# Class yii\validators\StringValidator

Inheritance | yii\validators\StringValidator » 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/StringValidator.php

StringValidator validates that the attribute value is of certain length.

Note, this validator should only be used with string-typed attributes.

## Public Properties

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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
$encoding | string | The encoding of the string value to be validated (e.g. 'UTF-8'). | yii\validators\StringValidator
$except | array|string | Scenarios that the validator should not be applied to. | yii\validators\Validator
$isEmpty | callable | A PHP callable that replaces the default implementation of isEmpty(). | yii\validators\Validator
$length | integer|array | Specifies the length limit of the value to be validated. | yii\validators\StringValidator
$max | integer | Maximum length. | yii\validators\StringValidator
$message | string | User-defined error message used when the value is not a string. | yii\validators\StringValidator
$min | integer | Minimum length. | yii\validators\StringValidator
$notEqual | string | User-defined error message used when the length of the value is not equal to $length. | yii\validators\StringValidator
$on | array|string | Scenarios that the validator can be applied to. | yii\validators\Validator
$skipOnEmpty | boolean | Whether this validation rule should be skipped if the attribute value is null or an empty string. | yii\validators\Validator
$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
$strict | boolean | Whether to require the value to be a string data type. | yii\validators\StringValidator
$tooLong | string | User-defined error message used when the length of the value is greater than $max. | yii\validators\StringValidator
$tooShort | string | User-defined error message used when the length of the value is smaller than $min. | yii\validators\StringValidator
$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

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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\StringValidator
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\StringValidator
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\StringValidator
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\StringValidator
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\StringValidator

## Property Details

$encoding public property

The encoding of the string value to be validated (e.g. 'UTF-8'). If this property is not set, yii\base\Application::$charset will be used.

public string $encoding = null
$length public property

Specifies the length limit of the value to be validated. This can be specified in one of the following forms:

- an integer: the exact length that the value should be of;
- an array of one element: the minimum length that the value should be of. For example, `[8]`. This will overwrite $min.
- an array of two elements: the minimum and maximum lengths that the value should be of. For example, `[8, 128]`. This will overwrite both $min and $max.

See also:

- $tooShort for the customized message for a too short string.
- $tooLong for the customized message for a too long string.
- $notEqual for the customized message for a string that does not match desired length.

public integer|array $length = null
$max public property

Maximum length. If not set, it means no maximum length limit.

See also $tooLong for the customized message for a too long string.

public integer $max = null
$message public property

User-defined error message used when the value is not a string.

public string $message = null
$min public property

Minimum length. If not set, it means no minimum length limit.

See also $tooShort for the customized message for a too short string.

public integer $min = null
$notEqual public property

User-defined error message used when the length of the value is not equal to $length.

public string $notEqual = null
$strict public property (available since version 2.0.33)

Whether to require the value to be a string data type. If false any scalar value will be treated as it's string equivalent.

public boolean $strict = true
$tooLong public property

User-defined error message used when the length of the value is greater than $max.

public string $tooLong = null
$tooShort public property

User-defined error message used when the length of the value is smaller than $min.

public string $tooShort = null

## 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.

validateValue() protected method

Validates a value.

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

protected array|null validateValue ( $value )
$value | mixed | The data value to be validated.

return

array|null

The error message and the array of parameters to be inserted into the error message. ```php 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