Add the Web Authentication.

lib/link_shortener_web/controllers/api/v1/user_controller.ex

@@ -8,7 +8,7 @@ defmodule LinkShortenerWeb.Api.V1.UserController do
   action_fallback LinkShortenerWeb.FallbackController
 
   def create(conn, %{"user" => user_params}) do
-    with {:ok, %User{} = user} <- Accounts.create_user(user_params),
+    with {:ok, %User{} = user} <- Accounts.register_user(user_params),
 	 {:ok, token, _claims} <- Guardian.encode_and_sign(user) do
       conn
       |> put_status(:created)

lib/link_shortener_web/controllers/user_auth.ex

@@ -0,0 +1,149 @@
+defmodule LinkShortenerWeb.UserAuth do
+  import Plug.Conn
+  import Phoenix.Controller
+
+  alias LinkShortener.Accounts
+  alias LinkShortenerWeb.Router.Helpers, as: Routes
+
+  # Make the remember me cookie valid for 60 days.
+  # If you want bump or reduce this value, also change
+  # the token expiry itself in UserToken.
+  @max_age 60 * 60 * 24 * 60
+  @remember_me_cookie "_link_shortener_web_user_remember_me"
+  @remember_me_options [sign: true, max_age: @max_age, same_site: "Lax"]
+
+  @doc """
+  Logs the user in.
+
+  It renews the session ID and clears the whole session
+  to avoid fixation attacks. See the renew_session
+  function to customize this behaviour.
+
+  It also sets a `:live_socket_id` key in the session,
+  so LiveView sessions are identified and automatically
+  disconnected on log out. The line can be safely removed
+  if you are not using LiveView.
+  """
+  def log_in_user(conn, user, params \\ %{}) do
+    token = Accounts.generate_user_session_token(user)
+    user_return_to = get_session(conn, :user_return_to)
+
+    conn
+    |> renew_session()
+    |> put_session(:user_token, token)
+    |> put_session(:live_socket_id, "users_sessions:#{Base.url_encode64(token)}")
+    |> maybe_write_remember_me_cookie(token, params)
+    |> redirect(to: user_return_to || signed_in_path(conn))
+  end
+
+  defp maybe_write_remember_me_cookie(conn, token, %{"remember_me" => "true"}) do
+    put_resp_cookie(conn, @remember_me_cookie, token, @remember_me_options)
+  end
+
+  defp maybe_write_remember_me_cookie(conn, _token, _params) do
+    conn
+  end
+
+  # This function renews the session ID and erases the whole
+  # session to avoid fixation attacks. If there is any data
+  # in the session you may want to preserve after log in/log out,
+  # you must explicitly fetch the session data before clearing
+  # and then immediately set it after clearing, for example:
+  #
+  #     defp renew_session(conn) do
+  #       preferred_locale = get_session(conn, :preferred_locale)
+  #
+  #       conn
+  #       |> configure_session(renew: true)
+  #       |> clear_session()
+  #       |> put_session(:preferred_locale, preferred_locale)
+  #     end
+  #
+  defp renew_session(conn) do
+    conn
+    |> configure_session(renew: true)
+    |> clear_session()
+  end
+
+  @doc """
+  Logs the user out.
+
+  It clears all session data for safety. See renew_session.
+  """
+  def log_out_user(conn) do
+    user_token = get_session(conn, :user_token)
+    user_token && Accounts.delete_session_token(user_token)
+
+    if live_socket_id = get_session(conn, :live_socket_id) do
+      LinkShortenerWeb.Endpoint.broadcast(live_socket_id, "disconnect", %{})
+    end
+
+    conn
+    |> renew_session()
+    |> delete_resp_cookie(@remember_me_cookie)
+    |> redirect(to: "/")
+  end
+
+  @doc """
+  Authenticates the user by looking into the session
+  and remember me token.
+  """
+  def fetch_current_user(conn, _opts) do
+    {user_token, conn} = ensure_user_token(conn)
+    user = user_token && Accounts.get_user_by_session_token(user_token)
+    assign(conn, :current_user, user)
+  end
+
+  defp ensure_user_token(conn) do
+    if user_token = get_session(conn, :user_token) do
+      {user_token, conn}
+    else
+      conn = fetch_cookies(conn, signed: [@remember_me_cookie])
+
+      if user_token = conn.cookies[@remember_me_cookie] do
+        {user_token, put_session(conn, :user_token, user_token)}
+      else
+        {nil, conn}
+      end
+    end
+  end
+
+  @doc """
+  Used for routes that require the user to not be authenticated.
+  """
+  def redirect_if_user_is_authenticated(conn, _opts) do
+    if conn.assigns[:current_user] do
+      conn
+      |> redirect(to: signed_in_path(conn))
+      |> halt()
+    else
+      conn
+    end
+  end
+
+  @doc """
+  Used for routes that require the user to be authenticated.
+
+  If you want to enforce the user email is confirmed before
+  they use the application at all, here would be a good place.
+  """
+  def require_authenticated_user(conn, _opts) do
+    if conn.assigns[:current_user] do
+      conn
+    else
+      conn
+      |> put_flash(:error, "You must log in to access this page.")
+      |> maybe_store_return_to()
+      |> redirect(to: Routes.user_session_path(conn, :new))
+      |> halt()
+    end
+  end
+
+  defp maybe_store_return_to(%{method: "GET"} = conn) do
+    put_session(conn, :user_return_to, current_path(conn))
+  end
+
+  defp maybe_store_return_to(conn), do: conn
+
+  defp signed_in_path(_conn), do: "/"
+end

