locale prefix support:

* set locale based on request header
* enforce locale path prefix when current locale is not the default
* note: don't use root_path anymore, instead use home_path

1 files changed, 62 insertions, 6 deletions

diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index de8d06b..35d6cb4 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -1,13 +1,14 @@
 class ApplicationController < ActionController::Base
   protect_from_forgery
+  before_filter :set_locale
   before_filter :no_cache_header
   before_filter :no_frame_header
+  before_filter :language_header
 
   ActiveSupport.run_load_hooks(:application_controller, self)
 
   protected
 
-
   rescue_from StandardError do |e|
     respond_to do |format|
       format.json { render_json_error(e) }
@@ -32,13 +33,59 @@ class ApplicationController < ActionController::Base
   end
   helper_method :bold
 
+  ##
+  ## LOCALE
+  ##
+
   #
-  # we want to prevent the browser from caching anything, just to be safe.
+  # URL paths for which we don't enforce the locale as the prefix of the path.
   #
-  def no_cache_header
-    response.headers["Cache-Control"] = "no-cache, no-store, must-revalidate"
-    response.headers["Pragma"] = "no-cache"
-    response.headers["Expires"] = "0"
+  NON_LOCALE_PATHS = /^\/(assets|webfinger|.well-known|rails|key|[0-9]+)($|\/)/
+
+  #
+  # Before filter to set the current locale. Possible outcomes:
+  #
+  #   (a) do nothing for certain routes and requests.
+  #   (b) if path already starts with locale, set I18n.locale and default_url_options.
+  #   (c) otherwise, redirect so that path starts with locale.
+  #
+  # If the locale happens to be the default local, no paths are prefixed with the locale.
+  #
+  def set_locale
+    if request.method == "GET" && request.format == 'text/html' && request.path !~ NON_LOCALE_PATHS
+      if params[:locale] && LOCALES_STRING.include?(params[:locale])
+        I18n.locale = params[:locale]
+        update_default_url_options
+      else
+        I18n.locale = http_accept_language.compatible_language_from(I18n.available_locales) || I18n.default_locale
+        update_default_url_options
+        if I18n.locale != I18n.default_locale
+          redirect_to url_for(params.merge(:locale => I18n.locale))
+        end
+      end
+    else
+      update_default_url_options
+    end
+  end
+
+  def update_default_url_options
+    if I18n.locale != I18n.default_locale
+      self.default_url_options[:locale] = I18n.locale
+    else
+      self.default_url_options[:locale] = nil
+    end
+  end
+
+  ##
+  ## HTTP HEADERS
+  ## These are in individual helpers so that controllers can disable them if needed.
+  ##
+
+  #
+  # Not necessary, but kind to let the browser know the current locale.
+  #
+  def language_header
+    response.headers["Content-Language"] = I18n.locale.to_s
   end
 
   #
@@ -48,4 +95,13 @@ class ApplicationController < ActionController::Base
     response.headers["X-Frame-Options"] = "DENY"
   end
 
+  #
+  # we want to prevent the browser from caching anything, just to be safe.
+  #
+  def no_cache_header
+    response.headers["Cache-Control"] = "no-cache, no-store, must-revalidate"
+    response.headers["Pragma"] = "no-cache"
+    response.headers["Expires"] = "0"
+  end
+
 end