Translations
The term "internationalization" (often abbreviated i18n) refers to the process of abstracting strings and other locale-specific pieces out of your application into a layer where they can be translated and converted based on the user's locale (i.e. language and country). For text, this means wrapping each with a function capable of translating the text (or "message") into the language of the user:
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// text will *always* print out in English
echo 'Hello World';
// text can be translated into the end-user's language or
// default to English
echo $translator->trans('Hello World');
Note
The term locale refers roughly to the user's language and country. It
can be any string that your application uses to manage translations and
other format differences (e.g. currency format). The ISO 639-1
language code, an underscore (_
), then the ISO 3166-1 alpha-2
country code (e.g. fr_FR
for French/France) is recommended.
Translations can be organized into groups, called domains. By default, all
messages use the default messages
domain:
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echo $translator->trans('Hello World', domain: 'messages');
The translation process has several steps:
- Enable and configure Symfony's translation service;
- Abstract strings (i.e. "messages") by wrapping them in calls to the
Translator
; - Create translation resources/files for each supported locale that translate each message in the application;
- Determine, set and manage the user's locale for the request and optionally on the user's entire session.
Installation
First, run this command to install the translator before using it:
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$ composer require symfony/translation
Configuration
The previous command creates an initial config file where you can define the default locale of the application and the directory where the translation files are located:
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# config/packages/translation.yaml
framework:
default_locale: 'en'
translator:
default_path: '%kernel.project_dir%/translations'
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<!-- config/packages/translation.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<container xmlns="http://symfony.com/schema/dic/services"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:framework="http://symfony.com/schema/dic/symfony"
xsi:schemaLocation="http://symfony.com/schema/dic/services
https://symfony.com/schema/dic/services/services-1.0.xsd
http://symfony.com/schema/dic/symfony
https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">
<framework:config default-locale="en">
<framework:translator
default-path="%kernel.project_dir%/translations"
/>
</framework:config>
</container>
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// config/packages/translation.php
use Symfony\Config\FrameworkConfig;
return static function (FrameworkConfig $framework): void {
// ...
$framework
->defaultLocale('en')
->translator()
->defaultPath('%kernel.project_dir%/translations')
;
};
Tip
You can also define the enabled_locales option to restrict the locales that your application is available in.
Basic Translation
Translation of text is done through the translator
service
(Translator). To translate a block of
text (called a message), use the
trans() method. Suppose,
for example, that you're translating a static message from inside a
controller:
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// ...
use Symfony\Contracts\Translation\TranslatorInterface;
public function index(TranslatorInterface $translator): Response
{
$translated = $translator->trans('Symfony is great');
// ...
}
When this code is run, Symfony will attempt to translate the message
"Symfony is great" based on the locale
of the user. For this to work,
you need to tell Symfony how to translate the message via a "translation
resource", which is usually a file that contains a collection of translations
for a given locale. This "dictionary" of translations can be created in several
different formats:
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# translations/messages.fr.yaml
Symfony is great: J'aime Symfony
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<!-- translations/messages.fr.xlf -->
<?xml version="1.0" encoding="UTF-8" ?>
<xliff version="1.2" xmlns="urn:oasis:names:tc:xliff:document:1.2">
<file source-language="en" datatype="plaintext" original="file.ext">
<body>
<trans-unit id="symfony_is_great">
<source>Symfony is great</source>
<target>J'aime Symfony</target>
</trans-unit>
</body>
</file>
</xliff>
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// translations/messages.fr.php
return [
'Symfony is great' => "J'aime Symfony",
];
You can find more information on where these files should be located.
Now, if the language of the user's locale is French (e.g. fr_FR
or fr_BE
),
the message will be translated into J'aime Symfony
. You can also translate
the message inside your templates.
Using Real or Keyword Messages
This example illustrates the two different philosophies when creating messages to be translated:
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$translator->trans('Symfony is great');
$translator->trans('symfony.great');
In the first method, messages are written in the language of the default locale (English in this case). That message is then used as the "id" when creating translations.
In the second method, messages are actually "keywords" that convey the
idea of the message. The keyword message is then used as the "id" for
any translations. In this case, translations must be made for the default
locale (i.e. to translate symfony.great
to Symfony is great
).
The second method is handy because the message key won't need to be changed in every translation file if you decide that the message should actually read "Symfony is really great" in the default locale.
The choice of which method to use is entirely up to you, but the "keyword" format is often recommended for multi-language applications, whereas for shared bundles that contain translation resources we recommend the real message, so your application can choose to disable the translator layer and you will see a readable message.
