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# `elixir-auth-github`

The _easiest_ way to add GitHub OAuth authentication
to your Elixir/Phoenix Apps.

[![Build Status](](
[![contributions welcome](](


# _Why_? 🤷

We needed a **_much_ simpler**
and **_extensively_ documented** way
to add "_**Sign-in** with **GitHub**_"
capability to our Elixir App(s). <br />

> We created this package
because everyone [@dwyl](
uses GitHub so using GitHub OAuth makes sense
for our internal (and external) tools.
By making it into a well-documented and tested
reusable module other people can benefit from it.

# _What_? 💭

An Elixir package that seamlessly handles
GitHub OAuth Authentication/Authorization
in as few steps as possible. <br />
Following best practices for security & privacy
and avoiding complexity
by having sensible defaults for all settings.

# _Who_? 👥

This module is for people building apps using Elixir/Phoenix
who want to ship the "Sign-in with GitHub" feature _faster_
and more maintainably.

It's targeted at _complete_ beginners
with no prior experience/knowledge
of auth "schemes" or "strategies". <br />
Just follow the detailed instructions
and you'll be up and running in 5 minutes.

# _How_? 💻

Add GitHub Auth to your Elixir/Phoenix project
by following these 5 simple steps:

> If you get stuck setting up your App,
checkout our working demo: <br />
> The demo is deployed on Heroku:

## 1. Add the hex package to `deps` 📦

Open your project's **`mix.exs`** file
and locate the **`deps`** (dependencies) section. <br />
Add a line for **`:elixir_auth_github`** in the **`deps`** list:

def deps do
    {:elixir_auth_github, "~> 1.0.3"}

Once you have added the line to your **`mix.exs`**,
remember to run the **`mix deps.get`** command
in your terminal
to _download_ the dependencies.

## 2. Create a GitHub App and OAuth2 Credentials 🆕

Create a GitHub Application if you don't already have one,
generate the OAuth2 Credentials for the application
and save the credentials as environment variables
accessible by your app.

> **Note**: There are a few steps
for creating a set of GitHub APIs credentials,
so if you don't already have a GitHub App,
we created the following step-by-step guide
to make it quick and _relatively_ painless:
[]( <br />
Don't be intimidated by all the buzz-words;
it's quite straightforward.
And if you get stuck,
[ask for help!](

By the end of this step
you should have these two environment variables set:


> ⚠️ Don't worry, these keys aren't valid
(_they were revoked **`before`** we published this guide_). <br />
They are just here for illustration purposes.

> 💡 Tip: We tend to use an
file to manage our environment variables on our `localhost`
and then use whichever system for environment variables appropriate
for our deployment.
e.g: [Heroku](
For an example `.env` file with the environment variables
required by `elixir-auth-github` see:

## 3. Create 2 New Files  ➕

Create two files in order to handle the requests
to the GitHub OAuth API and display data to people using your app.

### 3.1 Create a `GithubAuthController` in your Project

In order to process and _display_ the data
returned by the GitHub OAuth2 API,
we need to create a new `controller`.

Create a new file called

Add the folowing code to the file:

defmodule AppWeb.GithubAuthController do
  use AppWeb, :controller

  @doc """
  `index/2` handles the callback from GitHub Auth API redirect.
  def index(conn, %{"code" => code}) do
    {:ok, profile} = ElixirAuthGithub.github_auth(code)
    |> put_view(AppWeb.PageView)
    |> render(:welcome, profile: profile)
This function is invoked as the _callback_
when the person has successfully authenticated with GitHub.

The code does 2 things:
+ Request the person's profile data from GitHub
based on the `code` sent by GitHub's callback request.
+ Renders a `:welcome` view displaying some profile data
to confirm that login with GitHub was successful.

> **Note**: we are placing the `welcome.html.eex` template
in the `template/page` directory to save having to create
any more directories and view files.
You are free to organise your code however you prefer. 👍

### 3.2 Create `welcome` template 📝

Create a new file with the following path:

And type (_or paste_) the following code in it:
<section class="phx-hero">
  <h1> Welcome <%= %>!
  <img width="32px" src="<%= @profile.avatar_url %>" />
  <p> You are <strong>signed in</strong>
    with your <strong>GitHub Account</strong> <br />
    <strong style="color:teal;"><%= %></strong>

Invoking `ElixirAuthGithub.github_auth(code)`
in the `GithubAuthController`
`index` function will
make an HTTP request to the GitHub Auth API
and will return `{:ok, profile}`
where the `profile`
is the following format:

  site_admin: false,
  disk_usage: 265154,
  access_token: "8eeb143935d1a505692aaef856db9b4da8245f3c",
  private_gists: 0,
  followers_url: "",
  public_repos: 291,
  gists_url: "{/gist_id}",
  subscriptions_url: "",
  plan: %{
    "collaborators" => 0,
    "name" => "pro",
    "private_repos" => 9999,
    "space" => 976562499
  node_id: "MDQ6VXNlcjE5NDQwMA==",
  created_at: "2010-02-02T08:44:49Z",
  blog: "",
  type: "User",
  bio: "Learn something new every day.",
  following_url: "{/other_user}",
  repos_url: "",
  total_private_repos: 5,
  html_url: "",
  public_gists: 29,
  avatar_url: "",
  organizations_url: "",
  url: "",
  followers: 2778,
  updated_at: "2020-02-01T21:14:20Z",
  location: "London",
  hireable: nil,
  name: "Nelson",
  owned_private_repos: 5,
  company: "@dwyl",
  email: "",
  two_factor_authentication: true,
  starred_url: "{/owner}{/repo}",
  id: 194400,
  following: 173,
  login: "nelsonic",
  collaborators: 8

More info:

You can use this data however you see fit.
(_obviously treat it with respect,
  only store what you need and keep it secure_)

## 4. Add the `/auth/github/callback` to `router.ex`

Open your `lib/app_web/router.ex` file
and locate the section that looks like `scope "/", AppWeb do`

Add the following line:

get "/auth/github/callback", GithubAuthController, :index

That will direct the API request response
to the `GithubAuthController` `:index` function we defined above.

