Show login button on 404 page. Add routes to show login and signup modals when page/route loads. If logged in and showing 404 page, load ember app.

app/assets/javascripts/discourse/routes/application_routes.js

@@ -8,6 +8,7 @@ Discourse.Route.buildRoutes(function() {
   var router = this;
 
   // Generate static page routes
+  // e.g., faq, tos, privacy, login
   _.each(Discourse.StaticController.PAGES, function (page) {
     router.route(page, { path: '/' + page });
   });
@@ -90,4 +91,7 @@ Discourse.Route.buildRoutes(function() {
 
     this.route('invited');
   });
+
+  this.route('signup', {path: '/signup'});
+  this.route('login', {path: '/login'});
 });

app/assets/javascripts/discourse/routes/login_route.js

@@ -0,0 +1,11 @@
+Discourse.LoginRoute = Discourse.Route.extend({
+  beforeModel: function() {
+    if (!Discourse.SiteSetting.login_required) {
+      this.transitionTo('discovery.latest').then(function(e) {
+        Ember.run.next(function() {
+          e.send('showLogin');
+        });
+      });
+    }
+  }
+});

app/assets/javascripts/discourse/routes/signup_route.js

@@ -0,0 +1,9 @@
+Discourse.SignupRoute = Discourse.Route.extend({
+  beforeModel: function() {
+    this.transitionTo('discovery.latest').then(function(e) {
+      Ember.run.next(function() {
+        e.send('showCreateAccount');
+      });
+    });
+  }
+});

app/assets/javascripts/discourse/routes/static_route.js

@@ -26,3 +26,15 @@ _.each(Discourse.StaticController.PAGES, function(page) {
   });
 
 });
+
+Discourse.LoginRoute.reopen({
+  beforeModel: function() {
+    if (!Discourse.SiteSettings.login_required) {
+      this.transitionTo('discovery.latest').then(function(e) {
+        Ember.run.next(function() {
+          e.send('showLogin');
+        });
+      });
+    }
+  }
+});

app/controllers/application_controller.rb

@@ -104,7 +104,7 @@ class ApplicationController < ActionController::Base
       #       from the above rescue_from blocks will fail because that isn't valid json.
       render status: error, layout: false, text: (error == 404) ? build_not_found_page(error) : message
     else
-      render text: build_not_found_page(error, 'no_js')
+      render text: build_not_found_page(error, current_user ? 'application' : 'no_js')
     end
   end
 

app/views/layouts/no_js.html.erb

@@ -24,6 +24,11 @@
               <div class="title span13">
                 <a href="/"><img src="<%=SiteSetting.logo_url%>" alt="<%=SiteSetting.title%>" id="site-logo"></a>
               </div>
+              <% unless current_user %>
+                <div class='panel clearfix'>
+                  <a href="/login" class='btn btn-primary btn-small'><%= I18n.t('log_in') %></a>
+                </div>
+              <% end %>
             </div>
           </div>
         </div>

app/views/static/login.html.erb

@@ -1 +1,3 @@
-<%= markdown_content(:login_required_welcome_message) %>
+<% if SiteSetting.login_required %>
+  <%= markdown_content(:login_required_welcome_message) %>
+<% end %>

config/locales/server.en.yml

@@ -20,6 +20,7 @@ en:
   posts: "posts"
   loading: "Loading"
   powered_by_html: 'Powered by <a href="http://www.discourse.org">Discourse</a>, best viewed with JavaScript enabled'
+  log_in: "Log In"
 
   via: "%{username} via %{site_name}"
   is_reserved: "is reserved"

config/routes.rb

@@ -155,6 +155,7 @@ Discourse::Application.routes.draw do
   get "faq" => "static#show", id: "faq"
   get "tos" => "static#show", id: "tos"
   get "privacy" => "static#show", id: "privacy"
+  get "signup" => "list#latest"
 
   get "users/search/users" => "users#search_users"
   get "users/password-reset/:token" => "users#password_reset"