# Class yii\filters\HostControl

Inheritance | yii\filters\HostControl » yii\base\ActionFilter » yii\base\Behavior » yii\base\BaseObject
Implements | yii\base\Configurable
Available since version | 2.0.11
Source Code | https://github.com/yiisoft/yii2/blob/master/framework/filters/HostControl.php

HostControl provides simple control over requested host name.

This filter provides protection against 'host header' attacks, allowing action execution only for specified host names.

Application configuration example:

    return [
        'as hostControl' => [
            'class' => 'yii\filters\HostControl',
            'allowedHosts' => [
                'example.com',
                '*.example.com',
            ],
        ],
        // ...
    ];

Controller configuration example:

    use yii\web\Controller;
    use yii\filters\HostControl;

    class SiteController extends Controller
    {
        public function behaviors()
        {
            return [
                'hostControl' => [
                    'class' => HostControl::class,
                    'allowedHosts' => [
                        'example.com',
                        '*.example.com',
                    ],
                ],
            ];
        }

        // ...
    }

> Note: the best way to restrict allowed host names is usage of the web server 'virtual hosts' configuration. This filter should be used only if this configuration is not available or compromised.

## Public Properties

Hide inherited properties

Property | Type | Description | Defined By
--- | --- | --- | ---
$allowedHosts | array|Closure|null | List of host names, which are allowed. | yii\filters\HostControl
$denyCallback | callable|null | A callback that will be called if the current host does not match $allowedHosts. | yii\filters\HostControl
$except | array | List of action IDs that this filter should not apply to. | yii\base\ActionFilter
$fallbackHostInfo | string|null | Fallback host info (e.g. `https://www.yiiframework.com`) used when Request::$hostInfo is invalid. | yii\filters\HostControl
$only | array | List of action IDs that this filter should apply to. | yii\base\ActionFilter
$owner | yii\base\Component|null | The owner of this behavior | yii\base\Behavior

## 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
afterAction() | This method is invoked right after an action is executed. | yii\base\ActionFilter
afterFilter() |  | yii\base\ActionFilter
attach() | Attaches the behavior object to the component. | yii\base\ActionFilter
beforeAction() | This method is invoked right before an action is to be executed (after all possible filters.) You may override this method to do last-minute preparation for the action. | yii\filters\HostControl
beforeFilter() |  | yii\base\ActionFilter
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\ActionFilter
events() | Declares event handlers for the $owner's events. | yii\base\Behavior
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\base\BaseObject

## Protected Methods

Hide inherited methods

Method | Description | Defined By
--- | --- | ---
denyAccess() | Denies the access. | yii\filters\HostControl
getActionId() | Returns an action ID by converting yii\base\Action::$uniqueId into an ID relative to the module. | yii\base\ActionFilter
isActive() | Returns a value indicating whether the filter is active for the given action. | yii\base\ActionFilter

## Property Details

Hide inherited properties

$allowedHosts public property

List of host names, which are allowed. Each host can be specified as a wildcard pattern. For example:

    [
        'example.com',
        '*.example.com',
    ]

This field can be specified as a PHP callback of following signature:

    function (\yii\base\Action $action) {
        //return array of strings
    }

where `$action` is the current action object.

If this field is not set - no host name check will be performed.

public array|Closure|null $allowedHosts = null
$denyCallback public property

A callback that will be called if the current host does not match $allowedHosts. If not set, denyAccess() will be called.

The signature of the callback should be as follows:

    function (\yii\base\Action $action)

where `$action` is the current action object.

> Note: while implementing your own host deny processing, make sure you avoid usage of the current requested host name, creation of absolute URL links, caching page parts and so on.

public callable|null $denyCallback = null
$fallbackHostInfo public property

Fallback host info (e.g. `https://www.yiiframework.com`) used when Request::$hostInfo is invalid. This value will replace Request::$hostInfo before $denyCallback is called to make sure that an invalid host will not be used for further processing. You can set it to `null` to leave Request::$hostInfo untouched. Default value is empty string (this will result creating relative URLs instead of absolute).

See also yii\web\Request::getHostInfo().

public string|null $fallbackHostInfo = ''

## 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);
        }
    }

afterAction() public method

Defined in: yii\base\ActionFilter::afterAction()

This method is invoked right after an action is executed.

You may override this method to do some postprocessing for the action.

public mixed afterAction ( $action, $result )
$action | yii\base\Action | The action just executed.
$result | mixed | The action execution result
return | mixed | The processed action result.

Source code

                    public function afterAction($action, $result)
    {
        return $result;
    }

afterFilter() public method

Defined in: yii\base\ActionFilter::afterFilter()

public void afterFilter ( $event )
$event | yii\base\ActionEvent |

Source code

                    public function afterFilter($event)
    {
        $event->result = $this->afterAction($event->action, $event->result);
        $this->owner->off(Controller::EVENT_AFTER_ACTION, [$this, 'afterFilter']);
    }

attach() public method

Defined in: yii\base\ActionFilter::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;
        $owner->on(Controller::EVENT_BEFORE_ACTION, [$this, 'beforeFilter']);
    }

beforeAction() public method

This method is invoked right before an action is to be executed (after all possible filters.) You may override this method to do last-minute preparation for the action.

public boolean beforeAction ( $action )
$action | yii\base\Action | The action to be executed.
return | boolean | Whether the action should continue to be executed.

