User signup (demo)

This Charta explains how user sign is implemented.

hugoribeira

Built straight from my text editor.

We use Pow to handle most of the authentication boiler plate for us. Including Pow in the router registers a /registration route that our users can visit:

settings lib/charta_web/router.ex

1	`defmodule ChartaWeb.Router do`

2	`use ChartaWeb, :router`

3	`use Pow.Phoenix.Router`

Visiting /registrations renders our "new" template:

settings lib/charta_web/templates/pow/registration/new.html.eex

1	`<div class="page-authentication-container">`

2	`<h1>Create an account</h1>`

3

4	`<div class="page-authentication-form-container">`

5	`<%= form_for @changeset, @action, [as: :user], fn f -> %>`

6	`<%= if @changeset.action do %>`

7	`<div class="form-errors">`

8	`<p>Oops, something went wrong! Please check the errors below.</p>`

9	`</div>`

10	`<% end %>`

11

12	`<div class="form-field">`

13	`<%= label f, Pow.Ecto.Schema.user_id_field(@changeset) %>`

14	`<%= text_input f, Pow.Ecto.Schema.user_id_field(@changeset), placeholder: "Your email goes here", class: "full-width" %>`

15	`<%= error_tag f, Pow.Ecto.Schema.user_id_field(@changeset) %>`

16	`</div>`

17

18	`<div class="form-field">`

19	`<%= label f, :password %>`

20	`<%= password_input f, :password, placeholder: "password", class: "full-width" %>`

21	`<%= error_tag f, :password %>`

22	`</div class="form-field">`

23

24	`<div class="form-field">`

25	`<%= label f, :password_confirmation %>`

26	`<%= password_input f, :password_confirmation, placeholder: "password confirmation", class: "full-width" %>`

27	`<%= error_tag f, :password_confirmation %>`

28	`</div>`

29

30	`<div class="form-actions">`

31	`<%= submit "Register", class: "button primary" %>`

32	`</div>`

33	`<% end %>`

34	`</div>`

35	`<span>Already have an account? <%= link "Sign in", to: Routes.pow_session_path(@conn, :new) %></span>`

36	`</div>`

Once a user submits the registration form, the input is handled by Pow's registration controller. It creates a user record that is used by the rest of the platform.

The Accounts API

Pow is just an implementation detail - it handles user registration and authentication for us. However the rest of the platform depends on our public Accounts interface:

settings lib/charta/accounts/accounts.ex

1	`defmodule Charta.Accounts do`

2	`defmodule GuestUser do`

3	`defstruct id: 0, logged_in?: false`

4

5	`def new(), do: %GuestUser{}`

6	`end`

7

8	`alias Charta.Repo`

9	`alias __MODULE__.User`

10

11	`@doc """`

12	`Returns a default guest user to be used whenever a user is not logged in.`

13

14	`It essentially implements the null object pattern.`

15	`"""`

16	`def guest_user(), do: GuestUser.new()`

17

18	`@doc """`

19	`Find user for given id.`

20	`"""`

21	`def find_user(id) do`

22	`case Repo.get_by(User, id: id) do`

23	`nil -> {:error, :not_found}`

24	`user -> {:ok, user}`

25	`end`

26	`end`

27

28	`@doc """`

29	`Find user for given API token`

30	`"""`

31	`def find_user_by_token(token) do`

32	`case Phoenix.Token.verify(ChartaWeb.Endpoint, "user auth", token, max_age: 300) do`

33	`{:ok, %{user_id: user_id}} -> find_user(user_id)`

34	`{:error, _} = error -> error`

35	`end`

36	`end`

37

38	`@doc """`

39	`Generate token for given user`

40	`"""`

41	`def generate_token(user = %User{}) do`

42	`token = Phoenix.Token.sign(ChartaWeb.Endpoint, "user auth", %{user_id: user.id})`

43	`{:ok, token}`

44	`end`

45	`end`

If we wanted to replace Pow by something else, then we'd have to reimplement the authentication and registration code. Everything else would remain untouched as the rest of the code simply uses the Accounts public API.

Explore and document code. Straight from your editor.

Get started