Set locale based on Accept-Language header

Gemfile

@@ -28,6 +28,7 @@ gem 'high_voltage', '~> 3.0.0'
 gem 'bugsnag'
 gem 'rack-cors', :require => 'rack/cors'
 gem 'rack-jsonp'
+gem 'http_accept_language'
 
 # Upgraded to 1.0.0 for Rails 5.1.4
 gem 'activeadmin', '~> 1.0.0'

Gemfile.lock

@@ -190,6 +190,7 @@ GEM
       activesupport (>= 4.1, < 5.2)
     hashie (3.5.6)
     high_voltage (3.0.0)
+    http_accept_language (2.1.1)
     i18n (0.8.6)
     i18n_data (0.8.0)
     ice_nine (0.11.2)
@@ -407,6 +408,7 @@ DEPENDENCIES
   grape-swagger (~> 0.7.2)
   haml
   high_voltage (~> 3.0.0)
+  http_accept_language
   jbuilder (~> 2.5)
   jquery-rails
   kaminari (~> 0.17.0)
@@ -436,4 +438,4 @@ RUBY VERSION
    ruby 2.3.1p112
 
 BUNDLED WITH
-   1.14.6
+   1.15.3

app/controllers/application_controller.rb

@@ -3,9 +3,18 @@ class ApplicationController < ActionController::Base
   # For APIs, you may want to use :null_session instead.
   protect_from_forgery with: :exception
   before_action :mobile_filter_header
+  before_action :set_locale
 
   def mobile_filter_header
     @mobile = true
   end
 
+  def mobile_filter_header
+    @mobile = true
+  end
+
+   def set_locale
+     I18n.locale = http_accept_language.language_region_compatible_from(I18n.available_locales)
+   end
+
 end

config/application.rb

@@ -20,5 +20,10 @@ class Application < Rails::Application
         resource "/api/*", headers: :any, methods: [:get, :post, :options]
       end
     end
+
+    # I18n stuff
+    config.i18n.load_path += Dir[Rails.root.join('config', 'locales', '**', '*.{rb,yml}')]
+    config.i18n.available_locales = [:en]
+
   end
 end