     services.AddSingleton(sp =>
        {
            return new LanguageDetectionMiddleware(sp.GetService<IBotTelemetryClient>(), userState);
        });