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Class yii\filters\HttpCache

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Inheritanceyii\filters\HttpCache » yii\base\ActionFilter » yii\base\Behavior » yii\base\BaseObject
Implementsyii\base\Configurable
Available since version2.0
Source Code https://github.com/yiisoft/yii2/blob/master/framework/filters/HttpCache.php

HttpCache implements client-side caching by utilizing the Last-Modified and ETag HTTP headers.

It is an action filter that can be added to a controller and handles the beforeAction event.

To use HttpCache, declare it in the behaviors() method of your controller class. In the following example the filter will be applied to the index action and the Last-Modified header will contain the date of the last update to the user table in the database.

public function behaviors()
{
    return [
        [
            'class' => 'yii\filters\HttpCache',
            'only' => ['index'],
            'lastModified' => function ($action, $params) {
                $q = new \yii\db\Query();
                return $q->from('user')->max('updated_at');
            },
//            'etagSeed' => function ($action, $params) {
//                return // generate ETag seed here
//            }
        ],
    ];
}

Public Properties

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Property Type Description Defined By
$cacheControlHeader string|null The value of the Cache-Control HTTP header. yii\filters\HttpCache
$enabled boolean A value indicating whether this filter should be enabled. yii\filters\HttpCache
$etagSeed callable A PHP callback that generates the ETag seed string. yii\filters\HttpCache
$except array List of action IDs that this filter should not apply to. yii\base\ActionFilter
$lastModified callable A PHP callback that returns the UNIX timestamp of the last modification time. yii\filters\HttpCache
$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
$params mixed Additional parameters that should be passed to the $lastModified and $etagSeed callbacks. yii\filters\HttpCache
$sessionCacheLimiter string|null The name of the cache limiter to be set when session_cache_limiter() is called. yii\filters\HttpCache
$weakEtag boolean Whether to generate weak ETags. yii\filters\HttpCache

Public Methods

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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\HttpCache
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

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Method Description Defined By
generateEtag() Generates an ETag from the given seed string. yii\filters\HttpCache
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
sendCacheControlHeader() Sends the cache control header to the client. yii\filters\HttpCache
validateCache() Validates if the HTTP cache contains valid content. yii\filters\HttpCache

Property Details

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$cacheControlHeader public property

The value of the Cache-Control HTTP header. If null, the header will not be sent.

See also https://datatracker.ietf.org/doc/html/rfc2616#section-14.9.

public string|null $cacheControlHeader = 'public, max-age=3600'
$enabled public property

A value indicating whether this filter should be enabled.

public boolean $enabled = true
$etagSeed public property

A PHP callback that generates the ETag seed string. The callback's signature should be:

function ($action, $params)

where $action is the yii\base\Action object that this filter is currently handling; $params takes the value of $params. The callback should return a string serving as the seed for generating an ETag.

public callable $etagSeed = null
$lastModified public property

A PHP callback that returns the UNIX timestamp of the last modification time. The callback's signature should be:

function ($action, $params)

where $action is the yii\base\Action object that this filter is currently handling; $params takes the value of $params. The callback should return a UNIX timestamp.

See also https://datatracker.ietf.org/doc/html/rfc7232#section-2.2.

public callable $lastModified = null
$params public property

Additional parameters that should be passed to the $lastModified and $etagSeed callbacks.

public mixed $params = null
$sessionCacheLimiter public property

The name of the cache limiter to be set when session_cache_limiter() is called. The default value is an empty string, meaning turning off automatic sending of cache headers entirely. You may set this property to be public, private, private_no_expire, and nocache. Please refer to session_cache_limiter() for detailed explanation of these values.

If this property is null, then session_cache_limiter() will not be called. As a result, PHP will send headers according to the session.cache_limiter PHP ini setting.

public string|null $sessionCacheLimiter = ''
$weakEtag public property (available since version 2.0.8)

Whether to generate weak ETags.

Weak ETags should be used if the content should be considered semantically equivalent, but not byte-equal.