> Example:

## 5. Update `PageController.index`

In order to display the "Sign-in with GitHub" button in the UI,
we need to _generate_ the URL for the button in the relevant controller,
and pass it to the template.

Open the `lib/app_web/controllers/page_controller.ex` file
and update the `index` function:

def index(conn, _params) do
  render(conn, "index.html")

def index(conn, _params) do
  oauth_github_url = ElixirAuthGithub.login_url(%{scopes: ["user:email"]})
  render(conn, "index.html", [oauth_github_url: oauth_github_url])


### 5.1 Update the `page/index.html.eex` Template

Open the `/lib/app_web/templates/page/index.html.eex` file
and type (_or paste_) the following code:

<section class="phx-hero">
  <h1>Welcome to Awesome App!</h1>
  <p>To get started, login to your GitHub Account: <p>
  <a href="<%= @oauth_github_url %>">
    <img src="" alt="Sign in with GitHub" />

> **Note**: we are using an `<img>` button for code brevity. <br />
We suggest you use the `SVG+CSS` approach described
[below](#optimised-svgcss-button). 👇

## 6. _Run_ the App!

Run the app with the command:

mix phx.server

Visit the  home page of the app
where you will see a
"Sign in with GitHub" button:


Once the user authorizes the App,
they will be redirected
back to the Phoenix App
and will see welcome message:


## _Congratulations_! You have GitHub Oauth in your Elixir App! 🎉

<br />

> If you got stuck setting up your App,
check out our working demo: <br />
> The demo is deployed on Heroku:


Auth Step:




<br />

## _Testing_

@dwyl we feel that testing is 1/3 of the "deliverable"
(_with the other two thirds being docs and business logic_)
so we pay close attention to "testability".

With that in mind we have exported a _transparent_
which intercepts HTTP requests when the `MIX_ENV` is `"test"`.

To see the responses returned by the TestDouble,

And to see how the tests assert these responses,

<br /> <br />

## _Optimised_ SVG+CSS Button

In **step 5.1** above, we suggest using an `<img>`
for the `Sign in with GitHub` button.

But even though this image appears small **`357 × 61 px`** it is **`9kb`**:


We could spend some time in a graphics editor optimising the image,
but we _know_ we can do better by using our `CSS` skills! 💡

The following code re-creates the `<img>`
using the GitHub logo **`SVG`**
and `CSS` for layout/style:

<div style="display:flex; flex-direction:column; width:180px; margin-left:20px">
  <link href="">
  <a href="<%= @oauth_github_url %>"
    style="display:inline-flex; align-items:center; min-height:30px;
      background-color:#24292e; font-family:'Roboto',sans-serif;
      font-size:14px; color:white; text-decoration:none;">
    <div style="margin: 1px; padding-top:5px; min-height:30px;">
    <svg height="18" viewBox="0 0 16 16" width="32px" style="fill:white;">
      <path fill-rule="evenodd" d="M8 0C3.58 0 0 3.58 0 8c0 3.54 2.29 6.53 5.47
      1.08.58 1.21 1.87.87 0-.87.31-1.59.82-2.15-.08-.2-.36-1.02.08-2.12
      0 0 .67-.21 1.32-.27 2-.27.68 0 1.36.09 2 .27 1.53-1.04 2.2-.82 2.2-.82.44 1.1.16 1.92.08 1.27.82 2.15 0 3.07-1.87 3.75-3.65 1.48 0 1.07-.01 1.93-.01 2.2 0
      . 8.013 0 0016 8c0-4.42-3.58-8-8-8z"/>
    <div style="margin-left: 5px;">
      Sign in with GitHub

The result looks _better_ than the `<img>` button:


It can be scaled to any screen size so it will _always_ look great! <br />
Using we see that our SVG+CSS button is only **`1kb`**:

That is an **87.5%** bandwidth saving
on the **`9kb`** of the
[**`.png`** button](
And what's _more_ it reduces the number of HTTP requests
which means the page loads _even_ faster.

This is used in the Demo app:

### `i18n`

The _biggest_ advantage of having an SVG+CSS button
is that you can _translate_ the button text! <br />
Since the text/copy of the button is now _just_ text in standard HTML,
the user's web browser can _automatically_ translate it! <br />
e.g: _French_ 🇬🇧 > 🇫🇷


This is _much_ better UX for the **80%** of people in the world
who do _not_ speak English _fluently_.
The _single_ biggest engine for growth in startup companies
is [_translating_](
their user interface into more languages.
Obviously don't focus on translations
while you're building your MVP,
but if it's no extra _work_
to use this SVG+CSS button
and it means the person's web browser
can _automatically_ localise your App!

### _Accessibility_

The `SVG+CSS` button is more accessible than the image.
Even thought the `<img>` had an `alt` attribute
which is a lot better than nothing,
the `SVG+CSS` button can be re-interpreted
by a non-screen device and more easily transformed.

<br />

## Useful Links and Further Reading

+ GitHub Apps docs:
+ Authorizing OAuth Apps:
+ Basics of Authentication:
+ GitHub Logos and Usage: <br />
(_tldr: no official auth buttons but use of Octocat logo is encouraged
to help users identify that your App has a GitHub integration_)