# Class yii\behaviors\SluggableBehavior

Inheritance | yii\behaviors\SluggableBehavior » yii\behaviors\AttributeBehavior » yii\base\Behavior » yii\base\BaseObject
Implements | yii\base\Configurable
Available since version | 2.0
Source Code | https://github.com/yiisoft/yii2/blob/master/framework/behaviors/SluggableBehavior.php

SluggableBehavior automatically fills the specified attribute with a value that can be used a slug in a URL.

Note: This behavior relies on php-intl extension for transliteration. If it is not installed it falls back to replacements defined in yii\helpers\Inflector::$transliteration.

To use SluggableBehavior, insert the following code to your ActiveRecord class:

    use yii\behaviors\SluggableBehavior;

    public function behaviors()
    {
        return [
            [
                'class' => SluggableBehavior::class,
                'attribute' => 'title',
                // 'slugAttribute' => 'slug',
            ],
        ];
    }

By default, SluggableBehavior will fill the `slug` attribute with a value that can be used a slug in a URL when the associated AR object is being validated.

Because attribute values will be set automatically by this behavior, they are usually not user input and should therefore not be validated, i.e. the `slug` attribute should not appear in the rules() method of the model.

If your attribute name is different, you may configure the $slugAttribute property like the following:

    public function behaviors()
    {
        return [
            [
                'class' => SluggableBehavior::class,
                'slugAttribute' => 'alias',
            ],
        ];
    }

## Public Properties

Hide inherited properties

Property | Type | Description | Defined By
--- | --- | --- | ---
$attribute | string|array|null | The attribute or list of attributes whose value will be converted into a slug or `null` meaning that the `$value` property will be used to generate a slug. | yii\behaviors\SluggableBehavior
$attributes | array | List of attributes that are to be automatically filled with the value specified via $value. | yii\behaviors\AttributeBehavior
$ensureUnique | boolean | Whether to ensure generated slug value to be unique among owner class records. | yii\behaviors\SluggableBehavior
$immutable | boolean | Whether to generate a new slug if it has already been generated before. | yii\behaviors\SluggableBehavior
$owner | yii\base\Component|null | The owner of this behavior | yii\base\Behavior
$preserveNonEmptyValues | boolean | Whether to preserve non-empty attribute values. | yii\behaviors\AttributeBehavior
$skipOnEmpty | boolean | Whether to skip slug generation if $attribute is null or an empty string. | yii\behaviors\SluggableBehavior
$skipUpdateOnClean | boolean | Whether to skip this behavior when the `$owner` has not been modified | yii\behaviors\AttributeBehavior
$slugAttribute | string | The attribute that will receive the slug value | yii\behaviors\SluggableBehavior
$uniqueSlugGenerator | callable|null | Slug unique value generator. | yii\behaviors\SluggableBehavior
$uniqueValidator | array | Configuration for slug uniqueness validator. | yii\behaviors\SluggableBehavior
$value | callable|string|null | The value that will be used as a slug. | yii\behaviors\SluggableBehavior

## Public Methods

Hide inherited methods

Method | Description | Defined By
--- | --- | ---
__call() | Calls the named method which is not a class method. | yii\base\BaseObject
__construct() | Constructor. | yii\base\BaseObject
__get() | Returns the value of an object property. | yii\base\BaseObject
__isset() | Checks if a property is set, i.e. defined and not null. | yii\base\BaseObject
__set() | Sets value of an object property. | yii\base\BaseObject
__unset() | Sets an object property to null. | yii\base\BaseObject
attach() | Attaches the behavior object to the component. | yii\base\Behavior
canGetProperty() | Returns a value indicating whether a property can be read. | yii\base\BaseObject
canSetProperty() | Returns a value indicating whether a property can be set. | yii\base\BaseObject
className() | Returns the fully qualified name of this class. | yii\base\BaseObject
detach() | Detaches the behavior object from the component. | yii\base\Behavior
evaluateAttributes() | Evaluates the attribute value and assigns it to the current attributes. | yii\behaviors\AttributeBehavior
events() | Declares event handlers for the $owner's events. | yii\behaviors\AttributeBehavior
hasMethod() | Returns a value indicating whether a method is defined. | yii\base\BaseObject
hasProperty() | Returns a value indicating whether a property is defined. | yii\base\BaseObject
init() | Initializes the object. | yii\behaviors\SluggableBehavior