Additionally, the php
and yaml
file formats support nested ids to
avoid repeating yourself if you use keywords instead of real text for your
ids:
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symfony:
is:
# id is symfony.is.great
great: Symfony is great
# id is symfony.is.amazing
amazing: Symfony is amazing
has:
# id is symfony.has.bundles
bundles: Symfony has bundles
user:
# id is user.login
login: Login
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[
'symfony' => [
'is' => [
// id is symfony.is.great
'great' => 'Symfony is great',
// id is symfony.is.amazing
'amazing' => 'Symfony is amazing',
],
'has' => [
// id is symfony.has.bundles
'bundles' => 'Symfony has bundles',
],
],
'user' => [
// id is user.login
'login' => 'Login',
],
];
The Translation Process
To actually translate the message, Symfony uses the following process when
using the trans()
method:
- The
locale
of the current user, which is stored on the request is determined; this is typically set via a_locale
attribute on your routes; - A catalog of translated messages is loaded from translation resources
defined for the
locale
(e.g.fr_FR
). Messages from the fallback locale and the enabled locales are also loaded and added to the catalog if they don't already exist. The end result is a large "dictionary" of translations. - If the message is located in the catalog, the translation is returned. If not, the translator returns the original message.
Message Format
Sometimes, a message containing a variable needs to be translated:
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// ...
$translated = $translator->trans('Hello '.$name);
However, creating a translation for this string is impossible since the translator will try to look up the message including the variable portions (e.g. "Hello Ryan" or "Hello Fabien").
Another complication is when you have translations that may or may not be plural, based on some variable:
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There is one apple.
There are 5 apples.
To manage these situations, Symfony follows the ICU MessageFormat syntax by using PHP's MessageFormatter class. Read more about this in How to Translate Messages using the ICU MessageFormat.
Translatable Objects
Sometimes translating contents in templates is cumbersome because you need the original message, the translation parameters and the translation domain for each content. Making the translation in the controller or services simplifies your templates, but requires injecting the translator service in different parts of your application and mocking it in your tests.
Instead of translating a string at the time of creation, you can use a "translatable object", which is an instance of the TranslatableMessage class. This object stores all the information needed to fully translate its contents when needed:
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use Symfony\Component\Translation\TranslatableMessage;
// the first argument is required and it's the original message
$message = new TranslatableMessage('Symfony is great!');
// the optional second argument defines the translation parameters and
// the optional third argument is the translation domain
$status = new TranslatableMessage('order.status', ['%status%' => $order->getStatus()], 'store');
Templates are now much simpler because you can pass translatable objects to the
trans
filter:
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<h1>{{ message|trans }}</h1>
<p>{{ status|trans }}</p>
Tip
The translation parameters can also be a TranslatableMessage.
Tip
There's also a function called t(), available both in Twig and PHP, as a shortcut to create translatable objects.
Translations in Templates
Most of the time, translation occurs in templates. Symfony provides native support for both Twig and PHP templates.
Using Twig Filters
The trans
filter can be used to translate variable texts and complex expressions:
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{{ message|trans }}
{{ message|trans({'%name%': 'Fabien'}, 'app') }}
Tip
You can set the translation domain for an entire Twig template with a single tag:
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{% trans_default_domain 'app' %}
Note that this only influences the current template, not any "included" template (in order to avoid side effects).
By default, the translated messages are output escaped; apply the raw
filter after the translation filter to avoid the automatic escaping:
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{% set message = '<h3>foo</h3>' %}
{# strings and variables translated via a filter are escaped by default #}
{{ message|trans|raw }}
{{ '<h3>bar</h3>'|trans|raw }}
Using Twig Tags
Symfony provides a specialized Twig tag trans
to help with message
translation of static blocks of text:
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{% trans %}Hello %name%{% endtrans %}
Caution
The %var%
notation of placeholders is required when translating in
Twig templates using the tag.
Tip
If you need to use the percent character (%
) in a string, escape it by
doubling it: {% trans %}Percent: %percent%%%{% endtrans %}
You can also specify the message domain and pass some additional variables:
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{% trans with {'%name%': 'Fabien'} from 'app' %}Hello %name%{% endtrans %}
{% trans with {'%name%': 'Fabien'} from 'app' into 'fr' %}Hello %name%{% endtrans %}
Caution
Using the translation tag has the same effect as the filter, but with one major difference: automatic output escaping is not applied to translations using a tag.
Forcing the Translator Locale
When translating a message, the translator uses the specified locale or the
fallback
locale if necessary. You can also manually specify the locale to
use for translation:
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$translator->trans('Symfony is great', locale: 'fr_FR');
Extracting Translation Contents and Updating Catalogs Automatically
The most time-consuming task when translating an application is to extract all
the template contents to be translated and to keep all the translation files in
sync. Symfony includes a command called translation:extract
that helps you
with these tasks:
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# shows all the messages that should be translated for the French language
$ php bin/console translation:extract --dump-messages fr
# updates the French translation files with the missing strings for that locale
$ php bin/console translation:extract --force fr
# check out the command help to see its options (prefix, output format, domain, sorting, etc.)
$ php bin/console translation:extract --help
The translation:extract
command looks for missing translations in:
- Templates stored in the
templates/
directory (or any other directory defined in the twig.default_path and twig.paths config options); - Any PHP file/class that injects or autowires
the
translator
service and makes calls to thetrans()
method; - Any PHP file/class stored in the
src/
directory that creates translatable objects using the constructor or thet()
method or calls thetrans()
method; - Any PHP file/class stored in the
src/
directory that uses Constraints Attributes with*message
named argument(s).
