framework/di/Instance.php
<?php
/**
* @link https://www.yiiframework.com/
* @copyright Copyright (c) 2008 Yii Software LLC
* @license https://www.yiiframework.com/license/
*/
namespace yii\di;
use Yii;
use yii\base\InvalidConfigException;
/**
* Instance represents a reference to a named object in a dependency injection (DI) container or a service locator.
*
* You may use [[get()]] to obtain the actual object referenced by [[id]].
*
* Instance is mainly used in two places:
*
* - When configuring a dependency injection container, you use Instance to reference a class name, interface name
* or alias name. The reference can later be resolved into the actual object by the container.
* - In classes which use service locator to obtain dependent objects.
*
* The following example shows how to configure a DI container with Instance:
*
* ```php
* $container = new \yii\di\Container;
* $container->set('cache', [
* 'class' => 'yii\caching\DbCache',
* 'db' => Instance::of('db')
* ]);
* $container->set('db', [
* 'class' => 'yii\db\Connection',
* 'dsn' => 'sqlite:path/to/file.db',
* ]);
* ```
*
* And the following example shows how a class retrieves a component from a service locator:
*
* ```php
* class DbCache extends Cache
* {
* public $db = 'db';
*
* public function init()
* {
* parent::init();
* $this->db = Instance::ensure($this->db, 'yii\db\Connection');
* }
* }
* ```
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @since 2.0
*/
class Instance
{
/**
* @var string the component ID, class name, interface name or alias name
*/
public $id;
/**
* @var bool if null should be returned instead of throwing an exception
*/
public $optional;
/**
* Constructor.
* @param string $id the component ID
* @param bool $optional if null should be returned instead of throwing an exception
*/
protected function __construct($id, $optional = false)
{
$this->id = $id;
$this->optional = $optional;
}
/**
* Creates a new Instance object.
* @param string $id the component ID
* @param bool $optional if null should be returned instead of throwing an exception
* @return Instance the new Instance object.
*/
public static function of($id, $optional = false)
{
return new static($id, $optional);
}
/**
* Resolves the specified reference into the actual object and makes sure it is of the specified type.
*
* The reference may be specified as a string or an Instance object. If the former,
* it will be treated as a component ID, a class/interface name or an alias, depending on the container type.
*
* If you do not specify a container, the method will first try `Yii::$app` followed by `Yii::$container`.
*
* For example,
*
* ```php
* use yii\db\Connection;
*
* // returns Yii::$app->db
* $db = Instance::ensure('db', Connection::class);
* // returns an instance of Connection using the given configuration
* $db = Instance::ensure(['dsn' => 'sqlite:path/to/my.db'], Connection::class);
* ```
*
* @param object|string|array|static $reference an object or a reference to the desired object.
* You may specify a reference in terms of a component ID or an Instance object.
* Starting from version 2.0.2, you may also pass in a configuration array for creating the object.
* If the "class" value is not specified in the configuration array, it will use the value of `$type`.
* @param string|null $type the class/interface name to be checked. If null, type check will not be performed.
* @param ServiceLocator|Container|null $container the container. This will be passed to [[get()]].
* @return object the object referenced by the Instance, or `$reference` itself if it is an object.
* @throws InvalidConfigException if the reference is invalid
*/
public static function ensure($reference, $type = null, $container = null)
{
if (is_array($reference)) {
$class = isset($reference['class']) ? $reference['class'] : $type;
if (!$container instanceof Container) {
$container = Yii::$container;
}
unset($reference['class']);
$component = $container->get($class, [], $reference);
if ($type === null || $component instanceof $type) {
return $component;
}
throw new InvalidConfigException('Invalid data type: ' . $class . '. ' . $type . ' is expected.');
} elseif (empty($reference)) {
throw new InvalidConfigException('The required component is not specified.');
}
if (is_string($reference)) {
$reference = new static($reference);
} elseif ($type === null || $reference instanceof $type) {
return $reference;
}
if ($reference instanceof self) {
try {
$component = $reference->get($container);
} catch (\ReflectionException $e) {
throw new InvalidConfigException('Failed to instantiate component or class "' . $reference->id . '".', 0, $e);
}
if ($type === null || $component instanceof $type) {
return $component;
}
throw new InvalidConfigException('"' . $reference->id . '" refers to a ' . get_class($component) . " component. $type is expected.");
}
$valueType = is_object($reference) ? get_class($reference) : gettype($reference);
throw new InvalidConfigException("Invalid data type: $valueType. $type is expected.");
}
/**
* Returns the actual object referenced by this Instance object.
* @param ServiceLocator|Container|null $container the container used to locate the referenced object.
* If null, the method will first try `Yii::$app` then `Yii::$container`.
* @return object the actual object referenced by this Instance object.
*/
public function get($container = null)
{
try {
if ($container) {
return $container->get($this->id);
}
if (Yii::$app && Yii::$app->has($this->id)) {
return Yii::$app->get($this->id);
}
return Yii::$container->get($this->id);
} catch (\Exception $e) {
if ($this->optional) {
return null;
}
throw $e;
} catch (\Throwable $e) {
if ($this->optional) {
return null;
}
throw $e;
}
}
/**
* Restores class state after using `var_export()`.
*
* @param array $state
* @return Instance
* @throws InvalidConfigException when $state property does not contain `id` parameter
* @see https://www.php.net/manual/en/function.var-export.php
* @since 2.0.12
*/
public static function __set_state($state)
{
if (!isset($state['id'])) {
throw new InvalidConfigException('Failed to instantiate class "Instance". Required parameter "id" is missing');
}
return new self($state['id']);
}
}