Learn Chai, Microsoft and Rust

In this course, Chris takes a README-driven approach to build out a Rust CLI that supports content authoring for a digital garden.

Specifically, you'll work through the first command for the CLI, writing files. You start by initializing a new Cargo binary crate through creating the `write` command that allows you to create files (and their contents) to the folder that you set. 

Step by step you'll learn about:
- Handling user input
- Error handling
- Rust Move semantics
- Rust Copy semantics
- Integration testing

...and more!

Rust is a systems programming language that runs blazingly fast, prevents segfaults, and guarantees thread safety.

rust

Creating a Digital Garden CLI with Rust

Rust is a modern language that is close to the metal. It's got the performance of C, but with a more friendly syntax and community.

It's also memory safe, and ensures your applications are bug free by catching errors at compile time instead of runtime.

These features make Rust a great choice for developing code for embedded systems, web servers, and CLI apps. You can even compile Rust into WebAssembly in order to run it in-browser!

But as the saying goes, "before you learn to run, you must learn to walk".

In this course, you will write your first Rust application.

Starting from “Hello World” you’ll quickly move on to learning about Rust’s types, configuration files, and the `cargo` package manager along with classics like functions, loops, and handling user input.

More Rust-specific concepts like macros and pattern matching will also be introduced.

Check out these [**community notes for this course on Github**](https://github.com/eggheadio-projects/write-your-first-program-with-the-rust-language).

Next Steps: [Basic Types in Rust](https://egghead.io/playlists/data-types-in-rust-ab72)

Write Your First Program with the Rust Language

[Rustlings](https://github.com/rust-lang/rustlings) is a set of exercises that serves as a great introduction to the Rust language. It covers many concepts from the [Rust book](https://doc.rust-lang.org/book/) by asking you to work through sets of exercises.

This collection walks you through Rustlings in a way that explains what's going on in each exercise. We cover everything from basic types to generics and threading.

Learning Rust by Working Through the Rustlings Exercises

This collection contains videos that explore the basic types in Rust, including **Fixed size Integer**, **Pointer sized Integer**, **Boolean**, **Strings**, **Characters**, **Arrays**, **Tuples** and more.

If you're just starting out learning Rust and [wrote your first program](https://egghead.io/courses/write-your-first-program-with-the-rust-language), this collection is the right place to get more familiar with the language!

Basic Types in Rust

Many languages work on a compilation story to WebAssembly, but Rust is already ready for primetime. Why?


- Rust is a stable language and great replacement for C and C++. 
- Due to the reference and borrowing concept, Rust doesn’t need a Garbage Collector and can be used for a production-ready WebAssembly project. 
- The Rust/Wasm team has built some sophisticated tooling for straightforward interoperability between Rust and JavaScript.

This course gives you the tools to compile to WebAssembly with Rust. Over 11 lessons, we’ll set up a project and explore various paths of communication and interoperability between Rust and JavaScript.

Using WebAssembly with Rust

Chai is a BDD / TDD assertion library for node and the browser that can be delightfully paired with any javascript testing framework.

chai

Every dependable library needs to have tests to ensure that you don't push accidental bugs. In this lesson, see how you can set up mocha and chai to start testing your library.

Setting up Unit Testing with Mocha and Chai

Now that you've got everything set up with mocha and chai, it's time to actually write tests. In this lesson you'll learn how to use `describe` and `it` to outline your tests and make sure you don't break your library in the future.

Unit Testing with Mocha and Chai

In this lesson, we will use Chai's request method to test our Node application's API responses.
By the end of this lesson, you will know how to:
- install the prerequisites to use mocha and chai in your application
- test for HTTP status response codes
- test for a string of text on a page
- test for a json response and validate the properties of the object
- write tests that not only verify the response of your application, but the behavior as well


Test Node RESTful API with Mocha and Chai

Mocha is a feature-rich JavaScript test framework running on Node.js and in the browser, making asynchronous testing simple and fun. Mocha tests run serially, allowing for flexible and accurate reporting, while mapping uncaught exceptions to the correct test cases.

mocha

Writing great ES6 style Promises for Node.js is only half the battle. Your great modules must include tests as well to ensure future iterations don't break them. In this lesson, I show you a simple ES6 Promise in Node.js, then walk you through creating tests in Mocha using chai and chai-as-promised to test both resolve and reject methods.

Testing ES6 Promises in Node.js using Mocha and Chai

In this lesson, you will learn how to verify your API server is returning HTTP 400 responses when clients submit incorrect data. Returning HTTP 400 ensures that your clients are notified of the incorrect usage. Testing for them ensures your API returns errors instead of incorrect responses when supplied with incorrect data.