lib/link_shortener_web/controllers/user_confirmation_controller.ex

@@ -0,0 +1,56 @@
+defmodule LinkShortenerWeb.UserConfirmationController do
+  use LinkShortenerWeb, :controller
+
+  alias LinkShortener.Accounts
+
+  def new(conn, _params) do
+    render(conn, "new.html")
+  end
+
+  def create(conn, %{"user" => %{"email" => email}}) do
+    if user = Accounts.get_user_by_email(email) do
+      Accounts.deliver_user_confirmation_instructions(
+        user,
+        &Routes.user_confirmation_url(conn, :edit, &1)
+      )
+    end
+
+    conn
+    |> put_flash(
+      :info,
+      "If your email is in our system and it has not been confirmed yet, " <>
+        "you will receive an email with instructions shortly."
+    )
+    |> redirect(to: "/")
+  end
+
+  def edit(conn, %{"token" => token}) do
+    render(conn, "edit.html", token: token)
+  end
+
+  # Do not log in the user after confirmation to avoid a
+  # leaked token giving the user access to the account.
+  def update(conn, %{"token" => token}) do
+    case Accounts.confirm_user(token) do
+      {:ok, _} ->
+        conn
+        |> put_flash(:info, "User confirmed successfully.")
+        |> redirect(to: "/")
+
+      :error ->
+        # If there is a current user and the account was already confirmed,
+        # then odds are that the confirmation link was already visited, either
+        # by some automation or by the user themselves, so we redirect without
+        # a warning message.
+        case conn.assigns do
+          %{current_user: %{confirmed_at: confirmed_at}} when not is_nil(confirmed_at) ->
+            redirect(conn, to: "/")
+
+          %{} ->
+            conn
+            |> put_flash(:error, "User confirmation link is invalid or it has expired.")
+            |> redirect(to: "/")
+        end
+    end
+  end
+end

lib/link_shortener_web/controllers/user_registration_controller.ex

@@ -0,0 +1,30 @@
+defmodule LinkShortenerWeb.UserRegistrationController do
+  use LinkShortenerWeb, :controller
+
+  alias LinkShortener.Accounts
+  alias LinkShortener.Accounts.User
+  alias LinkShortenerWeb.UserAuth
+
+  def new(conn, _params) do
+    changeset = Accounts.change_user_registration(%User{})
+    render(conn, "new.html", changeset: changeset)
+  end
+
+  def create(conn, %{"user" => user_params}) do
+    case Accounts.register_user(user_params) do
+      {:ok, user} ->
+        {:ok, _} =
+          Accounts.deliver_user_confirmation_instructions(
+            user,
+            &Routes.user_confirmation_url(conn, :edit, &1)
+          )
+
+        conn
+        |> put_flash(:info, "User created successfully.")
+        |> UserAuth.log_in_user(user)
+
+      {:error, %Ecto.Changeset{} = changeset} ->
+        render(conn, "new.html", changeset: changeset)
+    end
+  end
+end