## Protected Methods

Hide inherited methods

Method | Description | Defined By
--- | --- | ---
generateSlug() | This method is called by getValue() to generate the slug. | yii\behaviors\SluggableBehavior
generateUniqueSlug() | Generates slug using configured callback or increment of iteration. | yii\behaviors\SluggableBehavior
getValue() | Returns the value for the current attributes. | yii\behaviors\SluggableBehavior
isEmpty() | Checks if $slugPart is empty string or null. | yii\behaviors\SluggableBehavior
isNewSlugNeeded() | Checks whether the new slug generation is needed This method is called by getValue() to check whether the new slug generation is needed. | yii\behaviors\SluggableBehavior
makeUnique() | This method is called by getValue() when $ensureUnique is true to generate the unique slug. | yii\behaviors\SluggableBehavior
validateSlug() | Checks if given slug value is unique. | yii\behaviors\SluggableBehavior

## Property Details

Hide inherited properties

$attribute public property

The attribute or list of attributes whose value will be converted into a slug or `null` meaning that the `$value` property will be used to generate a slug.

public string|array|null $attribute = null
$ensureUnique public property

Whether to ensure generated slug value to be unique among owner class records. If enabled behavior will validate slug uniqueness automatically. If validation fails it will attempt generating unique slug value from based one until success.

public boolean $ensureUnique = false
$immutable public property (available since version 2.0.2)

Whether to generate a new slug if it has already been generated before. If true, the behavior will not generate a new slug even if $attribute is changed.

public boolean $immutable = false
$skipOnEmpty public property (available since version 2.0.13)

Whether to skip slug generation if $attribute is null or an empty string. If true, the behaviour will not generate a new slug if $attribute is null or an empty string.

public boolean $skipOnEmpty = false
$slugAttribute public property

The attribute that will receive the slug value

public string $slugAttribute = 'slug'
$uniqueSlugGenerator public property

Slug unique value generator. It is used in case $ensureUnique enabled and generated slug is not unique. This should be a PHP callable with following signature:

    function ($baseSlug, $iteration, $model)
    {
        // return uniqueSlug
    }

If not set unique slug will be generated adding incrementing suffix to the base slug.

public callable|null $uniqueSlugGenerator = null
$uniqueValidator public property

Configuration for slug uniqueness validator. Parameter 'class' may be omitted - by default yii\validators\UniqueValidator will be used.

See also yii\validators\UniqueValidator.

public array $uniqueValidator = []
$value public property

The value that will be used as a slug. This can be an anonymous function or an arbitrary value or null. If the former, the return value of the function will be used as a slug. If `null` then the `$attribute` property will be used to generate a slug. The signature of the function should be as follows,

    function ($event)
    {
        // return slug
    }

public callable|string|null $value = null

## Method Details

Hide inherited methods

__call() public method

Defined in: yii\base\BaseObject::__call()

Calls the named method which is not a class method.

Do not call this method directly as it is a PHP magic method that will be implicitly called when an unknown method is being invoked.

public mixed __call ( $name, $params )
$name | string | The method name
$params | array | Method parameters
return | mixed | The method return value
throws | yii\base\UnknownMethodException | when calling unknown method

Source code

                    public function __call($name, $params)
    {
        throw new UnknownMethodException('Calling unknown method: ' . get_class($this) . "::$name()");
    }

__construct() public method

Defined in: yii\base\BaseObject::__construct()

Constructor.

The default implementation does two things:

- Initializes the object with the given configuration `$config`.
- Call init().

If this method is overridden in a child class, it is recommended that

- the last parameter of the constructor is a configuration array, like `$config` here.
- call the parent implementation at the end of the constructor.

public void __construct ( $config = [] )
$config | array | Name-value pairs that will be used to initialize the object properties

Source code

                    public function __construct($config = [])
    {
        if (!empty($config)) {
            Yii::configure($this, $config);
        }
        $this->init();
    }

__get() public method

Defined in: yii\base\BaseObject::__get()

Returns the value of an object property.

Do not call this method directly as it is a PHP magic method that will be implicitly called when executing `$value = $object->property;`.

See also __set().

public mixed __get ( $name )
$name | string | The property name
return | mixed | The property value
throws | yii\base\UnknownPropertyException | if the property is not defined
throws | yii\base\InvalidCallException | if the property is write-only

Source code

                    public function __get($name)
    {
        $getter = 'get' . $name;
        if (method_exists($this, $getter)) {
            return $this->$getter();
        } elseif (method_exists($this, 'set' . $name)) {
            throw new InvalidCallException('Getting write-only property: ' . get_class($this) . '::' . $name);
        }
        throw new UnknownPropertyException('Getting unknown property: ' . get_class($this) . '::' . $name);
    }

__isset() public method

Defined in: yii\base\BaseObject::__isset()

Checks if a property is set, i.e. defined and not null.

