src/Application.php

<?php
namespace Owl;

/**
 * @example
 *
 * $app = new \Owl\Application();
 *
 * $app->middleware(function($request, $response) {
 *     $start = microtime(true);
 *
 *     yield true;
 *
 *     $use_time = (microtime(true) - $start) * 1000;
 *     $response->withHeader('use-time', (int)$use_time.'ms');
 * });
 *
 * $app->middelware(function($request, $response) {
 *     yield true;
 *
 *     $logger = new \Monolog\Logger;
 *     $logger->debug(sprintf('Request %s, status: %d'), $request->getRequestTarget(), $response->getStatusCode());
 * });
 *
 * $router = new \Owl\Mvc\Router([
 *     'namespace' => '\Controller',
 * ]);
 * $app->middleware(function($request, $response) use ($router) {
 *     $router->execute($request, $response);
 *
 *     yield true;
 * });
 *
 * $app->setExceptionHandler(function($exception, $request, $response) {
 *     $response->withStatus(500);
 *     $response->write($exception->getMessage());
 * });
 *
 * $app->start();
 */
class Application
{
    protected $exception_handler;
    protected $middleware;

    public function __construct()
    {
        $this->middleware = new \Owl\Middleware();
    }

    /**
     * 添加中间件.
     *
     * @param callable $handler
     *
     * @return $this
     */
    public function middleware($handler)
    {
        $this->middleware->insert($handler);

        return $this;
    }

    /**
     * 清除所有已添加的中间件.
     */
    public function resetMiddleware()
    {
        $this->middleware->reset();
    }

    /**
     * 添加异常处理逻辑.
     *
     * @param \Closure $handler
     *
     * @return $this
     */
    public function setExceptionHandler($handler)
    {
        $this->exception_handler = $handler;

        return $this;
    }

    public function start()
    {
        $request = new \Owl\Http\Request();
        $response = new \Owl\Http\Response();

        return $this->execute($request, $response);
    }

    /**
     * 响应请求，依次执行添加的中间件逻辑.
     *
     * @param \Owl\Http\Request  $request
     * @param \Owl\Http\Response $response
     */
    public function execute(\Owl\Http\Request $request, \Owl\Http\Response $response)
    {
        $exception_handler = $this->getExceptionHandler();
        $method = $request->getMethod();
        try {
            if (!in_array($method, ['HEAD', 'OPTIONS', 'GET', 'POST', 'PUT', 'DELETE', 'PATCH'])) {
                throw \Owl\Http\Exception::factory(501);
            }

            $this->middleware->execute([$request, $response]);
        } catch (\Exception $exception) {
            call_user_func($exception_handler, $exception, $request, $response);
        } catch (\Throwable $error) {
            call_user_func($exception_handler, $error, $request, $response);
        }

        if (!TEST) {
            $response->end();
        }

        if (function_exists('fastcgi_finish_request')) {
            fastcgi_finish_request();
        }
    }

    protected function getExceptionHandler()
    {
        if ($this->exception_handler) {
            return $this->exception_handler;
        }

        return function ($exception, $request, $response) {
            $code = $exception instanceof \Owl\Http\Exception
            ? $exception->getCode()
            : 500;

            $response->withStatus($code)
                     ->withBody(new \Owl\Http\StringStream('')); // reset response body
        };
    }

    /**
     * class loader.
     *
     * @param string $namespace
     * @param string $path
     * @param string $classname For test
     *
     * @return void|string
     */
    public static function registerNamespace($namespace, $path, $classname = null)
    {
        $namespace = trim($namespace, '\\');
        $path = rtrim($path, '/\\');

        $loader = function ($classname, $return_filename = false) use ($namespace, $path) {
            if (class_exists($classname, false) || interface_exists($classname, false)) {
                return true;
            }

            $classname = trim($classname, '\\');

            if ($namespace && stripos($classname, $namespace) !== 0) {
                return false;
            } else {
                $filename = trim(substr($classname, strlen($namespace)), '\\');
            }

            $filename = $path . DIRECTORY_SEPARATOR . str_replace('\\', DIRECTORY_SEPARATOR, $filename) . '.php';

            if ($return_filename) {
                return $filename;
            } else {
                if (!file_exists($filename)) {
                    return false;
                }

                require $filename;

                return class_exists($classname, false) || interface_exists($classname, false);
            }
        };

        if ($classname === null) {
            spl_autoload_register($loader);
        } else {
            return $loader($classname, true);
        }
    }
}