Generate localized routes and a localized path helper module.
This module when use
d , provides a localize/1
macro that is designed to wrap the standard Phoenix route macros such as get/3
, put/3
and resources/3
. The routes are localised for each locale configured in a Gettext
backend module that is attached to a Cldr
backend module.
Translations for the parts of a given route path are performed at compile-time and are then combined into a localised route that is added to the standard Phoenix routing framework.
As a result, users can enter URLs using localised terms which can enhance user engagement and content relevance.
Similarly, localised path and URL helpers are generated that wrap the standard Phoenix helpers to support generating localised paths and URLs.
Lastly, Localized Verified Routes, introduced in Phoenix 1.7, are supported and their use encouraged in preference to URL Helpers. Localized Verified Routes are specified with the ~q
sigil in the same manner as Phoenix Verified Routes ~p
.
The first step is to configure and install by adding ex_cldr_routes
to your list of dependencies in mix.exs
then run mix deps.get
.
def deps do
[
{:ex_cldr_routes, "~> 1.0"}
]
end
The docs can be found at https://hexdocs.pm/ex_cldr_routes.
A Cldr
backend module that configures an associated gettext
backend is required. In addition, a Gettext
backend must be configured and added to the Cldr
configuration.
Path parts (the parts between "/") are translated at compile time using Gettext
. Therefore localization can only be applied to locales that are defined in a gettext backend module that is attached to a Cldr
backend module.
The following steps should be followed to set up the configuration for localized routes and helpers:
The first step is to ensure there is a configured Gettext
backend module:
defmodule MyApp.Gettext do
use Gettext.Backend, otp_app: :my_app
end
The next step is to configure a Cldr
backend module, including configuring it with the Gettext
module defined in the first step. The MyApp.Cldr
backend module is used to instrospect the configured locales that drive the route and helper localization.
defmodule MyApp.Cldr do
use Cldr,
locales: ["en", "fr"],
default_locale: "en",
gettext: MyApp.Gettext,
providers: [Cldr.Routes]
end
Note the addition of Cldr.Routes
to the :providers
configuration key is required.
Now we can configure the router module to use the localize/1
macro by adding use MyApp.Cldr.Routes
to the module and invoke the localize/1
macro to wrap the required routes. use MyApp.Cldr.Routes
must be added after use Phoenix.Router
. For example:
defmodule MyAppWeb.Router do
use Phoenix.Router
use MyApp.Cldr.Routes
localize do
get "/pages/:page", PageController, :show
resources "/users", UserController
end
end
The following routes are generated (assuming that translations are updated in the Gettext
configuration). For this example, the :fr
translations are the same as the :en
text with _fr
appended.
% mix phx.routes MyAppWeb.Router
page_de_path GET /pages_de/:page PageController :show
page_en_path GET /pages/:page PageController :show
page_fr_path GET /pages_fr/:page PageController :show
user_de_path GET /users_de UserController :index
user_de_path GET /users_de/:id/edit UserController :edit
user_de_path GET /users_de/new UserController :new
user_de_path GET /users_de/:id UserController :show
...
A route may be defined with elements of the locale interpolated into it. These interpolatins are specified using the normal #{}
interpolation syntax. However since route translation occurs at compile time only the following interpolations are supported:
locale
will interpolate the Cldr locale namelanguage
will interpolate the Cldr language nameterritory
will interpolate the Cldr territory codeSome examples are:
localize do
get "/#{locale}/locale/pages/:page", PageController, :show
get "/#{language}/language/pages/:page", PageController, :show
get "/#{territory}/territory/pages/:page", PageController, :show
end
Warning {: .warning}
Route helpers are deprecated in favor of verified routes as of Phoenix 1.7. Like Phoenix, localization route helpers can still be generated. When using
mix phx.new my_app
, theMyAppWeb
module will includeuse Phoenix.Routes, helpers: false
. This is also the recommendation when applyinguse MyApp.Cldr.Routes
.
Manually constructing the localized helper names shown in the example above would be tedious. Therefore a LocalizedHelpers
module is generated at compile-time. Assuming the router module is called MyAppWeb.Router
then the full name of the localized helper module is MyAppWeb.Router.LocalizedHelpers
.
The functions on this module are the non-localized versions that should be used by applications (they delegate ultimately to the localized routes based upon the current locale).
The functions on the LocalizedHelpers
module all respect the current locale, based upon Cldr.get_locale/1
, and will delegate to the appropriate localized function in the Helpers
function created automatically at compile time. For example:
iex> MyApp.Cldr.put_locale("en")
iex> MyAppWeb.Router.LocalizedHelpers.page_path %Plug.Conn{}, :show, 1
"/pages/1"
iex> MyApp.Cldr.put_locale("fr")
iex> MyAppWeb.Router.LocalizedHelpers.page_path %Plug.Conn{}, :show, 1
"/pages_fr/1"
Note The localized helpers translate the path based upon the :gettext_locale_name
for the currently set Cldr
locale. It is the developers responsibility to ensure that the locale is set appropriately before calling any localized path helpers.
For convenience in introspecting routes, a module called MyApp.Router.LocalizedRoutes
is generated that can be used with the mix phx.routes
mix task. For example:
% cldr_routes % mix phx.routes MyAppWeb.Router.LocalizedRoutes
page_path GET /pages_de/:page PageController :show
page_path GET /pages/:page PageController :show
page_path GET /pages_fr/:page PageController :show
user_path GET /users_de UserController :index
user_path GET /users_de/:id/edit UserController :edit
user_path GET /users_de/new UserController :new
...