Source code

                    public function beforeAction($action)
    {
        $allowedHosts = $this->allowedHosts;
        if ($allowedHosts instanceof \Closure) {
            $allowedHosts = call_user_func($allowedHosts, $action);
        }
        if ($allowedHosts === null) {
            return true;
        }
        if (!is_array($allowedHosts) && !$allowedHosts instanceof \Traversable) {
            $allowedHosts = (array) $allowedHosts;
        }
        $currentHost = Yii::$app->getRequest()->getHostName();
        foreach ($allowedHosts as $allowedHost) {
            if (StringHelper::matchWildcard($allowedHost, $currentHost)) {
                return true;
            }
        }
        // replace invalid host info to prevent using it in further processing
        if ($this->fallbackHostInfo !== null) {
            Yii::$app->getRequest()->setHostInfo($this->fallbackHostInfo);
        }
        if ($this->denyCallback !== null) {
            call_user_func($this->denyCallback, $action);
        } else {
            $this->denyAccess($action);
        }
        return false;
    }

beforeFilter() public method

Defined in: yii\base\ActionFilter::beforeFilter()

public void beforeFilter ( $event )
$event | yii\base\ActionEvent |

Source code

                    public function beforeFilter($event)
    {
        if (!$this->isActive($event->action)) {
            return;
        }
        $event->isValid = $this->beforeAction($event->action);
        if ($event->isValid) {
            // call afterFilter only if beforeFilter succeeds
            // beforeFilter and afterFilter should be properly nested
            $this->owner->on(Controller::EVENT_AFTER_ACTION, [$this, 'afterFilter'], null, false);
        } else {
            $event->handled = true;
        }
    }

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();
    }

denyAccess() protected method

Denies the access.

The default implementation will display 404 page right away, terminating the program execution. You may override this method, creating your own deny access handler. While doing so, make sure you avoid usage of the current requested host name, creation of absolute URL links, caching page parts and so on.

protected void denyAccess ( $action )
$action | yii\base\Action | The action to be executed.
throws | yii\web\NotFoundHttpException |

Source code

                    protected function denyAccess($action)
    {
        $exception = new NotFoundHttpException(Yii::t('yii', 'Page not found.'));
        // use regular error handling if $this->fallbackHostInfo was set
        if (!empty(Yii::$app->getRequest()->hostName)) {
            throw $exception;
        }
        $response = Yii::$app->getResponse();
        $errorHandler = Yii::$app->getErrorHandler();
        $response->setStatusCode($exception->statusCode, $exception->getMessage());
        $response->data = $errorHandler->renderFile($errorHandler->errorView, ['exception' => $exception]);
        $response->send();
        Yii::$app->end();
    }

detach() public method

Defined in: yii\base\ActionFilter::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) {
            $this->owner->off(Controller::EVENT_BEFORE_ACTION, [$this, 'beforeFilter']);
            $this->owner->off(Controller::EVENT_AFTER_ACTION, [$this, 'afterFilter']);
            $this->owner = null;
        }
    }

events() public method

Defined in: yii\base\Behavior::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 [];
    }

getActionId() protected method (available since version 2.0.7)

Defined in: yii\base\ActionFilter::getActionId()

Returns an action ID by converting yii\base\Action::$uniqueId into an ID relative to the module.

protected string getActionId ( $action )
$action | yii\base\Action |

Source code

                    protected function getActionId($action)
    {
        if ($this->owner instanceof Module) {
            $mid = $this->owner->getUniqueId();
            $id = $action->getUniqueId();
            if ($mid !== '' && strpos($id, $mid) === 0) {
                $id = substr($id, strlen($mid) + 1);
            }
        } else {
            $id = $action->id;
        }
        return $id;
    }

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

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

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()
    {
    }

isActive() protected method

Defined in: yii\base\ActionFilter::isActive()

Returns a value indicating whether the filter is active for the given action.

protected boolean isActive ( $action )
$action | yii\base\Action | The action being filtered
return | boolean | Whether the filter is active for the given action.

Source code

                    protected function isActive($action)
    {
        $id = $this->getActionId($action);
        if (empty($this->only)) {
            $onlyMatch = true;
        } else {
            $onlyMatch = false;
            foreach ($this->only as $pattern) {
                if (StringHelper::matchWildcard($pattern, $id)) {
                    $onlyMatch = true;
                    break;
                }
            }
        }
        $exceptMatch = false;
        foreach ($this->except as $pattern) {
            if (StringHelper::matchWildcard($pattern, $id)) {
                $exceptMatch = true;
                break;
            }
        }
        return !$exceptMatch && $onlyMatch;
    }