Silex/Symfony表單驗證器：確保一個值是唯一的

Question

我使用Silex和Form和Validator提供程序。

我有一個非常簡單的登記表格：

• 用戶名
• 密碼
• 密碼

的用戶名必須是唯一的確認，如何檢查？

這是我的代碼：

$form = $app['form.factory']->createBuilder('form') 
     ->add('username', 'text', array(
     'constraints' => array(
      new Assert\NotBlank(), 
      new Assert\Length(array('min' => 6, 'max' => 20))) 
     )) 
     ->add('password', 'repeated', array(
     'constraints' => array(
      new Assert\NotBlank(), 
      new Assert\Length(array('min' => 6, 'max' => 20)) 
     ) 
     )) 
     ->getForm(); 

隨着Symfony的，我知道有是UniqueEntity約束，但它與學說，我只使用Doctrine DBAL（Silex的提供商）

我想我可以使用回調約束，但我想知道是否有比使用SQL查詢寫回調更好的解決方案...或寫我自己的約束對象

謝謝

Answer 1

好吧，我決定創建自己的約束，因爲我可以重用它的電子郵件例如。 所以，這是我的實現：

UniqueEntry.php：

<?php 
/** 
* Ensure a value is unique in the database 
* 
* @author Thomas KELLER 
*/ 

use Symfony\Component\Validator\Constraint; 
use Symfony\Component\Validator\Exception\MissingOptionsException; 
use Symfony\Component\Validator\Exception\InvalidArgumentException; 

/** 
* @Annotation 
*/ 
class UniqueEntry extends Constraint { 

    public $notUniqueMessage = 'This value already exist in the database'; 
    public $dbal_connection; 
    public $table; 
    public $field; 

    public function __construct($options = null) 
    { 
    parent::__construct($options); 

    if ($this->dbal_connection === null) 
     throw new MissingOptionsException(sprintf('The option "dbal_connection" is mandatory for constraint %s', __CLASS__), array('dbal_connection')); 

    if (!$this->dbal_connection instanceof \Doctrine\DBAL\Connection) 
     throw new InvalidArgumentException(sprintf('The option "dbal_connection" must be an instance of Doctrine\DBAL\Connection for constraint %s', __CLASS__)); 

    if ($this->table === null) 
     throw new MissingOptionsException(sprintf('The option "table" is mandatory for constraint %s', __CLASS__), array('table')); 

    if (!is_string($this->table) OR $this->table == '') 
     throw new InvalidArgumentException(sprintf('The option "table" must be a valid string for constraint %s', __CLASS__)); 

    if ($this->field === null) 
     throw new MissingOptionsException(sprintf('The option "field" is mandatory for constraint %s', __CLASS__), array('field')); 

    if (!is_string($this->field) OR $this->field == '') 
     throw new InvalidArgumentException(sprintf('The option "field" must be a valid string for constraint %s', __CLASS__)); 
    } 
} 

UniqueEntryValidator.php：

<?php 
use Symfony\Component\Validator\Constraint; 
use Symfony\Component\Validator\ConstraintValidator; 

class UniqueEntryValidator extends ConstraintValidator 
{ 
    public function validate($value, Constraint $constraint) 
    { 
    $query = sprintf('SELECT `%s` FROM `%s` WHERE `%s` = ?', 
     $constraint->field, 
     $constraint->table, 
     $constraint->field); 

    $stmt = $constraint->dbal_connection->executeQuery($query, array($value)); 

    if ($stmt->fetch()) 
     $this->context->addViolation($constraint->notUniqueMessage); 
    } 
} 

我張貼我的實現有建議可以隨意評論它;）