# Class yii\filters\PageCache

Inheritance | yii\filters\PageCache » yii\base\ActionFilter » yii\base\Behavior » yii\base\BaseObject
Implements | yii\base\Configurable, yii\base\DynamicContentAwareInterface
Uses Traits | yii\base\DynamicContentAwareTrait
Available since version | 2.0
Source Code | https://github.com/yiisoft/yii2/blob/master/framework/filters/PageCache.php

PageCache implements server-side caching of whole pages.

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

To use PageCache, declare it in the `behaviors()` method of your controller class. In the following example the filter will be applied to the `index` action and cache the whole page for maximum 60 seconds or until the count of entries in the post table changes. It also stores different versions of the page depending on the application language.

    public function behaviors()
    {
        return [
            'pageCache' => [
                'class' => 'yii\filters\PageCache',
                'only' => ['index'],
                'duration' => 60,
                'dependency' => [
                    'class' => 'yii\caching\DbDependency',
                    'sql' => 'SELECT COUNT(*) FROM post',
                ],
                'variations' => [
                    \Yii::$app->language,
                ]
            ],
        ];
    }

## Public Properties

Hide inherited properties

Property | Type | Description | Defined By
--- | --- | --- | ---
$cache | yii\caching\CacheInterface|array|string | The cache object or the application component ID of the cache object. | yii\filters\PageCache
$cacheCookies | boolean|array | A boolean value indicating whether to cache all cookies, or an array of cookie names indicating which cookies can be cached. | yii\filters\PageCache
$cacheHeaders | boolean|array | A boolean value indicating whether to cache all HTTP headers, or an array of HTTP header names (case-insensitive) indicating which HTTP headers can be cached. | yii\filters\PageCache
$dependency | array|yii\caching\Dependency | The dependency that the cached content depends on. | yii\filters\PageCache
$duration | integer | Number of seconds that the data can remain valid in cache. | yii\filters\PageCache
$dynamicPlaceholders | array | A list of placeholders. | yii\base\DynamicContentAwareTrait
$enabled | boolean | Whether to enable the page cache. | yii\filters\PageCache
$except | array | List of action IDs that this filter should not apply to. | yii\base\ActionFilter
$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
$variations | string[]|string | List of factors that would cause the variation of the content being cached. | yii\filters\PageCache
$varyByRoute | boolean | Whether the content being cached should be differentiated according to the route. | yii\filters\PageCache
$view | yii\base\View | The view component to use for caching. | yii\filters\PageCache

## 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
addDynamicPlaceholder() | Adds a placeholder for dynamic content. | yii\base\DynamicContentAwareTrait
afterAction() | This method is invoked right after an action is executed. | yii\base\ActionFilter
afterFilter() |  | yii\base\ActionFilter
afterRestoreResponse() | This method is invoked right after the response restoring is finished (but before the response is sent). | yii\filters\PageCache
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\PageCache
beforeCacheResponse() | This method is invoked right before the response caching is to be started. | yii\filters\PageCache
beforeFilter() |  | yii\base\ActionFilter
cacheResponse() | Caches response properties. | yii\filters\PageCache
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
getDynamicPlaceholders() | Returns a list of placeholders for dynamic content. This method is used internally to implement the content caching feature. | yii\base\DynamicContentAwareTrait
getView() |  | yii\filters\PageCache
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\filters\PageCache
setDynamicPlaceholders() | Sets a list of placeholders for dynamic content. This method is used internally to implement the content caching feature. | yii\base\DynamicContentAwareTrait

## Protected Methods

Hide inherited methods

Method | Description | Defined By
--- | --- | ---
calculateCacheKey() |  | yii\filters\PageCache
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
restoreResponse() | Restores response properties from the given data. | yii\filters\PageCache
updateDynamicContent() | Replaces placeholders in $content with results of evaluated dynamic statements. | yii\base\DynamicContentAwareTrait

