# Action

> Action is the base class for action classes that implement RESTful API.

[API reference](/docs/api/index.md) › [yii](/docs/api/yii/index.md) › [rest](/docs/api/yii/rest/index.md) › Action

| class | `yii\rest\Action` |
| --- | --- |
| Extends | [`yii\base\Action`](/docs/api/yii/base/action/index.md) » [`yii\base\Component`](/docs/api/yii/base/component/index.md) » [`yii\base\BaseObject`](/docs/api/yii/base/baseobject/index.md) |
| Implements | [`yii\base\Configurable`](/docs/api/yii/base/configurable/index.md) |
| Since | 2.0 |
| Source | [`framework/rest/Action.php`](https://github.com/yiisoft/yii2/blob/22.0/framework/rest/Action.php#L27) |

5 subclasses:

- [`CreateAction`](/docs/api/yii/rest/createaction/index.md)
- [`DeleteAction`](/docs/api/yii/rest/deleteaction/index.md)
- [`IndexAction`](/docs/api/yii/rest/indexaction/index.md)
- [`UpdateAction`](/docs/api/yii/rest/updateaction/index.md)
- [`ViewAction`](/docs/api/yii/rest/viewaction/index.md)

Action is the base class for action classes that implement RESTful API.

For more details and usage information on Action, see the [guide article on rest controllers](/docs/guide/rest-controllers/index.md).

## Properties

| Property | Type | Description | Defined by |
| --- | --- | --- | --- |
| <span id="property-behaviors"></span>[`$behaviors`](/docs/api/yii/base/component/index.md#property-behaviors) read-only | `array<`[`yii\base\Behavior`](/docs/api/yii/base/behavior/index.md)`<static>>` | List of behaviors attached to this component. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| [`$checkAccess`](#property-checkAccess) | `callable\|null` | A PHP callable that will be called when running an action to determine if the current user has the permission to execute the action. Default: `null`. | `Action` |
| <span id="property-controller"></span>[`$controller`](/docs/api/yii/base/action/index.md#property-controller) | `yii\base\T\|null` | The controller that owns this action, or `null` when the action runs standalone. via [`Module::$actionMap`](/docs/api/yii/base/module/index.md#property-actionMap) Default: `null`. | [`yii\base\Action`](/docs/api/yii/base/action/index.md) |
| [`$findModel`](#property-findModel) | `callable\|null` | A PHP callable that will be called to return the model corresponding to the specified primary key value. Default: `null`. | `Action` |
| <span id="property-id"></span>[`$id`](/docs/api/yii/base/action/index.md#property-id) | `string\|null` | ID of the action; `null` between construction and dispatcher post-assignment for standalone actions resolved through [`Module::$actionMap`](/docs/api/yii/base/module/index.md#property-actionMap) or [`Module::$actionNamespace`](/docs/api/yii/base/module/index.md#property-actionNamespace). Default: `null`. | [`yii\base\Action`](/docs/api/yii/base/action/index.md) |
| [`$modelClass`](#property-modelClass) | `string` | Class name of the model which will be handled by this action. Default: `null`. | `Action` |
| <span id="property-module"></span>[`$module`](/docs/api/yii/base/action/index.md#property-module) | [`yii\base\Module`](/docs/api/yii/base/module/index.md)`\|null` | The owning module, or `null` if neither a module nor a controller is attached. Available since 22.0. | [`yii\base\Action`](/docs/api/yii/base/action/index.md) |
| <span id="property-uniqueId"></span>[`$uniqueId`](/docs/api/yii/base/action/index.md#property-uniqueId) read-only | `string` | The unique ID of this action among the whole application. | [`yii\base\Action`](/docs/api/yii/base/action/index.md) |

