New admin setting: open/close registrations, with custom message, from the admin UI

app/controllers/about_controller.rb

@@ -4,7 +4,9 @@ class AboutController < ApplicationController
   before_action :set_body_classes
 
   def index
-    @description = Setting.site_description
+    @description                  = Setting.site_description
+    @open_registrations           = Setting.open_registrations
+    @closed_registrations_message = Setting.closed_registrations_message
 
     @user = User.new
     @user.build_account

app/controllers/admin/settings_controller.rb

@@ -11,9 +11,13 @@ class Admin::SettingsController < ApplicationController
 
   def update
     @setting = Setting.where(var: params[:id]).first_or_initialize(var: params[:id])
+    value    = settings_params[:value]
 
-    if @setting.value != params[:setting][:value]
-      @setting.value = params[:setting][:value]
+    # Special cases
+    value = value == 'true' if @setting.var == 'open_registrations'
+
+    if @setting.value != value
+      @setting.value = value
       @setting.save
     end
 
@@ -22,4 +26,10 @@ class Admin::SettingsController < ApplicationController
       format.json { respond_with_bip(@setting) }
     end
   end
+
+  private
+
+  def settings_params
+    params.require(:setting).permit(:value)
+  end
 end

app/controllers/auth/registrations_controller.rb

@@ -3,7 +3,7 @@
 class Auth::RegistrationsController < Devise::RegistrationsController
   layout :determine_layout
 
-  before_action :check_single_user_mode
+  before_action :check_enabled_registrations, only: [:new, :create]
   before_action :configure_sign_up_params, only: [:create]
 
   protected
@@ -27,12 +27,12 @@ class Auth::RegistrationsController < Devise::RegistrationsController
     new_user_session_path
   end
 
-  def check_single_user_mode
-    redirect_to root_path if Rails.configuration.x.single_user_mode
+  def check_enabled_registrations
+    redirect_to root_path if Rails.configuration.x.single_user_mode || !Setting.open_registrations
   end
-  
+
   private
-  
+
   def determine_layout
     %w(edit update).include?(action_name) ? 'admin' : 'auth'
   end