Advanced Internationalization with Rails

Advanced Internationalization with Rails Clinton R. Nixon Viget Labs

Hola! Qué tal? Me llamo Clinton R. Nixon. Soy programador de software. Vivo en los Estados Unidos. Mi cuidad es de Durham en Carolina del Norte. Hablo un poco de español. Entiendo un poco mas. Me encanta Ruby y Rails.

The current state of Rails i18n Key-value lookup ActiveRecord support Interpolation Weak pluralization Localized formats Localized views (index.es.html.erb)

Key-value lookup en: site_title: The Lost Tourist add_tourism_office: Add a New Tourism Office add_city: Add a New City es: site_title: El Turista que se Pierde add_tourism_office: Crear una Nueva Oficina de Turismo add_city: Crear una Nueva Cuidad link_to(t(:site_title), root_url)

ActiveRecord support es: activerecord: errors: messages: phone_number: "no se puede en blanco a menos que el número de teléfono de trabajo, número de teléfono móvil, o otro número de teléfono" models: business: Negocio business_plan: Plan de Negocios business_process: Función Crítica attributes: pet: name: Nombre species: Especies special_needs: Este Mascota Tiene Necesidades Especiales Médicas

Interpolation es: welcome_to: "Bienvenido a {{city}}!" t(:welcome_to, :city => @city.name)

Pluralization es: city_has_x_tourism_offices: one: "Hay {{count}} oficina de turismo de {{city}}." other: "Hay {{count}} oficinas de turismo de {{city}}." t(:city_has_x_tourism_offices, :city => @city.name, :count => @city.tourism_offices.count)

Localized formats es: number: format: # Sets the separator between the units (e.g. 1.0 / 2.0 == 0.5) separator: "," # Delimits thousands (e.g. 1,000,000 is a million) delimiter: "." # Number of decimals (1 with a precision of 2 gives: 1.00) precision: 3 # Used in number_to_currency() currency: format: # %u is the currency unit, %n the number (default: $5.00) format: "%n %u" unit: "€" # These three are to override number.format and are optional separator: "," delimiter: "." precision: 2

Localized views app/ views/ cities/ show.haml # used by default locale show.es.haml # used by :es locale

Difﬁculties File-based key-value lookup is not user-editable. Model attributes are not translated. The Rails inﬂector is not multi-lingual.

Plugins to help Newsdesk Translate translatable_columns Globalize2

Model attribute translations test "returns the value for the correct locale" do post = Post.create :subject => 'foo' I18n.locale = 'de' post.subject = 'bar' post.save I18n.locale = 'en' post = Post.first assert_equal 'foo', post.subject I18n.locale = 'de' assert_equal 'bar', post.subject end

Other Globalize2 features Locale fallbacks I18n.fallbacks[:"es-‐MX"] # => [:"es-‐MX", :es, :"en-‐US", :en] Custom pluralization @backend.add_pluralizer :cz, lambda{|c| c == 1 ? :one : (2..4).include?(c) ? :few : :other } Metadata rails = I18n.t :rails # if no translation can be found: rails.locale # => :en rails.requested_locale # => :es rails.fallback? # => true rails.options # returns the options passed to #t rails.plural_key # returns the plural_key (e.g. :one, :other) rails.original # returns the original translation

Translating models Globalize2 and translatable_models work well for this.

How to start building a backend The easiest way is to extend I18n::Backend::Simple. Key methods are: init_translations (protected) store_translations translate localize available_locales

Example: DB-backed backend class SnippetBackend < I18n::Backend::Simple # These are the only supported locales LOCALES = [:en, :es] protected def init_translations load_translations(*I18n.load_path.flatten) load_translations_from_database @initialized = true end # ... end

Storing the translations class Snippet < ActiveRecord::Base validates_presence_of :name, :en_text, :es_text validates_uniqueness_of :name validate :name_must_not_be_subset_of_other_name private def name_must_not_be_subset_of_other_name if self.name =~ /./ snippets = Snippet.find(:all, :conditions => ['name LIKE ?', "#{self.name}%"]) snippets.reject! { |s| s.id == self.id } unless self.new_record? unless snippets.empty? errors.add(:name, "must not be a subset of another snippet name") end end end end

