如何解决复杂路由与多层应用分发问题？使用middlewares/base-path-router让你的PHP应用结构更清晰！

<code class="bash">composer require middlewares/base-path-router</code>

<pre class="brush:php;toolbar:false;"><?php

require 'vendor/autoload.php';

use Laminas\Stratigility\MiddlewarePipe;
use Middlewares\BasePathRouter;
use Middlewares\RequestHandler;
use Nyholm\Psr7\Factory\Psr17Factory;
use Nyholm\Psr7Server\ServerRequestCreator;
use Laminas\HttpHandlerRunner\Emitter\SapiEmitter;

// 1. 创建 PSR-7 请求对象 (从全局变量中获取)
$psr17Factory = new Psr17Factory();
$request = (new ServerRequestCreator(
    $psr17Factory, // ServerRequestFactory
    $psr17Factory, // UriFactory
    $psr17Factory, // UploadedFileFactory
    $psr17Factory  // StreamFactory
))->fromGlobals();

// 2. 定义你的子应用或处理程序
// 这些可以是任何实现了 Psr\Http\Server\MiddlewareInterface 的对象，
// 或者是可调用的闭包 (Closure)，它们会接收到一个请求对象和下一个处理程序。

// 模拟一个后台管理子应用
$adminApp = new class implements \Psr\Http\Server\MiddlewareInterface {
    public function process(\Psr\Http\Message\ServerRequestInterface $request, \Psr\Http\Server\RequestHandlerInterface $handler): \Psr\Http\Message\ResponseInterface
    {
        $response = (new Psr17Factory())->createResponse(200);
        $response->getBody()->write('Hello from Admin! Current Path: ' . $request->getUri()->getPath());
        return $response;
    }
};

// 模拟一个博客子应用
$blogApp = new class implements \Psr\Http\Server\MiddlewareInterface {
    public function process(\Psr\Http\Message\ServerRequestInterface $request, \Psr\Http\Server\RequestHandlerInterface $handler): \Psr\Http\Message\ResponseInterface
    {
        $response = (new Psr17Factory())->createResponse(200);
        $response->getBody()->write('Welcome to the Blog! Current Path: ' . $request->getUri()->getPath());
        return $response;
    }
};

// 模拟一个默认的公共页面处理程序
$defaultApp = new class implements \Psr\Http\Server\MiddlewareInterface {
    public function process(\Psr\Http\Message\ServerRequestInterface $request, \Psr\Http\Server\RequestHandlerInterface $handler): \Psr\Http\Message\ResponseInterface
    {
        $response = (new Psr17Factory())->createResponse(200);
        $response->getBody()->write('Welcome to the Homepage! Current Path: ' . $request->getUri()->getPath());
        return $response;
    }
};

// 3. 配置 BasePathRouter
// 将不同的路径前缀映射到对应的子应用
$router = new BasePathRouter([
    '/admin' => $adminApp,
    '/blog' => $blogApp,
    // 如果没有匹配到任何前缀，BasePathRouter 默认会继续到下一个中间件
    // 或者你可以为根路径 '/' 设置一个默认处理
    '/' => $defaultApp,
]);

// 4. 构建主中间件管道 (Dispatcher)
$app = new MiddlewarePipe();
$app->pipe($router);
// RequestHandler 中间件会从请求属性中获取由 BasePathRouter 存储的处理器并执行它。
// 如果 BasePathRouter 没有匹配到任何路径，它会继续到下一个中间件，
// 此时 RequestHandler 可能找不到处理器，你可以添加一个 404 处理器作为兜底。
$app->pipe(new RequestHandler());

// 5. 添加一个 404 处理器作为最终的兜底，以防所有路由都未匹配
$app->pipe(new class implements \Psr\Http\Server\MiddlewareInterface {
    public function process(\Psr\Http\Message\ServerRequestInterface $request, \Psr\Http\Server\RequestHandlerInterface $handler): \Psr\Http\Message\ResponseInterface
    {
        $response = (new Psr17Factory())->createResponse(404);
        $response->getBody()->write('404 Not Found: ' . $request->getUri()->getPath());
        return $response;
    }
});

// 6. 运行应用并发送响应
$response = $app->handle($request);
(new SapiEmitter())->emit($response);

// 示例访问：
// - 访问 /admin/dashboard 会显示 "Hello from Admin! Current Path: /dashboard"
// - 访问 /blog/posts/123 会显示 "Welcome to the Blog! Current Path: /posts/123"
// - 访问 / 会显示 "Welcome to the Homepage! Current Path: /"
// - 访问 /foo/bar (未匹配的路径) 会显示 "404 Not Found: /foo/bar"