Tip
Install the nikic/php-parser
package in your project to improve the
results of the translation:extract
command. This package enables an
AST parser that can find many more translatable items:
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$ composer require nikic/php-parser
Translation Resource/File Names and Locations
Symfony looks for message files (i.e. translations) in the following default locations:
- the
translations/
directory (at the root of the project); - the
translations/
directory inside of any bundle (and also theirResources/translations/
directory, which is no longer recommended for bundles).
The locations are listed here with the highest priority first. That is, you can override the translation messages of a bundle in the first directory.
The override mechanism works at a key level: only the overridden keys need to be listed in a higher priority message file. When a key is not found in a message file, the translator will automatically fall back to the lower priority message files.
The filename of the translation files is also important: each message file
must be named according to the following path: domain.locale.loader
:
- domain: The translation domain;
- locale: The locale that the translations are for (e.g.
en_GB
,en
, etc); - loader: How Symfony should load and parse the file (e.g.
xlf
,php
,yaml
, etc).
The loader can be the name of any registered loader. By default, Symfony provides many loaders which are selected based on the following file extensions:
.yaml
: YAML file (you can also use the.yml
file extension);.xlf
: XLIFF file (you can also use the.xliff
file extension);.php
: a PHP file that returns an array with the translations;.csv
: CSV file;.json
: JSON file;.ini
: INI file;.dat
,.res
: ICU resource bundle;.mo
: Machine object format;.po
: Portable object format;.qt
: QT Translations TS XML file;
The choice of which loader to use is entirely up to you and is a matter of taste. The recommended option is to use YAML for simple projects and use XLIFF if you're generating translations with specialized programs or teams.
Caution
Each time you create a new message catalog (or install a bundle that includes a translation catalog), be sure to clear your cache so that Symfony can discover the new translation resources:
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$ php bin/console cache:clear
Note
You can add other directories with the paths option in the configuration:
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# config/packages/translation.yaml
framework:
translator:
paths:
- '%kernel.project_dir%/custom/path/to/translations'
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<!-- config/packages/translation.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<container xmlns="http://symfony.com/schema/dic/services"
xmlns:framework="http://symfony.com/schema/dic/symfony"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-Instance"
xsi:schemaLocation="http://symfony.com/schema/dic/services
https://symfony.com/schema/dic/services/services-1.0.xsd
http://symfony.com/schema/dic/symfony
https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">
<framework:config>
<framework:translator>
<framework:path>%kernel.project_dir%/custom/path/to/translations</framework:path>
</framework:translator>
</framework:config>
</container>
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// config/packages/translation.php
use Symfony\Config\FrameworkConfig;
return static function (FrameworkConfig $framework): void {
$framework->translator()
->paths(['%kernel.project_dir%/custom/path/to/translations'])
;
};
Translations of Doctrine Entities
Unlike the contents of templates, it's not practical to translate the contents stored in Doctrine Entities using translation catalogs. Instead, use the Doctrine Translatable Extension or the Translatable Behavior. For more information, read the documentation of those libraries.
Custom Translation Resources
If your translations use a format not supported by Symfony or you store them in a special way (e.g. not using files or Doctrine entities), you need to provide a custom class implementing the LoaderInterface interface. See the Built-in Symfony Service Tags tag for more information.
Translation Providers
When using external translators to translate your application, you must send them the new contents to translate frequently and merge the results back in the application.
Instead of doing this manually, Symfony provides integration with several third-party translation services. You can upload and download (called "push" and "pull") translations to/from these services and merge the results automatically in the application.
Installing and Configuring a Third Party Provider
Before pushing/pulling translations to a third-party provider, you must install the package that provides integration with that provider:
Provider | Install with |
---|---|
Crowdin | composer require symfony/crowdin-translation-provider |
Loco (localise.biz) | composer require symfony/loco-translation-provider |
Lokalise | composer require symfony/lokalise-translation-provider |
Phrase | composer require symfony/phrase-translation-provider |
Each library includes a Symfony Flex recipe that will add
a configuration example to your .env
file. For example, suppose you want to
use Loco. First, install it:
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$ composer require symfony/loco-translation-provider
You'll now have a new line in your .env
file that you can uncomment:
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# .env
LOCO_DSN=loco://API_KEY@default
The LOCO_DSN
isn't a real address: it's a convenient format that offloads
most of the configuration work to Symfony. The loco
scheme activates the
Loco provider that you just installed, which knows all about how to push and
pull translations via Loco. The only part you need to change is the
API_KEY
placeholder.