Loading translations from DB def load_translations_from_database data = { } LOCALES.each { |locale| data[locale] = {} } Snippet.all.each do |snippet| path = snippet.name.split(".") key = path.pop current = {} LOCALES.each { |locale| current[locale] = data[locale] } path.each do |group| LOCALES.each do |locale| current[locale][group] ||= {} current[locale] = current[locale][group] end end LOCALES.each { |locale| current[locale][key] = snippet.read_attribute("#{locale}_text") } end data.each { |locale, d| merge_translations(locale, d) } end

Example: a bad idea module Traductor class GoogleBackend < I18n::Backend::Simple def translate(locale, key, options = {}) if locale.to_s == 'en' key else Translate.t(key, 'en', locale.to_s) end end end

Translation data format {:en => { "pets" => { "canine" => "dog", "feline" => "cat" }, "greeting" => "Hello!", "farewell" => "Goodbye!" }, :es => { "pets" => { "canine" => "perro", "feline" => "gato" }, "greeting" => "¡Hola!", "farewell" => "¡Hasta luego!" } } One could override merge_translations if you needed to bring in data in another format.

Improving inﬂections Let’s make the Rails inﬂector multilingual! This will be incredibly invasive, full of monkey- patching, and quite dangerous.

Why? Generated forms: Formtastic, Typus %h2= City.human_name.pluralize

Black magic module ActiveSupport::Inflector def inflections(locale = nil) locale ||= I18n.locale locale_class = ActiveSupport::Inflector.const_get( "Inflections_#{locale}") rescue nil if locale_class.nil? ActiveSupport::Inflector.module_eval %{ class ActiveSupport::Inflector::Inflections_#{locale} < ActiveSupport::Inflector::Inflections end } locale_class = ActiveSupport::Inflector.const_get( "Inflections_#{locale}") end block_given? ? yield locale_class.instance : locale_class.instance end

Success! ActiveSupport::Inflector.inflections(:es) do |inflect| inflect.plural /$/, 's' inflect.plural /([^aeioué])$/, '1es' inflect.plural /([aeiou]s)$/, '1' inflect.plural /z$/, 'ces' inflect.plural /á([sn])$/, 'a1es' inflect.plural /í([sn])$/, 'i1es' inflect.plural /ó([sn])$/, 'o1es' inflect.plural /ú([sn])$/, 'u1es' inflect.singular /s$/, '' inflect.singular /es$/, '' inflect.irregular('papá', 'papás') inflect.irregular('mamá', 'mamás') inflect.irregular('sofá', 'sofás') end

A minor problem "oficina de turismo".pluralize # => "oficina de turismos" "contacto de emergencia".pluralize # => "contacto de emergencias"

Lambdas to the rescue def pluralize(word, locale = nil) locale ||= I18n.locale result = word.to_s.dup # ... elided ... inflections(locale).plurals.each do |(rule, replacement)| if replacement.respond_to?(:call) break if result.gsub!(rule, &replacement) else break if result.gsub!(rule, replacement) end end result end

Lambdas to the rescue ActiveSupport::Inflector.inflections(:es) do |inflect| # ... elided ... inflect.plural(/^(w+)s(.+)$/, lambda { |match| head, tail = match.split(/s+/, 2) "#{head.pluralize} #{tail}" }) # ... elided ... end

Success! I18n.locale = :es "oficina de turismo".pluralize # => "oficinas de turismo" "contacto de emergencia".pluralize # => "contactos de emergencia" I18n.locale = :en "emergency contact".pluralize # => "emergency contacts"

The inﬂector is used everywhere Because of the wide-spread use of the inﬂector, we have to patch: ActiveSupport::ModelName#initialize String#pluralize, singularize AS::Inflector#pluralize, singularize, tableize ActiveRecord::Base.human_name, undecorated_table_name AR::Reflection::AssociationReflection#derive_class_name ActionController::PolymorphicRoutes#build_named_route_call

An interesting side-effect ActiveRecord::Schema.define do create_table "oficinas_de_turismo" do |t| t.string "nombre" t.string "calle" end end context "En español" do setup { I18n.default_locale = :es } context "OficinaDeTurismo" do should("use the right table") { OficinaDeTurismo.table_name }.equals "oficinas_de_turismo" end end

Muchas gracias a todos! crnixon@gmail.com http://crnixon.org http://github.com/crnixon/traductor http://delicious.com/crnixon/conferencia.rails+i18n

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Advanced Internationalization with Rails

by Clinton R. Nixon on Dec 29, 2009

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Advanced Internationalization with Rails — Presentation Transcript