Learn Express, Puppeteer and Svelte

As developers, we have a responsibility to protect the data our users trust us with. No one wants to wake up to the news that their site was hacked and all of the user accounts stolen.

Security is important, yet it is often overlooked and forgotten.

Part of the reason for this is that security seems hard to get right. This results in developers crossing their fingers and hoping for the best.

In this course, you'll learn how to protect your application by learning how to attack it.

Start your journey into web security today!

Check out these [**community notes for this course on Github**](https://github.com/wjohnson85/eggheadio-web-security-essentails).

Express is a minimal and flexible Node.js web application framework that provides a robust set of features for web and mobile applications.

express

Web Security Essentials: MITM, CSRF, and XSS

OpenGraph images are the images you see when you paste a link into a social platform and it "unfurls" into an image, title, and description. This happens on Twitter, Discord, Slack, and many other platforms. This collection goes over everything from designing OpenGraph images in Figma, to implementing them in CodeSandbox, to returning headless browser screenshots from Netlify Functions, and finally using Cloudinary as a write-through cache. 

You will come away from this collection with the ability to ship an API that you can use on any of your sites, and also on-demand, that can generate images for not only OpenGraph unfurls, but also for Instagram, GitHub, and more. Using headless browsers with playwright to generate our images means we get full access to all the responsive power of CSS and all the logical power of JS to handle layout, importing assets like pngs, choosing different fonts, and more.

The image below is generated via the project you'll build and deploy in this course

![An example opengraph image](https://relaxed-payne-d1bfbe.netlify.com/opengraph?title=Building%20an%20OpenGraph%20image%20generation%20API%20with%20Cloudinary%20Netlify%20Functions%20and%20React&tags=figma,netlify%20functions,playwright&author=chrisbiscardi)

React is one of the web’s most popular frameworks for building JavaScript applications. 

If you know what you’re doing, React can drastically simplify how you build, use, and maintain code.

Whether you’re a React newbie or you’re ready for advanced techniques, you can level-up with egghead. Explore our in-depth courses, lessons, and community resources to build more powerful applications and crack open your career.

react

Building an OpenGraph image generation API with Cloudinary, Netlify Functions, and React

Express is a well-known and supported framework for Node web applications. It provides a lot of excellent functionality to process requests, interact with other APIs, handle authentication and return appropriate requests for any client.

This collection will look at providing an API for a specific application but will explore concepts that will be helpful in building a wide variety of applications.

Building an API with Express

JavaScript community has been shaken recently by a release of Svelte 3 and for a good reason - it's a completely different approach than React or Vue. To quote the docs:

"[Svelte](https://svelte.dev/) is a radical new approach to building user interfaces. Whereas traditional frameworks like React and Vue do the bulk of their work in the browser, Svelte shifts that work into a compile step that happens when you build your app."

**The best part?** If you have 26 spare minutes you can learn the basics of Svelte 3 and start building your own apps with it!

Enjoy!



The magical disappearing UI framework

 - The web's JavaScript bloat crisis, solved. Svelte turns your templates into tiny, framework-less vanilla JavaScript.
 - Simple and familiar. Build apps out of composable, easy-to-write blocks using languages you already know.
 - Super fast, rock solid. Compile-time static analysis ensures the browser does no more work than it needs to.

svelte

Up and running with Svelte 3

Modern applications know how to keep users informed of realtime updates through notifications, popups, and other messages.

On the development side, the ability to not only create web apps but have them communicate in realtime is a quirky, standout skill for your resume. It’s interesting, useful, and powerful.

In this course, Mark Barton will show you how to use Socket.io to facilitate bi-directional client-server communication and notifications using Vue on the frontend. Socket.io is a JS library that connects a client-side library to a node.js server. In the course, you’ll see how to use Socket.io to broadcast simultaneously to all or targeted clients based on filters you set up — so the right people see the right message at the right time.

You’ll learn to set up and connect Socket.io with node.js and Vue, and you’ll get practice making informed, complex architectural decisions around realtime broadcast messaging.

