php - Laravel 6 - 在构造函数中绑定(bind)实现数组

Question

我正在尝试将某个接口(interface)的一组实现注入(inject)订阅者类。

这是我的服务提供商中的代码:

$this->app->tag([TrackerServiceOne::class, TrackerServiceTwo::class], 'trackers');
$this->app->bind(EventSubscriber::class, function ($app) {
    return new EventSubscriber($this->app->tagged('trackers'));
});

这是我的 EventSubscriber 类中的构造函数:

public function __construct(array $trackers)
{
    $this->trackers = $trackers;
}

这是我遇到的错误:

Unresolvable dependency resolving [Parameter #0 [ <required> array $trackers ]] in class Path\To\EventSubscriber

Answer 1

尝试使用服务容器中的 makeWith 解析 EventSubscriber 而不是实例化 new 实例:

$this->app->bind(EventSubscriber::class, function ($app) {
    return $app->makeWith(EventSubscriber::class, [
        'trackers' => $this->app->tagged('trackers')
    ]);
});

这应该正确地将 $trackers 参数注入(inject)到 EventSubscriber 的构造函数中。

来自Docs :

If some of your class' dependencies are not resolvable via the container, you may inject them by passing them as an associative array into the makeWith method:

$api = $this->app->makeWith('HelpSpot\API', ['id' => 1]);

---

更新

在试用了 Laravel 6 之后，我设法让它工作了，尽管与文档中描述的不完全一样:

app()->bind('TrackerServiceOne', function () {
  return new TrackerServiceOne();
});

app()->bind('TrackerServiceTwo', function () {
  return new TrackerServiceTwo();
});

app()->tag([
  'TrackerServiceOne', 
  'TrackerServiceTwo'
], 'trackers');

app()->bind(EventSubscriber::class, function () {
  $trackers = [];

  foreach (app()->tagged('trackers') as $tracker) {
    $trackers[] = $tracker;
  }

  return new EventSubscriber($trackers);
});

$subscriber = resolve(EventSubscriber::class);

dd($subscriber->getTrackers());

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