This table shows the full list of available DSN formats for each provider:
Provider | DSN |
---|---|
Crowdin | crowdin://PROJECT_ID:API_TOKEN@ORGANIZATION_DOMAIN.default |
Loco (localise.biz) | loco://API_KEY@default |
Lokalise | lokalise://PROJECT_ID:API_KEY@default |
Phrase | phrase://PROJECT_ID:API_TOKEN@default?userAgent=myProject |
To enable a translation provider, customize the DSN in your .env
file and
configure the providers
option:
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# config/packages/translation.yaml
framework:
translator:
providers:
loco:
dsn: '%env(LOCO_DSN)%'
domains: ['messages']
locales: ['en', 'fr']
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<!-- config/packages/translation.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<container xmlns="http://symfony.com/schema/dic/services"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:framework="http://symfony.com/schema/dic/symfony"
xsi:schemaLocation="http://symfony.com/schema/dic/services
https://symfony.com/schema/dic/services/services-1.0.xsd
http://symfony.com/schema/dic/symfony
https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">
<framework:config>
<framework:translator>
<framework:provider name="loco" dsn="%env(LOCO_DSN)%">
<framework:domain>messages</framework:domain>
<!-- ... -->
<framework:locale>en</framework:locale>
<framework:locale>fr</framework:locale>
<!-- ... -->
</framework:provider>
</framework:translator>
</framework:config>
</container>
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# config/packages/translation.php
$container->loadFromExtension('framework', [
'translator' => [
'providers' => [
'loco' => [
'dsn' => env('LOCO_DSN'),
'domains' => ['messages'],
'locales' => ['en', 'fr'],
],
],
],
]);
Important
If you use Phrase as a provider you must configure a user agent in your dsn. See Identification via User-Agent for reasoning and some examples.
Also make the locale _names_ in Phrase should be as defined in RFC4646 (e.g. pt-BR rather than pt_BR). Not doing so will result in Phrase creating a new locale for the imported keys.
Tip
If you use Crowdin as a provider and some of your locales are different from the Crowdin Language Codes, you have to set the Custom Language Codes in the Crowdin project for each of your locales, in order to override the default value. You need to select the "locale" placeholder and specify the custom code in the "Custom Code" field.
Tip
If you use Lokalise as a provider and a locale format following the ISO 639-1 (e.g. "en" or "fr"), you have to set the Custom Language Name setting in Lokalise for each of your locales, in order to override the default value (which follow the ISO 639-1 succeeded by a sub-code in capital letters that specifies the national variety (e.g. "GB" or "US" according to ISO 3166-1 alpha-2)).
Tip
The Phrase provider uses Phrase's tag feature to map translations to Symfony's translation domains. If you need some assistance with organising your tags in Phrase, you might want to consider the Phrase Tag Bundle which provides some commands helping you with that.
Pushing and Pulling Translations
After configuring the credentials to access the translation provider, you can now use the following commands to push (upload) and pull (download) translations:
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# push all local translations to the Loco provider for the locales and domains
# configured in config/packages/translation.yaml file.
# it will update existing translations already on the provider.
$ php bin/console translation:push loco --force
# push new local translations to the Loco provider for the French locale
# and the validators domain.
# it will **not** update existing translations already on the provider.
$ php bin/console translation:push loco --locales fr --domains validators
# push new local translations and delete provider's translations that not
# exists anymore in local files for the French locale and the validators domain.
# it will **not** update existing translations already on the provider.
$ php bin/console translation:push loco --delete-missing --locales fr --domains validators
# check out the command help to see its options (format, domains, locales, etc.)
$ php bin/console translation:push --help
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# pull all provider's translations to local files for the locales and domains
# configured in config/packages/translation.yaml file.
# it will overwrite completely your local files.
$ php bin/console translation:pull loco --force
# pull new translations from the Loco provider to local files for the French
# locale and the validators domain.
# it will **not** overwrite your local files, only add new translations.
$ php bin/console translation:pull loco --locales fr --domains validators
# check out the command help to see its options (format, domains, locales, intl-icu, etc.)
$ php bin/console translation:pull --help
# the "--as-tree" option will write YAML messages as a tree-like structure instead
# of flat keys
$ php bin/console translation:pull loco --force --as-tree
Creating Custom Providers
In addition to using Symfony's built-in translation providers, you can create your own providers. To do so, you need to create two classes:
- The first class must implement ProviderInterface;
- The second class needs to be a factory which will create instances of the first class. It must implement
ProviderFactoryInterface (you can extend AbstractProviderFactory to simplify its creation).
After creating these two classes, you need to register your factory as a service and tag it with translation.provider_factory.
