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diff --git a/guides/source/i18n.md b/guides/source/i18n.md index eda1881e73..33daa79133 100644 --- a/guides/source/i18n.md +++ b/guides/source/i18n.md @@ -7,21 +7,28 @@ The process of "internationalization" usually means to abstract all strings and So, in the process of _internationalizing_ your Rails application you have to: -* Ensure you have support for i18n -* Tell Rails where to find locale dictionaries -* Tell Rails how to set, preserve and switch locales +* Ensure you have support for i18n. +* Tell Rails where to find locale dictionaries. +* Tell Rails how to set, preserve and switch locales. In the process of _localizing_ your application you'll probably want to do the following three things: -* Replace or supplement Rails' default locale -- e.g. date and time formats, month names, Active Record model names, etc. -* Abstract strings in your application into keyed dictionaries -- e.g. flash messages, static text in your views, etc. -* Store the resulting dictionaries somewhere +* Replace or supplement Rails' default locale - e.g. date and time formats, month names, Active Record model names, etc. +* Abstract strings in your application into keyed dictionaries - e.g. flash messages, static text in your views, etc. +* Store the resulting dictionaries somewhere. This guide will walk you through the I18n API and contains a tutorial on how to internationalize a Rails application from the start. +After reading this guide, you will know: + +* How I18n works in Ruby on Rails +* How to correctly use I18n into a RESTful application in various ways +* How to use I18n to translate ActiveRecord errors or ActionMailer E-mail subjects +* Some other tools to go further with the translation process of your application + -------------------------------------------------------------------------------- -NOTE: The Ruby I18n framework provides you with all necessary means for internationalization/localization of your Rails application. You may, however, use any of various plugins and extensions available, which add additional functionality or features. See the Rails [I18n Wiki](http://rails-i18n.org/wiki) for more information. +NOTE: The Ruby I18n framework provides you with all necessary means for internationalization/localization of your Rails application. You may, however, use any of various plugins and extensions available, which add additional functionality or features. See the Ruby [I18n Wiki](http://ruby-i18n.org/wiki) for more information. How I18n in Ruby on Rails Works ------------------------------- @@ -31,13 +38,13 @@ Internationalization is a complex problem. Natural languages differ in so many w * providing support for English and similar languages out of the box * making it easy to customize and extend everything for other languages -As part of this solution, **every static string in the Rails framework** -- e.g. Active Record validation messages, time and date formats -- **has been internationalized**, so _localization_ of a Rails application means "over-riding" these defaults. +As part of this solution, **every static string in the Rails framework** - e.g. Active Record validation messages, time and date formats - **has been internationalized**, so _localization_ of a Rails application means "over-riding" these defaults. ### The Overall Architecture of the Library Thus, the Ruby I18n gem is split into two parts: -* The public API of the i18n framework -- a Ruby module with public methods that define how the library works +* The public API of the i18n framework - a Ruby module with public methods that define how the library works * A default backend (which is intentionally named _Simple_ backend) that implements these methods As a user you should always only access the public methods on the I18n module, but it is useful to know about the capabilities of the backend. @@ -90,17 +97,17 @@ en: hello: "Hello world" ``` -This means, that in the `:en` locale, the key _hello_ will map to the _Hello world_ string. Every string inside Rails is internationalized in this way, see for instance Active Record validation messages in the [`activerecord/lib/active_record/locale/en.yml`](https://github.com/rails/rails/blob/master/activerecord/lib/active_record/locale/en.yml file or time and date formats in the [`activesupport/lib/active_support/locale/en.yml`](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml) file. You can use YAML or standard Ruby Hashes to store translations in the default (Simple) backend. +This means, that in the `:en` locale, the key _hello_ will map to the _Hello world_ string. Every string inside Rails is internationalized