elixir-auth-github demo

A basic example/tutorial showing GitHub OAuth in a Phoenix App using elixir-auth-github.

Try it: elixir-auth-github-demo.fly.dev

No data is stored. Try and break it. Open an issue if you spot something.

• elixir-auth-github demo
• Why? 🤷
• What? 💭
• Who? 👥
• How? 💻
  • 0. Create a New Phoenix App
  • 1. Add the elixir_auth_github package to mix.exs 📦
  • 2. Create the GitHub OAuth Application and Get Credentials ✨
  • 3. Create 3 New Files ➕
    • 3.1 Create a GithubAuthController in your Project
    • 3.2 Create welcome template 📝
    • 3.3 Create the github_auth_html.ex file
  • 4. Add the /auth/github/callback to router.ex
  • 5. Update PageController.index
    • 5.1 Update the page/index.html.eex Template
  • 6. Run the App!
  • Deployment?
    • Deploy to Fly.io

Why? 🤷

We love having detailed docs and examples that explain exactly how to get up-and-running. We write examples because we want them for ourselves, if you find them useful, please ⭐️ the repo to let us know.

What? 💭

This project is a barebones demo of using elixir-auth-github to add "Sign-in with GitHub" support to any Phoenix App.

Who? 👥

This demos is intended for people of all Elixir/Phoenix skill levels. Anyone who wants the "Sign-in with GitHub" functionality without the extra steps to configure a whole auth framework.

Following all the steps in this example should take around 10 minutes. However if you get stuck, please don't suffer in silence! Get help by opening an issue: dwyl/elixir-auth-github/issues

How? 💻

This example follows the step-by-instructions in the docs dwyl/elixir-auth-github

0. Create a New Phoenix App

Create a new project if you don't already have one:

If you're adding elixir_auth_github to an existing app, you can skip this step.
Just make sure your app is in a known working state before proceeding.

mix phx.new app 

Note: In creating this demo app we ran the command with the following flags:
mix phx.new app --no-assets --no-dashboard --no-ecto --no-gettext --no-mailer
to keep the project as basic as possible. You may need some or all of the features of Phoenix, so check which flags are applicable to you.

If prompted to install dependencies:

Fetch and install dependencies? [Yn]

Type y and hit the [Enter] key to install.

You should see something like this:

* running mix deps.get
* running mix deps.compile

Make sure that everything works before proceeding:

mix test

You should see:

Generated app app
...

Finished in 0.02 seconds
3 tests, 0 failures

The default tests pass and you know phoenix is compiling.

Run the web application:

mix phx.server

and visit the endpoint in your web browser: http://localhost:4000/

1. Add the elixir_auth_github package to mix.exs 📦

Open your mix.exs file and add the following line to your deps list:

def deps do
  [
    {:elixir_auth_github, "~> 1.6.5"}
  ]
end

Run the mix deps.get command to download.

2. Create the GitHub OAuth Application and Get Credentials ✨

Create your GitHub App and download the API keys by follow the instructions in: /create-github-app-guide.md

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

GITHUB_CLIENT_ID=631770888008-6n0oruvsm16kbkqg6u76p5cv5kfkcekt
GITHUB_CLIENT_SECRET=MHxv6-RGF5nheXnxh1b0LNDq

⚠️ Don't worry, these keys aren't valid. They are just here for illustration purposes.

3. Create 3 New Files ➕

We need to create two files in order to handle the requests to the GitHub OAuth API and display data to people using our 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 lib/app_web/controllers/github_auth_controller.ex

and add the following code:

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)
    render(conn, :welcome, [layout: false, profile: profile])
  end
end

This code does 3 things:

• Create a one-time auth token based on the response code sent by GitHub after the person authenticates.
• Request the person's profile data from GitHub based on an access_token
• 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: lib/app_web/controllers/github_auth_html/welcome.html.heex

And type (or paste) the following code in it:

<script src="https://cdn.tailwindcss.com"></script>

<section class="flex flex-col items-center justify-center px-6 py-8 mx-auto md:h-screen lg:py-0">
  <h1 class="text-4xl text-center font-bold leading-tight tracking-tight text-gray-900 md:text-2xl">
    Welcome <%= @profile.name %>!
    <img class="float-right h-8 w-8 rounded-full" alt="avatar image" width="32px" 
      src={@profile.avatar_url} />
  </h1>
  <p> You are <strong>signed in</strong>
    with your <strong>GitHub Account</strong> <br />
    <strong style="color:teal;"><%= @profile.email %></strong>
  </p>
</section>

