How can I put a select box on my rails application to choose the language of the site?

Question

I'm new to rails, and I already learned how to use locales to change my website language, but I'd like to put a selectbox on the rightside of my navbar that could pass a variable/session to change the whole website language. Would that be possible ? I'm using windows with Ruby: 1.9.3, Rails:3.2.2

This is my navbar on "layouts/application.html.erb" so far:

<div class="upmenu">
    <ul align="left">
        <li><a href="/issues"><%=t "nav.issues.list" %></a></li>
        <li><a href="/issues/new"><%=t "nav.issues.new" %></a></li>
        <li><a href="/timeline/index"><%=t "nav.timeline" %></a></li>
        <li><a href="/projects"><%=t "nav.projects" %></a></li>
        <%= yield :nav %>       
    </ul>
    <ul id="language">
        <li><%= select_tag(:lang, options_for_select([['Portuguese', 'pt'], ['English', 'en']])) %></li>
    </ul>
</div>

Remembering I used the following scope for my url, so it is something like >"Localhost:3000/en/issues/"

  scope "/:locale" do

    get "/timeline/index", to: "timeline#index"

    resources :projects

    resources :issues
  end

And this are my routes:

timeline_index GET    /:locale/timeline/index(.:format)    timeline#index
      projects GET    /:locale/projects(.:format)          projects#index
               POST   /:locale/projects(.:format)          projects#create
   new_project GET    /:locale/projects/new(.:format)      projects#new
  edit_project GET    /:locale/projects/:id/edit(.:format) projects#edit
       project GET    /:locale/projects/:id(.:format)      projects#show
               PUT    /:locale/projects/:id(.:format)      projects#update                                                           
               DELETE /:locale/project
               DELETE /:locale/projects/:id(.:format)      projects#destroy                                                          
.:format)            issues#index
        issues GET    /:locale/issues(.:format)            issues#index
               POST   /:locale/issues(.:format)            issues#create                                                             
               PUT    /:locale/projects/:id(.:format)      projects#update
               DELETE /:locale/projects/:id(.:format)      projects#destroy
        issues GET    /:locale/issues(.:format)            issues#index
               POST   /:locale/issues(.:format)            issues#create
     new_issue GET    /:locale/issues/new(.:format)        issues#new
    edit_issue GET    /:locale/issues/:id/edit(.:format)   issues#edit
         issue GET    /:locale/issues/:id(.:format)        issues#show
               PUT    /:locale/issues/:id(.:format)        issues#update
               DELETE /:locale/issues/:id(.:format)        issues#destroy

Answer 1

You do not necessarily have to use a select box for this.

This is the solution that I came up with:

config/application.rb

config.i18n.available_locales = [:en, :de, :es]
config.i18n.default_locale = :en

---

app/controllers/application_controller.rb

class ApplicationController

  around_action :set_locale

private

  def set_locale(&action)
    locale = params[:locale] || I18n.default_locale
    I18n.with_locale(locale, &action)
  end

end

---

app/helpers/language_helper.rb

module LanguageHelper

  LANGUAGES = {
    :en => "English",
    :de => "Deutsch",
    :es => "Español"
  }

  def language_selector
    active_locale = I18n.locale
    inactive_locales = I18n.available_locales - [active_locale]
    content_tag :li do
      elements = [
        link_to(LANGUAGES[active_locale], nil, :class => "dropdown")
      ]
      elements << content_tag(:ul) do
        links = []
        inactive_locales.each do |locale|
          link = link_to LANGUAGES[locale], params.permit(:locale).merge(:locale => locale)
          links << content_tag(:li, link)
        end
        links.join.html_safe
      end
      elements.join.html_safe
    end
  end

end

---

Now simply put language_selector where you need it, for example in the upper right corner of your page. The markup it generates is this (it might need some CSS styling and / or Javascript functionality):

<li>
  <a class="dropdown" href="/de">Deutsch</a>
  <ul>
    <li><a href="/en">English</a></li>
    <li><a href="/es">Español</a></li>
  </ul>
</li>

Enjoy!

Answer 2

yes this is possible

In your view

<li><%= select_tag(:locale, options_for_select([['Portuguese', 'pt'], ['English', 'en']])) %></li>

In your ApplicationController

before_action :set_locale
 def set_locale
    I18n.locale = params[:locale] || I18n.default_locale
  end