A demo sample for session attributes of Alexa

guessthenumber.js

// This sample demonstrates handling intents from an Alexa skill using the Alexa Skills Kit SDK (v2).
// Please visit https://alexa.design/cookbook for additional examples on implementing slots, dialog management,
// session persistence, api calls, and more.var
const Alexa = require('ask-sdk-core');

const SKILL_NAME = "Number";
const ANSWER_THIS_MESSAGE = "Answer this : ";
const HELP_MESSAGE = 'What can I help you with?';
const HELP_REPROMPT = 'What can I help you with?';
const STOP_MESSAGE = 'Enjoy the day...Goodbye!';
const SKIP_MESSAGE = 'Ok, here is another one,';
const CORRECT_ANSWER_MESSAGE = 'Correct Answer!!';
const WRONG_ANSWER_MESSAGE = 'Oops, Wrong anwser!!';
const MORE_MESSAGE = 'Do you want another one?';
const ERROR_MESSAGE = 'Oops, Something went wrong, please try later!!';
const PAUSE = '<break time="0.3s" />';
const WHISPER = '<amazon:effect name="whispered"/>';
const FALLBACK_REPROMPT = 'shall I fetch you one?';
const FALLBACK = SKILL_NAME + 'skill cant help with that, but I can help you with finding a QUESTION:  for you to guess.' + PAUSE + FALLBACK_REPROMPT;
const FALLBACK_MESSAGE_DURING_GAME = `The ${SKILL_NAME} skill can't help you with that.  Try answering the question. `;
const FALLBACK_REPROMPT_DURING_GAME = 'Try answering the question.';


var gameStates = {
  started: 'started',
  waiting: 'waiting',
  ended: 'ended'
};
var currentState = gameStates.started;

const LaunchRequestHandler = {
  canHandle(handlerInput) {
    return handlerInput.requestEnvelope.request.type === 'LaunchRequest';
  },
  handle(handlerInput) {
    const speechObj = getAQuestion();
    saveCurrentStateWith(handlerInput);

    return handlerInput.responseBuilder
      .speak(speechObj.speechText)
      .reprompt(speechObj.reprompt)
      .getResponse();
  }
};
const SkipTheQuestionIntentHandler = {
  canHandle(handlerInput) {
   var isWaitingForAnswer = true;
    const state = fetchCurrentSavedState(handlerInput);
    if (state !== gameStates.waiting) {
      isWaitingForAnswer = false;
    }
    return isWaitingForAnswer && handlerInput.requestEnvelope.request.type === 'IntentRequest' &&
      handlerInput.requestEnvelope.request.intent.name === 'SkipTheQuestion';
  },
  handle(handlerInput) {
    const speechObj = getAQuestion();
    saveCurrentStateWith(handlerInput);
    return handlerInput.responseBuilder
      .speak(SKIP_MESSAGE + speechObj.speechText)
      .reprompt(speechObj.reprompt)
      .getResponse();
  }
};
const GuessTheAnswerIntentHandler = {
  canHandle(handlerInput) {
    return handlerInput.requestEnvelope.request.type === 'IntentRequest' &&
      handlerInput.requestEnvelope.request.intent.name === 'GuessTheAnswer';
  },
  handle(handlerInput) {
    const speechObj = getAQuestion();
    saveCurrentStateWith(handlerInput);
    return handlerInput.responseBuilder
      .speak(speechObj.speechText)
      .reprompt(speechObj.reprompt)
      .getResponse();
  }
};
const AnswerIntentHandler = {
  canHandle(handlerInput) {
    var isWaitingForAnswer = true;
    const state = fetchCurrentSavedState(handlerInput);
    if (state !== gameStates.waiting) {
      isWaitingForAnswer = false;
    }
    return isWaitingForAnswer && handlerInput.requestEnvelope.request.type === 'IntentRequest' &&
      handlerInput.requestEnvelope.request.intent.name === 'AnswerIntent';
  },
  handle(handlerInput) {
    var answer = handlerInput.requestEnvelope.request.intent.slots.answer.value;
    var lowerAnswer = answer.toLowerCase()
    const speechObj = validateAnswerAndPrepareResponse(lowerAnswer);
    saveCurrentStateWith(handlerInput);
    if (speechObj.reprompt) {
      return handlerInput.responseBuilder
        .speak(speechObj.speechText)
        .reprompt(speechObj.reprompt)
        .getResponse();
    } else {
      return handlerInput.responseBuilder
        .speak(speechObj.speechText)
        .getResponse();
    }

