diff options
Diffstat (limited to 'guides/source/i18n.md')
| -rw-r--r-- | guides/source/i18n.md | 175 |
1 files changed, 106 insertions, 69 deletions
diff --git a/guides/source/i18n.md b/guides/source/i18n.md index 33daa79133..8340d6807f 100644 --- a/guides/source/i18n.md +++ b/guides/source/i18n.md @@ -92,7 +92,7 @@ Rails adds all `.rb` and `.yml` files from the `config/locales` directory to you The default `en.yml` locale in this directory contains a sample pair of translation strings: -```ruby +```yaml en: hello: "Hello world" ``` @@ -101,7 +101,7 @@ This means, that in the `:en` locale, the key _hello_ will map to the _Hello wor 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 [Globalize3](https://github.com/svenfuchs/globalize3) 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/globalize/globalize) 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. @@ -137,7 +137,7 @@ 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_action` in the `ApplicationController` like this: @@ -179,7 +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.map(&:to_s).include?(parsed_locale) ? parsed_locale : nil end ``` @@ -192,7 +192,7 @@ We can also set the locale from the _subdomain_ in a very similar way: # in your /etc/hosts file to try this out locally def extract_locale_from_subdomain parsed_locale = request.subdomains.first - I18n.available_locales.include?(parsed_locale.to_sym) ? parsed_locale : nil + I18n.available_locales.map(&:to_s).include?(parsed_locale) ? parsed_locale : nil end ``` @@ -212,17 +212,16 @@ The most usual way of setting (and passing) the locale would be to include it in 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). +Rails contains infrastructure for "centralizing dynamic decisions about the URLs" in its [`ApplicationController#default_url_options`](http://api.rubyonrails.org/classes/ActionDispatch/Routing/Mapper/Base.html#method-i-default_url_options), which is useful precisely in this scenario: it enables us to set "defaults" for [`url_for`](http://api.rubyonrails.org/classes/ActionDispatch/Routing/UrlFor.html#method-i-url_for) and helper methods dependent on it (by implementing/overriding this method). We can include something like this in our `ApplicationController` then: ```ruby # app/controllers/application_controller.rb -def default_url_options(options={}) - logger.debug "default_url_options is passed options: #{options.inspect}\n" - { locale: I18n.locale } +def default_url_options(options = {}) + { locale: I18n.locale }.merge options end ``` @@ -310,7 +309,7 @@ You most probably have something like this in one of your applications: ```ruby # config/routes.rb -Yourapp::Application.routes.draw do +Rails.application.routes.draw do root to: "home#index" end ``` @@ -370,7 +369,7 @@ NOTE: Rails adds a `t` (`translate`) helper method to your views so that you do So let's add the missing translations into the dictionary files (i.e. do the "localization" part): -```ruby +```yaml # config/locales/en.yml en: hello_world: Hello world! @@ -422,7 +421,7 @@ OK! Now let's add a timestamp to the view, so we can demo the **date/time locali And in our pirate translations file let's add a time format (it's already there in Rails' defaults for English): -```ruby +```yaml # config/locales/pirate.yml pirate: time: @@ -492,12 +491,14 @@ Overview of the I18n API Features You should have good understanding of using the i18n library now, knowing all necessary aspects of internationalizing a basic Rails application. In the following chapters, we'll cover it's features in more depth. +These chapters will show examples using both the `I18n.translate` method as well as the [`translate` view helper method](http://api.rubyonrails.org/classes/ActionView/Helpers/TranslationHelper.html#method-i-translate) (noting the additional feature provide by the view helper method). + Covered are features like these: * looking up translations * interpolating data into translations * pluralizing translations -* using safe HTML translations +* using safe HTML translations (view helper method only) * localizing dates, numbers, currency, etc. ### Looking up Translations @@ -585,6 +586,8 @@ you can look up the `books.index.title` value **inside** `app/views/books/index. <%= t '.title' %> ``` +NOTE: Automatic translation scoping by partial is only available from the `translate` view helper method. + ### Interpolation In many cases you want to abstract your translations so that **variables can be interpolated into the translation**. For this reason the I18n API provides an interpolation feature. @@ -654,7 +657,7 @@ I18n.default_locale = :de ### Using Safe HTML Translations -Keys with a '_html' suffix and keys named 'html' are marked as HTML safe. Use them in views without escaping. +Keys with a '_html' suffix and keys named 'html' are marked as HTML safe. When you use them in views the HTML will not be escaped. ```yaml # config/locales/en.yml @@ -673,56 +676,9 @@ en: <div><%= t('title.html') %></div> ``` - - -How to Store your Custom Translations -------------------------------------- - -The Simple backend shipped with Active Support allows you to store translations in both plain Ruby and YAML format.