An example of standalone usage of the symfony validator component

.gitignore

/vendor/*
/composer.lock

# ignore certain files
*.pyc
*.swp
*.dmg
*.gz
*.iso
*.jar
*.rar
*.tar
*.zip
*.7z

# ignore compiled files
*.com
*.class
*.dll
*.exe
*.app
*.o
*.so


# system files
.DS_Store*
ehthumbs.db
Icon?
Thumbs.db

# ignore Sass cache
.sass-cache

composer.json

{
    "name": "chrisguitarguy/symfony-validation-example",
    "description": "Standalone validator usage example.",
    "keywords": ["symfony", "validator"],
    "require": {
        "php": ">=5.5",
        "symfony/validator": "~2.6",
        "symfony/config": "~2.6"
    },
    "autoload": {
        "psr-4": {
            "Chrisguitarguy\\ValidatorExample\\": "."
        }
    }
}

example.php

<?php

require __DIR__.'/vendor/autoload.php';

use Symfony\Component\Validator\Validation;
use Chrisguitarguy\ValidatorExample\User;

$validator = Validation::createValidatorBuilder()
    ->setApiVersion(Validation::API_VERSION_2_5)
    ->addXmlMapping(__DIR__.'/validation.xml')
    ->getValidator();

$user = new User('notAnEmail', null);

$errors = $validator->validate($user);
foreach ($errors as $error) {
    echo $error->getPropertyPath(), ': ', $error->getMessage(), PHP_EOL;
    // or for debugging:
    echo $error, PHP_EOL;
}

$validUser = new User('test@example.com', 'aPassword');
$errors = $validator->validate($validUser);
echo count($errors), PHP_EOL;

User.php

<?php

namespace Chrisguitarguy\ValidatorExample;

final class User
{
    private $email;

    private $password;

    public function __construct($email, $password)
    {
        $this->email = $email;
        $this->password = $password;
    }

    public function getEmail()
    {
        return $this->email;
    }

    public function getPassword()
    {
        return $this->password;
    }
}

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="Chrisguitarguy\ValidatorExample\User">
        <property name="email">
            <constraint name="NotBlank" />
            <constraint name="Email" />
        </property>
        <property name="password">
            <constraint name="NotBlank" />
        </property>
    </class>
</constraint-mapping>