Preserve the url hash when changing locales.

WcaOnRails/app/assets/javascripts/application.js

@@ -379,3 +379,23 @@ $(function() {
     $(this).text(formatted);
   });
 });
+
+// Handler for locale changes.
+$(function() {
+  $('#locale-selector').on('click', 'a', function(e) {
+    e.preventDefault();
+    e.stopPropagation();
+
+    // More or less copied from
+    // https://github.com/rails/jquery-ujs/blob/9e805c90c8cfc57b39967052e1e9013ccb318cf8/src/rails.js#L215.
+    var csrfToken = $('meta[name=csrf-token]').attr('content');
+    var csrfParam = $('meta[name=csrf-param]').attr('content');
+    var form = $('<form method="post" action="' + this.href + '"></form>');
+    var metadataInput = '<input name="_method" value="patch" type="hidden" />';
+    metadataInput += '<input name="' + csrfParam + '" value="' + csrfToken + '" type="hidden" />';
+    metadataInput += '<input name="current_url" value="' + window.location.toString() + '" type="hidden" />';
+
+    form.hide().append(metadataInput).appendTo('body');
+    form.submit();
+  });
+});

WcaOnRails/app/assets/stylesheets/navbar-static-top.scss

@@ -10,7 +10,7 @@
     margin-right: 10px;
   }
 
-  .dropdown-menu.countries {
+  #locale-selector {
     min-width: 0;
     li {
       text-align: left;

WcaOnRails/app/controllers/application_controller.rb

@@ -43,7 +43,7 @@ def update_locale
     else
       flash[:danger] = I18n.t('users.update_locale.unavailable')
     end
-    redirect_to request.referer || root_path
+    redirect_to params[:current_url] || root_path
   end
 
   # https://github.com/doorkeeper-gem/doorkeeper/wiki/Customizing-the-response-body-when-unauthorized

WcaOnRails/app/views/layouts/_navigation.html.erb

@@ -90,10 +90,10 @@
             <%= flag_icon active_locale_info[:flag_id] %> <span class="hidden-sm"><%= active_locale_info[:name] %></span>
             <span class="caret"></span>
           </a>
-          <ul class="dropdown-menu countries" role="menu">
+          <ul class="dropdown-menu" id="locale-selector" role="menu">
             <% Locales::AVAILABLE.each do |l, data| %>
               <li class="<%= l == I18n.locale ? "active" : "" %>">
-                <%= link_to update_locale_path(l), method: :patch do %>
+                <%= link_to update_locale_path(l) do %>
                   <%= flag_icon data[:flag_id] %> <%= data[:name] %>
                 <% end %>
               </li>

WcaOnRails/spec/controllers/application_controller_spec.rb

@@ -15,5 +15,17 @@
       expect(user.preferred_locale).to eq "fr"
       expect(session[:locale]).to eq "fr"
     end
+
+    it "redirects to given current_url" do
+      sign_in user
+      patch :update_locale, params: { locale: :fr, current_url: "http://foo.com#bar" }
+      expect(response).to redirect_to "http://foo.com#bar"
+    end
+
+    it "redirects to root if not given current_url" do
+      sign_in user
+      patch :update_locale, params: { locale: :fr }
+      expect(response).to redirect_to root_url
+    end
   end
 end

WcaOnRails/spec/features/set_locale_spec.rb

@@ -3,22 +3,31 @@
 require "rails_helper"
 
 RSpec.feature "Set the locale" do
-  context "As a visitor" do
-    let(:user) { FactoryBot.create :user }
-
-    scenario "visiting the home page and changing the locale" do
-      visit "/"
-      expect(I18n.locale).to eq I18n.default_locale
-      click_on "Français"
-      visit "/"
-      expect(I18n.locale).to eq :fr
-    end
-
-    scenario "signing in updates to the preferred_locale" do
-      user.update!(preferred_locale: "fr")
-      sign_in user
-      visit "/"
-      expect(I18n.locale).to eq :fr
-    end
+  scenario "visiting the home page while not signed in and changing the locale", js: true do
+    visit "/#foo"
+    expect(page).to have_content "English"
+    expect(page).not_to have_content "Français"
+
+    click_on "English" # Activate the locale selection dropdown.
+    click_on "Français"
+
+    expect(page.current_path).to eq "/"
+    expect(URI.parse(page.current_url).fragment).to eq "foo"
+
+    expect(page).not_to have_content "English"
+    expect(page).to have_content "Français"
+  end
+
+  scenario "signing in updates to the preferred_locale", js: true do
+    visit "/"
+    expect(page).to have_content "English"
+    expect(page).not_to have_content "Français"
+
+    user = FactoryBot.create :user, preferred_locale: "fr"
+    sign_in user
+    visit "/"
+
+    expect(page).not_to have_content "English"
+    expect(page).to have_content "Français"
   end
 end

WcaOnRails/spec/rails_helper.rb

@@ -31,6 +31,12 @@
 # If you are not using ActiveRecord, you can remove this line.
 ActiveRecord::Migration.maintain_test_schema!
 
+# To debug feature specs using phantomjs, set `Capybara.javascript_driver = :poltergeist_debug`
+# and then call `page.driver.debug` in your feature spec.
+Capybara.register_driver :poltergeist_debug do |app|
+  Capybara::Poltergeist::Driver.new(app, inspector: true, phantomjs: Phantomjs.path, debug: true)
+end
+
 Capybara.javascript_driver = :poltergeist
 Capybara.server = :webrick