Learn Http, Mocha and Serverless

Starting from a prebuilt frontend, Jason Lengstorf guides you through the creation of a "Corgi Up-boop App" that uses Netlify Functions and Hasura. You can view [the deployed final product on Netlify](https://egghead-serverless-functions.netlify.app/).

You'll set up the Netlify CLI, and configure a local development environment before writing and deploying functions with a few different use cases.

The first example function bypasses CORS restrictions to retrieve corgi data from an example third-party API.

Next, you'll configure environmental variables to securely communicate with the Unsplash API without exposing private keys to the client.

Serverless functions don't persist data by themselves, so we will use  Hasura to create a GraphQL API for tracking the number of "boops" each corgi receives.

This course is an excellent illustration of the speed of Serverless functions, and how fast you can implement functionality in your web applications.

An all-in-one workflow that combines global deployment, continuous integration, and automatic HTTPS.

netlify

Build a Corgi Up-boop Web App with Netlify Serverless Functions and Hasura

In this course, we will learn the fundamentals of the Hypertext Transport Protocol (HTTP) by exploring several popular HTTP APIs such as the GitHub API. Starting with the basic structure of an HTTP request and response, we will then delve into the specifics of each element of the request/response messages. Using concrete examples from these APIs, we will cover request methods, response status codes, messages headers, and message bodies. Along the way, you'll learn about specific message headers, such as `Cache-Control`, and `Cookie`  and how they control the behavior of clients/browsers and HTTP API services.

This course uses HTTPie, if you would like to follow along with the instructor you can download the client [here](https://httpie.org/).

The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypermedia information systems. It is a generic, stateless, protocol which can be used for many tasks beyond its use for hypertext, such as name servers and distributed object management systems, through extension of its request methods, error codes and headers.

http

Understand the Basics of HTTP

Create a serverless application and deploy it in under thirty minutes!

We'll be using Netlify, Vite, TypeScript, and React in our project. This stack synergizes extremely well for rapidly developing professional-quality applications. 

If you haven't heard of Vite, it's the French word for quick! It's also a build tool that consists of a dev-server and an extremely fast bundler. It makes for a rapid development loop.

As for the rest. Netlify makes hosting fast and easy with serverless functions and continuous deployment. React enables you to quickly create reusable components. And TypeScript helps you write cleaner code that is easier to refactor. 

So get started and learn how to use this stack in your own applications!

Create a TypeScript powered serverless React application

As developers, we're often working closely with APIs to make requests in the browser or on the backend with a server, but we might not always know exactly how those requests work or how they should look.

Postman is a tool that lets us create, manage, and test API endpoints all within a UI so we can wrangle our APIs and understand how they work.

Create, Manage, and Test API Requests with Postman

The HTTP GET & HEAD methods are used to retrieve information about a resource. The GET method will retrieve the metadata about the resource, encoded in the HTTP headers, as well as a representation of the resource itself in the message body (e.g. a JSON document with fields that describe a user). The HEAD method behaves like GET, but only retrieves the status and headers; this can be useful when you need some metadata about a resource (e.g. the Last-Modification time), but don't want to waste time or bandwidth fetch the resource itself in the message body. Finally, we discuss the idempotent and safe natures of these HTTP methods.

Use HTTP GET & HEAD Methods

The 2xx family of status codes are used in HTTP responses to indicate success. Beyond the generic `200 OK` status code, there are a set of more specific success status codes that provide additional context or details about the specific nature of the successful request/response. We will explore the available success status codes, and what additional information they convey.

Understand 2xx HTTP Status Code Responses

The body of an HTTP request or response can serve many functions, from including the input data to a POST request, to returning varied representations of a resource in response to a GET request. This lesson details how message bodies are handled in requests and responses, and the associated HTTP headers that provide metadata about the included message body.

Examine HTTP Message Bodies

The HTTP DELETE method is used to request that the server perform a delete operation on the specified resource with resource specific semantics. Behind the scenes, the delete operation may result in a removal of a file from the filesystem, or an update to the database to reflect the change. Because multiple requests to delete the same resource has the same effect as a single one, the DELETE method is considered ‘idempotent’, but not considered safe.