## Methods

| Method | Description | Defined by |
| --- | --- | --- |
| <span id="method-__construct"></span>[`__construct()`](/docs/api/yii/base/action/index.md#method-__construct) | Constructor. | [`yii\base\Action`](/docs/api/yii/base/action/index.md) |
| <span id="method-__call"></span>[`__call()`](/docs/api/yii/base/component/index.md#method-__call) | Calls the named method which is not a class method. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-__clone"></span>[`__clone()`](/docs/api/yii/base/component/index.md#method-__clone) | This method is called after the object is created by cloning an existing one. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-__get"></span>[`__get()`](/docs/api/yii/base/component/index.md#method-__get) | Returns the value of a component property. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-__isset"></span>[`__isset()`](/docs/api/yii/base/component/index.md#method-__isset) | Checks if a property is set, i.e. defined and not null. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-__set"></span>[`__set()`](/docs/api/yii/base/component/index.md#method-__set) | Sets the value of a component property. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-__unset"></span>[`__unset()`](/docs/api/yii/base/component/index.md#method-__unset) | Sets a component property to be null. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-attachBehavior"></span>[`attachBehavior()`](/docs/api/yii/base/component/index.md#method-attachBehavior) | Attaches a behavior to this component. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-attachBehaviors"></span>[`attachBehaviors()`](/docs/api/yii/base/component/index.md#method-attachBehaviors) | Attaches a list of behaviors to the component. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-behaviors"></span>[`behaviors()`](/docs/api/yii/base/component/index.md#method-behaviors) | Returns a list of behaviors that this component should behave as. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-canGetProperty"></span>[`canGetProperty()`](/docs/api/yii/base/component/index.md#method-canGetProperty) | Returns a value indicating whether a property can be read. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-canSetProperty"></span>[`canSetProperty()`](/docs/api/yii/base/component/index.md#method-canSetProperty) | Returns a value indicating whether a property can be set. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-className"></span>[`className()`](/docs/api/yii/base/baseobject/index.md#method-className) static | Returns the fully qualified name of this class. | [`yii\base\BaseObject`](/docs/api/yii/base/baseobject/index.md) |
| <span id="method-detachBehavior"></span>[`detachBehavior()`](/docs/api/yii/base/component/index.md#method-detachBehavior) | Detaches a behavior from the component. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-detachBehaviors"></span>[`detachBehaviors()`](/docs/api/yii/base/component/index.md#method-detachBehaviors) | Detaches all behaviors from the component. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-ensureBehaviors"></span>[`ensureBehaviors()`](/docs/api/yii/base/component/index.md#method-ensureBehaviors) | Makes sure that the behaviors declared in [`behaviors()`](/docs/api/yii/base/component/index.md#method-behaviors) are attached to this component. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| [`findModel()`](#method-findModel) | Returns the data model based on the primary key given. | `Action` |
| <span id="method-getBehavior"></span>[`getBehavior()`](/docs/api/yii/base/component/index.md#method-getBehavior) | Returns the named behavior object. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-getBehaviors"></span>[`getBehaviors()`](/docs/api/yii/base/component/index.md#method-getBehaviors) | Returns all behaviors attached to this component. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-getModule"></span>[`getModule()`](/docs/api/yii/base/action/index.md#method-getModule) | Returns the module that owns this action when invoked standalone. | [`yii\base\Action`](/docs/api/yii/base/action/index.md) |
| <span id="method-getUniqueId"></span>[`getUniqueId()`](/docs/api/yii/base/action/index.md#method-getUniqueId) | Returns the unique ID of this action among the whole application. | [`yii\base\Action`](/docs/api/yii/base/action/index.md) |
| <span id="method-hasEventHandlers"></span>[`hasEventHandlers()`](/docs/api/yii/base/component/index.md#method-hasEventHandlers) | Returns a value indicating whether there is any handler attached to the named event. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-hasMethod"></span>[`hasMethod()`](/docs/api/yii/base/component/index.md#method-hasMethod) | Returns a value indicating whether a method is defined. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-hasProperty"></span>[`hasProperty()`](/docs/api/yii/base/component/index.md#method-hasProperty) | Returns a value indicating whether a property is defined for this component. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| [`init()`](#method-init) | Initializes the object. | `Action` |
| <span id="method-off"></span>[`off()`](/docs/api/yii/base/component/index.md#method-off) | Detaches an existing event handler from this component. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-on"></span>[`on()`](/docs/api/yii/base/component/index.md#method-on) | Attaches an event handler to an event. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-runWithParams"></span>[`runWithParams()`](/docs/api/yii/base/action/index.md#method-runWithParams) | Runs this action with the specified parameters. | [`yii\base\Action`](/docs/api/yii/base/action/index.md) |
| <span id="method-setModule"></span>[`setModule()`](/docs/api/yii/base/action/index.md#method-setModule) | Sets the module that owns this action when invoked standalone. | [`yii\base\Action`](/docs/api/yii/base/action/index.md) |
| <span id="method-trigger"></span>[`trigger()`](/docs/api/yii/base/component/index.md#method-trigger) | Triggers an event. | [`yii\base\Component`](/docs/api/yii/base/component/index.md) |
| <span id="method-afterRun"></span>[`afterRun()`](/docs/api/yii/base/action/index.md#method-afterRun) protected | This method is called right after `run()` is executed. | [`yii\base\Action`](/docs/api/yii/base/action/index.md) |
| <span id="method-beforeRun"></span>[`beforeRun()`](/docs/api/yii/base/action/index.md#method-beforeRun) protected | This method is called right before `run()` is executed. | [`yii\base\Action`](/docs/api/yii/base/action/index.md) |
| <span id="method-resolveStandaloneParams"></span>[`resolveStandaloneParams()`](/docs/api/yii/base/action/index.md#method-resolveStandaloneParams) protected | Resolves typed parameters of `run()` when the action is invoked without a hosting controller. | [`yii\base\Action`](/docs/api/yii/base/action/index.md) |

