# Class yii\validators\FilterValidator

Inheritance | yii\validators\FilterValidator » yii\validators\Validator » yii\base\Component » yii\base\BaseObject
Implements | yii\base\Configurable
Available since version | 2.0
Source Code | https://github.com/yiisoft/yii2/blob/master/framework/validators/FilterValidator.php

FilterValidator converts the attribute value according to a filter.

FilterValidator is actually not a validator but a data processor. It invokes the specified filter callback to process the attribute value and save the processed value back to the attribute. The filter must be a valid PHP callback with the following signature:

    function foo($value) {
        // compute $newValue here
        return $newValue;
    }

Many PHP functions qualify this signature (e.g. `trim()`).

To specify the filter, set $filter property to be the callback.

## Public Properties

Hide inherited properties

Property | Type | Description | Defined By
--- | --- | --- | ---
$attributeNames | array | Attribute names. This property is read-only. | yii\validators\Validator
$attributes | array|string | Attributes to be validated by this validator. | yii\validators\Validator
$behaviors | yii\base\Behavior[] | List of behaviors attached to this component. This property is read-only. | yii\base\Component
$builtInValidators | array | List of built-in validators (name => class or configuration) | yii\validators\Validator
$enableClientValidation | boolean | Whether to enable client-side validation for this validator. | yii\validators\Validator
$except | array|string | Scenarios that the validator should not be applied to. | yii\validators\Validator
$filter | callable | The filter. | yii\validators\FilterValidator
$isEmpty | callable | A PHP callable that replaces the default implementation of isEmpty(). | yii\validators\Validator
$message | string | The user-defined error message. | yii\validators\Validator
$on | array|string | Scenarios that the validator can be applied to. | yii\validators\Validator
$skipOnArray | boolean | Whether the filter should be skipped if an array input is given. | yii\validators\FilterValidator
$skipOnEmpty | boolean | This property is overwritten to be false so that this validator will be applied when the value being validated is empty. | yii\validators\FilterValidator
$skipOnError | boolean | Whether this validation rule should be skipped if the attribute being validated already has some validation error according to some previous rules. | yii\validators\Validator
$validationAttributes | array | List of attribute names. This property is read-only. | yii\validators\Validator
$when | callable | A PHP callable whose return value determines whether this validator should be applied. | yii\validators\Validator
$whenClient | string | A JavaScript function name whose return value determines whether this validator should be applied on the client-side. | yii\validators\Validator

## Public Methods

Hide inherited methods

Method | Description | Defined By
--- | --- | ---
__call() | Calls the named method which is not a class method. | yii\base\Component
__clone() | This method is called after the object is created by cloning an existing one. | yii\base\Component
__construct() | Constructor. | yii\base\BaseObject
__get() | Returns the value of a component property. | yii\base\Component
__isset() | Checks if a property is set, i.e. defined and not null. | yii\base\Component
__set() | Sets the value of a component property. | yii\base\Component
__unset() | Sets a component property to be null. | yii\base\Component
addError() | Adds an error about the specified attribute to the model object. | yii\validators\Validator
attachBehavior() | Attaches a behavior to this component. | yii\base\Component
attachBehaviors() | Attaches a list of behaviors to the component. | yii\base\Component
behaviors() | Returns a list of behaviors that this component should behave as. | yii\base\Component
canGetProperty() | Returns a value indicating whether a property can be read. | yii\base\Component
canSetProperty() | Returns a value indicating whether a property can be set. | yii\base\Component
className() | Returns the fully qualified name of this class. | yii\base\BaseObject
clientValidateAttribute() | Returns the JavaScript needed for performing client-side validation. | yii\validators\FilterValidator
createValidator() | Creates a validator object. | yii\validators\Validator
detachBehavior() | Detaches a behavior from the component. | yii\base\Component
detachBehaviors() | Detaches all behaviors from the component. | yii\base\Component
ensureBehaviors() | Makes sure that the behaviors declared in behaviors() are attached to this component. | yii\base\Component
getAttributeNames() | Returns cleaned attribute names without the `!` character at the beginning. | yii\validators\Validator
getBehavior() | Returns the named behavior object. | yii\base\Component
getBehaviors() | Returns all behaviors attached to this component. | yii\base\Component
getClientOptions() | Returns the client-side validation options. | yii\validators\FilterValidator
getValidationAttributes() | Returns a list of attributes this validator applies to. | yii\validators\Validator
hasEventHandlers() | Returns a value indicating whether there is any handler attached to the named event. | yii\base\Component
hasMethod() | Returns a value indicating whether a method is defined. | yii\base\Component
hasProperty() | Returns a value indicating whether a property is defined for this component. | yii\base\Component
init() | Initializes the object. | yii\validators\FilterValidator
isActive() | Returns a value indicating whether the validator is active for the given scenario and attribute. | yii\validators\Validator
isEmpty() | Checks if the given value is empty. | yii\validators\Validator
off() | Detaches an existing event handler from this component. | yii\base\Component
on() | Attaches an event handler to an event. | yii\base\Component
trigger() | Triggers an event. | yii\base\Component
validate() | Validates a given value. | yii\validators\Validator
validateAttribute() | Validates a single attribute. | yii\validators\FilterValidator
validateAttributes() | Validates the specified object. | yii\validators\Validator