Handling the User's Locale
Translating happens based on the user's locale. The locale of the current user
is stored in the request and is accessible via the Request
object:
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use Symfony\Component\HttpFoundation\Request;
public function index(Request $request): void
{
$locale = $request->getLocale();
}
To set the user's locale, you may want to create a custom event listener so that it's set before any other parts of the system (i.e. the translator) need it:
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public function onKernelRequest(RequestEvent $event): void
{
$request = $event->getRequest();
// some logic to determine the $locale
$request->setLocale($locale);
}
Note
The custom listener must be called before LocaleListener
, which
initializes the locale based on the current request. To do so, set your
listener priority to a higher value than LocaleListener
priority (which
you can obtain by running the debug:event kernel.request
command).
Read Sessions for more information on making the user's locale "sticky" to their session.
Note
Setting the locale using $request->setLocale()
in the controller is
too late to affect the translator. Either set the locale via a listener
(like above), the URL (see next) or call setLocale()
directly on the
translator
service.
See the Translations section below about setting the locale via routing.
The Locale and the URL
Since you can store the locale of the user in the session, it may be tempting
to use the same URL to display a resource in different languages based on the
user's locale. For example, http://www.example.com/contact
could show
content in English for one user and French for another user. Unfortunately,
this violates a fundamental rule of the Web: that a particular URL returns the
same resource regardless of the user. To further muddy the problem, which
version of the content would be indexed by search engines?
A better policy is to include the locale in the URL using the special _locale parameter:
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// src/Controller/ContactController.php
namespace App\Controller;
// ...
class ContactController extends AbstractController
{
#[Route(
path: '/{_locale}/contact',
name: 'contact',
requirements: [
'_locale' => 'en|fr|de',
],
)]
public function contact(): Response
{
// ...
}
}
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# config/routes.yaml
contact:
path: /{_locale}/contact
controller: App\Controller\ContactController::index
requirements:
_locale: en|fr|de
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<!-- config/routes.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<routes xmlns="http://symfony.com/schema/routing"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://symfony.com/schema/routing
https://symfony.com/schema/routing/routing-1.0.xsd">
<route id="contact" path="/{_locale}/contact">
controller="App\Controller\ContactController::index">
<requirement key="_locale">en|fr|de</requirement>
</route>
</routes>
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// config/routes.php
use App\Controller\ContactController;
use Symfony\Component\Routing\Loader\Configurator\RoutingConfigurator;
return function (RoutingConfigurator $routes): void {
$routes->add('contact', '/{_locale}/contact')
->controller([ContactController::class, 'index'])
->requirements([
'_locale' => 'en|fr|de',
])
;
};
When using the special _locale
parameter in a route, the matched locale
is automatically set on the Request and can be retrieved via the
getLocale() method. In
other words, if a user visits the URI /fr/contact
, the locale fr
will
automatically be set as the locale for the current request.
You can now use the locale to create routes to other translated pages in your application.
Tip
Define the locale requirement as a container parameter to avoid hardcoding its value in all your routes.
Setting a Default Locale
What if the user's locale hasn't been determined? You can guarantee that a
locale is set on each user's request by defining a default_locale
for
the framework:
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# config/packages/translation.yaml
framework:
default_locale: en
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<!-- config/packages/translation.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<container xmlns="http://symfony.com/schema/dic/services"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:framework="http://symfony.com/schema/dic/symfony"
xsi:schemaLocation="http://symfony.com/schema/dic/services
https://symfony.com/schema/dic/services/services-1.0.xsd
http://symfony.com/schema/dic/symfony
https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">
<framework:config default-locale="en"/>
</container>
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// config/packages/translation.php
use Symfony\Config\FrameworkConfig;
return static function (FrameworkConfig $framework): void {
$framework->defaultLocale('en');
};
This default_locale
is also relevant for the translator, as shown in the
next section.
Selecting the Language Preferred by the User
If your application supports multiple languages, the first time a user visits your
site it's common to redirect them to the best possible language according to their
preferences. This is achieved with the getPreferredLanguage()
method of the
Request object:
1 2 3 4 5
// get the Request object somehow (e.g. as a controller argument)
$request = ...
// pass an array of the locales (their script and region parts are optional) supported
// by your application and the method returns the best locale for the current user
$locale = $request->getPreferredLanguage(['pt', 'fr_Latn_CH', 'en_US'] );
Symfony finds the best possible language based on the locales passed as argument
and the value of the Accept-Language
HTTP header. If it can't find a perfect
match between them, Symfony will try to find a partial match based on the language
(e.g. fr_CA
would match fr_Latn_CH
because their language is the same).
If there's no perfect or partial match, this method returns the first locale passed
as argument (that's why the order of the passed locales is important).
7.1
The feature to match locales partially was introduced in Symfony 7.1.
