terminate延迟处理

异步处理一般需要接触消息队列，翻laravel源码找到一种实现伪异步的办法

源码分析

laravel入口文件public/index.php

$app = require_once __DIR__.'/../bootstrap/app.php';
/*
|--------------------------------------------------------------------------
| Run The Application
|--------------------------------------------------------------------------
|
| Once we have the application, we can handle the incoming request
| through the kernel, and send the associated response back to
| the client's browser allowing them to enjoy the creative
| and wonderful application we have prepared for them.
|
*/
$kernel = $app->make(Illuminate\Contracts\Http\Kernel::class);
 //结合bootstrap/app.php中代码可知
 //$kernel=App\Http\Kernel::class
$response = $kernel->handle(
    $request = Illuminate\Http\Request::capture()
);
//$response 实际上是Symfony\Component\HttpFoundation\Response
$response->send(); 
//send() 实际上执行了fastcgi_finish_request()
$kernel->terminate($request, $response); 
//响应结束之后可以继续do someting...

Illuminate\Foundation\Http\Kernel.php

    /**
     * Call the terminate method on any terminable middleware.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Illuminate\Http\Response  $response
     * @return void
     */
    public function terminate($request, $response)
    {
        $this->terminateMiddleware($request, $response);//执行terminate中间件
        $this->app->terminate();
    }
  /**
     * Call the terminate method on any terminable middleware.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Illuminate\Http\Response  $response
     * @return void
     */
    protected function terminateMiddleware($request, $response)
    {
        $middlewares = $this->app->shouldSkipMiddleware() ? [] : array_merge(
            $this->gatherRouteMiddleware($request),
            $this->middleware
        );
        foreach ($middlewares as $middleware) {
            if (! is_string($middleware)) {
                continue;
            }
            [$name] = $this->parseMiddleware($middleware);
            $instance = $this->app->make($name);
            if (method_exists($instance, 'terminate')) {
                $instance->terminate($request, $response);//执行中间件中的terminate
            }
        }
    }

fastcgi_finish_request()把数据返回给客户端之后关闭连接，但是php进程仍然在执行。
利用这个特性可以在响应结束之后，进程结束之前做一些不重要的耗时任务，
当然如果耗时非常长还是应该使用真正的异步例如消息队列等，不然出现php-fpm无法及时关闭而进程数过多。fpm模型是另外一个话题这里就不展开叙述了
由上面源码可知中间件中定义terminate方法既可以完成伪异步

实现步骤

创建terminate事件

namespace App\Light\TerminateHandle;
class TerminateEvent
{
    //回调函数
    public $callback;
    public function __construct(callable $callback)
    {
        $this->callback = $callback;
    }
}

创建Handler

namespace App\Light\TerminateHandle;
class Handler
{
    //保存需要执行的事件
    public $events = [];
    /**
     * 处理事件
     */
    public function terminate()
    {
        if (!empty($this->events)) {
            foreach ($this->events as $event) {
                call_user_func($event->callback);
            }
        }
    }
    /**
     * 添加事件
     * @param TerminateEvent $event
     */
    public function add(TerminateEvent $event)
    {
        $this->events[] = $event;
    }
}

创建门面类

namespace App\Light\TerminateHandle;
use Illuminate\Support\Facades\Facade;
/**
 * 支持IDE语法提示
 * @method static \App\Light\TerminateHandle\Handler terminate()
 * @method static \App\Light\TerminateHandle\Handler add(TerminateEvent $event)
 */
class TerminateHandle extends Facade
{
    protected static function getFacadeAccessor()
    {
        return 'TerminateHandle';
    }
}

创建terminate中间件

namespace App\Light\TerminateHandle;
class TerminateMiddleware
{
    public function handle($request, \Closure $next)
    {
        return $next($request);
    }
    /**
     * 响应结束之后，进程结束之前执行
     * @param $request
     * @param $response
     */
    public function terminate($request, $response)
    {
        TerminateHandle::terminate();
    }
}

创建服务提供者

namespace App\Light\TerminateHandle;
use Illuminate\Support\ServiceProvider;
class TerminateHandleServiceProvider extends ServiceProvider
{
    public function register()
    {
        //绑定单例
        $this->app->singleton('TerminateHandle', function () {
            return new Handler();
        });
        //注册中间件
        $kernel = $this->app[\Illuminate\Contracts\Http\Kernel::class];
        $kernel->pushMiddleware(TerminateMiddleware::class);
    }
}

注册服务提供者

config/app.php中加入

    //注册terminate middleware服务提供者
        App\Light\TerminateHandle\TerminateHandleServiceProvider::class,

使用方法

class WelcomeController extends Controller
{
    public function index()
    {
        TerminateHandle::add(new TerminateEvent(function (){
            info('一个事件');
        }));
        TerminateHandle::add(new TerminateEvent(function (){
            info('另一个事件');
        }));
        return ['code' => 1];
    }
}