Validator

API reference › yii › validators › Validator

class	`yii\validators\Validator`
Extends	`yii\base\Component` » `yii\base\BaseObject`
Implements	`yii\base\Configurable`
Since	2.0
Source	`framework/validators/Validator.php`

22 subclasses

Validator is the base class for all validators.

Child classes should override the validateValue() and/or validateAttribute() methods to provide the actual logic of performing data validation. Child classes may also override clientValidateAttribute() to provide client-side validation support.

Validator declares a set of built-in validators which can be referenced using short names. They are listed as follows:

For more details and usage information on Validator, see the guide article on validators.

Properties

Property	Type	Description	Defined by
`$attributeNames` read-only	`array`	Attribute names.	`Validator`
`$attributes`	`array\|string`	Attributes to be validated by this validator. Default: `[]`.	`Validator`
`$behaviors` read-only	`array<yii\base\Behavior<static>>`	List of behaviors attached to this component.	`yii\base\Component`
`$builtInValidators` static	`array`	List of built-in validators (name => class or configuration) Default: ['boolean' => 'yii\validators\BooleanValidator', 'captcha' => 'yii\captcha\CaptchaValidator', 'compare' => 'yii\validators\CompareValidator', 'date' => 'yii\validators\DateValidator', 'datetime' => ['class' => 'yii\validators\DateValidator', 'type' => \yii\validators\DateValidator::TYPE_DATETIME], 'time' => ['class' => 'yii\validators\DateValidator', 'type' => \yii\validators\DateValidator::TYPE_TIME], 'default' => 'yii\validators\DefaultValueValidator', 'double' => 'yii\validators\NumberValidator', 'each' => 'yii\validators\EachValidator', 'email' => 'yii\validators\EmailValidator', 'exist' => 'yii\validators\ExistValidator', 'file' => 'yii\validators\FileValidator', 'filter' => 'yii\validators\FilterValidator', 'image' => 'yii\validators\ImageValidator', 'in' => 'yii\validators\RangeValidator', 'integer' => ['class' => 'yii\validators\NumberValidator', 'integerOnly' => true], 'match' => 'yii\validators\RegularExpressionValidator', 'number' => 'yii\validators\NumberValidator', 'required' => 'yii\validators\RequiredValidator', 'safe' => 'yii\validators\SafeValidator', 'string' => 'yii\validators\StringValidator', 'trim' => ['class' => 'yii\validators\TrimValidator', 'skipOnArray' => true], 'unique' => 'yii\validators\UniqueValidator', 'url' => 'yii\validators\UrlValidator', 'ip' => 'yii\validators\IpValidator'].	`Validator`
`$enableClientValidation`	`bool`	Whether to enable client-side validation for this validator. Default: `true`.	`Validator`
`$except`	`array\|string`	Scenarios that the validator should not be applied to. Default: `[]`.	`Validator`
`$isEmpty`	`callable\|null`	A PHP callable that replaces the default implementation of `isEmpty()`. Default: `null`.	`Validator`
`$message`	`string\|null`	The user-defined error message. Default: `null`.	`Validator`
`$on`	`array\|string`	Scenarios that the validator can be applied to. Default: `[]`.	`Validator`
`$skipOnEmpty`	`bool`	Whether this validation rule should be skipped if the attribute value is null or an empty string. Default: `true`.	`Validator`
`$skipOnError`	`bool`	Whether this validation rule should be skipped if the attribute being validated already has some validation error according to some previous rules. Default: `true`.	`Validator`
`$validationAttributes` read-only	`array\|null`	List of attribute names.	`Validator`
`$when`	`callable\|null`	A PHP callable whose return value determines whether this validator should be applied. Default: `null`.	`Validator`
`$whenClient`	`string\|null`	A JavaScript function name whose return value determines whether this validator should be applied on the client-side. Default: `null`.	`Validator`

Methods

Method	Description	Defined by
`__construct()`	Constructor.	`yii\base\BaseObject`
`__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`
`__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.	`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()` static	Returns the fully qualified name of this class.	`yii\base\BaseObject`
`clientValidateAttribute()`	Returns the JavaScript needed for performing client-side validation.	`Validator`
`createValidator()` static	Creates a validator object.	`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.	`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.	`Validator`
`getFormattedClientMessage()`	Returns the formatted validation message for client-side validation.	`Validator`
`getValidationAttributes()`	Returns a list of attributes this validator applies to.	`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.	`Validator`
`isActive()`	Returns a value indicating whether the validator is active for the given scenario and attribute.	`Validator`
`isEmpty()`	Checks if the given value is empty.	`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.	`Validator`
`validateAttribute()`	Validates a single attribute.	`Validator`
`validateAttributes()`	Validates the specified object.	`Validator`
`formatMessage()` protected	Formats a mesage using the I18N, or simple strtr if `\Yii::$app` is not available.	`Validator`
`validateValue()` protected	Validates a value.	`Validator`

Property details

$attributes

public array|string $attributes = []

Attributes to be validated by this validator.