See also https://datatracker.ietf.org/doc/html/rfc7232#section-2.3.

public boolean $weakEtag = false

Method Details

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__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

 

                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

 

                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

 

                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).

 

                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

 

                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.

 

                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.

 

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

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

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

                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.

 

                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.

 

                public function beforeAction($action)
{
    if (!$this->enabled) {
        return true;
    }
    $verb = Yii::$app->getRequest()->getMethod();
    if ($verb !== 'GET' && $verb !== 'HEAD' || $this->lastModified === null && $this->etagSeed === null) {
        return true;
    }
    $lastModified = $etag = null;
    if ($this->lastModified !== null) {
        $lastModified = call_user_func($this->lastModified, $action, $this->params);
    }
    if ($this->etagSeed !== null) {
        $seed = call_user_func($this->etagSeed, $action, $this->params);
        if ($seed !== null) {
            $etag = $this->generateEtag($seed);
        }
    }
    $this->sendCacheControlHeader();
    $response = Yii::$app->getResponse();
    if ($etag !== null) {
        $response->getHeaders()->set('Etag', $etag);
    }
    $cacheValid = $this->validateCache($lastModified, $etag);
    // https://tools.ietf.org/html/rfc7232#section-4.1
    if ($lastModified !== null && (!$cacheValid || ($cacheValid && $etag === null))) {
        $response->getHeaders()->set('Last-Modified', gmdate('D, d M Y H:i:s', $lastModified) . ' GMT');
    }
    if ($cacheValid) {
        $response->setStatusCode(304);
        return false;
    }
    return true;
}
beforeFilter() public method

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

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

                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

 

                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

 

                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.

 

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

                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).

 

                public function events()
{
    return [];
}
generateEtag() protected method

Generates an ETag from the given seed string.

protected string generateEtag ( $seed )
$seed string

Seed for the ETag
return string

The generated ETag

 

                protected function generateEtag($seed)
{
    $etag = '"' . rtrim(base64_encode(sha1($seed, true)), '=') . '"';
    return $this->weakEtag ? 'W/' . $etag : $etag;
}
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 

                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

 

                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:

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

 

                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 ( )

                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.

 

                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;
}
sendCacheControlHeader() protected method

Sends the cache control header to the client.

See also $cacheControlHeader.

protected void sendCacheControlHeader ( )

                protected function sendCacheControlHeader()
{
    if ($this->sessionCacheLimiter !== null) {
        if ($this->sessionCacheLimiter === '' && !headers_sent() && Yii::$app->getSession()->getIsActive()) {
            header_remove('Expires');
            header_remove('Cache-Control');
            header_remove('Last-Modified');
            header_remove('Pragma');
        }
        Yii::$app->getSession()->setCacheLimiter($this->sessionCacheLimiter);
    }
    $headers = Yii::$app->getResponse()->getHeaders();
    if ($this->cacheControlHeader !== null) {
        $headers->set('Cache-Control', $this->cacheControlHeader);
    }
}
validateCache() protected method

Validates if the HTTP cache contains valid content.

If both Last-Modified and ETag are null, returns false.

protected boolean validateCache ( $lastModified, $etag )
$lastModified integer|null

The calculated Last-Modified value in terms of a UNIX timestamp. If null, the Last-Modified header will not be validated.
$etag string|null

The calculated ETag value. If null, the ETag header will not be validated.
return boolean

Whether the HTTP cache is still valid.

 

                protected function validateCache($lastModified, $etag)
{
    if (Yii::$app->request->headers->has('If-None-Match')) {
        // HTTP_IF_NONE_MATCH takes precedence over HTTP_IF_MODIFIED_SINCE
        // https://datatracker.ietf.org/doc/html/rfc7232#section-3.3
        return $etag !== null && in_array($etag, Yii::$app->request->getETags(), true);
    } elseif (Yii::$app->request->headers->has('If-Modified-Since')) {
        return $lastModified !== null && @strtotime(Yii::$app->request->headers->get('If-Modified-Since')) >= $lastModified;
    }
    return false;
}