Vue (pronounced /vjuː/, like view) is a progressive framework for building user interfaces. Unlike other monolithic frameworks, Vue is designed from the ground up to be incrementally adoptable. The core library is focused on the view layer only, and is very easy to pick up and integrate with other libraries or existing projects. On the other hand, Vue is also perfectly capable of powering sophisticated Single-Page Applications when used in combination with modern tooling and supporting libraries.

Vue and Socket.io for Real-Time Communication

Learn how to build a simple REST API to store notes using the latest built-in node features including native ES modules, the fs/promises API, async/await, the nullish coalescing operator, and destructuring. No compilers, no build steps, pure code.

This collection of lessons is great for beginners to Express as long as they are familiar with JavaScript and the HTTP protocol. Those more familiar with node and express will appreciate a fast-paced, modern take on using these popular tools and will likely benefit most from the lessons on input validation, models (which emphasizes a lot of new syntax), using fs/promises to serialize a `Map`, and accessing asynchronous data with `async/await`.

Pre-requisites:

- [Install curl](https://curl.haxx.se/)
- [Install node 14](http://nodejs.org/)
- Be familiar with the terminal

View the source for this project in the [project's github repo](https://github.com/xjamundx/egghead-express).

**Notes**:

- I'm not very pedantic about REST and basically just mean an API over HTTP
- [Express 5](https://expressjs.com/en/guide/migrating-5.html) is still in alpha (and has been for over two years), but most of these lessons apply to Express 4 as long you use something like [express-async-errors](https://www.npmjs.com/package/express-async-errors) to add support for `async` routes and middleware

Build a REST API with Express 5 and node 14

While this course is for IBM Domino Developers who are looking to utilize Node.js alongside their applications, or Javascript developers looking to integrate with a Domino server. There are quite a few tips and tricks you can learn for integrating Node.js as a proxy server for any REST API you might want to communicate with your JavaScript Application.

We cover how you can continue to use cookies provided by IBM Domino for user authentication and authorization while accessing a Node.js / Express based application, including modifying the standard login form to expose authentication errors.  

We show how to store user level information inside a JWT giving the option to store functional levels of access safely.  This stateless token can then be decoded server side to list what user roles a user has and therefore can restrict functionality without having to refer back to Domino each time.

The course will demonstrate Create, Read, Update and Delete methods using the Domino Data Services all via the NodeJS application but still maintaining Domino security.

And finally, we show how you can reuse Domino generated HTML inside a handlebars template by scraping and manipulating the HTML.

Integrate IBM Domino with Node.js

End-to-end testing assures you of a few things: that all the integrated pieces of an application properly function, all those pieces work together as expected, and your tests include and simulate real-user scenarios — something unit and integration tests just don't do.

This course introduces you to two great tools for E2E testing: 

* Puppeteer opens and runs applications in a Chromium browser and performs the actions it's given.
* Jest asserts that the integrated pieces work as expected and that add-on libraries like Faker and pixelmatch take our tests to the next level.

Over 9 lessons, we will create common application features and use Puppeteer and Jest to run different types of tests against them. You'll get practice using these tools to render content, mimic user activity, automate tests, and measure the overall performance of your application.

jest

End to End Testing with Google's Puppeteer and Jest

JSON Web Token (JWT) is a low overhead option for authentication that is easy to implement and scales with your application. There is no need to store session data as everything you need is stored in an encoded string sent in the JWT, significantly reducing database overhead for your servers.

In this course, we will build a simple authentication server that will act as a token issuer, and we will use those tokens to access resources on an API.  Starting from scratch, you will learn how easy token based authentication can be and will understand how to use them on your APIs as well as on the front end of your web applications.

JSON Web Token (JWT) Authentication with Node.js and Auth0

JavaScript® (often shortened to JS) is a lightweight, interpreted, object-oriented language with first-class functions, most known as the scripting language for Web pages, but used in many non-browser environments as well such as node.js or Apache CouchDB. It is a prototype-based, multi-paradigm scripting language that is dynamic, and supports object-oriented, imperative, and functional programming styles.

javascript

Nodejs

Express is a minimal web server built on Node.js that provides essential functionality for delivering web applications to the browser and mobile devices. This series will guide you through the first steps of using Express for building your own applications.