For multiple attributes, please specify them as an array; for single attribute, you may use either a string or an array.

$enableClientValidation

public bool $enableClientValidation = true

Whether to enable client-side validation for this validator.

The actual client-side validation is done via the JavaScript code returned by clientValidateAttribute(). If that method returns null, even if this property is true, no client-side validation will be done by this validator.

$except

public array|string $except = []

Scenarios that the validator should not be applied to.

For multiple scenarios, please specify them as an array; for single scenario, you may use either a string or an array.

$isEmpty

public callable|null $isEmpty = null

A PHP callable that replaces the default implementation of isEmpty().

If not set, isEmpty() will be used to check if a value is empty. The signature of the callable should be function ($value) which returns a boolean indicating whether the value is empty.

$message

public string|null $message = null

The user-defined error message.

It may contain the following placeholders which will be replaced accordingly by the validator:

{attribute}: the label of the attribute being validated
{value}: the value of the attribute being validated

Note that some validators may introduce other properties for error messages used when specific validation conditions are not met. Please refer to individual class API documentation for details about these properties. By convention, this property represents the primary error message used when the most important validation condition is not met.

$on

public array|string $on = []

Scenarios that the validator can be applied to.

For multiple scenarios, please specify them as an array; for single scenario, you may use either a string or an array.

$skipOnEmpty

public bool $skipOnEmpty = true

Whether this validation rule should be skipped if the attribute value is null or an empty string.

This property is used only when validating Model.

$skipOnError

public bool $skipOnError = true

Whether this validation rule should be skipped if the attribute being validated already has some validation error according to some previous rules.

Defaults to true.

$when

public callable|null $when = null

A PHP callable whose return value determines whether this validator should be applied.

The signature of the callable should be function ($model, $attribute), where $model and $attribute refer to the model and the attribute currently being validated. The callable should return a boolean value.

This property is mainly provided to support conditional validation on the server-side. If this property is not set, this validator will be always applied on the server-side.

The following example will enable the validator only when the country currently selected is USA:

function ($model) {
    return $model->country == Country::USA;
}

$whenClient

public string|null $whenClient = null

A JavaScript function name whose return value determines whether this validator should be applied on the client-side.

The signature of the function should be function (attribute, value), where attribute is an object describing the attribute being validated (see clientValidateAttribute()) and value the current value of the attribute.

This property is mainly provided to support conditional validation on the client-side. If this property is not set, this validator will be always applied on the client-side.

The following example will enable the validator only when the country currently selected is USA:

function (attribute, value) {
    return $('#country').val() === 'USA';
}

Method details

addError()

public function addError(yii\base\Model $model, string $attribute, string $message, array $params = []): mixed

Adds an error about the specified attribute to the model object.

This is a helper method that performs message selection and internationalization.

Parameters

Parameter	Type	Description
`$model`	`yii\base\Model`	The data model being validated
`$attribute`	`string`	The attribute being validated
`$message`	`string`	The error message
`$params`	`array`	Values for the placeholders in the error message

Returns

mixed

clientValidateAttribute()

public function clientValidateAttribute(yii\base\Model $model, string $attribute, yii\web\View $view): string|null

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

Parameters

Parameter	Type	Description
`$model`	`yii\base\Model`	The data model being validated
`$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.

Returns

string|null: The client-side validation script. Null if the validator does not support client-side validation.

See also

createValidator()

public static function createValidator(string|Closure $type, yii\base\Model $model, array|string $attributes, array $params = []): yii\validators\Validator

Creates a validator object.

Parameters

Parameter	Type	Description
`$type`	`string\|Closure`	The validator type. This can be either: * a built-in validator name listed in `$builtInValidators`; * a method name of the model class; * an anonymous function; * a validator class name.
`$model`	`yii\base\Model`	The data model to be validated.
`$attributes`	`array\|string`	List of attributes to be validated. This can be either an array of the attribute names or a string of comma-separated attribute names.
`$params`	`array`	Initial values to be applied to the validator properties.