lib/link_shortener_web/controllers/user_reset_password_controller.ex

@@ -0,0 +1,58 @@
+defmodule LinkShortenerWeb.UserResetPasswordController do
+  use LinkShortenerWeb, :controller
+
+  alias LinkShortener.Accounts
+
+  plug :get_user_by_reset_password_token when action in [:edit, :update]
+
+  def new(conn, _params) do
+    render(conn, "new.html")
+  end
+
+  def create(conn, %{"user" => %{"email" => email}}) do
+    if user = Accounts.get_user_by_email(email) do
+      Accounts.deliver_user_reset_password_instructions(
+        user,
+        &Routes.user_reset_password_url(conn, :edit, &1)
+      )
+    end
+
+    conn
+    |> put_flash(
+      :info,
+      "If your email is in our system, you will receive instructions to reset your password shortly."
+    )
+    |> redirect(to: "/")
+  end
+
+  def edit(conn, _params) do
+    render(conn, "edit.html", changeset: Accounts.change_user_password(conn.assigns.user))
+  end
+
+  # Do not log in the user after reset password to avoid a
+  # leaked token giving the user access to the account.
+  def update(conn, %{"user" => user_params}) do
+    case Accounts.reset_user_password(conn.assigns.user, user_params) do
+      {:ok, _} ->
+        conn
+        |> put_flash(:info, "Password reset successfully.")
+        |> redirect(to: Routes.user_session_path(conn, :new))
+
+      {:error, changeset} ->
+        render(conn, "edit.html", changeset: changeset)
+    end
+  end
+
+  defp get_user_by_reset_password_token(conn, _opts) do
+    %{"token" => token} = conn.params
+
+    if user = Accounts.get_user_by_reset_password_token(token) do
+      conn |> assign(:user, user) |> assign(:token, token)
+    else
+      conn
+      |> put_flash(:error, "Reset password link is invalid or it has expired.")
+      |> redirect(to: "/")
+      |> halt()
+    end
+  end
+end

lib/link_shortener_web/controllers/user_session_controller.ex

@@ -0,0 +1,27 @@
+defmodule LinkShortenerWeb.UserSessionController do
+  use LinkShortenerWeb, :controller
+
+  alias LinkShortener.Accounts
+  alias LinkShortenerWeb.UserAuth
+
+  def new(conn, _params) do
+    render(conn, "new.html", error_message: nil)
+  end
+
+  def create(conn, %{"user" => user_params}) do
+    %{"email" => email, "password" => password} = user_params
+
+    if user = Accounts.get_user_by_email_and_password(email, password) do
+      UserAuth.log_in_user(conn, user, user_params)
+    else
+      # In order to prevent user enumeration attacks, don't disclose whether the email is registered.
+      render(conn, "new.html", error_message: "Invalid email or password")
+    end
+  end
+
+  def delete(conn, _params) do
+    conn
+    |> put_flash(:info, "Logged out successfully.")
+    |> UserAuth.log_out_user()
+  end
+end