Note: There's a fair amount of TailwindCSS sprinkled in that template, if you're new to Tailwind or need a refresher, please see: /learn-tailwind

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 data has the following format:

%{
  followers_url: "https://api.github.com/users/nelsonic/followers",
  public_repos: 291,
  plan: %{
    "collaborators" => 0,
    "name" => "pro",
    "private_repos" => 9999,
    "space" => 976562499
  },
  created_at: "2010-02-02T08:44:49Z",
  name: "Nelson",
  company: "@dwyl",
  email: "nelson@gmail.com",
  two_factor_authentication: true,
  starred_url: "https://api.github.com/users/nelsonic/starred{/owner}{/repo}",
  id: 194400,
  following: 173,
  login: "nelsonic",
  collaborators: 28,
  avatar_url: "https://avatars3.githubusercontent.com/u/194400?v=4",
  etc: "you get the idea ..."
}

More info: https://developer.github.com/v3/users

Use this data how you see fit. (obviously treat it with respect, only store what you need and keep it secure!)

3.3 Create the github_auth_html.ex file

Create a file with the path: lib/app_web/controllers/github_auth_html.ex

and add the following code to it:

defmodule AppWeb.GithubAuthHTML do
  use AppWeb, :html

  embed_templates "github_auth_html/*"
end

This is required so Phoenix knows where to find the template.

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.

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:

From:

  def home(conn, _params) do
    # The home page is often custom made,
    # so skip the default app layout.
    render(conn, :home, layout: false)
  end

To:

def home(conn, _params) do
  oauth_github_url = ElixirAuthGithub.login_url_with_scope(["user:email"])
  render(conn, :home, [layout: false, oauth_github_url: oauth_github_url])
end

5.1 Update the page/index.html.eex Template

Open the /lib/app_web/controllers/page_html/home.html.heex file and type (or paste) the following code:

<script src="https://cdn.tailwindcss.com"></script>

<section class="">
  <div class="flex flex-col items-center justify-center px-6 py-8 mx-auto md:h-screen lg:py-0">
      <div class="w-full bg-white rounded-lg shadow dark:border md:mt-0 sm:max-w-md xl:p-0 dark:bg-gray-200 dark:border-gray-700">
          <div class="p-6 space-y-4 md:space-y-6 sm:p-8">
              <h1 class="text-3xl text-center font-bold leading-tight tracking-tight text-gray-900 md:text-2xl">
                Welcome to Awesome App!
              </h1>
              <p class="text-center">
                To get started, login with your GitHub Account:
              </p>
              <a href={ @oauth_github_url } class="py-8 flex items-center justify-center">
                <img src="https://i.imgur.com/qwoHBIZ.png" alt="Sign in with GitHub" />
              </a>
          </div>
      </div>
  </div>
</section>

Note: the login button is an image for brevity. In our production version we use CSS and SVG, see: /elixir-auth-github#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: http://localhost:4000

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

Deployment?

This guide is meant to get your Phoenix App up-and-running with elixir-auth-github on localhost.

The demo is deployed to Fly.io to demonstrate that everything works as expected:

No data is saved by the demo app, so feel free to try an break it!

https://elixir-auth-github-demo.fly.dev

Authorization screen:

Welcome (success):

Deploy to Fly.io

If you want to deploy your own Phoenix App to Fly.io, simply follow the official Elixir Getting Started guide: fly.io/docs/elixir/getting-started

fly launch

Speed through the prompts to create the App and then add the add the 3 required environment variables:

fly secrets set GITHUB_CLIENT_ID=4458109151751aetc
fly secrets set GITHUB_CLIENT_SECRET=256df107df6454001a90d667fetc
SECRET_KEY_BASE=fephli94y1u1X7F8Snh9RUvz5l0fd1ySaz9WtzaUAX+NmfB0uE2xwetc

Note: none of these keys are valid. They are just for illustration purposes. Follow the instructions: dwyl/elixir-auth-google/blob/main/create-google-app-guide.md to get your Google App keys.

Refer to the Dockerfile and fly.toml in this demo project if you need an example.

Recommended reading: "Deploying with Releases" hexdocs.pm/phoenix/releases.html

For Continuous Deployment to Fly.io, read: fly.io/docs/app-guides/continuous-deployment-with-github-actions