In addition, each localized path stores the Cldr
locale in the :private
field for the route under the :cldr_locale
key. This allows the developer to recognise which locale was used to generate the localized route.
This information is also used by functions in the ex_cldr_plugs library to:
Cldr.Plug.PutLocale
Cldr.Plug.PutSession
on_mount/3
callback with Cldr.Plug.put_locale_from_session/2
Sigil_q
implements localized verified routes for Phoenix 1.7 and later.
Adding
use MyApp.Cldr.VerifiedRoutes,
router: MyApp.Router,
endpoint: MyApp.Endpoint
to a module gives access to sigil_q
which is functionally equal to Phoenix Verified Routes sigil_p
. In fact the result of using sigil_q
is code that looks like this:
# ~q"/users" generates the following code for a
# Cldr backend that has configured the locales
# :en, :fr and :de
case MyApp.Cldr.get_locale().cldr_locale_name do
:de -> ~p"/users_de"
:en -> ~p"/users"
:fr -> ~p"/users_fr"
end
Some use cases call for the locale, language or territory to be part of the URL. Sigl_q
makes this easy by providing
the following interpolations into a Sigil_q
path:
:locale
is replaced with Cldr locale name.:language
is replaced with the Cldr language code.:territory
is replaced with the Cldr territory code.# ~q"/users/:locale" generates the following code for a
# Cldr backend that has configured the locales
# :en, :fr and :de. Note the interpolation of the locale
# information which is performed at compile time.
case MyApp.Cldr.get_locale().cldr_locale_name do
:de -> ~p"/users_de/de"
:en -> ~p"/users/en"
:fr -> ~p"/users_fr/fr"
end
Since localized routes, route helpers and verified routes have the same function and API as the standard Phoenix equivalent modules it is possible to update the generated Phoenix configuration. Assuming the presence of myapp_web.ex
defining the module MyAppWeb
then the following changes should be considered in the my_web_app.ex
file:
def router do
quote do
use Phoenix.Router, helpers: false
# Add localized routes
use MyApp.Cldr.Routes, helpers: false
# Import common connection and controller functions to use in pipelines
import Plug.Conn
import Phoenix.Controller
import Phoenix.LiveView.Router
end
end
Change Phoenix.VerifiedRoutes
to MyApp.Cldr.VerifiedRoutes
:
def verified_routes do
quote do
use MyApp.Cldr.VerifiedRoutes,
endpoint: PhxCldrWeb.Endpoint,
router: PhxCldrWeb.Router,
statics: PhxCldrWeb.static_paths()
end
end
When the same content is produced in multiple languages it is important to cross-link the different editions of the content to each other. This is good practise in general but strong advised by goggle to reduce SEO risks for your site.
This cross-linking can be done with the aid of HTTP headers or with <link />
tags in the <head>
section of an HTML document. Helpers are generated by ex_cldr_routes
to facilitate the creating of these links. These functions are generated in the MyAppWeb.Router.LocalizedHelpers
module (where MyAppWeb.Router
is the name of your Phoenix router module).
MyAppWeb.Router.LocalizedHelpers.<helper>_links
generated a mapping of locales for a given route to the URLs for those locales.MyAppWeb.Router.LocalizedHelpers.hreflang_links/1
take the generated map and produces link headers ready for insertion into an HTML document.The functions can be used as follows:
:assigns
defmodule MyAppWeb.UserController do
use MyAppWeb, :controller
# This alias would normally be set in the
# MyAppWeb.controller/0 and MyAppWeb.view_helpers/0
# functions
alias MyAppWeb.Router.LocalizedHelpers, as: Routes
alias MyApp.Accounts
alias MyApp.Accounts.User
def show(conn, %{"id" => id}) do
user = Accounts.get_user!(id)
hreflang_links = Routes.user_links(conn, :show, id)
render(conn, "show.html", user: user, hreflang_links: hreflang_links)
end
end
<html lang="en">
<head>
<meta charset="utf-8"/>
<meta http-equiv="X-UA-Compatible" content="IE=edge"/>
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
<%= Routes.hreflang_links(assigns[:hreflang_links]) %>
<%= csrf_meta_tag() %>
<%= live_title_tag assigns[:page_title] || "Routing", suffix: " · Phoenix Framework" %>
<link phx-track-static rel="stylesheet" href={Routes.static_path(@conn, "/assets/app.css")}/>
<script defer phx-track-static type="text/javascript" src={Routes.static_path(@conn, "/assets/app.js")}></script>
</head>
<body>
...
<%= @inner_content %>
</body>
</html>
In order for routes to be localized, translations must be provided for each path segment. This translation is performed by dgettext/3
with the domain "routes". Therefore for each configured locale, a "routes.pot" file is required containing the path segment translations for that locale.
Using the example Cldr backend that has "en" and "fr" Gettext locales then the directory structure would look like the following (if the default Gettext configuration is used):
priv/gettext
├── default.pot
├── en
│ └── LC_MESSAGES
│ ├── default.po
│ ├── errors.po
│ └── routes.po
├── errors.pot
└── fr
└── LC_MESSAGES
├── default.po
├── errors.po
└── routes.po
The mix
tasks gettext.extract
and gettext.merge
can be used to support the extraction of routing segments and to create new translation locales.