Do not call this method directly as it is a PHP magic method that will be implicitly called when executing `isset($object->property)`.

Note that if the property is not defined, false will be returned.

See also https://www.php.net/manual/en/function.isset.php.

public boolean __isset ( $name )
$name | string | The property name or the event name
return | boolean | Whether the named property is set (not null).

Source code

                    public function __isset($name)
    {
        $getter = 'get' . $name;
        if (method_exists($this, $getter)) {
            return $this->$getter() !== null;
        }
        return false;
    }

__set() public method

Defined in: yii\base\BaseObject::__set()

Sets value of an object property.

Do not call this method directly as it is a PHP magic method that will be implicitly called when executing `$object->property = $value;`.

See also __get().

public void __set ( $name, $value )
$name | string | The property name or the event name
$value | mixed | The property value
throws | yii\base\UnknownPropertyException | if the property is not defined
throws | yii\base\InvalidCallException | if the property is read-only

Source code

                    public function __set($name, $value)
    {
        $setter = 'set' . $name;
        if (method_exists($this, $setter)) {
            $this->$setter($value);
        } elseif (method_exists($this, 'get' . $name)) {
            throw new InvalidCallException('Setting read-only property: ' . get_class($this) . '::' . $name);
        } else {
            throw new UnknownPropertyException('Setting unknown property: ' . get_class($this) . '::' . $name);
        }
    }

__unset() public method

Defined in: yii\base\BaseObject::__unset()

Sets an object property to null.

Do not call this method directly as it is a PHP magic method that will be implicitly called when executing `unset($object->property)`.

Note that if the property is not defined, this method will do nothing. If the property is read-only, it will throw an exception.

See also https://www.php.net/manual/en/function.unset.php.

public void __unset ( $name )
$name | string | The property name
throws | yii\base\InvalidCallException | if the property is read only.

Source code

                    public function __unset($name)
    {
        $setter = 'set' . $name;
        if (method_exists($this, $setter)) {
            $this->$setter(null);
        } elseif (method_exists($this, 'get' . $name)) {
            throw new InvalidCallException('Unsetting read-only property: ' . get_class($this) . '::' . $name);
        }
    }

attach() public method

Defined in: yii\base\Behavior::attach()

Attaches the behavior object to the component.

The default implementation will set the $owner property and attach event handlers as declared in events(). Make sure you call the parent implementation if you override this method.

public void attach ( $owner )
$owner | yii\base\Component | The component that this behavior is to be attached to.

Source code

                    public function attach($owner)
    {
        $this->owner = $owner;
        foreach ($this->events() as $event => $handler) {
            $this->_attachedEvents[$event] = $handler;
            $owner->on($event, is_string($handler) ? [$this, $handler] : $handler);
        }
    }

canGetProperty() public method

Defined in: yii\base\BaseObject::canGetProperty()

Returns a value indicating whether a property can be read.

A property is readable if:

- the class has a getter method associated with the specified name (in this case, property name is case-insensitive);
- the class has a member variable with the specified name (when `$checkVars` is true);

See also canSetProperty().

public boolean canGetProperty ( $name, $checkVars = true )
$name | string | The property name
$checkVars | boolean | Whether to treat member variables as properties
return | boolean | Whether the property can be read

Source code

                    public function canGetProperty($name, $checkVars = true)
    {
        return method_exists($this, 'get' . $name) || $checkVars && property_exists($this, $name);
    }

canSetProperty() public method

Defined in: yii\base\BaseObject::canSetProperty()

Returns a value indicating whether a property can be set.

A property is writable if:

- the class has a setter method associated with the specified name (in this case, property name is case-insensitive);
- the class has a member variable with the specified name (when `$checkVars` is true);

See also canGetProperty().

public boolean canSetProperty ( $name, $checkVars = true )
$name | string | The property name
$checkVars | boolean | Whether to treat member variables as properties
return | boolean | Whether the property can be written

Source code

                    public function canSetProperty($name, $checkVars = true)
    {
        return method_exists($this, 'set' . $name) || $checkVars && property_exists($this, $name);
    }

className() public static method
Deprecated since 2.0.14. On PHP >=5.5, use `::class` instead.

