LEX SDK

Overview

With LEX SDK for Node.js (TypeScript), you can create Amazon Lex code in the same way as Alexa SDK V2.

Version

0.1.2

Install

npm install --save lex-sdk

Importing Dependencies

JavaScript

const Lex = require('lex-sdk');

TypeScript

import * as Lex from 'lex-sdk';

Adding Request Handlers

The following code example shows how to configure a handler to be invoked when the skill receives the OrderFlowers(Intent).

JavaScript

const OrderIntentHandler = {
    canHandle(h) {
        return (h.intentName == 'OrderFlowers')
    },
    handle(h) {
        
        if (h.source === Lex.InvocationSource.DialogCodeHook) {
            
            return h.responseBuilder
                .getDelegateResponse(h.attributes, h.slots)
 
        } else {  // FulfillmentCodeHook
 
            const message =  {
                 contentType: Lex.ContentType.PlainText,
                 content: `Thank you for your order.` };
 
            return h.responseBuilder
            .getCloseResponse(
                h.attributes,
                Lex.FulfillmentState.Fulfilled,
                message)
        }
    }
}
 

TypeScript

const OrderIntentHandler: Lex.RequestHandler = {
    canHandle(h: Lex.HandlerInput) {
        return (h.intentName == 'OrderFlowers')
    },
    handle(h: Lex.HandlerInput) {
        
        if (h.source === Lex.InvocationSource.DialogCodeHook) {
            
            return h.responseBuilder
                .getDelegateResponse(h.attributes, h.slots)
 
        } else {  // FulfillmentCodeHook
 
            const message =  { 
                contentType: Lex.ContentType.PlainText,
                content: `Thank you for your order.` };
 
            return h.responseBuilder
            .getCloseResponse(
                h.attributes,
                Lex.FulfillmentState.Fulfilled,
                message)
        }
    }
}

Adding Error Handler

The error handler is suitable for injecting unprocessed requests, error handling logic. In the next sample, the bot will return an error message if all errors occur.

JavaScript

const ErrorHandler = {
    canHandle(h, error) {
        return true;
    },
    handle(h, error) {
        const message =  {
            contentType: Lex.ContentType.PlainText,
            content: "ERROR " + error.message };
        return h.responseBuilder
        .getCloseResponse(
            h.attributes,
            Lex.FulfillmentState.Fulfilled,
            message)
    }
}

TypeScript

const ErrorHandler = {
    canHandle(_h: Lex.HandlerInput, _error: Error) {
        return true;
    },
    handle(h: Lex.HandlerInput, error: Error) {
        const message =  {
            contentType: Lex.ContentType.PlainText, 
            content: "ERROR " + error.message };
        return h.responseBuilder
        .getCloseResponse(
            h.attributes,
            Lex.FulfillmentState.Fulfilled,
            message)
    }
}

Creating the Lambda Handler

The entry point of the Lambda function.

The following code example is an example of processing requests to all Lambda with SDK.

JavaScript

let bot;
exports.handler = async function (event, context) {
    if (!bot) {
        bot = Lex.BotBuilder()
            .addRequestHandlers(
                OrderIntentHandler)
            .addErrorHandler(ErrorHandler)
            .create();
    }
    return bot.invoke(event, context);
}

TypeScript

let bot: Lex.Bot;
exports.handler = async function (event: Lex.IntentRequest, context: any) {
    if (!bot) {
        bot = Lex.BotBuilder()
            .addRequestHandlers(
                OrderIntentHandler)
            .addErrorHandler(ErrorHandler)
            .create();
    }
    return bot.invoke(event, context);
}