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2 | 2 | single: Validator; Metadata |
3 | 3 |
|
4 | 4 | Metadata |
5 | | -======== |
| 5 | +======== |
| 6 | + |
| 7 | +The :class:`Symfony\\Component\\Validator\\Mapping\\ClassMetadata` class represents and manages all the configured constraints on a given class. |
| 8 | + |
| 9 | +Properties |
| 10 | +---------- |
| 11 | + |
| 12 | +Validating class properties is the most basic validation technique. Validation component |
| 13 | +allows you to validate private, protected or public properties. The next |
| 14 | +listing shows you how to configure the ``$firstName`` property of an ``Author`` |
| 15 | +class to have at least 3 characters:: |
| 16 | + |
| 17 | + // ... |
| 18 | + use Symfony\Component\Validator\Mapping\ClassMetadata; |
| 19 | + use Symfony\Component\Validator\Constraints as Assert; |
| 20 | + |
| 21 | + class Author |
| 22 | + { |
| 23 | + private $firstName; |
| 24 | + |
| 25 | + public static function loadValidatorMetadata(ClassMetadata $metadata) |
| 26 | + { |
| 27 | + $metadata->addPropertyConstraint('firstName', new Assert\NotBlank()); |
| 28 | + $metadata->addPropertyConstraint( |
| 29 | + 'firstName', |
| 30 | + new Assert\Length(array("min" => 3)) |
| 31 | + ); |
| 32 | + } |
| 33 | + } |
| 34 | + |
| 35 | +Getters |
| 36 | +------- |
| 37 | + |
| 38 | +Constraints can also be applied to the return value of a method. Symfony |
| 39 | +allows you to add a constraint to any public method whose name starts with |
| 40 | +"get" or "is". In this guide, both of these types of methods are referred |
| 41 | +to as "getters". |
| 42 | + |
| 43 | +The benefit of this technique is that it allows you to validate your object |
| 44 | +dynamically. For example, suppose you want to make sure that a password field |
| 45 | +doesn't match the first name of the user (for security reasons). You can |
| 46 | +do this by creating an ``isPasswordLegal`` method, and then asserting that |
| 47 | +this method must return ``true``:: |
| 48 | + |
| 49 | + // ... |
| 50 | + use Symfony\Component\Validator\Mapping\ClassMetadata; |
| 51 | + use Symfony\Component\Validator\Constraints as Assert; |
| 52 | + |
| 53 | + class Author |
| 54 | + { |
| 55 | + public static function loadValidatorMetadata(ClassMetadata $metadata) |
| 56 | + { |
| 57 | + $metadata->addGetterConstraint('passwordLegal', new Assert\True(array( |
| 58 | + 'message' => 'The password cannot match your first name', |
| 59 | + ))); |
| 60 | + } |
| 61 | + } |
| 62 | + |
| 63 | +Now, create the ``isPasswordLegal()`` method and include the logic you need:: |
| 64 | + |
| 65 | + public function isPasswordLegal() |
| 66 | + { |
| 67 | + return $this->firstName !== $this->password; |
| 68 | + } |
| 69 | + |
| 70 | +.. note:: |
| 71 | + |
| 72 | + The keen-eyed among you will have noticed that the prefix of the getter |
| 73 | + ("get" or "is") is omitted in the mapping. This allows you to move the |
| 74 | + constraint to a property with the same name later (or vice versa) without |
| 75 | + changing your validation logic. |
| 76 | + |
| 77 | +Classes |
| 78 | +------- |
| 79 | + |
| 80 | +Some constraints apply to the entire class being validated. For example, |
| 81 | +the :doc:`Callback </reference/constraints/Callback>` constraint is a generic |
| 82 | +constraint that's applied to the class itself. When that class is validated, |
| 83 | +methods specified by that constraint are simply executed so that each can |
| 84 | +provide more custom validation. |
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