  }
};
const HelpIntentHandler = {
  canHandle(handlerInput) {
    return handlerInput.requestEnvelope.request.type === 'IntentRequest' &&
      handlerInput.requestEnvelope.request.intent.name === 'AMAZON.HelpIntent';
  },
  handle(handlerInput) {
    const speechText = HELP_MESSAGE;

    return handlerInput.responseBuilder
      .speak(speechText)
      .reprompt(speechText)
      .getResponse();
  }
};
const CancelAndStopIntentHandler = {
  canHandle(handlerInput) {
    return handlerInput.requestEnvelope.request.type === 'IntentRequest' &&
      (handlerInput.requestEnvelope.request.intent.name === 'AMAZON.CancelIntent' ||
        handlerInput.requestEnvelope.request.intent.name === 'AMAZON.StopIntent');
  },
  handle(handlerInput) {
    const speechObj = stopAndExit();
    saveCurrentStateWith(handlerInput)
    return handlerInput.responseBuilder
      .speak(speechObj.speechText)
      .getResponse();
  }
};
const YesIntentHandler = {
  canHandle(handlerInput) {
    var isWaitingForAnswer = true;
    const state = fetchCurrentSavedState(handlerInput);
    if (state !== gameStates.waiting) {
      isWaitingForAnswer = false;
    }
    return !isWaitingForAnswer && handlerInput.requestEnvelope.request.type === 'IntentRequest' &&
      handlerInput.requestEnvelope.request.intent.name === 'AMAZON.YesIntent';
  },
  handle(handlerInput) {
    const speechObj = getAQuestion();
    saveCurrentStateWith(handlerInput)
    return handlerInput.responseBuilder
      .speak(speechObj.speechText)
      .reprompt(speechObj.reprompt)
      .getResponse();
  }
};

const NoIntentHandler = {
  canHandle(handlerInput) {
    var isWaitingForAnswer = true;
    const state = fetchCurrentSavedState(handlerInput);
    if (state !== gameStates.waiting) {
      isWaitingForAnswer = false;
    }
    return !isWaitingForAnswer && handlerInput.requestEnvelope.request.type === 'IntentRequest' &&
      handlerInput.requestEnvelope.request.intent.name === 'AMAZON.NoIntent';
  },
  handle(handlerInput) {
    const speechObj = stopAndExit();
    saveCurrentStateWith(handlerInput)
    return handlerInput.responseBuilder
      .withShouldEndSession(true)
      .speak(speechObj.speechText)
      .getResponse();
  }
};

const FallbackIntentHandler = {
    canHandle(handlerInput) {
      return handlerInput.requestEnvelope.request.type === 'IntentRequest' &&
        handlerInput.requestEnvelope.request.intent.name === 'AMAZON.FallbackIntent' ||
        handlerInput.requestEnvelope.request.intent.name === 'AMAZON.YesIntent' ||
        handlerInput.requestEnvelope.request.intent.name === 'AMAZON.NoIntent' ||
        handlerInput.requestEnvelope.request.intent.name === 'SkipTheQuestion' ||
        handlerInput.requestEnvelope.request.intent.name === 'AnswerIntent';
  },
  handle(handlerInput) {

    var isWaitingForAnswer = true;
    const state = fetchCurrentSavedState(handlerInput);
    const speechObj = fallback(state);
    return handlerInput.responseBuilder
      .speak(speechObj.speechText)
      .reprompt(speechObj.reprompt)
      .getResponse();
  }
};
const SessionEndedRequestHandler = {
  canHandle(handlerInput) {
    return handlerInput.requestEnvelope.request.type === 'SessionEndedRequest';
  },
  handle(handlerInput) {
    // Any cleanup logic goes here.
    return handlerInput.responseBuilder.getResponse();
  }
};

// The intent reflector is used for interaction model testing and debugging.
// It will simply repeat the intent the user said. You can create custom handlers
// for your intents by defining them above, then also adding them to the request
// handler chain below.
const IntentReflectorHandler = {
  canHandle(handlerInput) {
    return handlerInput.requestEnvelope.request.type === 'IntentRequest';
  },
  handle(handlerInput) {
    const intentName = handlerInput.requestEnvelope.request.intent.name;
    const speechText = `You just triggered ${intentName}`;

    return handlerInput.responseBuilder
      .speak(speechText)
      //.reprompt('add a reprompt if you want to keep the session open for the user to respond')
      .getResponse();
  }
};