## Constants

Hide inherited constants

Constant | Value | Description | Defined By
--- | --- | --- | ---
PAGE_CACHE_VERSION | 1 | Page cache version, to detect incompatibilities in cached values when the data format of the cache changes. | yii\filters\PageCache

## Property Details

$cache public property

The cache object or the application component ID of the cache object. After the PageCache object is created, if you want to change this property, you should only assign it with a cache object. Starting from version 2.0.2, this can also be a configuration array for creating the object.

public yii\caching\CacheInterface|array|string $cache = 'cache'
$cacheCookies public property (available since version 2.0.4)

A boolean value indicating whether to cache all cookies, or an array of cookie names indicating which cookies can be cached. Be very careful with caching cookies, because it may leak sensitive or private data stored in cookies to unwanted users.

See also insertResponseCollectionIntoData().

public boolean|array $cacheCookies = false
$cacheHeaders public property (available since version 2.0.4)

A boolean value indicating whether to cache all HTTP headers, or an array of HTTP header names (case-insensitive) indicating which HTTP headers can be cached. Note if your HTTP headers contain sensitive information, you should white-list which headers can be cached.

See also insertResponseCollectionIntoData().

public boolean|array $cacheHeaders = true
$dependency public property

The dependency that the cached content depends on. This can be either a yii\caching\Dependency object or a configuration array for creating the dependency object. For example,

    [
        'class' => 'yii\caching\DbDependency',
        'sql' => 'SELECT MAX(updated_at) FROM post',
    ]

would make the output cache depend on the last modified time of all posts. If any post has its modification time changed, the cached content would be invalidated.

If $cacheCookies or $cacheHeaders is enabled, then yii\caching\Dependency::$reusable should be enabled as well to save performance. This is because the cookies and headers are currently stored separately from the actual page content, causing the dependency to be evaluated twice.

public array|yii\caching\Dependency $dependency = null
$duration public property

Number of seconds that the data can remain valid in cache. Use `0` to indicate that the cached data will never expire.

public integer $duration = 60
$enabled public property

Whether to enable the page cache. You may use this property to turn on and off the page cache according to specific setting (e.g. enable page cache only for GET requests).

public boolean $enabled = true
$variations public property

List of factors that would cause the variation of the content being cached. Each factor is a string representing a variation (e.g. the language, a GET parameter). The following variation setting will cause the content to be cached in different versions according to the current application language:

    [
        Yii::$app->language,
    ]

public string[]|string $variations = null
$varyByRoute public property

Whether the content being cached should be differentiated according to the route. A route consists of the requested controller ID and action ID. Defaults to `true`.

public boolean $varyByRoute = true
$view public property

The view component to use for caching. If not set, the default application view component yii\web\Application::$view will be used.

public yii\base\View $view = null

## Method Details

afterRestoreResponse() public method (available since version 2.0.11)

This method is invoked right after the response restoring is finished (but before the response is sent).

You may override this method to do last-minute preparation before the response is sent.

public void afterRestoreResponse ( $data )
$data | array|null | An array of an additional data stored in a cache entry or `null`.

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.

beforeCacheResponse() public method (available since version 2.0.11)

This method is invoked right before the response caching is to be started.

You may override this method to cancel caching by returning `false` or store an additional data in a cache entry by returning an array instead of `true`.

public boolean|array beforeCacheResponse ( )
return | boolean|array | Whether to cache or not, return an array instead of `true` to store an additional data.

cacheResponse() public method (available since version 2.0.3)

Caches response properties.

public void cacheResponse ( )

calculateCacheKey() protected method (available since version 2.0.3)

protected array calculateCacheKey ( )
return | array | The key used to cache response properties.

getView() public method

public void getView ( )

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 ( )

restoreResponse() protected method (available since version 2.0.3)

Restores response properties from the given data.

protected void restoreResponse ( $response, $data )
$response | yii\web\Response | The response to be restored.
$data | array | The response property data.