Test for HTTP 400 responses with Mocha and Chai

Microsoft Windows is a group of several graphical operating system families, all of which are developed, marketed, and sold by Microsoft. Each family caters to a certain sector of the computing industry.

microsoft

For a production Windows server it makes sense to run NodeJS applications as a Windows service.  This way they can be automatically restarted if the server is rebooted.

It also makes it easier to use monitoring tools like datadog to detect if there are issues with the service which is critical for production systems.

Install a Node.js Application as a Windows Service

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

express

To replicate your production application its helpful when developing a local NodeJS Express application is running under SSL. 

There are some web technologies which do not play nicely with standard http and its likely to become more common e.g. Web Push Notifications.

This lesson will show you how to create a local SSL certificate for localhost and then convert it into a format that will work with Express.  It will also show you how to make sure that Chrome will trust it.

This lesson is for Windows as it uses a powershell command, as well as the Microsoft Management Console (MMC)
 

Create Local SSL Certificates for an Express App on Windows

In order to setup a project we need to install the nightly build of Rust and add the WebAssembly target. For an improved workflow we also install the CLI tools wasm-pack and wasm-gc.

Setup Rust for WebAssembly

In this lesson we are going to setup a project from scratch by introducing the JavaScript snippet to load a WebAssembly module. We demonstrate two different ways and showcase the benefit of the streaming solution. Once the module is loaded we can invoke a function previously exported from our Rust code.

Load a WebAssembly Function Written in Rust and Invoke it from JavaScript

In some cases it’s useful to be able to invoke a JavaScript function inside Rust. This session showcases how this can be done, by passing along our JavaScript functions to the WebAssembly module instantiation.

Pass a JavaScript Function to WebAssembly and Invoke it from Rust

webpack is a tool to build JavaScript modules in your application. To start using webpack from its cli or api, follow the Installation instructions. webpack simplifies your workflow by quickly constructing a dependency graph of your application and bundling them in the right order. webpack can be configured to customise optimisations to your code, to split vendor/css/js code for production, run a development server that hot-reloads your code without page refresh and many such cool features.

webpack

Interoperability between JavaScript and Rust is limited to numerics and accessing memory directly. Since this can be exhausting and overwhelming to do manually the Rust/Wasm team has created the wasm-bindgen project to facilitate high-level interactions between Rust and JavaScript.

Set up wasm-bindgen for easy Rust/JavaScript Interoperability

Having some kind of debugging tool in our belt is extremely useful before writing a lot of code. In this lesson we build a println!()-style syntax using JavaScript’s console.log to be able to log out values in Rust.

Debug a WebAssembly Module Written in Rust using console.log

While JavaScript has a garbage-collected heap, WebAssembly has a linear memory space. Nevertheless using a JavaScript ArrayBuffer, we can read and write to WebAssembly’s memory space.

Access WebAssembly Memory Directly from JavaScript

The goal of this course is to explain how to setup a project using JavaScript and WebAssembly with Rust.

We start out with building our first WebAssembly module and loading it. Then we gradually build up until to a point where we use wasm-bindgen to invoke functions and pass data between JavaScript and Rust without a hassel.

Further we explore various tools like wasm-pack to build our Rust code with ease and use them in combination with Node or Webpack.

Course Overview: Using WebAssembly with Rust

Node.js is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.

node

WebAssembly is great for targeting performance bottlenecks in the browser. Now with node-loader, we can do the same on the server through Node.js

While Node offers also bindings to native extensions for C/C++ via node-gyp, there was no straight forward way to write Rust extensions. In addition did the node-gyp API change often and developers had to be careful to make their C/C++ code work with various operating systems.

Compiling Rust to WebAssembly solves both of these issues. The API is stable and once compiled to WebAssembly it will run on every operating system supported by Node.

Since Node doesn't support loading `.wasm` files a loader is needed. The loader flag though is only supported when using the `--experimental-modules` flag in Node 10 or higher.

Run WebAssembly in Node.js using the node-loader

`wasm-pack` is a tool that seeks to be a one-stop shop for building and working with Rust generated WebAssembly that you would like to interop with JavaScript. This includes ability to publish modules so that you can share your Rust generated WebAssembly code with others. 

In this lesson we create a npm package and export a Rust function that will log to the console in the browser. We publish the module to NPM and afterwards use a `rust-webpack-template` to install and use the newly published package.