## Protected Methods

Hide inherited methods

Method | Description | Defined By
--- | --- | ---
formatMessage() | Formats a mesage using the I18N, or simple strtr if `\Yii::$app` is not available. | yii\validators\Validator
validateValue() | Validates a value. | yii\validators\Validator

## Property Details

$filter public property

The filter. This can be a global function name, anonymous function, etc. The function signature must be as follows,

    function foo($value) {
        // compute $newValue here
        return $newValue;
    }

public callable $filter = null
$skipOnArray public property

Whether the filter should be skipped if an array input is given. If true and an array input is given, the filter will not be applied.

public boolean $skipOnArray = false
$skipOnEmpty public property

This property is overwritten to be false so that this validator will be applied when the value being validated is empty.

public boolean $skipOnEmpty = false

## Method Details

clientValidateAttribute() public method

Returns the JavaScript needed for performing client-side validation.

Calls getClientOptions() to generate options array for client-side validation.

You may override this method to return the JavaScript validation code if the validator can support client-side validation.

The following JavaScript variables are predefined and can be used in the validation code:

- `attribute`: an object describing the the attribute being validated.
- `value`: the value being validated.
- `messages`: an array used to hold the validation error messages for the attribute.
- `deferred`: an array used to hold deferred objects for asynchronous validation
- `$form`: a jQuery object containing the form element

The `attribute` object contains the following properties:

- `id`: a unique ID identifying the attribute (e.g. "loginform-username") in the form
- `name`: attribute name or expression (e.g. "[0]content" for tabular input)
- `container`: the jQuery selector of the container of the input field
- `input`: the jQuery selector of the input field under the context of the form
- `error`: the jQuery selector of the error tag under the context of the container
- `status`: status of the input field, 0: empty, not entered before, 1: validated, 2: pending validation, 3: validating

public string|null clientValidateAttribute ( $model, $attribute, $view )
$model | yii\base\Model | The data model being validated
$attribute | string | The name of the attribute to be validated.
$view | yii\web\View | The view object that is going to be used to render views or view files containing a model form with this validator applied.
return | string|null | The client-side validation script. Null if the validator does not support client-side validation.

getClientOptions() public method (available since version 2.0.11)

Returns the client-side validation options.

This method is usually called from clientValidateAttribute(). You may override this method to modify options that will be passed to the client-side validation.

public array getClientOptions ( $model, $attribute )
$model | yii\base\Model | The model being validated
$attribute | string | The attribute name being validated
return | array | The client-side validation options

init() public method

Initializes the object.

This method is invoked at the end of the constructor after the object is initialized with the given configuration.

public void init ( )

validateAttribute() public method

Validates a single attribute.

Child classes must implement this method to provide the actual validation logic.

public void validateAttribute ( $model, $attribute )
$model | yii\base\Model | The data model to be validated
$attribute | string | The name of the attribute to be validated.