An article explaining about Laravel kernel instantiation

The following tutorial column of Laravel will introduce to you about Laravel kernel instantiation F. I hope it will be helpful to friends in need!

Laravel kernel instantiation

$kernel = $app->make(Illuminate\Contracts\Http\Kernel::class);

Instantiation Kernel

When the application is instantiated, many basic operations have been initialized. Therefore, the following construction method will directly use the dependency injection of the service container to resolve the dependencies between classes.

// \Illuminate\Contracts\Http\Kernel 类构造器依赖 \Illuminate\Contracts\Foundation\Application 和 \Illuminate\Routing\Router，将会通过服务容器来处理依赖关系
public function __construct(Application $app, Router $router)
{
    $this->app = $app;

    // 主要委托 $router 来处理
    $this->router = $router;
    // 以下均为中间件的设置
    $router->middlewarePriority = $this->middlewarePriority;

    foreach ($this->middlewareGroups as $key => $middleware) {
        $router->middlewareGroup($key, $middleware);
    }

    foreach ($this->routeMiddleware as $key => $middleware) {
        $router->aliasMiddleware($key, $middleware);
    }
}

\Illuminate\Contracts\Foundation\Application 的处理：
make 时通过别名方式直接调用 $this->instances['app']

\Illuminate\Routing\Router 的处理:
make 时通过别名方式直接调用 $this->bindings['router'] 数组里面 concrete 对应的匿名函数
Router 依赖 \Illuminate\Contracts\Events\Dispatcher 和 \Illuminate\Container\Container
public function __construct(Dispatcher $events, Container $container = null)
{
    $this->events = $events;
    $this->routes = new RouteCollection;
    $this->container = $container ?: new Container;
}

\Illuminate\Contracts\Events\Dispatcher 的处理：
make 时通过别名方式直接调用 $this->bindings['events'] 数组里面 concrete 对应的匿名函数
Dispatcher 依赖 \Illuminate\Contracts\Container\Container
public function __construct(ContainerContract $container = null)
{
    $this->container = $container ?: new Container;
}

\Illuminate\Container\Container 的处理:
make 时直接调用 $this->instances['Illuminate\Container\Container'] = Object(app)
\Illuminate\Contracts\Container\Container 的处理:
make 时调用别名直接调用 $this->instances['app'] = Object(app)
上面两个一样，没有区别

Note: The dependencies listed above are all directly entrusted to the service container for automatic processing. There is no need to be afraid

of $this-> For the processing of bindings['router'] and $this->bindings['events'] binding events, the anonymous function corresponding to the array key concrete will be directly called during make.

Code snippets used during make

##############################################
if ($concrete instanceof Closure) {            
    return $concrete($this, end($this->with)); 
}
###############################################

$this->bindings['router'] = [
        'concrete' => function ($app) {
                            return new Router($app['events'], $app);
                        },
        'shared' => 'true',
    ];
$router = new Router($app['events'], $app);

\Illuminate\Routing\Router
public function __construct(Dispatcher $events, Container $container = null)
{
    $this->events = $events;
    $this->routes = new RouteCollection;
    $this->container = $container ?: new Container;
}

Returns a Router object and resets $this->instances['router'] = $router object for direct call next time .

$this->bindings['events'] = [
    'concrete' => function ($app) {
            return (new Dispatcher($app))->setQueueResolver(function () use ($app) {
                return $app->make(QueueFactoryContract::class);
            });
            }
    'shared' => 'true',
];

$dispatcher = (new \Illuminate\Events\Dispatcher($app))->setQueueResolver(function () use ($app) {
                return $app->make(QueueFactoryContract::class);
            });

Illuminate\Events\Dispatcher:
public function __construct(ContainerContract $container = null)
{
    $this->container = $container ?: new Container;
}
public function setQueueResolver(callable $resolver)
{
    $this->queueResolver = $resolver;

    return $this;
}

Returns a Dispatcher object and resets $this->instances['events'] = $dispatcher object for direct call next time.

Note:
The kernel object is an object that combines application and routing, and the routing injects the IlluminateEventsDispatcher object, which is the core object.

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