Getting Started with Express.js

Creating forms is one of the simplest and most complicated things at the same time. A basic form consists of many different things happening, we have to retain the value, we have to keep watch of validation and we have to show error messages when something is invalid, this is on both the fields and on the entire form itself if we send a request off to the backend service.

So we're going to create a form using just the normal svelte features. Then we'll look into creating a form using the svelte forms lib. 

Create forms in Svelte with Svelte Forms Lib

In this lesson we create a very simple web page to connect to our socket Server.

Once a client connects, it is assigned a unique random identifier as its socket ID and we will log this out to the Server console.

We will send out a random number on the socket every second and demonstrate multiple clients receiving this value at the same time.



Set up a simple Socket.io client to connect to the server.

Using a HTTP POST to trigger a message which is broadcast to all connected clients via Socket.io.  The message is displayed within a Vue component, which in this case is a [Vuetify snackbar](https://vuetifyjs.com/en/components/snackbars) component. 

As part of the lesson we demonstrate transmitting an object so we can dynamically change the snackbar color, as well as the message itself.

An example where this approach might be used is where you want a server monitoring system call a web hook on your server when there is an issue, this in turn pushes a message to connected clients, simultaneously and in real time.

Display a broadcast message using a Vuetify snackbar component which is sent via Socket.io

**Note:** If you want to understand and follow along with the logging service Mark uses, watch this lesson: [NodeJS Logging using Winston and Papertrail](https://egghead.io/lessons/javascript-nodejs-logging-using-winston-and-papertrail)

In this lesson we will get an Express Server up and running with Socket.io.  We will build the Socket.io logic in a seperate file to demonstrate how the Socket.io instance can be used within other parts of the Express Application.

This lesson is short and sweet and lays the groundwork for the other lessons in this course. 

If you get an error starting the server which indicates a Papertrail connection error then you have not updated the Papertrail host and port in the logger.js.

You can safely ignore this error if you do not wish to use Papertrail - else you can sign up to a free Papertrail account and add the correct host and port.

Getting started with Express and Socket.io

Svelte is a new approach to building user interfaces. 

Instead of doing the vast majority of work at the runtime as other frameworks do, Svelte shifts that work into the _compile_ step which happens when you build your app. As such, you're shipping heavily optimized code to your users.

In this quick lesson we are going to learn how to create a brand new project with Svelte 3 from scratch.

Create a new project with Svelte 3

In most Web applications we want to be able to render different HTML markup depending on values passed in from JavaScript code.

In this lesson we are going to learn how to render JavaScript variable in HTML markup when using Svelte 3.

Add data to HTML markup using Svelte 3

In Svelte 3, the same as in regular HTML we can add CSS styles to a component and this is what we're going to learn in this lesson.

Important note - styles are _scoped to the component_ which means that if we style a `h1` tag in component A, it won't automatically affect `h1` tags in component B.

Add styles to Svelte 3 component

It's highly unlikely that we'd like to have an entire app in a single file. Instead, what we'd like to do is to spread our code across multiple components and render them in one another.

In this lesson we are going to learn how to create a `<Surname />` Svelte 3 component which we're going to use in our main `App.svelte` file to display a user's surname.

Create a new Svelte 3 component to render it inside of another component

One of the key advantages of having a component system is the ability to render the component differently based on what kind of properties (shortened to 'props' in Svelte) were passed in to the component.

In this lesson we are going to learn how to declare properties inside of a Svelte component and how to pass in data to be rendered inside of a `<UserInfo />` component. We're also going to learn how to use default props which are used if a value for a property was not passed in.

Declare and pass in properties to a Svelte 3 component

Svelte automatically updates the DOM when your component's state changes. Often, some parts of a component's state need to be computed from other parts. This is where _reactive declarations_ come in.

In this lesson we are going to learn how to use reactive declarations to re-compute (and render) square of a counter value in a simple counter example whenever user clicks on a button.

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