Returns

Validator: The validator

getAttributeNames()

public function getAttributeNames(): array

Returns cleaned attribute names without the ! character at the beginning.

Returns

array: Attribute names.

Since

2.0.12

getClientOptions()

public function getClientOptions(yii\base\Model $model, string $attribute): array

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.

Parameters

Parameter	Type	Description
`$model`	`yii\base\Model`	The model being validated
`$attribute`	`string`	The attribute name being validated

Returns

array: The client-side validation options

Since

2.0.11

getFormattedClientMessage()

public function getFormattedClientMessage(string $message, array<string, mixed> $params): string

Returns the formatted validation message for client-side validation.

This method can be overridden in subclasses to provide custom message formatting with validator-specific parameters.

Parameters

Parameter	Type	Description
`$message`	`string`	The message template to be formatted
`$params`	`array<string, mixed>`	The parameters to be inserted into the message

Returns

string: The formatted validation message

Since

22.0

getValidationAttributes()

public function getValidationAttributes(array|string|null $attributes = null): array|null

Returns a list of attributes this validator applies to.

Parameters

Parameter	Type	Description
`$attributes`	`array\|string\|null`	The list of attributes to be validated. - If this is `null`, the result will be equal to `getAttributeNames()`. - If this is a string or an array, the intersection of `getAttributeNames()` and the specified attributes will be returned.

Returns

array|null: List of attribute names.

Since

2.0.16

init()

public function init(): mixed

Initializes the object.

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

Returns

mixed

isActive()

public function isActive(string $scenario): bool

Returns a value indicating whether the validator is active for the given scenario and attribute.

A validator is active if

the validator’s on property is empty, or
the validator’s on property contains the specified scenario

Parameters

Parameter	Type	Description
`$scenario`	`string`	Scenario name

Returns

bool: Whether the validator applies to the specified scenario.

isEmpty()

public function isEmpty(mixed $value): bool

Checks if the given value is empty.

A value is considered empty if it is null, an empty array, or an empty string. Note that this method is different from PHP empty(). It will return false when the value is 0.

Parameters

Parameter	Type	Description
`$value`	`mixed`	The value to be checked

Returns

bool: Whether the value is empty

validate()

public function validate(mixed $value, string|null &$error = null): bool

Validates a given value.

You may use this method to validate a value out of the context of a data model.

Parameters

Parameter	Type	Description
`$value`	`mixed`	The data value to be validated.
`$error`	`string\|null`	The error message to be returned, if the validation fails.

Returns

bool: Whether the data is valid.

validateAttribute()

public function validateAttribute(yii\base\Model $model, string $attribute): mixed

Validates a single attribute.

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

Parameters

Parameter	Type	Description
`$model`	`yii\base\Model`	The data model to be validated
`$attribute`	`string`	The name of the attribute to be validated.

Returns

mixed

validateAttributes()

public function validateAttributes(yii\base\Model $model, array|string|null $attributes = null): mixed

Validates the specified object.

Parameters

Parameter	Type	Description
`$model`	`yii\base\Model`	The data model being validated
`$attributes`	`array\|string\|null`	The list of attributes to be validated. Note that if an attribute is not associated with the validator - it will be ignored. If this parameter is null, every attribute listed in `$attributes` will be validated.

Returns

mixed

formatMessage()

protected function formatMessage(string $message, array $params): string

Formats a mesage using the I18N, or simple strtr if \Yii::$app is not available.

Parameters

Parameter	Type	Description
`$message`	`string`
`$params`	`array`

Returns

string

Since

2.0.12

validateValue()

protected function validateValue(mixed $value): array|null

Validates a value.

A validator class can implement this method to support data validation out of the context of a data model.

Parameters

Parameter	Type	Description
`$value`	`mixed`	The data value to be validated.

Returns

array|null: The error message and the array of parameters to be inserted into the error message. if (!$valid) { return [$this->message, [ ‘param1’ => $this->param1, ‘formattedLimit’ => Yii::$app->formatter->asShortSize($this->getSizeLimit()), ‘mimeTypes’ => implode(’, ’, $this->mimeTypes), ‘param4’ => ‘etc…’, ]]; } return null; for this example message template can contain {param1}, {formattedLimit}, {mimeTypes}, {param4} Null should be returned if the data is valid.

Throws

yii\base\NotSupportedException: if the validator does not supporting data validation without a model