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Getting Started with Building Chatbots using AWS Lex and Node.js

Amazon and a lot of cloud vendors such as Microsoft and Google have services around machine learning (ML), artificial intelligence (AI), and virtual assistants. A popular one that might come to mind is Amazon Alexa, something I’ve written quite a few tutorials around over the years.

The concept around Alexa is simple. Provide the Alexa service some audio, have that audio converted into text or some other format that can be evaluated, execute some code, and respond with something to be spoken to the user. However, what if you didn’t necessarily want to use a virtual assistant with audio, but integrate as part of a chat application in the form of a chatbot?

In this tutorial we’re going to look at using Amazon Web Services (AWS) Lex, which is a service for adding conversational interfaces to your applications. If you’re coming from an Amazon Alexa background, the concepts will be similar as AWS Lex shares the same deep learning technologies.

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Password Hashing and JWTs for NativeScript Apps with an Express.js Backend

When building an application that allows users to have accounts, you have to ensure that access to these accounts is secure. When building a user account system, an important factor to keep in mind is how passwords are stored. Storing passwords as plain text is a complete rookie move that leaves your users vulnerable to all sorts of data breaches.

The best way to protect passwords is to employ hashing and salting and in this tutorial, we’ll show you exactly how to do this. We’ll also show you how to generate JSON Web Tokens (JWT) on a Node.js server backend that can be used to authenticate and authorize users, as well as how to store those tokens on the client NativeScript application.

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Building a Simple Web Application in Dart

Dart is a programming language developed by Google and made popular by Flutter, their mobile development framework for cross-platform application development.

The Dart language is a general-purpose language, built to be used for far more than just mobile development, and, in this short tutorial, I will show you how to build a basic web application, using Dart.

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Using Socket.io to Create a Multiplayer Game with Angular and Node.js

When it comes to client and server communication, there are quite a few approaches towards solving the problem. You could create a RESTful API or GraphQL API on your server and consume it on-demand with your client, or you can go the socket approach and interact in real-time through events. There isn’t a wrong way to do things, but some ways are better than others given the task at hand.

Let’s take for example gaming and online multiplayer games. While certain aspects of the game would make sense to use REST or GraphQL, not everything would feel responsive enough. Instead it makes sense to use sockets.

In this tutorial we’re going to explore Socket.io for our client and server communication. We’re going to create a Socket.io server with Node.js and that server will communicate with each of our games running as Angular applications.

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Service Workers With Workbox In A Hugo Static Generated Site

As you know, The Polyglot Developer is a static generated website that is built with Hugo. Given the nature of static generated websites, they are generally much faster than the CMS alternatives, but just because they’re fast, doesn’t mean they pass all of Google’s tests by default.

In an ongoing effort to try to satisfy Google PageSpeed Insights and Lighthouse when it comes to search engine optimization (SEO) and other best practices, I was lead to the progressive web application (PWA) test. There are many factors that determine if something is a PWA, but one of those resides in the use of service workers. In case you’re unfamiliar, service workers accomplish many things, with the most common of those things being caching.

Implementing service workers in an application is not necessarily the most complicated task, but as your applications evolve, things might become more chaotic. This is where Workbox comes in. With Workbox, you can use very clean APIs to pre-cache your static site resources as well as cache resources at runtime. We’re going to see how to use Workbox to implement service workers for caching Hugo content and other resources such as images, fonts, and scripts.

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Track Element Viewability With JavaScript Or Google Tag Manager

As you might know, sponsored advertisements are one of the things that are funding The Polyglot Developer and everything it accomplishes, so keeping sponsors happy and supplying them the metrics they need is very important. However, in most circumstances, more specifically when it comes to banner creatives, page views is not enough. For example if your sponsors or potential sponsors asked how many impressions each of your advertisement zones gets, you can’t just list off the page views that those particular pages get because how do you know if the user actually saw the advertisement?

I’ve heard a few names when it comes to element impressions. Some call it element or image visibility, and some call it viewability. It doesn’t really matter as they are both trying to determine if the user has actually seen the image or element on their screen.

In this tutorial we’re going to take a look at tracking if users have seen a particular image or set of images using simple JavaScript as well as an alternative method that links directly with Google Analytics (GA) called Google Tag Manager (GTM).

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Two-Factor Authentication With TOTP Using Node.js And Speakeasy

Almost two years ago I had written a tutorial around 2FA in a Node.js API with time-based one-time passwords. If you’re unfamiliar, two-factor authentication is becoming the norm, which it wasn’t necessarily back in 2017. If you’re managing user accounts in your web applications, it is critical that you offer your users a second factor of authentication to prevent phishing and malicious login attempts.

While the previous tutorial is still valid, it uses a less popular library to accomplish the task. This time around we’re going to explore using a more popular library called Speakeasy to manage two-factor authentication (2FA) within our Node.js with Express.js application.

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