lib/link_shortener_web/controllers/user_settings_controller.ex

@@ -0,0 +1,74 @@
+defmodule LinkShortenerWeb.UserSettingsController do
+  use LinkShortenerWeb, :controller
+
+  alias LinkShortener.Accounts
+  alias LinkShortenerWeb.UserAuth
+
+  plug :assign_email_and_password_changesets
+
+  def edit(conn, _params) do
+    render(conn, "edit.html")
+  end
+
+  def update(conn, %{"action" => "update_email"} = params) do
+    %{"current_password" => password, "user" => user_params} = params
+    user = conn.assigns.current_user
+
+    case Accounts.apply_user_email(user, password, user_params) do
+      {:ok, applied_user} ->
+        Accounts.deliver_update_email_instructions(
+          applied_user,
+          user.email,
+          &Routes.user_settings_url(conn, :confirm_email, &1)
+        )
+
+        conn
+        |> put_flash(
+          :info,
+          "A link to confirm your email change has been sent to the new address."
+        )
+        |> redirect(to: Routes.user_settings_path(conn, :edit))
+
+      {:error, changeset} ->
+        render(conn, "edit.html", email_changeset: changeset)
+    end
+  end
+
+  def update(conn, %{"action" => "update_password"} = params) do
+    %{"current_password" => password, "user" => user_params} = params
+    user = conn.assigns.current_user
+
+    case Accounts.update_user_password(user, password, user_params) do
+      {:ok, user} ->
+        conn
+        |> put_flash(:info, "Password updated successfully.")
+        |> put_session(:user_return_to, Routes.user_settings_path(conn, :edit))
+        |> UserAuth.log_in_user(user)
+
+      {:error, changeset} ->
+        render(conn, "edit.html", password_changeset: changeset)
+    end
+  end
+
+  def confirm_email(conn, %{"token" => token}) do
+    case Accounts.update_user_email(conn.assigns.current_user, token) do
+      :ok ->
+        conn
+        |> put_flash(:info, "Email changed successfully.")
+        |> redirect(to: Routes.user_settings_path(conn, :edit))
+
+      :error ->
+        conn
+        |> put_flash(:error, "Email change link is invalid or it has expired.")
+        |> redirect(to: Routes.user_settings_path(conn, :edit))
+    end
+  end
+
+  defp assign_email_and_password_changesets(conn, _opts) do
+    user = conn.assigns.current_user
+
+    conn
+    |> assign(:email_changeset, Accounts.change_user_email(user))
+    |> assign(:password_changeset, Accounts.change_user_password(user))
+  end
+end

lib/link_shortener_web/router.ex

@@ -1,6 +1,8 @@
 defmodule LinkShortenerWeb.Router do
   use LinkShortenerWeb, :router
 
+  import LinkShortenerWeb.UserAuth
+
   pipeline :browser do
     plug :accepts, ["html"]
     plug :fetch_session
@@ -8,6 +10,7 @@ defmodule LinkShortenerWeb.Router do
     plug :put_root_layout, {LinkShortenerWeb.LayoutView, :root}
     plug :protect_from_forgery
     plug :put_secure_browser_headers
+    plug :fetch_current_user
   end
 
   pipeline :api do
@@ -60,4 +63,37 @@ defmodule LinkShortenerWeb.Router do
       forward "/mailbox", Plug.Swoosh.MailboxPreview
     end
   end
+
+  ## Authentication routes
+
+  scope "/", LinkShortenerWeb do
+    pipe_through [:browser, :redirect_if_user_is_authenticated]
+
+    get "/users/register", UserRegistrationController, :new
+    post "/users/register", UserRegistrationController, :create
+    get "/users/log_in", UserSessionController, :new
+    post "/users/log_in", UserSessionController, :create
+    get "/users/reset_password", UserResetPasswordController, :new
+    post "/users/reset_password", UserResetPasswordController, :create
+    get "/users/reset_password/:token", UserResetPasswordController, :edit
+    put "/users/reset_password/:token", UserResetPasswordController, :update
+  end
+
+  scope "/", LinkShortenerWeb do
+    pipe_through [:browser, :require_authenticated_user]
+
+    get "/users/settings", UserSettingsController, :edit
+    put "/users/settings", UserSettingsController, :update
+    get "/users/settings/confirm_email/:token", UserSettingsController, :confirm_email
+  end
+
+  scope "/", LinkShortenerWeb do
+    pipe_through [:browser]
+
+    delete "/users/log_out", UserSessionController, :delete
+    get "/users/confirm", UserConfirmationController, :new
+    post "/users/confirm", UserConfirmationController, :create
+    get "/users/confirm/:token", UserConfirmationController, :edit
+    post "/users/confirm/:token", UserConfirmationController, :update
+  end
 end

lib/link_shortener_web/templates/layout/_user_menu.html.heex

@@ -0,0 +1,10 @@
+<ul>
+<%= if @current_user do %>
+  <li><%= @current_user.email %></li>
+  <li><%= link "Settings", to: Routes.user_settings_path(@conn, :edit) %></li>
+  <li><%= link "Log out", to: Routes.user_session_path(@conn, :delete), method: :delete %></li>
+<% else %>
+  <li><%= link "Register", to: Routes.user_registration_path(@conn, :new) %></li>
+  <li><%= link "Log in", to: Routes.user_session_path(@conn, :new) %></li>
+<% end %>
+</ul>