Fallback Translation Locales
Imagine that the user's locale is es_AR
and that you're translating the
key Symfony is great
. To find the Spanish translation, Symfony actually
checks translation resources for several locales:
- First, Symfony looks for the translation in a
es_AR
(Argentinean Spanish) translation resource (e.g.messages.es_AR.yaml
); - If it wasn't found, Symfony looks for the translation in the
parent locale, which is automatically defined only for some locales. In
this example, the parent locale is
es_419
(Latin American Spanish); - If it wasn't found, Symfony looks for the translation in a
es
(Spanish) translation resource (e.g.messages.es.yaml
); If the translation still isn't found, Symfony uses the
fallbacks
option, which can be configured as follows. When this option is not defined, it defaults to thedefault_locale
setting mentioned in the previous section.1 2 3 4 5
# config/packages/translation.yaml framework: translator: fallbacks: ['en'] # ...
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
<!-- config/packages/translation.xml --> <?xml version="1.0" encoding="UTF-8" ?> <container xmlns="http://symfony.com/schema/dic/services" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:framework="http://symfony.com/schema/dic/symfony" xsi:schemaLocation="http://symfony.com/schema/dic/services https://symfony.com/schema/dic/services/services-1.0.xsd http://symfony.com/schema/dic/symfony https://symfony.com/schema/dic/symfony/symfony-1.0.xsd"> <framework:config> <framework:translator> <framework:fallback>en</framework:fallback> <!-- ... --> </framework:translator> </framework:config> </container>
1 2 3 4 5 6 7 8 9
// config/packages/translation.php use Symfony\Config\FrameworkConfig; return static function (FrameworkConfig $framework): void { // ... $framework->translator() ->fallbacks(['en']) ; };
Note
When Symfony can't find a translation in the given locale, it will add the missing translation to the log file. For details, see Framework Configuration Reference (FrameworkBundle).
Switch Locale Programmatically
Sometimes you need to change the locale of the application dynamically just to run some code. Imagine a console command that renders Twig templates of emails in different languages. You need to change the locale only to render those templates.
The LocaleSwitcher
class allows you to change at once the locale
of:
- All the services that are tagged with
kernel.locale_aware
; \Locale::setDefault()
;If the
RequestContext
service is available, the_locale
parameter (so urls are generated with the new locale):1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42
use Symfony\Component\Translation\LocaleSwitcher; class SomeService { public function __construct( private LocaleSwitcher $localeSwitcher, ) { } public function someMethod(): void { // you can get the current application locale like this: $currentLocale = $this->localeSwitcher->getLocale(); // you can set the locale for the entire application like this: // (from now on, the application will use 'fr' (French) as the // locale; including the default locale used to translate Twig templates) $this->localeSwitcher->setLocale('fr'); // reset the current locale of your application to the configured default locale // in config/packages/translation.yaml, by option 'default_locale' $this->localeSwitcher->reset(); // you can also run some code with a certain locale, without // changing the locale for the rest of the application $this->localeSwitcher->runWithLocale('es', function() { // e.g. render here some Twig templates using 'es' (Spanish) locale }); // you can optionally declare an argument in your callback to receive the // injected locale $this->localeSwitcher->runWithLocale('es', function(string $locale) { // here, the $locale argument will be set to 'es' }); // ... } }
When using autowiring, type-hint any controller or
service argument with the LocaleSwitcher
class to inject the locale switcher service. Otherwise, configure your services
manually and inject the translation.locale_switcher
service.
How to Find Missing or Unused Translation Messages
When you work with many translation messages in different languages, it can be
hard to keep track which translations are missing and which are not used
anymore. The debug:translation
command helps you to find these missing or
unused translation messages templates:
1 2 3 4
{# messages can be found when using the trans filter and tag #}
{% trans %}Symfony is great{% endtrans %}
{{ 'Symfony is great'|trans }}
Caution
The extractors can't find messages translated outside templates (like form
labels or controllers) unless using translatable objects or calling the trans()
method on a translator
(since Symfony 5.3). Dynamic translations using variables or expressions in
templates are not detected either:
1 2 3
{# this translation uses a Twig variable, so it won't be detected #}
{% set message = 'Symfony is great' %}
{{ message|trans }}
Suppose your application's default_locale is fr
and you have configured
en
as the fallback locale (see configuration and fallback for
how to configure these). And suppose you've already set up some translations
for the fr
locale:
1 2 3 4 5 6 7 8 9 10 11 12
<!-- translations/messages.fr.xlf -->
<?xml version="1.0" encoding="UTF-8" ?>
<xliff version="1.2" xmlns="urn:oasis:names:tc:xliff:document:1.2">
<file source-language="en" datatype="plaintext" original="file.ext">
<body>
<trans-unit id="1">
<source>Symfony is great</source>
<target>J'aime Symfony</target>
</trans-unit>
</body>
</file>
</xliff>
1 2
# translations/messages.fr.yaml
Symfony is great: J'aime Symfony
1 2 3 4
// translations/messages.fr.php
return [
'Symfony is great' => 'J\'aime Symfony',
];
and for the en
locale:
1 2 3 4 5 6 7 8 9 10 11 12
<!-- translations/messages.en.xlf -->
<?xml version="1.0" encoding="UTF-8" ?>
<xliff version="1.2" xmlns="urn:oasis:names:tc:xliff:document:1.2">
<file source-language="en" datatype="plaintext" original="file.ext">
<body>
<trans-unit id="1">
<source>Symfony is great</source>
<target>Symfony is great</target>
</trans-unit>
</body>
</file>
</xliff>
1 2
# translations/messages.en.yaml
Symfony is great: Symfony is great
1 2 3 4
// translations/messages.en.php
return [
'Symfony is great' => 'Symfony is great',
];
To inspect all messages in the fr
locale for the application, run:
1 2 3 4 5 6 7
$ php bin/console debug:translation fr
--------- ------------------ ---------------------- -------------------------------
State Id Message Preview (fr) Fallback Message Preview (en)
--------- ------------------ ---------------------- -------------------------------
unused Symfony is great J'aime Symfony Symfony is great
--------- ------------------ ---------------------- -------------------------------
It shows you a table with the result when translating the message in the fr
locale and the result when the fallback locale en
would be used. On top
of that, it will also show you when the translation is the same as the fallback
translation (this could indicate that the message was not correctly translated).