in this way, see for instance Active Model validation messages in the [`activemodel/lib/active_model/locale/en.yml`](https://github.com/rails/rails/blob/master/activemodel/lib/active_model/locale/en.yml) file or time and date formats in the [`activesupport/lib/active_support/locale/en.yml`](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml) file. You can use YAML or standard Ruby Hashes to store translations in the default (Simple) backend. The I18n library will use **English** as a **default locale**, i.e. if you don't set a different locale, `:en` will be used for looking up translations. -NOTE: The i18n library takes a **pragmatic approach** to locale keys (after [some discussion](http://groups.google.com/group/rails-i18n/browse_thread/thread/14dede2c7dbe9470/80eec34395f64f3c?hl=en), including only the _locale_ ("language") part, like `:en`, `:pl`, not the _region_ part, like `:en-US` or `:en-GB`, which are traditionally used for separating "languages" and "regional setting" or "dialects". Many international applications use only the "language" element of a locale such as `:cs`, `:th` or `:es` (for Czech, Thai and Spanish). However, there are also regional differences within different language groups that may be important. For instance, in the `:en-US` locale you would have $ as a currency symbol, while in `:en-GB`, you would have £. Nothing stops you from separating regional and other settings in this way: you just have to provide full "English - United Kingdom" locale in a `:en-GB` dictionary. Various [Rails I18n plugins](http://rails-i18n.org/wiki) such as [Globalize2](https://github.com/joshmh/globalize2/tree/master) may help you implement it. +NOTE: The i18n library takes a **pragmatic approach** to locale keys (after [some discussion](http://groups.google.com/group/rails-i18n/browse_thread/thread/14dede2c7dbe9470/80eec34395f64f3c?hl=en), including only the _locale_ ("language") part, like `:en`, `:pl`, not the _region_ part, like `:en-US` or `:en-GB`, which are traditionally used for separating "languages" and "regional setting" or "dialects". Many international applications use only the "language" element of a locale such as `:cs`, `:th` or `:es` (for Czech, Thai and Spanish). However, there are also regional differences within different language groups that may be important. For instance, in the `:en-US` locale you would have $ as a currency symbol, while in `:en-GB`, you would have £. Nothing stops you from separating regional and other settings in this way: you just have to provide full "English - United Kingdom" locale in a `:en-GB` dictionary. Various [Rails I18n plugins](http://rails-i18n.org/wiki) such as [Globalize3](https://github.com/svenfuchs/globalize3) may help you implement it. The **translations load path** (`I18n.load_path`) is just a Ruby Array of paths to your translation files that will be loaded automatically and available in your application. You can pick whatever directory and translation file naming scheme makes sense for you. NOTE: The backend will lazy-load these translations when a translation is looked up for the first time. This makes it possible to just swap the backend with something else even after translations have already been announced. -The default initializer `locale.rb` file has instructions on how to add locales from another directory and how to set a different default locale. Just uncomment and edit the specific lines. +The default `application.rb` files has instructions on how to add locales from another directory and how to set a different default locale. Just uncomment and edit the specific lines. ```ruby # The default locale is :en and all translations from config/locales/*.rb,yml are auto loaded. @@ -130,12 +137,12 @@ If you want to translate your Rails application to a **single language other tha However, you would probably like to **provide support for more locales** in your application. In such case, you need to set and pass the locale between requests. -WARNING: You may be tempted to store the chosen locale in a _session_ or a <em>cookie</em>, however **do not do this**. The locale should be transparent and a part of the URL. This way you won't break people's basic assumptions about the web itself: if you send a URL to a friend, they should see the same page and content as you. A fancy word for this would be that you're being [<em>RESTful</em>](http://en.wikipedia.org/wiki/Representational_State_Transfer. Read more about the RESTful approach in [Stefan Tilkov's articles](http://www.infoq.com/articles/rest-introduction). Sometimes there are exceptions to this rule and those are discussed below. +WARNING: You may