// Generic error handling to capture any syntax or routing errors. If you receive an error
// stating the request handler chain is not found, you have not implemented a handler for
// the intent being invoked or included it in the skill builder below.
const ErrorHandler = {
  canHandle() {
    return true;
  },
  handle(handlerInput, error) {
    console.log(`~~~~ Error handled: ${error.message}`);
    const speechText = `Sorry, I couldn't understand what you said. Please try again.`;

    return handlerInput.responseBuilder
      .speak(speechText)
      .reprompt(speechText)
      .getResponse();
  }
};

function getAQuestion() {

  var welcomeSpeechOutput = `Welcome to ${SKILL_NAME} <break time="0.3s" />`;
  const topic = prepareAQuestion();
  const tempOutput = WHISPER + ANSWER_THIS_MESSAGE + topic + PAUSE;
  const speechOutput = welcomeSpeechOutput + tempOutput;
  const more = ANSWER_THIS_MESSAGE;

  currentState = gameStates.waiting;

  var jsonObj = {
    speechText: speechOutput,
    reprompt: more,
    topic: topic
  };

  return jsonObj

}

function validateAnswerAndPrepareResponse(answer) {
  var responseText = '';
  var more = MORE_MESSAGE;
  var jsonObj;
  if (answer) {
    // If the answer given by the user falls in any of the possible answers then return true
    responseText += CORRECT_ANSWER_MESSAGE;
    responseText += MORE_MESSAGE;
    jsonObj = {
      speechText: responseText,
      reprompt: more
    };
  } else {
    responseText += ERROR_MESSAGE;
    jsonObj = {
      speechText: responseText
    };
  }
  currentState = gameStates.ended;
  return jsonObj
}

function saveCurrentStateWith(handlerInput) {

  const attributesManager = handlerInput.attributesManager;
  const sessionAttributes = attributesManager.getSessionAttributes();
  sessionAttributes.gameState = currentState;

}

function fetchCurrentSavedState(handlerInput) {
  const attributesManager = handlerInput.attributesManager;
  const sessionAttributes = attributesManager.getSessionAttributes();
  if (sessionAttributes.gameState) {
    currentState = sessionAttributes.gameState
    return currentState
  } else {
    sessionAttributes.gameState = currentState;
    return currentState
  }
}

function prepareAQuestion() {

  const randomQuestion = 'What is the answer of 9 + 9'
  return randomQuestion + PAUSE + randomQuestion

}

function stopAndExit() {

  const speechOutput = STOP_MESSAGE;
  currentState = gameStates.ended;
  var jsonObj = {
    speechText: speechOutput
  };
  return jsonObj;
}

function fallback(state) {
  var speechOutput = FALLBACK;
  var reprompt = FALLBACK_REPROMPT;
  if (state === gameStates.waiting) {
    speechOutput = FALLBACK_MESSAGE_DURING_GAME;
    reprompt = FALLBACK_REPROMPT_DURING_GAME;
  }
  var jsonObj = {
    speechText: speechOutput,
    reprompt: reprompt
  };
  return jsonObj;
}

function help() {

  const speechOutput = HELP_MESSAGE;
  const reprompt = HELP_REPROMPT;
  var jsonObj = {
    speechText: speechOutput,
    reprompt: reprompt
  };
  return jsonObj;
}

// This handler acts as the entry point for your skill, routing all request and response
// payloads to the handlers above. Make sure any new handlers or interceptors you've
// defined are included below. The order matters - they're processed top to bottom.
exports.handler = Alexa.SkillBuilders.custom()
  .addRequestHandlers(
    LaunchRequestHandler,
    GuessTheAnswerIntentHandler,
    SkipTheQuestionIntentHandler,
    AnswerIntentHandler,
    YesIntentHandler,
    NoIntentHandler,
    HelpIntentHandler,
    FallbackIntentHandler,
    HelpIntentHandler,
    CancelAndStopIntentHandler,
    SessionEndedRequestHandler,
    IntentReflectorHandler) // make sure IntentReflectorHandler is last so it doesn't override your custom intent handlers
  .addErrorHandlers(
    ErrorHandler)
  .lambda();