Furthermore, it indicates that the message Symfony is great
is unused
because it is translated, but you haven't used it anywhere yet.
Now, if you translate the message in one of your templates, you will get this output:
1 2 3 4 5 6 7
$ php bin/console debug:translation fr
--------- ------------------ ---------------------- -------------------------------
State Id Message Preview (fr) Fallback Message Preview (en)
--------- ------------------ ---------------------- -------------------------------
Symfony is great J'aime Symfony Symfony is great
--------- ------------------ ---------------------- -------------------------------
The state is empty which means the message is translated in the fr
locale
and used in one or more templates.
If you delete the message Symfony is great
from your translation file
for the fr
locale and run the command, you will get:
1 2 3 4 5 6 7
$ php bin/console debug:translation fr
--------- ------------------ ---------------------- -------------------------------
State Id Message Preview (fr) Fallback Message Preview (en)
--------- ------------------ ---------------------- -------------------------------
missing Symfony is great Symfony is great Symfony is great
--------- ------------------ ---------------------- -------------------------------
The state indicates the message is missing because it is not translated in
the fr
locale but it is still used in the template. Moreover, the message
in the fr
locale equals to the message in the en
locale. This is a
special case because the untranslated message id equals its translation in
the en
locale.
If you copy the content of the translation file in the en
locale to the
translation file in the fr
locale and run the command, you will get:
1 2 3 4 5 6 7
$ php bin/console debug:translation fr
---------- ------------------ ---------------------- -------------------------------
State Id Message Preview (fr) Fallback Message Preview (en)
---------- ------------------ ---------------------- -------------------------------
fallback Symfony is great Symfony is great Symfony is great
---------- ------------------ ---------------------- -------------------------------
You can see that the translations of the message are identical in the fr
and en
locales which means this message was probably copied from English
to French and maybe you forgot to translate it.
By default, all domains are inspected, but it is possible to specify a single domain:
1
$ php bin/console debug:translation en --domain=messages
When the application has a lot of messages, it is useful to display only the
unused or only the missing messages, by using the --only-unused
or
--only-missing
options:
1 2
$ php bin/console debug:translation en --only-unused
$ php bin/console debug:translation en --only-missing
Debug Command Exit Codes
The exit code of the debug:translation
command changes depending on the
status of the translations. Use the following public constants to check it:
1 2 3 4 5 6 7 8 9 10 11 12 13
use Symfony\Bundle\FrameworkBundle\Command\TranslationDebugCommand;
// generic failure (e.g. there are no translations)
TranslationDebugCommand::EXIT_CODE_GENERAL_ERROR;
// there are missing translations
TranslationDebugCommand::EXIT_CODE_MISSING;
// there are unused translations
TranslationDebugCommand::EXIT_CODE_UNUSED;
// some translations are using the fallback translation
TranslationDebugCommand::EXIT_CODE_FALLBACK;
These constants are defined as "bit masks", so you can combine them as follows:
1 2 3
if (TranslationDebugCommand::EXIT_CODE_MISSING | TranslationDebugCommand::EXIT_CODE_UNUSED) {
// ... there are missing and/or unused translations
}
How to Find Errors in Translation Files
Symfony processes all the application translation files as part of the process that compiles the application code before executing it. If there's an error in any translation file, you'll see an error message explaining the problem.