be tempted to store the chosen locale in a _session_ or a <em>cookie</em>, however **do not do this**. The locale should be transparent and a part of the URL. This way you won't break people's basic assumptions about the web itself: if you send a URL to a friend, they should see the same page and content as you. A fancy word for this would be that you're being [<em>RESTful</em>](http://en.wikipedia.org/wiki/Representational_State_Transfer). Read more about the RESTful approach in [Stefan Tilkov's articles](http://www.infoq.com/articles/rest-introduction). Sometimes there are exceptions to this rule and those are discussed below. -The _setting part_ is easy. You can set the locale in a `before_filter` in the `ApplicationController` like this: +The _setting part_ is easy. You can set the locale in a `before_action` in the `ApplicationController` like this: ```ruby -before_filter :set_locale +before_action :set_locale def set_locale I18n.locale = params[:locale] || I18n.default_locale @@ -158,7 +165,7 @@ One option you have is to set the locale from the domain name where your applica You can implement it like this in your `ApplicationController`: ```ruby -before_filter :set_locale +before_action :set_locale def set_locale I18n.locale = extract_locale_from_tld || I18n.default_locale @@ -172,7 +179,7 @@ end # in your /etc/hosts file to try this out locally def extract_locale_from_tld parsed_locale = request.host.split('.').last - I18n.available_locales.include?(parsed_locale.to_sym) ? parsed_locale : nil + I18n.available_locales.include?(parsed_locale.to_sym) ? parsed_locale : nil end ``` @@ -201,11 +208,11 @@ This solution has aforementioned advantages, however, you may not be able or may ### Setting the Locale from the URL Params -The most usual way of setting (and passing) the locale would be to include it in URL params, as we did in the `I18n.locale = params[:locale]` _before_filter_ in the first example. We would like to have URLs like `www.example.com/books?locale=ja` or `www.example.com/ja/books` in this case. +The most usual way of setting (and passing) the locale would be to include it in URL params, as we did in the `I18n.locale = params[:locale]` _before_action_ in the first example. We would like to have URLs like `www.example.com/books?locale=ja` or `www.example.com/ja/books` in this case. This approach has almost the same set of advantages as setting the locale from the domain name: namely that it's RESTful and in accord with the rest of the World Wide Web. It does require a little bit more work to implement, though. -Getting the locale from `params` and setting it accordingly is not hard; including it in every URL and thus **passing it through the requests** is. To include an explicit option in every URL (e.g. `link_to( books_url(:locale => I18n.locale))`) would be tedious and probably impossible, of course. +Getting the locale from `params` and setting it accordingly is not hard; including it in every URL and thus **passing it through the requests** is. To include an explicit option in every URL (e.g. `link_to( books_url(locale: I18n.locale))`) would be tedious and probably impossible, of course. Rails contains infrastructure for "centralizing dynamic decisions about the URLs" in its [`ApplicationController#default_url_options`](http://api.rubyonrails.org/classes/ActionController/Base.html#M000515, which is useful precisely in this scenario: it enables us to set "defaults" for [`url_for`](http://api.rubyonrails.org/classes/ActionController/Base.html#M000503) and helper methods dependent on it (by implementing/overriding this method). @@ -215,7 +222,7 @@ We can include something like this in our `ApplicationController` then: # app/controllers/application_controller.rb def default_url_options(options={}) logger.debug "default_url_options is passed options: #{options.inspect}\n" - { :locale => I18n.locale } + { locale: I18n.locale } end ``` @@ -238,29 +245,29 @@ If you don't want to force the use of a locale in your routes you can use an opt ```ruby # config/routes.rb -scope "(:locale)", :locale => /en|nl/ do +scope "(:locale)", locale: /en|nl/ do resources :books end ``` With this approach you will not get a `Routing Error` when accessing your resources such as `http://localhost:3001/books` without a locale. This is useful for when you want to use the default locale when one is not specified. -Of course, you need to take special care of the root URL (usually "homepage" or "dashboard") of your application. An URL like `http://localhost:3001/nl` will not work automatically, because the `root :to => "books#index"` declaration in your `routes.rb` doesn't take locale into