AWS Lex Helpers

AWS Lex helper classes and functions to build responses

Response Types

• ElicitSlot - Informs Amazon Lex that the user is expected to provide a slot value in the response
• ElicitIntent - Informs Amazon Lex that the user is expected to respond with an utterance that includes an intent
• ConfirmIntent - Informs Amazon Lex that the user is expected to give a yes or no answer to confirm or deny the current intent
• Close - Informs Amazon Lex not to expect a response from the user
• Delegate - Directs Amazon Lex to choose the next course of action based on the bot configuration

View more details on Lex Documentation

Response Message Components

• PlainTextMessage
• ResponseCard
  • ResponseCardAttachment
    • AttachmentButton

Lambda Function Response Structure

Your lambda functions need to response in the following format

{
    "sessionAttributes": {
    "key1": "value1",
    "key2": "value2"
    ...
  },
  "dialogAction": {
    "type": "ElicitIntent, ElicitSlot, ConfirmIntent, Delegate, or Close",
    Full structure based on the type field. See below for details.
  }
}

Using this module, you can easily generate the above response like below.

1. Generate the dialog action content using message components (ResponseCard,ResponseCardAttachment,AttachmentButton,PlainTextMessage)
2. Generate the lambda response using the message component generated in step 1

Usage

Installation

npm install aws-lex-helpers --save

Initialization

const AWSLexHelpers = require('aws-lex-helpers');
 
// Response generator
const Responses = AWSLexHelpers.Responses;
 
 
// Message components
const {ResponseCard,ResponseCardAttachment,AttachmentButton,PlainTextMessage,Constants} = AWSLexHelpers;
 

Plain Text Message

let plainTextMessage = new PlainTextMessage()
                .setMessage('hey there this is a plain text message')
                .build();

Response Card

let firstAttachmentButton = new AttachmentButton()
        .setText('First Button')
        .setValue('first button')
        .build();
 
let secondAttachmentButton = new AttachmentButton()
        .setText('Second Button')
        .setValue('second button')
        .build();
 
let responseCardAttachment = new ResponseCardAttachment()
        .setTitle('Attachment Title')
        .setSubTitle('Attachment subtitle')
        .setImageUrl('<IMAGE_URL>') // Hosted url of the image
        .setAttachmentLinkUrl('<LINK_URL>') // URL to be opened once click on the image
        .setButtons([firstAttachmentButton, secondAttachmentButton])
        .build();
        
let responseCard = new ResponseCard()
        .setGenericAttachments([responseCardAttachment]) // Response card attachments can be provided as an array
        .build();

Generating lambda response

let sessionAttributes = {YOUR_SESSION_ATTRIBUTES};
let intentName = 'YOUR_INTENT_NAME';
let slots = {YOUR_SLOTS};

Elicit Slot

let slotToElicit = {YOUR_SLOTS_TO_ELICIT};
 
let response = Responses.elicitSlot(sessionAttributes, intentName, slots, slotToElicit, plainTextMessage,responseCard);

Elicit Intent

let response = Responses.elicitIntent(sessionAttributes, plainTextMessage, responseCard);

Confirm Intent

let response = Responses.confirmIntent(sessionAttributes, intentName, slots, plainTextMessage,responseCard);

Close Intent

let fulfillmentState = Constants.FULFILMENT_STATES.FULFILLED; // or FAILED
 
let response = Responses.close(sessionAttributes, fulfillmentState, plainTextMessage, responseCard);

Delegate Intent

let response = Responses.delegate(sessionAttributes, slots);

Return the response above from your lambda function

Additional Resources

Constants

• FULFILMENT_STATES

  • FULFILLED
  • FAILED

• INVOCATION_SOURCE

  • DIALOG_CODE_HOOK
  • FULFILMENT_CODE_HOOK