lib/link_shortener_web/templates/layout/root.html.heex

@@ -18,6 +18,7 @@
               <li><%= link "LiveDashboard", to: Routes.live_dashboard_path(@conn, :home) %></li>
             <% end %>
           </ul>
+          <%= render "_user_menu.html", assigns %>
         </nav>
         <a href={Routes.page_path(@conn, :index)} class="phx-logo">
           Link Shortener

lib/link_shortener_web/templates/user_confirmation/edit.html.heex

@@ -0,0 +1,12 @@
+<h1>Confirm account</h1>
+
+<.form let={_f} for={:user} action={Routes.user_confirmation_path(@conn, :update, @token)}>
+  <div>
+    <%= submit "Confirm my account" %>
+  </div>
+</.form>
+
+<p>
+  <%= link "Register", to: Routes.user_registration_path(@conn, :new) %> |
+  <%= link "Log in", to: Routes.user_session_path(@conn, :new) %>
+</p>

lib/link_shortener_web/templates/user_confirmation/new.html.heex

@@ -0,0 +1,15 @@
+<h1>Resend confirmation instructions</h1>
+
+<.form let={f} for={:user} action={Routes.user_confirmation_path(@conn, :create)}>
+  <%= label f, :email %>
+  <%= email_input f, :email, required: true %>
+
+  <div>
+    <%= submit "Resend confirmation instructions" %>
+  </div>
+</.form>
+
+<p>
+  <%= link "Register", to: Routes.user_registration_path(@conn, :new) %> |
+  <%= link "Log in", to: Routes.user_session_path(@conn, :new) %>
+</p>

lib/link_shortener_web/templates/user_registration/new.html.heex

@@ -0,0 +1,26 @@
+<h1>Register</h1>
+
+<.form let={f} for={@changeset} action={Routes.user_registration_path(@conn, :create)}>
+  <%= if @changeset.action do %>
+    <div class="alert alert-danger">
+      <p>Oops, something went wrong! Please check the errors below.</p>
+    </div>
+  <% end %>
+
+  <%= label f, :email %>
+  <%= email_input f, :email, required: true %>
+  <%= error_tag f, :email %>
+
+  <%= label f, :password %>
+  <%= password_input f, :password, required: true %>
+  <%= error_tag f, :password %>
+
+  <div>
+    <%= submit "Register" %>
+  </div>
+</.form>
+
+<p>
+  <%= link "Log in", to: Routes.user_session_path(@conn, :new) %> |
+  <%= link "Forgot your password?", to: Routes.user_reset_password_path(@conn, :new) %>
+</p>

lib/link_shortener_web/templates/user_reset_password/edit.html.heex

@@ -0,0 +1,26 @@
+<h1>Reset password</h1>
+
+<.form let={f} for={@changeset} action={Routes.user_reset_password_path(@conn, :update, @token)}>
+  <%= if @changeset.action do %>
+    <div class="alert alert-danger">
+      <p>Oops, something went wrong! Please check the errors below.</p>
+    </div>
+  <% end %>
+
+  <%= label f, :password, "New password" %>
+  <%= password_input f, :password, required: true %>
+  <%= error_tag f, :password %>
+
+  <%= label f, :password_confirmation, "Confirm new password" %>
+  <%= password_input f, :password_confirmation, required: true %>
+  <%= error_tag f, :password_confirmation %>
+
+  <div>
+    <%= submit "Reset password" %>
+  </div>
+</.form>
+
+<p>
+  <%= link "Register", to: Routes.user_registration_path(@conn, :new) %> |
+  <%= link "Log in", to: Routes.user_session_path(@conn, :new) %>
+</p>

lib/link_shortener_web/templates/user_reset_password/new.html.heex

@@ -0,0 +1,15 @@
+<h1>Forgot your password?</h1>
+
+<.form let={f} for={:user} action={Routes.user_reset_password_path(@conn, :create)}>
+  <%= label f, :email %>
+  <%= email_input f, :email, required: true %>
+
+  <div>
+    <%= submit "Send instructions to reset password" %>
+  </div>
+</.form>
+
+<p>
+  <%= link "Register", to: Routes.user_registration_path(@conn, :new) %> |
+  <%= link "Log in", to: Routes.user_session_path(@conn, :new) %>
+</p>