account. (And rightly so: there's only one "root" URL.) +Of course, you need to take special care of the root URL (usually "homepage" or "dashboard") of your application. An URL like `http://localhost:3001/nl` will not work automatically, because the `root to: "books#index"` declaration in your `routes.rb` doesn't take locale into account. (And rightly so: there's only one "root" URL.) You would probably need to map URLs like these: ```ruby # config/routes.rb -match '/:locale' => 'dashboard#index' +get '/:locale' => 'dashboard#index' ``` Do take special care about the **order of your routes**, so this route declaration does not "eat" other ones. (You may want to add it directly before the `root :to` declaration.) -NOTE: Have a look at two plugins which simplify work with routes in this way: Sven Fuchs's [routing_filter](https://github.com/svenfuchs/routing-filter/tree/master and Raul Murciano's [translate_routes](https://github.com/raul/translate_routes/tree/master). +NOTE: Have a look at two plugins which simplify work with routes in this way: Sven Fuchs's [routing_filter](https://github.com/svenfuchs/routing-filter/tree/master) and Raul Murciano's [translate_routes](https://github.com/raul/translate_routes/tree/master). ### Setting the Locale from the Client Supplied Information -In specific cases, it would make sense to set the locale from client-supplied information, i.e. not from the URL. This information may come for example from the users' preferred language (set in their browser), can be based on the users' geographical location inferred from their IP, or users can provide it simply by choosing the locale in your application interface and saving it to their profile. This approach is more suitable for web-based applications or services, not for websites -- see the box about _sessions_, _cookies_ and RESTful architecture above. +In specific cases, it would make sense to set the locale from client-supplied information, i.e. not from the URL. This information may come for example from the users' preferred language (set in their browser), can be based on the users' geographical location inferred from their IP, or users can provide it simply by choosing the locale in your application interface and saving it to their profile. This approach is more suitable for web-based applications or services, not for websites - see the box about _sessions_, _cookies_ and RESTful architecture above. #### Using `Accept-Language` @@ -275,21 +282,22 @@ def set_locale I18n.locale = extract_locale_from_accept_language_header logger.debug "* Locale set to '#{I18n.locale}'" end + private -def extract_locale_from_accept_language_header - request.env['HTTP_ACCEPT_LANGUAGE'].scan(/^[a-z]{2}/).first -end + def extract_locale_from_accept_language_header + request.env['HTTP_ACCEPT_LANGUAGE'].scan(/^[a-z]{2}/).first + end ``` -Of course, in a production environment you would need much more robust code, and could use a plugin such as Iain Hecker's [http_accept_language](https://github.com/iain/http_accept_language/tree/master or even Rack middleware such as Ryan Tomayko's [locale](https://github.com/rack/rack-contrib/blob/master/lib/rack/contrib/locale.rb). +Of course, in a production environment you would need much more robust code, and could use a plugin such as Iain Hecker's [http_accept_language](https://github.com/iain/http_accept_language/tree/master) or even Rack middleware such as Ryan Tomayko's [locale](https://github.com/rack/rack-contrib/blob/master/lib/rack/contrib/locale.rb). #### Using GeoIP (or Similar) Database -Another way of choosing the locale from client information would be to use a database for mapping the client IP to the region, such as [GeoIP Lite Country](http://www.maxmind.com/app/geolitecountry). The mechanics of the code would be very similar to the code above -- you would need to query the database for the user's IP, and look up your preferred locale for the country/region/city returned. +Another way of choosing the locale from client information would be to use a database for mapping the client IP to the region, such as [GeoIP Lite Country](http://www.maxmind.com/app/geolitecountry). The mechanics of the code would be very similar to the code above - you would need to query the database for the user's IP, and look up your preferred locale for the country/region/city returned. #### User Profile -You can also provide users of your application with means to set (and possibly over-ride) the locale in your application interface, as well. Again, mechanics for this approach would be very similar to the code above -- you'd probably let users choose a locale from a dropdown list and save it