Use HTTP DELETE Method

The HTTP OPTIONS method is used to request information about the communication options available for the target resource. The response may include an Allow header indicating allowed HTTP methods on the resource, or various Cross Origin Resource Sharing headers. The HTTP OPTIONS method is both safe and idempotent, as it is intended only for use in querying information about ways to interact with a resource.

Use HTTP OPTIONS Method

The HTTP PATCH method is used to make modifications to existing resources. In particular, it is designed for "partial updates", as opposed to replacing an entire resource using the HTTP PUT method. Although certain HTTP PATCH requests may behave idempotently, this is not true of all possible PATCH requests, so this request method is not idempotent, nor considered safe. The request body of a PATCH request may be simple `application/json`, or a more specialized type, such as `application/json-patch+json`.

Use HTTP PATCH Method

The HTTP POST method is used to request the resource process the included request message body representation according to resource specific semantics. HTTP POST is loosely defined by definition, and can be used in many different scenarios, such as creating a new resource based on the request representation, appending data to an existing representation, or generic processing of an HTML form submission. Due to the nature of POST performing arbitrary resource specific processing, it is considered neither ‘safe’, nor ‘idempotent’.

Use HTTP POST Method

The 4xx family of status codes are used in HTTP responses to inform the client/browser of an error relating to the user’s request. The status codes in this family are intended to indicate a problem that should be possible to fix or remedy by the user or developer. For example, a 401 Unauthorized status code lets the user/developer know they need to provide authorization information with their request; should they re-submit the request with the additional authorization header, the request may succeed. We will explore the available client error status codes, and what additional information they convey.

Understand HTTP 4xx Client Error Response Codes

The 5xx family of status codes are used in HTTP responses to inform the client that the server experienced an error. The status codes in this family are intended to indicate server or network errors that do not pertaining to a problem with client or the client’s request. For example, a response with a 503 Service Unavailable status code is unlikely to be resolved by resubmitting the request with different content type or additional headers. We will explore the available server error status codes, and what additional information they convey.

Understand 5xx Server Error Response Codes

Previously to tackle manual restarts due to server crashes , process management tools were used. 

Forever is one such module that is runs on the node ecosystem. So, we need not move away from the rich ecosystem of Node.js.

Use ``` npm install --global forever ``` to install forever module globally.
 

Running your server forever using forever in Node.js

Understand the three basic parts of making HTTP requests in Elm: 1) Building the request, 2) Writing a JSON decoder, 3) Sending the request using the Elm runtime, and reacting to the results with messages.

HTTP requests are just pieces of data in Elm. When we want to send them, we hand them off to Elm's runtime, and it notifies us when the request is done. An important part of working with HTTP requests that fetch JSON is JSON decoding, the process by which we can turn untyped JSON data into Elm types that are safe to work with.

Specs:

- Editor: Atom
- Theme: [Nebula (with Nebula syntax theme)](https://atom.io/themes/nebula-ui)
- Font: [Iosevka with ligatures enabled](https://github.com/be5invis/Iosevka)
- Plugin used for imports: [Elmjutsu](https://atom.io/packages/elmjutsu)
- Plugin used for formatting: [Elm-format](https://atom.io/packages/elm-format)
- Plugin used for linting: [linter-elm-make](https://atom.io/packages/linter-elm-make)


Make an HTTP Request in Elm

The 3xx family of status codes are used in HTTP responses to inform the client/browser should look somewhere else for the requested resource. Most often, this is used to indicate a resource is temporarily or permanently found at a new URL, but it may also be used to inform the client that the client’s own cache is the other location where the requested resource can be found. We will explore the available redirection status codes, and what additional information they convey.

Understand HTTP 3xx Redirection Response Codes

Let's look at several HTTP requests to learn the basic structure of these messages, and how the various elements communicate important information from the client/browser to the API service. 
Follow the instructions at [HTTPie](https://httpie.org/) to download the CLI tool and follow along.

Understand what an HTTP Request is

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

Let's look at several HTTP responses to learn the basic structure of these messages, and how the various elements communicate important information from the API service to the client/browser.

Understand what an HTTP Response is

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

Mocha is a testing framework that provides structure for unit tests. In this lesson, we will be setting up Mocha with npm and npm scripts, writing a "Hello World" unit test, then writing the code to make the test pass (as an example of Test Driven Development (TDD), with the "red-green-refactor" workflow).