Defined in: yii\base\BaseObject::className()

Returns the fully qualified name of this class.

public static string className ( )
return | string | The fully qualified name of this class.

Source code

                    public static function className()
    {
        return get_called_class();
    }

detach() public method

Defined in: yii\base\Behavior::detach()

Detaches the behavior object from the component.

The default implementation will unset the $owner property and detach event handlers declared in events(). Make sure you call the parent implementation if you override this method.

public void detach ( )

Source code

                    public function detach()
    {
        if ($this->owner) {
            foreach ($this->_attachedEvents as $event => $handler) {
                $this->owner->off($event, is_string($handler) ? [$this, $handler] : $handler);
            }
            $this->_attachedEvents = [];
            $this->owner = null;
        }
    }

evaluateAttributes() public method

Defined in: yii\behaviors\AttributeBehavior::evaluateAttributes()

Evaluates the attribute value and assigns it to the current attributes.

public void evaluateAttributes ( $event )
$event | yii\base\Event |

Source code

                    public function evaluateAttributes($event)
    {
        if (
            $this->skipUpdateOnClean
            && $event->name == ActiveRecord::EVENT_BEFORE_UPDATE
            && empty($this->owner->dirtyAttributes)
        ) {
            return;
        }
        if (!empty($this->attributes[$event->name])) {
            $attributes = (array) $this->attributes[$event->name];
            $value = $this->getValue($event);
            foreach ($attributes as $attribute) {
                // ignore attribute names which are not string (e.g. when set by TimestampBehavior::updatedAtAttribute)
                if (is_string($attribute)) {
                    if ($this->preserveNonEmptyValues && !empty($this->owner->$attribute)) {
                        continue;
                    }
                    $this->owner->$attribute = $value;
                }
            }
        }
    }

events() public method

Defined in: yii\behaviors\AttributeBehavior::events()

Declares event handlers for the $owner's events.

Child classes may override this method to declare what PHP callbacks should be attached to the events of the $owner component.

The callbacks will be attached to the $owner's events when the behavior is attached to the owner; and they will be detached from the events when the behavior is detached from the component.

The callbacks can be any of the following:

- method in this behavior: `'handleClick'`, equivalent to `[$this, 'handleClick']`
- object method: `[$object, 'handleClick']`
- static method: `['Page', 'handleClick']`
- anonymous function: `function ($event) { ... }`

The following is an example:

    [
        Model::EVENT_BEFORE_VALIDATE => 'myBeforeValidate',
        Model::EVENT_AFTER_VALIDATE => 'myAfterValidate',
    ]

public array events ( )
return | array | Events (array keys) and the corresponding event handler methods (array values).

Source code

                    public function events()
    {
        return array_fill_keys(
            array_keys($this->attributes),
            'evaluateAttributes'
        );
    }

generateSlug() protected method

This method is called by getValue() to generate the slug.

You may override it to customize slug generation. The default implementation calls yii\helpers\Inflector::slug() on the input strings concatenated by dashes (`-`).

protected string generateSlug ( $slugParts )
$slugParts | array | An array of strings that should be concatenated and converted to generate the slug value.
return | string | The conversion result.

Source code

                    protected function generateSlug($slugParts)
    {
        return Inflector::slug(implode('-', $slugParts));
    }

generateUniqueSlug() protected method

Generates slug using configured callback or increment of iteration.

protected string generateUniqueSlug ( $baseSlug, $iteration )
$baseSlug | string | Base slug value
$iteration | integer | Iteration number
return | string | New slug value
throws | yii\base\InvalidConfigException |

Source code

                    protected function generateUniqueSlug($baseSlug, $iteration)
    {
        if (is_callable($this->uniqueSlugGenerator)) {
            return call_user_func($this->uniqueSlugGenerator, $baseSlug, $iteration, $this->owner);
        }
        return $baseSlug . '-' . ($iteration + 1);
    }

getValue() protected method

Returns the value for the current attributes.