to their profile in the database. Then you'd set the locale to this value. +You can also provide users of your application with means to set (and possibly over-ride) the locale in your application interface, as well. Again, mechanics for this approach would be very similar to the code above - you'd probably let users choose a locale from a dropdown list and save it to their profile in the database. Then you'd set the locale to this value. Internationalizing your Application ----------------------------------- @@ -303,7 +311,18 @@ You most probably have something like this in one of your applications: ```ruby # config/routes.rb Yourapp::Application.routes.draw do - root :to => "home#index" + root to: "home#index" +end +``` + +```ruby +# app/controllers/application_controller.rb +class ApplicationController < ActionController::Base + before_action :set_locale + + def set_locale + I18n.locale = params[:locale] || I18n.default_locale + end end ``` @@ -381,7 +400,7 @@ You can use variables in the translation messages and pass their values from the ```erb # app/views/home/index.html.erb -<%=t 'greet_username', :user => "Bill", :message => "Goodbye" %> +<%=t 'greet_username', user: "Bill", message: "Goodbye" %> ``` ```yaml @@ -392,13 +411,13 @@ en: ### Adding Date/Time Formats -OK! Now let's add a timestamp to the view, so we can demo the **date/time localization** feature as well. To localize the time format you pass the Time object to `I18n.l` or (preferably) use Rails' `#l` helper. You can pick a format by passing the `:format` option -- by default the `:default` format is used. +OK! Now let's add a timestamp to the view, so we can demo the **date/time localization** feature as well. To localize the time format you pass the Time object to `I18n.l` or (preferably) use Rails' `#l` helper. You can pick a format by passing the `:format` option - by default the `:default` format is used. ```erb # app/views/home/index.html.erb <h1><%=t :hello_world %></h1> <p><%= flash[:notice] %></p -<p><%= l Time.now, :format => :short %></p> +<p><%= l Time.now, format: :short %></p> ``` And in our pirate translations file let's add a time format (it's already there in Rails' defaults for English): @@ -415,7 +434,7 @@ So that would give you:  -TIP: Right now you might need to add some more date/time formats in order to make the I18n backend work as expected (at least for the 'pirate' locale). Of course, there's a great chance that somebody already did all the work by **translating Rails' defaults for your locale**. See the [rails-i18n repository at Github](https://github.com/svenfuchs/rails-i18n/tree/master/rails/locale) for an archive of various locale files. When you put such file(s) in `config/locales/` directory, they will automatically be ready for use. +TIP: Right now you might need to add some more date/time formats in order to make the I18n backend work as expected (at least for the 'pirate' locale). Of course, there's a great chance that somebody already did all the work by **translating Rails' defaults for your locale**. See the [rails-i18n repository at GitHub](https://github.com/svenfuchs/rails-i18n/tree/master/rails/locale) for an archive of various locale files. When you put such file(s) in `config/locales/` directory, they will automatically be ready for use. ### Inflection Rules For Other Locales @@ -492,10 +511,10 @@ I18n.t :message I18n.t 'message' ``` -The `translate` method also takes a `:scope` option which can contain one or more additional keys that will be used to specify a “namespace” or scope for a translation key: +The `translate` method also takes a `:scope` option which can contain one or more additional keys that will be used to specify a "namespace" or scope for a translation key: ```ruby -I18n.t :record_invalid, :scope => [:activerecord, :errors, :messages] +I18n.t :record_invalid, scope: [:activerecord, :errors, :messages] ``` This looks up the `:record_invalid` message in the Active Record error messages. @@ -510,9 +529,9 @@ Thus the following calls are equivalent: ```ruby I18n.t 'activerecord.errors.messages.record_invalid' -I18n.t 'errors.messages.record_invalid', :scope => :active_record -I18n.t :record_invalid, :scope => 'activerecord.errors.messages' -I18n.t :record_invalid, :scope => [:activerecord, :errors, :messages] +I18n.t 'errors.messages.record_invalid', scope: :active_record +I18n.t :record_invalid, scope: 'activerecord.errors.messages' +I18n.t :record_invalid, scope: [:activerecord, :errors, :messages] ``` #### Defaults @@ -520,7 +539,7 @@ I18n.t :record_invalid, :scope => [:activerecord, :errors, :messages] When a `:default` option is given, its value will be returned if the translation is missing: ```ruby -I18n.t :missing, :default => 'Not here' +I18n.t :missing, default: 'Not here' # => 'Not here' ``` @@ -529,7 +548,7 @@ If the `:default` value is a Symbol, it will be used as a key and translated. On E.g., the following first tries to translate the key `:missing` and then the key `:also_missing.