[^2] - -For example a Ruby Hash providing translations can look like this: - -```ruby -{ - pt: { - foo: { - bar: "baz" - } - } -} -``` - -The equivalent YAML file would look like this: - -```ruby -pt: - foo: - bar: baz -``` +NOTE: Automatic conversion to HTML safe translate text is only available from the `translate` view helper method. -As you see, in both cases the top level key is the locale. `:foo` is a namespace key and `:bar` is the key for the translation "baz". - -Here is a "real" example from the Active Support `en.yml` translations YAML file: - -```ruby -en: - date: - formats: - default: "%Y-%m-%d" - short: "%b %d" - long: "%B %d, %Y" -``` - -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] -``` - -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. + ### Translations for Active Record Models @@ -730,7 +686,7 @@ You can use the methods `Model.model_name.human` and `Model.human_attribute_name For example when you add the following translations: -```ruby +```yaml en: activerecord: models: @@ -745,7 +701,7 @@ Then `User.model_name.human` will return "Dude" and `User.human_attribute_name(" You can also set a plural form for model names, adding as following: -```ruby +```yaml en: activerecord: models: @@ -756,6 +712,19 @@ en: Then `User.model_name.human(count: 2)` will return "Dudes". With `count: 1` or without params will return "Dude". +In the event you need to access nested attributes within a given model, you should nest these under `model/attribute` at the model level of your translation file: + +```yaml +en: + activerecord: + attributes: + user/gender: + female: "Female" + male: "Male" +``` + +Then `User.human_attribute_name("gender.female")` will return "Female". + #### 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. @@ -818,7 +787,7 @@ This way you can provide special translations for various error messages at diff The translated model name, translated attribute name, and value are always available for interpolation. -So, for example, instead of the default error message `"can not be blank"` you could use the attribute name like this : `"Please fill in your %{attribute}"`. +So, for example, instead of the default error message `"cannot be blank"` you could use the attribute name like this : `"Please fill in your %{attribute}"`. * `count`, where available, can be used for pluralization if present: @@ -827,6 +796,7 @@ So, for example, instead of the default error message `"can not be blank"` you c | confirmation | - | :confirmation | - | | acceptance | - | :accepted | - | | presence | - | :blank | - | +| absence | - | :present | - | | length | :within, :in | :too_short | count | | length | :within, :in | :too_long | count | | length | :is | :wrong_length | count | @@ -890,6 +860,24 @@ en: subject: "Welcome to Rails Guides!" ``` +To send parameters to interpolation use the `default_i18n_subject` method on the mailer. + +```ruby +# user_mailer.rb +class UserMailer < ActionMailer::Base + def welcome(user) + mail(to: user.email, subject: default_i18n_subject(user: user.name)) + end +end +``` + +```yaml +en: + user_mailer: + welcome: + subject: "%{user}, 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. @@ -914,12 +902,61 @@ Rails uses fixed strings and other localizations, such as format strings and oth * `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. +How to Store your Custom Translations +------------------------------------- + +The Simple backend shipped with Active Support allows you to store translations in both plain Ruby and YAML format.[^2] + +For example a Ruby Hash providing translations can look like this: + +```yaml +{ + pt: { + foo: { + bar: "baz" + } + } +} +``` + +The equivalent YAML file would look like this: + +```yaml +pt: + foo: + bar: baz +``` + +As you see, in both cases the top level key is the locale. `:foo` is a namespace key and `:bar` is the key for the translation "baz". + +Here is a "real" example from the Active Support `en.yml` translations YAML file: + +```yaml +en: + date: + formats: + default: "%Y-%m-%d" + short: "%b %d" + long: "%B %d, %Y" +``` + +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] +``` + +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. + Customize your I18n Setup ------------------------- ### Using Different Backends -For several reasons the Simple backend shipped with Active Support only does the "simplest thing that could possibly work" _for Ruby on Rails_[^3] ... which means that it is only guaranteed to work for English and, as a side effect, languages that are very similar to English. Also, the simple backend is only capable of reading translations but can not dynamically store them to any format. +For several reasons the Simple backend shipped with Active Support only does the "simplest thing that could possibly work" _for Ruby on Rails_[^3] ... which means that it is only guaranteed to work for English and, as a side effect, languages that are very similar to English. Also, the simple backend is only capable of reading translations but cannot dynamically store them to any format. That does not mean you're stuck with these limitations, though. The Ruby I18n gem makes it very easy to exchange the Simple backend implementation with something else that fits better for your needs. E.g. you could exchange it with Globalize's Static backend: @@ -1029,7 +1066,7 @@ If you found this guide useful, please consider recommending its authors on [wor Footnotes --------- -[^1]: Or, to quote [Wikipedia](http://en.wikipedia.org/wiki/Internationalization_and_localization:) _"Internationalization is the process of designing a software application so that it can be adapted to various languages and regions without engineering changes. Localization is the process of adapting software for a specific region or language by adding locale-specific components and translating text."_ +[^1]: Or, to quote [Wikipedia](http://en.wikipedia.org/wiki/Internationalization_and_localization): _"Internationalization is the process of designing a software application so that it can be adapted to various languages and regions without engineering changes. Localization is the process of adapting software for a specific region or language by adding locale-specific components and translating text."_ [^2]: Other backends might allow or require to use other formats, e.g. a GetText backend might allow to read GetText files. |