发布于 2015-08-27 16:43:38 | 159 次阅读 | 评论: 0 | 来源: 网络整理
This constraint allows you to use an expression for more complex, dynamic validation. See Basic Usage for an example. See Callback for a different constraint that gives you similar flexibility.
Applies to | class or property/method |
Options | |
Class | Expression |
Validator | ExpressionValidator |
Imagine you have a class BlogPost
with category
and isTechnicalPost
properties:
namespace AcmeDemoBundleModel;
use SymfonyComponentValidatorConstraints as Assert;
class BlogPost
{
private $category;
private $isTechnicalPost;
// ...
public function getCategory()
{
return $this->category;
}
public function setIsTechnicalPost($isTechnicalPost)
{
$this->isTechnicalPost = $isTechnicalPost;
}
// ...
}
To validate the object, you have some special requirements:
isTechnicalPost
is true, then category
must be either php
or symfony
;isTechnicalPost
is false, then category
can be anything.One way to accomplish this is with the Expression constraint:
# src/Acme/DemoBundle/Resources/config/validation.yml
AcmeDemoBundleModelBlogPost:
constraints:
- Expression:
expression: "this.getCategory() in ['php', 'symfony'] or !this.isTechnicalPost()"
message: "If this is a tech post, the category should be either php or symfony!"
// src/Acme/DemoBundle/Model/BlogPost.php
namespace AcmeDemoBundleModel;
use SymfonyComponentValidatorConstraints as Assert;
/**
* @AssertExpression(
* "this.getCategory() in ['php', 'symfony'] or !this.isTechnicalPost()",
* message="If this is a tech post, the category should be either php or symfony!"
* )
*/
class BlogPost
{
// ...
}
<!-- src/Acme/DemoBundle/Resources/config/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="AcmeDemoBundleModelBlogPost">
<constraint name="Expression">
<option name="expression">
this.getCategory() in ['php', 'symfony'] or !this.isTechnicalPost()
</option>
<option name="message">
If this is a tech post, the category should be either php or symfony!
</option>
</constraint>
</class>
</constraint-mapping>
// src/Acme/DemoBundle/Model/BlogPost.php
namespace AcmeDemoBundleModel;
use SymfonyComponentValidatorMappingClassMetadata;
use SymfonyComponentValidatorConstraints as Assert;
class BlogPost
{
public static function loadValidatorMetadata(ClassMetadata $metadata)
{
$metadata->addConstraint(new AssertExpression(array(
'expression' => 'this.getCategory() in ["php", "symfony"] or !this.isTechnicalPost()',
'message' => 'If this is a tech post, the category should be either php or symfony!',
)));
}
// ...
}
The expression option is the expression that must return true in order for validation to pass. To learn more about the expression language syntax, see The Expression Syntax.
For more information about the expression and what variables are available to you, see the expression option details below.
type: string
[default option]
The expression that will be evaluated. If the expression evaluates to a false
value (using ==
, not ===
), validation will fail.
To learn more about the expression language syntax, see The Expression Syntax.
Inside of the expression, you have access to up to 2 variables:
Depending on how you use the constraint, you have access to 1 or 2 variables in your expression:
this
: The object being validated (e.g. an instance of BlogPost);value
: The value of the property being validated (only available when
the constraint is applied directly to a property);type: string
default: This value is not valid.
The default message supplied when the expression evaluates to false.
type: mixed
default: null
2.6 新版功能: The payload
option was introduced in Symfony 2.6.
This option can be used to attach arbitrary domain-specific data to a constraint. The configured payload is not used by the Validator component, but its processing is completely up to.
For example, you may want to used several error levels to present failed constraint differently in the front-end depending on the severity of the error.