## Property details

### $checkAccess <span id="property-checkAccess"></span>

```php
public callable|null $checkAccess = null
```

A PHP callable that will be called when running an action to determine if the current user has the permission to execute the action.

If not set, the access
check will not be performed. The signature of the callable should be as follows,

```
function ($action, $model = null) {
    // $model is the requested model instance.
    // If null, it means no specific model (e.g. IndexAction)
}
```

### $findModel <span id="property-findModel"></span>

```php
public callable|null $findModel = null
```

A PHP callable that will be called to return the model corresponding to the specified primary key value.

If not set, [`findModel()`](/docs/api/yii/rest/action/index.md#method-findModel) will be used instead.
The signature of the callable should be:

```
function ($id, $action) {
    // $id is the primary key value. If composite primary key, the key values
    // will be separated by comma.
    // $action is the action object currently running
}
```

The callable should return the model found, or throw an exception if not found.

### $modelClass <span id="property-modelClass"></span>

```php
public string $modelClass = null
```

Class name of the model which will be handled by this action.

The model class must implement [`ActiveRecordInterface`](/docs/api/yii/db/activerecordinterface/index.md).
This property must be set.

## Method details

### findModel() <span id="method-findModel"></span>

```php
public function findModel(string $id): yii\db\ActiveRecordInterface
```

Returns the data model based on the primary key given.

If the data model is not found, a 404 HTTP exception will be raised.

**Parameters**

| Parameter | Type | Description |
| --- | --- | --- |
| `$id` | `string` | The ID of the model to be loaded. If the model has a composite primary key, the ID must be a string of the primary key values separated by commas. The order of the primary key values should follow that returned by the `primaryKey()` method of the model. |

**Returns**

[`yii\db\ActiveRecordInterface`](/docs/api/yii/db/activerecordinterface/index.md): The model found

**Throws**

- [`yii\web\NotFoundHttpException`](/docs/api/yii/web/notfoundhttpexception/index.md): if the model cannot be found

### init() <span id="method-init"></span>

```php
public function init(): mixed
```

Initializes the object.

This method is invoked at the end of the constructor after the object is initialized with the
given configuration.

**Returns**

`mixed`