lib/link_shortener_web/templates/user_session/new.html.heex

@@ -0,0 +1,27 @@
+<h1>Log in</h1>
+
+<.form let={f} for={@conn} action={Routes.user_session_path(@conn, :create)} as={:user}>
+  <%= if @error_message do %>
+    <div class="alert alert-danger">
+      <p><%= @error_message %></p>
+    </div>
+  <% end %>
+
+  <%= label f, :email %>
+  <%= email_input f, :email, required: true %>
+
+  <%= label f, :password %>
+  <%= password_input f, :password, required: true %>
+
+  <%= label f, :remember_me, "Keep me logged in for 60 days" %>
+  <%= checkbox f, :remember_me %>
+
+  <div>
+    <%= submit "Log in" %>
+  </div>
+</.form>
+
+<p>
+  <%= link "Register", to: Routes.user_registration_path(@conn, :new) %> |
+  <%= link "Forgot your password?", to: Routes.user_reset_password_path(@conn, :new) %>
+</p>

lib/link_shortener_web/templates/user_settings/edit.html.heex

@@ -0,0 +1,53 @@
+<h1>Settings</h1>
+
+<h3>Change email</h3>
+
+<.form let={f} for={@email_changeset} action={Routes.user_settings_path(@conn, :update)} id="update_email">
+  <%= if @email_changeset.action do %>
+    <div class="alert alert-danger">
+      <p>Oops, something went wrong! Please check the errors below.</p>
+    </div>
+  <% end %>
+
+  <%= hidden_input f, :action, name: "action", value: "update_email" %>
+
+  <%= label f, :email %>
+  <%= email_input f, :email, required: true %>
+  <%= error_tag f, :email %>
+
+  <%= label f, :current_password, for: "current_password_for_email" %>
+  <%= password_input f, :current_password, required: true, name: "current_password", id: "current_password_for_email" %>
+  <%= error_tag f, :current_password %>
+
+  <div>
+    <%= submit "Change email" %>
+  </div>
+</.form>
+
+<h3>Change password</h3>
+
+<.form let={f} for={@password_changeset} action={Routes.user_settings_path(@conn, :update)} id="update_password">
+  <%= if @password_changeset.action do %>
+    <div class="alert alert-danger">
+      <p>Oops, something went wrong! Please check the errors below.</p>
+    </div>
+  <% end %>
+
+  <%= hidden_input f, :action, name: "action", value: "update_password" %>
+
+  <%= label f, :password, "New password" %>
+  <%= password_input f, :password, required: true %>
+  <%= error_tag f, :password %>
+
+  <%= label f, :password_confirmation, "Confirm new password" %>
+  <%= password_input f, :password_confirmation, required: true %>
+  <%= error_tag f, :password_confirmation %>
+
+  <%= label f, :current_password, for: "current_password_for_password" %>
+  <%= password_input f, :current_password, required: true, name: "current_password", id: "current_password_for_password" %>
+  <%= error_tag f, :current_password %>
+
+  <div>
+    <%= submit "Change password" %>
+  </div>
+</.form>

lib/link_shortener_web/views/user_confirmation_view.ex

@@ -0,0 +1,3 @@
+defmodule LinkShortenerWeb.UserConfirmationView do
+  use LinkShortenerWeb, :view
+end

lib/link_shortener_web/views/user_registration_view.ex

@@ -0,0 +1,3 @@
+defmodule LinkShortenerWeb.UserRegistrationView do
+  use LinkShortenerWeb, :view
+end

lib/link_shortener_web/views/user_reset_password_view.ex

@@ -0,0 +1,3 @@
+defmodule LinkShortenerWeb.UserResetPasswordView do
+  use LinkShortenerWeb, :view
+end

lib/link_shortener_web/views/user_session_view.ex

@@ -0,0 +1,3 @@
+defmodule LinkShortenerWeb.UserSessionView do
+  use LinkShortenerWeb, :view
+end

lib/link_shortener_web/views/user_settings_view.ex

@@ -0,0 +1,3 @@
+defmodule LinkShortenerWeb.UserSettingsView do
+  use LinkShortenerWeb, :view
+end