Add configurable prevention of user registration

Should be done appropriately soon.

lib/outlook_web/components/layouts/root.html.heex

@@ -24,9 +24,6 @@
           <.link href={~p"/users/log_out"} method="delete">Log out</.link>
         </li>
       <% else %>
-        <li>
-          <.link href={~p"/users/register"}>Register</.link>
-        </li>
         <li>
           <.link href={~p"/users/log_in"}>Log in</.link>
         </li>

lib/outlook_web/live/user_login_live.ex

@@ -7,11 +7,13 @@ defmodule OutlookWeb.UserLoginLive do
       <.header class="text-center">
         Sign in to account
         <:subtitle>
+          <%= unless System.get_env("DISABLE_REGISTRATION") do %>
           Don't have an account?
           <.link navigate={~p"/users/register"} class="font-semibold text-brand hover:underline">
             Sign up
           </.link>
           for an account now.
+          <% end %>
         </:subtitle>
       </.header>
 

lib/outlook_web/prevent_registration.ex

@@ -0,0 +1,20 @@
+defmodule Outlook.PreventRegistration do
+
+  import Plug.Conn
+  import Phoenix.Controller
+
+  def prevent_registration(conn, _) do
+    if System.get_env("DISABLE_REGISTRATION") && is_registration_path(conn) do
+      conn
+      |> put_flash(:error, "User Registration is disabled.")
+      |> redirect(to: "/users/log_in")
+      |> halt()
+    else
+      conn
+    end
+  end
+
+  defp is_registration_path(conn) do
+    "/users/register" == current_path(conn, %{})
+  end
+end

lib/outlook_web/router.ex

@@ -3,6 +3,8 @@ defmodule OutlookWeb.Router do
 
   import OutlookWeb.UserAuth
 
+  import Outlook.PreventRegistration
+
   pipeline :browser do
     plug :accepts, ["html"]
     plug :fetch_session
@@ -18,6 +20,10 @@ defmodule OutlookWeb.Router do
     plug :put_layout, {OutlookWeb.Layouts, :public}
   end
 
+  pipeline :check_registration do
+    plug :prevent_registration
+  end
+
   pipeline :api do
     plug :accepts, ["json"]
   end
@@ -56,7 +62,7 @@ defmodule OutlookWeb.Router do
   ## Authentication routes
 
   scope "/", OutlookWeb do
-    pipe_through [:browser, :redirect_if_user_is_authenticated]
+    pipe_through [:browser, :redirect_if_user_is_authenticated, :check_registration]
 
     live_session :redirect_if_user_is_authenticated,
       on_mount: [{OutlookWeb.UserAuth, :redirect_if_user_is_authenticated}] do