` As both do not yield a result, the string "Not here" will be returned: ```ruby -I18n.t :missing, :default => [:also_missing, 'Not here'] +I18n.t :missing, default: [:also_missing, 'Not here'] # => 'Not here' ``` @@ -538,7 +557,7 @@ I18n.t :missing, :default => [:also_missing, 'Not here'] To look up multiple translations at once, an array of keys can be passed: ```ruby -I18n.t [:odd, :even], :scope => 'errors.messages' +I18n.t [:odd, :even], scope: 'errors.messages' # => ["must be odd", "must be even"] ``` @@ -546,7 +565,7 @@ Also, a key can translate to a (potentially nested) hash of grouped translations ```ruby I18n.t 'activerecord.errors.messages' -# => { :inclusion => "is not included in the list", :exclusion => ... } +# => {:inclusion=>"is not included in the list", :exclusion=> ... } ``` #### "Lazy" Lookup @@ -573,8 +592,8 @@ In many cases you want to abstract your translations so that **variables can be All options besides `:default` and `:scope` that are passed to `#translate` will be interpolated to the translation: ```ruby -I18n.backend.store_translations :en, :thanks => 'Thanks %{name}!' -I18n.translate :thanks, :name => 'Jeremy' +I18n.backend.store_translations :en, thanks: 'Thanks %{name}!' +I18n.translate :thanks, name: 'Jeremy' # => 'Thanks Jeremy!' ``` @@ -587,14 +606,14 @@ In English there are only one singular and one plural form for a given string, e The `:count` interpolation variable has a special role in that it both is interpolated to the translation and used to pick a pluralization from the translations according to the pluralization rules defined by CLDR: ```ruby -I18n.backend.store_translations :en, :inbox => { - :one => 'one message', - :other => '%{count} messages' +I18n.backend.store_translations :en, inbox: { + one: 'one message', + other: '%{count} messages' } -I18n.translate :inbox, :count => 2 +I18n.translate :inbox, count: 2 # => '2 messages' -I18n.translate :inbox, :count => 1 +I18n.translate :inbox, count: 1 # => 'one message' ``` @@ -623,8 +642,8 @@ I18n.l Time.now Explicitly passing a locale: ```ruby -I18n.t :foo, :locale => :de -I18n.l Time.now, :locale => :de +I18n.t :foo, locale: :de +I18n.l Time.now, locale: :de ``` The `I18n.locale` defaults to `I18n.default_locale` which defaults to :`en`. The default locale can be set like this: @@ -665,9 +684,9 @@ For example a Ruby Hash providing translations can look like this: ```ruby { - :pt => { - :foo => { - :bar => "baz" + pt: { + foo: { + bar: "baz" } } } @@ -694,13 +713,13 @@ en: long: "%B %d, %Y" ``` -So, all of the following equivalent lookups will return the `:short` date format `"%B %d"`: +So, all of the following equivalent lookups will return the `:short` date format `"%b %d"`: ```ruby I18n.t 'date.formats.short' -I18n.t 'formats.short', :scope => :date -I18n.t :short, :scope => 'date.formats' -I18n.t :short, :scope => [:date, :formats] +I18n.t 'formats.short', scope: :date +I18n.t :short, scope: 'date.formats' +I18n.t :short, scope: [:date, :formats] ``` Generally we recommend using YAML as a format for storing translations. There are cases, though, where you want to store Ruby lambdas as part of your locale data, e.g. for special date formats. @@ -724,6 +743,19 @@ en: Then `User.model_name.human` will return "Dude" and `User.human_attribute_name("login")` will return "Handle". +You can also set a plural form for model names, adding as following: + +```ruby +en: + activerecord: + models: + user: + one: Dude + other: Dudes +``` + +Then `User.model_name.human(count: 2)` will return "Dudes". With `count: 1` or without params will return "Dude". + #### Error Message Scopes Active Record validation error messages can also be translated easily. Active Record gives you a couple of namespaces where you can place your message translations in order to provide different messages and translation for certain models, attributes, and/or validations. It also transparently takes single table inheritance into account. @@ -734,7 +766,7 @@ Consider a User model with a validation for the name attribute like this: ```ruby class User < ActiveRecord::Base - validates :name, :presence => true + validates :name, presence: true end ``` @@ -764,7 +796,7 @@ For example, you might have an Admin model inheriting from User: ```ruby class Admin < User - validates :name, :presence => true + validates :name, presence: true end ``` @@ -811,6 +843,7 @@ So, for example, instead of the default error message `"can not be blank"` you c | numericality | :equal_to | :equal_to | count | | numericality | :less_than | :less_than | count | | numericality | :less_than_or_equal_to | :less_than_or_equal_to | count | +| numericality | :only_integer | :not_an_integer | - | | numericality | :odd | :odd | - | | numericality | :even | :even | - | @@ -835,21 +868,43 @@ en: NOTE: In order to use this helper, you need to install [DynamicForm](https://github.com/joelmoss/dynamic_form) gem by adding this line to your Gemfile: `gem 'dynamic_form'`. +### Translations for Action Mailer E-Mail Subjects + +If you don't pass a subject to the `mail` method, Action Mailer will try to find +it in your translations. The performed lookup will use the pattern +`<mailer_scope>.<action_name>.subject` to construct the key. + +```ruby +# user_mailer.rb +class UserMailer < ActionMailer::Base + def welcome(user) + #... + end +end +``` + +```yaml +en: + user_mailer: + welcome: + subject: "Welcome to Rails Guides!" +``` + ### Overview of Other Built-In Methods that Provide I18n Support Rails uses fixed strings and other localizations, such as format strings and other format information in a couple of helpers. Here's a brief overview. #### Action View Helper Methods -* `distance_of_time_in_words` translates and pluralizes its result and interpolates the number of seconds, minutes, hours, and so on. See [datetime.distance_in_words](https://github.com/rails/rails/blob/master/actionpack/lib/action_view/locale/en.yml#L51) translations. +* `distance_of_time_in_words` translates and pluralizes its result and interpolates the number of seconds, minutes, hours, and so on. See [datetime.distance_in_words](https://github.com/rails/rails/blob/master/actionview/lib/action_view/locale/en.yml#L4) translations. -* `datetime_select` and `select_month` use translated month names for populating the resulting select tag. See [date.month_names](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml#L15) for translations. `datetime_select` also looks up the order option from [date.order](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml#L18) (unless you pass the option explicitly). All date selection helpers translate the prompt using the translations in the [datetime.prompts](https://github.com/rails/rails/blob/master/actionpack/lib/action_view/locale/en.yml#L83) scope if applicable. +* `datetime_select` and `select_month` use translated month names for populating the resulting select tag. See [date.month_names](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml#L15) for translations. `datetime_select` also looks up the order option from [date.order](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml#L18) (unless you pass the option explicitly). All date selection helpers translate the prompt using the translations in the [datetime.prompts](https://github.com/rails/rails/blob/master/actionview/lib/action_view/locale/en.yml#L39) scope if applicable. -* The `number_to_currency`, `number_with_precision`, `number_to_percentage`, `number_with_delimiter`, and `number_to_human_size` helpers use the number format settings located in the [number](https://github.com/rails/rails/blob/master/actionpack/lib/action_view/locale/en.yml#L2) scope. +* The `number_to_currency`, `number_with_precision`, `number_to_percentage`, `number_with_delimiter`, and `number_to_human_size` helpers use the number format settings located in the [number](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml#L37) scope. #### Active Model Methods -* `model_name.human` and `human_attribute_name` use translations for model names and attribute names if available in the [activerecord.models](https://github.com/rails/rails/blob/master/activerecord/lib/active_record/locale/en.yml#L29) scope. They also support translations for inherited class names (e.g. for use with STI) as explained above in "Error message scopes". +* `model_name.human` and `human_attribute_name` use translations for model names and attribute names if available in the [activerecord.models](https://github.com/rails/rails/blob/master/activerecord/lib/active_record/locale/en.yml#L36) scope. They also support translations for inherited class names (e.g. for use with STI) as explained above in "Error message scopes". * `ActiveModel::Errors#generate_message` (which is used by Active Model validations but may also be used manually) uses `model_name.human` and `human_attribute_name` (see above). It also translates the error message and supports translations for inherited class names as