Voximplant ASR example #4: voice bot

asr_voice_bot.js

// Enable ASR module
require(Modules.ASR);

var call, asr;

// Answer inbound call
VoxEngine.addEventListener(AppEvents.CallAlerting, function (e) {
	call = e.call;
	call.addEventListener(CallEvents.Connected, onCallConnected);
	call.addEventListener(CallEvents.Disconnected, VoxEngine.terminate);
	call.answer();
});

function onCallConnected(callevent) {
    // create ASR instance
	asr = VoxEngine.createASR(ASRLanguage.ENGLISH_US);
  
    // Recognition result
	asr.addEventListener(ASREvents.Result, function (e) {        
        Net.httpRequestAsync("http://botservice.xyz/input?=" + encodeURIComponent(e.text))
            .then(function (result) {
              // assuming that webservice returns text that bot should say
              if (result.code == 200) {
                call.say(result.text, Language.US_ENGLISH_FEMALE);
                call.addEventListener(CallEvents.PlaybackFinished, function (e) {
                    call.removeEventListener(CallEvents.PlaybackFinished);
                    call.sendMediaTo(asr);
                });
              }
            }) 
            .catch(function (err) {
                Logger.write(err);
            });
	});
  
    // Speech captured - stop sending data to ASR
	asr.addEventListener(ASREvents.SpeechCaptured, function (e) {        
		call.stopMediaTo(asr);
	});

	call.say("Hi sir, how can I help you?", Language.US_ENGLISH_FEMALE);
    
	call.addEventListener(CallEvents.PlaybackFinished, function (e) {
        call.removeEventListener(CallEvents.PlaybackFinished);
		call.sendMediaTo(asr);
	});
}

In this scenario how a ASR event is aware of the call, meaning i don't see any link between call & asr. So how asr is aware that a call is going on and it should start doing the speech recognition.

Because of call.sendMediaTo(asr);

OK thanks for the reply. In that case is it possible to add any external ASR module. Can we do something like
call.sendMediaTo(externalAsr) where externalAsr can be any asr other than voximplant ASR ?

You can stream media via Websockets for external recognition, see https://voximplant.com/blog/websocket-introduction

That looks very interesting. Thank you for quick reply.