This method is called by evaluateAttributes(). Its return value will be assigned to the attributes corresponding to the triggering event.

protected mixed getValue ( $event )
$event | yii\base\Event | The event that triggers the current attribute updating.
return | mixed | The attribute value

Source code

                    protected function getValue($event)
    {
        if (!$this->isNewSlugNeeded()) {
            return $this->owner->{$this->slugAttribute};
        }
        if ($this->attribute !== null) {
            $slugParts = [];
            foreach ((array) $this->attribute as $attribute) {
                $part = ArrayHelper::getValue($this->owner, $attribute);
                if ($this->skipOnEmpty && $this->isEmpty($part)) {
                    return $this->owner->{$this->slugAttribute};
                }
                $slugParts[] = $part;
            }
            $slug = $this->generateSlug($slugParts);
        } else {
            $slug = parent::getValue($event);
        }
        return $this->ensureUnique ? $this->makeUnique($slug) : $slug;
    }

hasMethod() public method

Defined in: yii\base\BaseObject::hasMethod()

Returns a value indicating whether a method is defined.

The default implementation is a call to php function `method_exists()`. You may override this method when you implemented the php magic method `__call()`.

public boolean hasMethod ( $name )
$name | string | The method name
return | boolean | Whether the method is defined

Source code

                    public function hasMethod($name)
    {
        return method_exists($this, $name);
    }

hasProperty() public method

Defined in: yii\base\BaseObject::hasProperty()

Returns a value indicating whether a property is defined.

A property is defined if:

- the class has a getter or setter method associated with the specified name (in this case, property name is case-insensitive);
- the class has a member variable with the specified name (when `$checkVars` is true);

See also:

- canGetProperty()
- canSetProperty()

public boolean hasProperty ( $name, $checkVars = true )
$name | string | The property name
$checkVars | boolean | Whether to treat member variables as properties
return | boolean | Whether the property is defined

Source code

                    public function hasProperty($name, $checkVars = true)
    {
        return $this->canGetProperty($name, $checkVars) || $this->canSetProperty($name, false);
    }

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 ( )

Source code

                    public function init()
    {
        parent::init();
        if (empty($this->attributes)) {
            $this->attributes = [BaseActiveRecord::EVENT_BEFORE_VALIDATE => $this->slugAttribute];
        }
        if ($this->attribute === null && $this->value === null) {
            throw new InvalidConfigException('Either "attribute" or "value" property must be specified.');
        }
    }

isEmpty() protected method (available since version 2.0.13)

Checks if $slugPart is empty string or null.

protected boolean isEmpty ( $slugPart )
$slugPart | string | One of attributes that is used for slug generation.
return | boolean | Whether $slugPart empty or not.

Source code

                    protected function isEmpty($slugPart)
    {
        return $slugPart === null || $slugPart === '';
    }

isNewSlugNeeded() protected method (available since version 2.0.7)

Checks whether the new slug generation is needed This method is called by getValue() to check whether the new slug generation is needed.

You may override it to customize checking.

protected boolean isNewSlugNeeded ( )

Source code

                    protected function isNewSlugNeeded()
    {
        if (empty($this->owner->{$this->slugAttribute})) {
            return true;
        }
        if ($this->immutable) {
            return false;
        }
        if ($this->attribute === null) {
            return true;
        }
        foreach ((array) $this->attribute as $attribute) {
            if ($this->owner->isAttributeChanged($attribute)) {
                return true;
            }
        }
        return false;
    }

makeUnique() protected method (available since version 2.0.7)

This method is called by getValue() when $ensureUnique is true to generate the unique slug.

Calls generateUniqueSlug() until generated slug is unique and returns it.

See also:

- getValue()
- generateUniqueSlug()

protected string makeUnique ( $slug )
$slug | string | Basic slug value
return | string | Unique slug

Source code

                    protected function makeUnique($slug)
    {
        $uniqueSlug = $slug;
        $iteration = 0;
        while (!$this->validateSlug($uniqueSlug)) {
            $iteration++;
            $uniqueSlug = $this->generateUniqueSlug($slug, $iteration);
        }
        return $uniqueSlug;
    }

validateSlug() protected method

Checks if given slug value is unique.

protected boolean validateSlug ( $slug )
$slug | string | Slug value
return | boolean | Whether slug is unique.

Source code

                    protected function validateSlug($slug)
    {
        /* @var $validator UniqueValidator */
        /* @var $model BaseActiveRecord */
        $validator = Yii::createObject(array_merge(
            [
                'class' => UniqueValidator::className(),
            ],
            $this->uniqueValidator
        ));
        $model = clone $this->owner;
        $model->clearErrors();
        $model->{$this->slugAttribute} = $slug;
        $validator->validateAttribute($model, $this->slugAttribute);
        return !$model->hasErrors();
    }