explained above in "Error message scopes". @@ -857,7 +912,7 @@ Rails uses fixed strings and other localizations, such as format strings and oth #### Active Support Methods -* `Array#to_sentence` uses format settings as given in the [support.array](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml#L30) scope. +* `Array#to_sentence` uses format settings as given in the [support.array](https://github.com/rails/rails/blob/master/activesupport/lib/active_support/locale/en.yml#L33) scope. Customize your I18n Setup ------------------------- @@ -891,11 +946,11 @@ ReservedInterpolationKey # the translation contains a reserved interpolation UnknownFileType # the backend does not know how to handle a file type that was added to I18n.load_path ``` -The I18n API will catch all of these exceptions when they are thrown in the backend and pass them to the default_exception_handler method. This method will re-raise all exceptions except for `MissingTranslationData` exceptions. When a `MissingTranslationData` exception has been caught, it will return the exception’s error message string containing the missing key/scope. +The I18n API will catch all of these exceptions when they are thrown in the backend and pass them to the default_exception_handler method. This method will re-raise all exceptions except for `MissingTranslationData` exceptions. When a `MissingTranslationData` exception has been caught, it will return the exception's error message string containing the missing key/scope. The reason for this is that during development you'd usually want your views to still render even though a translation is missing. -In other contexts you might want to change this behaviour, though. E.g. the default exception handling does not allow to catch missing translations during automated tests easily. For this purpose a different exception handler can be specified. The specified exception handler must be a method on the I18n module or a class with `#call` method: +In other contexts you might want to change this behavior, though. E.g. the default exception handling does not allow to catch missing translations during automated tests easily. For this purpose a different exception handler can be specified. The specified exception handler must be a method on the I18n module or a class with `#call` method: ```ruby module I18n @@ -925,12 +980,12 @@ else end ``` -Another example where the default behaviour is less desirable is the Rails TranslationHelper which provides the method `#t` (as well as `#translate`). When a `MissingTranslationData` exception occurs in this context, the helper wraps the message into a span with the CSS class `translation_missing`. +Another example where the default behavior is less desirable is the Rails TranslationHelper which provides the method `#t` (as well as `#translate`). When a `MissingTranslationData` exception occurs in this context, the helper wraps the message into a span with the CSS class `translation_missing`. To do so, the helper forces `I18n#translate` to raise exceptions no matter what exception handler is defined by setting the `:raise` option: ```ruby -I18n.t :foo, :raise => true # always re-raises exceptions from the backend +I18n.t :foo, raise: true # always re-raises exceptions from the backend ``` Conclusion @@ -956,8 +1011,8 @@ Resources * [rails-i18n.org](http://rails-i18n.org) - Homepage of the rails-i18n project. You can find lots of useful resources on the [wiki](http://rails-i18n.org/wiki). * [Google group: rails-i18n](http://groups.google.com/group/rails-i18n) - The project's mailing list. -* [Github: rails-i18n](https://github.com/svenfuchs/rails-i18n/tree/master) - Code repository for the rails-i18n project. Most importantly you can find lots of [example translations](https://github.com/svenfuchs/rails-i18n/tree/master/rails/locale) for Rails that should work for your application in most cases. -* [Github: i18n](https://github.com/svenfuchs/i18n/tree/master) - Code repository for the i18n gem. +* [GitHub: rails-i18n](https://github.com/svenfuchs/rails-i18n/tree/master) - Code repository for the rails-i18n project. Most importantly you can find lots of [example translations](https://github.com/svenfuchs/rails-i18n/tree/master/rails/locale) for Rails that should work for your application in most cases. +* [GitHub: i18n](https://github.com/svenfuchs/i18n/tree/master) - Code repository for the i18n gem. * [Lighthouse: rails-i18n](http://i18n.lighthouseapp.com/projects/14948-rails-i18n/overview) - Issue tracker for the rails-i18n project. * [Lighthouse: i18n](http://i18n.lighthouseapp.com/projects/14947-ruby-i18n/overview) - Issue tracker for the i18n gem. |