PHP MVC，谁拥有 URL？

Question

我正在使用 MVC 技术实现一个 PHP 应用程序。加载http://site/photos/25?options的简单介绍，重写为http://site/index.php?page=photos&id=25&options:

• index.php -> 实例化并调用PhotoController对象
• PhotoController 实例化 PhotoView 并将正确的 Photo (模型)加载到其中
• PhotoController 调用 PhotoView->render() 和页眉/页脚 View
• PhotoView 可以访问 Photo 模型和它需要的其他模型数据

PhotoView 将输出 HTML 并希望超链接到不同的页面。当该 View 生成超链接时，我对哪一层应该拥有 URL 感到困惑。我看到的选项概述如下。请帮助我选择正确的方法。

---

模型层拥有 URL

Models have a getURL() method

优点:

• View 基类可以合并 Open Graph 属性
• PhotoView 可以这样做:$folderHref = $photo->getFolder()->url

缺点:

• 一些 Controller 没有单一对应的模型，例如 LoginController、AdminController，我如何获取这些的 URL？

---

Controller 拥有 URL

Controllers have url and title properties. To create a link, the presenting controller creates target controllers and passes to the view. The view accesses the url and title from the passed object.

优点:

• 每个 URL 都直接映射到一个 Controller (在 index.php 中)，因此反过来看起来很干净

缺点:

• 需要其他 View URL 的 View 将需要以下丑陋的技巧之一:

  • 查询不相关的 Controller $folderHref = Controllers\FolderController::urlForFolder($photo->getFolder())

  • View 对它们的 Controller 了解太多$folderHref = $photo->getFolder()->getControllerAndSetURL()->getURL()

  • View 与其 Controller 之间的过度通信 $folderHref = $this->delegate->getURLForFolder($photo->getFolder()) 和 $adminHref = $this ->delegate->getURLForAdminHref() with delegate 有很多方法

---

每个人都拥有 URL

A base class OpenGraphObject is the parent class for Controllers AND Models and has a method getURL()

Controllers 和 Models 仅当它可以不带参数运行时才实现它。 (例如，PhotoController 返回 NULL，因为 URL 取决于要显示的 Photo)。

优点:

• 上述所有优势

缺点

• 困惑
• 吊销我的编程许可证

Answer 1

为了分离关注点，我会像这样分解它:

/**
 * Responsible for processing and rendering user output
 */
interface View {

    public function render();
}

/**
 * Used just to further formalize the messages between Photo and View
 */
interface PhotoView extends View {

    public function setPhotoData($id, $title, $link);
}

/**
 * Among other things knows how to generate URLs to routes
 */
interface Router {

    /**
     * Returns the URL to route based on route name
     * @param string $routeName
     * @param array $params
     */
    public function urlTo($routeName, $params = null);
}

我不会实现每个类，您可以使用许多现成的解决方案，例如模板引擎和路由器。

基于 id 显示图像的示例 Controller 可以是:

class PhotoController {

    public function displayAction($photoId) {
        $photo = Photo::findById($photoId);

        $templateFile = $this->pathTo('photo-template.php');

        //can be a singleton for example, it holds all the routes for the application
        //and knows how to render them based on the name and parameters
        $router = AppRouter::instance();

        return $photo->render(new ConcretePhotoView($templateFile, $router));
    }

}

在此示例中，Photo 需要能够从数据库中获取自身，然后将自身呈现给 PhotoView:

class Photo {

    private $id;
    private $title;
    private $sourceLink;

    //other methods...

    public function render(PhotoView $view) {
        $view->setPhotoData($this->id, $this->title, $this->sourceLink);

        return $view->render();
    }

}

假设 HTML 模板 photo-template.php 如下所示:

<a href="<?= $userLogin['href'] ?>"><?= $userLogin['label'] ?></a>
<a href="<?= $userRegister['href'] ?>"><?= $userRegister['label'] ?></a>
<div>
    <img src="<?= $photo['src'] ?>" title="<?= $photo['title'] ?>" />
    <a href="<?= $photoLink['href'] ?>"><?= $photoLink['label'] ?></a>
</div>

这个模板需要什么变量应该足够清楚了。里面没有逻辑，只是纯粹的显示，虽然一些基本的控制就可以了。

剩下的就是编写 ConcretePhotoView 代码，它将使用提供的模板文件和路由器来调整领域对象 Photo 和具体 html 模板之间的数据:

class ConcretePhotoView implements PhotoView {

    private $templateEngine;
    private $router;

    public function __construct($templateFile, Router $router) {
        $this->templateEngine = new SomeTemplateEngine($templateFile);
        $this->router = $router;
    }

    public function render() {
        //router has a route userLogin with no params
        $this->templateEngine->assign('userLogin', array(
            'href' => $this->router->urlTo('userLogin'),
            'label' => 'Login'
        ));

        $this->templateEngine->assign('userRegister', array(
            //router has a route named userRegister that requires no params
            'href' => $this->router->urlTo('userRegister'),
            'label' => 'Register'
        ));

        return $this->templateEngine->render();
    }

    public function setPhotoData($id, $title, $link) {
        $this->templateEngine->assign('photo', array(
            'src' => $link,
            'title' => $title
        ));

        $this->templateEngine->assign('photoLink', array(
            //router has a route named photo that requires an id
            'href' => $this->router->urlTo('photo', array('id' => $id)),
            'label' => $title
        ));
    }

}

终于要回答“谁拥有 URL？”这个问题了。 - 路由器。这些知识被封装在那里并且特定于应用程序配置。其他对象使用它来生成链接。