If you prefer, you can also validate the syntax of any YAML and XLIFF
translation file using the lint:yaml
and lint:xliff
commands:
1 2 3 4 5 6 7 8 9 10 11
# lint a single file
$ php bin/console lint:yaml translations/messages.en.yaml
$ php bin/console lint:xliff translations/messages.en.xlf
# lint a whole directory
$ php bin/console lint:yaml translations
$ php bin/console lint:xliff translations
# lint multiple files or directories
$ php bin/console lint:yaml translations path/to/trans
$ php bin/console lint:xliff translations/messages.en.xlf translations/messages.es.xlf
The linter results can be exported to JSON using the --format
option:
1 2
$ php bin/console lint:yaml translations/ --format=json
$ php bin/console lint:xliff translations/ --format=json
When running these linters inside GitHub Actions, the output is automatically adapted to the format required by GitHub, but you can force that format too:
1 2
$ php bin/console lint:yaml translations/ --format=github
$ php bin/console lint:xliff translations/ --format=github
Tip
The Yaml component provides a stand-alone yaml-lint
binary allowing
you to lint YAML files without having to create a console application:
1
$ php vendor/bin/yaml-lint translations/
The lint:yaml
and lint:xliff
commands validate the YAML and XML syntax
of the translation files, but not their contents. Use the following command
to check that the translation contents are also correct:
1 2 3 4 5
# checks the contents of all the translation catalogues in all locales $ php bin/console lint:translations # checks the contents of the translation catalogues for Italian (it) and Japanese (ja) locales $ php bin/console lint:translations --locales=it --locales=ja
7.2
The lint:translations
command was introduced in Symfony 7.2.
Pseudo-localization translator
Note
The pseudolocalization translator is meant to be used for development only.
The following image shows a typical menu on a webpage:
This other image shows the same menu when the user switches the language to Spanish. Unexpectedly, some text is cut and other contents are so long that they overflow and you can't see them:
These kind of errors are very common, because different languages can be longer or shorter than the original application language. Another common issue is to only check if the application works when using basic accented letters, instead of checking for more complex characters such as the ones found in Polish, Czech, etc.
These problems can be solved with pseudolocalization, a software testing method used for testing internationalization. In this method, instead of translating the text of the software into a foreign language, the textual elements of an application are replaced with an altered version of the original language.
For example, Account Settings
is translated as [!!! Àççôûñţ
Šéţţîñĝš !!!]
. First, the original text is expanded in length with characters
like [!!! !!!]
to test the application when using languages more verbose
than the original one. This solves the first problem.
In addition, the original characters are replaced by similar but accented characters. This makes the text highly readable, while allowing to test the application with all kinds of accented and special characters. This solves the second problem.
Full support for pseudolocalization was added to help you debug internationalization issues in your applications. You can enable and configure it in the translator configuration:
1 2 3 4 5 6 7 8 9 10 11 12 13 14
# config/packages/translation.yaml
framework:
translator:
pseudo_localization:
# replace characters by their accented version
accents: true
# wrap strings with brackets
brackets: true
# controls how many extra characters are added to make text longer
expansion_factor: 1.4
# maintain the original HTML tags of the translated contents
parse_html: true
# also translate the contents of these HTML attributes
localizable_html_attributes: ['title']
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28
<!-- config/packages/translation.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<container xmlns="http://symfony.com/schema/dic/services"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:framework="http://symfony.com/schema/dic/symfony"
xsi:schemaLocation="http://symfony.com/schema/dic/services
https://symfony.com/schema/dic/services/services-1.0.xsd
http://symfony.com/schema/dic/symfony
https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">
<framework:config>
<framework:translator>
<!-- accents: replace characters by their accented version -->
<!-- brackets: wrap strings with brackets -->
<!-- expansion_factor: controls how many extra characters are added to make text longer -->
<!-- parse_html: maintain the original HTML tags of the translated contents -->
<framework:pseudo-localization
accents="true"
brackets="true"
expansion_factor="1.4"
parse_html="true"
>
<!-- also translate the contents of these HTML attributes -->
<framework:localizable-html-attribute>title</framework:localizable-html-attribute>
</framework:pseudo-localization>
</framework:translator>
</framework:config>
</container>
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
// config/packages/translation.php
use Symfony\Config\FrameworkConfig;
return static function (FrameworkConfig $framework) {
// ...
$framework
->translator()
->pseudoLocalization()
// replace characters by their accented version
->accents(true)
// wrap strings with brackets
->brackets(true)
// controls how many extra characters are added to make text longer
->expansionFactor(1.4)
// maintain the original HTML tags of the translated contents
->parseHtml(true)
// also translate the contents of these HTML attributes
->localizableHtmlAttributes(['title'])
;
};
That's all. The application will now start displaying those strange, but readable, contents to help you internationalize it. See for example the difference in the Symfony Demo application. This is the original page:
And this is the same page with pseudolocalization enabled:
Summary
With the Symfony Translation component, creating an internationalized application no longer needs to be a painful process and boils down to these steps:
- Abstract messages in your application by wrapping each in the trans() method;
- Translate each message into multiple locales by creating translation message files. Symfony discovers and processes each file because its name follows a specific convention;
- Manage the user's locale, which is stored on the request, but can also be set on the user's session.