I18nliner is I18n made simple.

No .yml files. Inline defaults. Optional keys. Inferred interpolation values. Wrappers and blocks, so your templates look template-y and your translations stay HTML-free.


I18nliner lets you do stuff like this:

t "Ohai %{@user.name}, my default translation is right here in the code. " \
  "Inferred keys and placeholder values, oh my!"

and even this:

<%= t do %>
  Hey <%= amigo %>!
  Although I am <%= link_to "linking to something", random_path %> and
  have some <strong>bold text</strong>, the translators will see
  <strong><em>absolutely no markup</em></strong> and will only have a
  single string to translate :o
<% end %>


Add the following to your Gemfile:

gem 'i18nliner'


No more en.yml

Instead of maintaining .yml files and doing stuff like this:

I18n.t :account_page_title

Forget the .yml and just do:

I18n.t :account_page_title, "My Account"

Regular I18n options follow the (optional) default translation, so you can do the usual stuff (placeholders, etc.).

Okay, but don't the translators need en.yml?

Sure, but you don't need to write it. Just run:

rake i18nliner:dump

This extracts all default translations from your codebase, merges them with any other ones (from rails or pre-existing .yml files), and outputs them to config/locales/generated/en.yml (or rather, "#{I18n.default_locale}.yml").

It's okay to lose your keys

Why waste time coming up with keys that are less descriptive than the default translation? I18nliner makes keys optional, so you can just do this:

I18n.t "My Account"

I18nliner will create a unique key based on the translation (e.g. :my_account), so you don't have to. See I18nliner.inferred_key_format for more information.

This can actually be a good thing, because when the en changes, the key changes, which means you know you need to get it retranslated (instead of letting a now-inaccurate translation hang out indefinitely). Whether you want to show "[ missing translation ]" or the en value in the meantime is up to you.

Inferred Interpolation Values

Interpolation values may be inferred by I18nliner if not provided. So long as it's an instance variable or method (or chain), you don't need to specify its value. So this:

  <%= t "Hello, %{user}. This request was a %{request_method}.",
        user: @user.name,
        request_method: request.method

Can just be this:

  <%= t "Hello, %{@user.name}. This request was a %{request.method}." %>

Note that local variables cannot be inferred.

Wrappers and Blocks

The Problem

Suppose you have something like this in your ERB:

  You can <%= link_to "lead", new_discussion_path %> a new discussion or
  <%= link_to "join", discussion_search_path %> an existing one.

You might try something like this:

  <%= t("You can %{lead} a new discussion or %{join} an existing one.",
        lead: link_to(t("lead"), new_discussion_path),
        join: link_to(t("join"), discussion_search_path)).html_safe

This is not great, because:

  1. There are three strings to translate.
  2. When translating the verbs, the translator has no context for where it's being used... Is "lead" a verb or a noun?
  3. Translators have their hands somewhat tied as far as what is inside the links and what is not.

So you might try this instead:

  <%= t :discussion_html,
        "You can <a href="%{lead_url}">lead</a> a new discussion or " \
        "<a href="%{join_url}">join</a> an existing one.",
        lead_url: new_discussion_path,
        join_url: discussion_search_path

This isn't much better, because now you have HTML in your translations. If you want to add a class to the link, you have to go update all the translations. A translator could accidentally break your page (or worse, cross-site script it).

So what do you do?


I18nliner lets you specify wrappers, so you can keep HTML out the translations, while still just having a single string needing translation:

  <%= t "You can *lead* a new discussion or **join** an existing one.",
        wrappers: [
          link_to('\1', new_discussion_path),
          link_to('\1', discussion_search_path)

Default delimiters are increasing numbers of asterisks, but you can specify any string as a delimiter by using a hash rather than an array.


But wait, there's more!

Perhaps you want your templates to look like, well, templates. Try this:

  <%= t do %>
    Welcome to the internets, <%= user.name %>
  <% end %>

Or even this:

  <%= t do %>
    <b>Ohai <%= user.name %>,</b>
    you can <%= link_to "lead", new_discussion_path %> a new discussion or
    <%= link_to "join", discussion_search_path %> an existing one.
  <% end %>

In case you're curious about the man behind the curtain, I18nliner adds an ERB pre-processor that turns the second example into something like this right before it hits ERB:

  <%= t :some_unique_key,
        "*Ohai %{user_name}*, you can **lead** a new discussion or ***join*** an existing one.",
        user_name: user.name,
        wrappers: [
          link_to('\1', new_discussion_path),
          link_to('\1', discussion_search_path)

In other words, it will infer wrappers from your (balanced) markup and link_to calls, and will create placeholders for any other (inline) ERB expressions. ERB statements (e.g. <% if some_condition %>...) and block expressions (e.g. <%= form_for @person do %>...) are not supported within a block translation. The only exception to this rule is nested translation calls, e.g. this is totally fine:

<%= t do %>
  Be sure to
  <a href="/account/" title="<%= t do %>Account Settings<% end %>">
    set up your account
<% end %>

HTML Safety

I18nliner ensures translations, interpolated values, and wrappers all play nicely (and safely) when it comes to HTML escaping. If any translation, interpolated value, or wrapper is HTML-safe, everything else will be HTML- escaped.

Inline Pluralization Support

Pluralization can be tricky, but I18n gives you some flexibility. I18nliner brings this inline with a default translation hash, e.g.

t({one: "There is one light!", other: "There are %{count} lights!"},
  count: picard.visible_lights.count)

Note that the :count interpolation value needs to be explicitly set when doing pluralization.

If you just want to pluralize a single word, there's a shortcut:

t "person", count: users.count

This is equivalent to:

t({one: "1 person", other: "%{count} people"},
  count: users.count)

I18nliner uses String#pluralize to determine the default one/other values, so if your I18n.default_locale is something other than English, you may need to add some inflections.

Rake Tasks


Ensures that there are no problems with your translate calls (e.g. missing interpolation values, reusing a key for a different translation, etc.). Go add this to your Jenkins/Travis tasks.


Does an i18nliner:check, and then extracts all default translations from your codebase, merges them with any other ones (from rails or pre-existing .yml files), and outputs them to config/locales/generated/en.yml.

Dynamic Translations

Note that check and dump commands require all translation keys and defaults to be literals. This is because it reads your code, it doesn't run it. If you know what you are doing and want to pass in a variable or other expression, you can use the t! (or translate!) method. It works the same as t at runtime, but signals to the extractor that it shouldn't complain. You should only do this if you are sure that the specified key/string is extracted elsewhere or already in your yml.

.i18nignore and more

By default, the check and dump tasks will look for inline translations in any .rb or .erb files. You can tell it to always skip certain files/directories/patterns by creating a .i18nignore file. The syntax is the same as .gitignore, though it supports a few extra things.

If you only want to check a particular file/directory/pattern, you can set the environment variable ONLY when you run the command, e.g.

rake i18nliner:check ONLY=/app/**/user*


I18nliner is backwards compatible with I18n, so you can add it to an established (and already internationalized) Rails app. Your existing translation calls, keys and yml files will still just work without modification.

I18nliner requires at least Ruby 1.9.3 and Rails 3.


Copyright (c) 2015 Jon Jensen, released under the MIT license