How to Translate Validation Constraint Messages

If you're using validation constraints with the Form component, then translating the error messages is done in the translation resource for the validators domain.

To start, suppose you've created a plain-old-PHP object that you need to use somewhere in your application:

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        // src/Entity/Author.php
namespace App\Entity;

class Author
{
    public $name;
}
    

Add constraints through any of the supported methods. Set the message option to the translation source text. For example, to guarantee that the $name property is not empty, add the following:

Annotations
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        // src/Entity/Author.php
use Symfony\Component\Validator\Constraints as Assert;

class Author
{
    /**
     * @Assert\NotBlank(message="author.name.not_blank")
     */
    public $name;
}
    

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        # config/validator/validation.yaml
App\Entity\Author:
    properties:
        name:
            - NotBlank: { message: 'author.name.not_blank' }
    

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        <!-- config/validator/validation.xml -->
<?xml version="1.0" encoding="UTF-8" ?>
<constraint-mapping xmlns="http://symfony.com/schema/dic/constraint-mapping"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://symfony.com/schema/dic/constraint-mapping
        http://symfony.com/schema/dic/constraint-mapping/constraint-mapping-1.0.xsd">

    <class name="App\Entity\Author">
        <property name="name">
            <constraint name="NotBlank">
                <option name="message">author.name.not_blank</option>
            </constraint>
        </property>
    </class>
</constraint-mapping>
    

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        // src/Entity/Author.php

// ...
use Symfony\Component\Validator\Mapping\ClassMetadata;
use Symfony\Component\Validator\Constraints\NotBlank;

class Author
{
    public $name;

    public static function loadValidatorMetadata(ClassMetadata $metadata)
    {
        $metadata->addPropertyConstraint('name', new NotBlank([
            'message' => 'author.name.not_blank',
        ]));
    }
}
    

Now, create a validators catalog file in the translations/ directory:

XML
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        <!-- translations/validators.en.xlf -->
<?xml version="1.0"?>
<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="author.name.not_blank">
                <source>author.name.not_blank</source>
                <target>Please enter an author name.</target>
            </trans-unit>
        </body>
    </file>
</xliff>
    

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        # translations/validators.en.yaml
author.name.not_blank: Please enter an author name.
    

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        // translations/validators.en.php
return [
    'author.name.not_blank' => 'Please enter an author name.',
];
    

You may need to clear your cache (even in the dev environment) after creating this file for the first time.

This work, including the code samples, is licensed under a Creative Commons BY-SA 3.0 license.