在Yii 中，控制器通過處理用戶請求、交互模型和渲染視圖來協(xié)調(diào)應(yīng)用邏輯。控制器的主要職責(zé)包括：① 處理HTTP 請求；② 與模型交互獲取或保存數(shù)據(jù)；③ 決定顯示哪個視圖並傳遞數(shù)據(jù)；④ 處理表單提交；⑤ 返回HTML、JSON 或重定向響應(yīng)。 Yii 控制器通常繼承自yii\web\Controller，每個公共方法對應(yīng)一個可通過URL 訪問的動作。例如，訪問http://example.com/site/index 會調(diào)用SiteController 的actionIndex() 方法。常見任務(wù)包括驗證輸入、調(diào)用模型、渲染視圖、重定向及返回JSON 響應(yīng)。開發(fā)建議包括保持控制器簡潔、使用過濾器、合理組織動作、正確使用命名空間以及返回合適的HTTP 狀態(tài)碼?？刂破鲙椭鷮崿F(xiàn)代碼的可維護性和擴展性，是MVC 架構(gòu)的重要組成部分。

In Yii, controllers are the central part of handling user requests. They act as a middleman between models (data) and views (what users see). When you visit a page in a Yii application, the URL determines which controller and action to run, and based on that, it fetches data or performs operations, then returns the appropriate response—like displaying a page or sending JSON.

What Does a Controller Do?

A controller's main job is to process incoming HTTP requests and decide what to do with them. This usually involves:

• Interacting with models to get or save data
• Deciding which view to display
• Passing data to views
• Handling form submissions
• Returning different types of responses (HTML, JSON, redirects)

Controllers help organize your code by grouping related actions together. For example, a PostController might handle all actions related to blog posts—viewing, creating, editing, deleting.

Structure of a Controller in Yii

In Yii, a controller is typically a PHP class that extends yii\web\Controller . Each public method in that class is called an action , and each action can be accessed via a URL.

For example, if you have a controller named SiteController.php , and inside it there's a method called actionIndex() , you can access that action using a URL like:

 http://example.com/index.php?r=site/index

Here:

• site refers to SiteController
• index refers to actionIndex

You can also use pretty URLs with URL rewriting enabled, making the URL cleaner:

 http://example.com/site/index

Common Tasks Controllers Handle

Here are some typical things you'll find a controller doing:

• Validating input from forms or API requests
• Calling model methods to retrieve or update data
• Rendering views with dynamic content
• Redirecting users after an action (like submitting a form)
• Returning JSON responses for AJAX calls

Let's say you're building a simple blog. In your PostController , you might have:

 public function actionView($id)
{
    $post = Post::findOne($id);
    if (!$post) {
        throw new NotFoundHttpException('The requested post does not exist.');
    }
    return $this->render('view', ['post' => $post]);
}

This action:

1. Gets the $id parameter from the URL
2. Fetches the post from the database
3. Throws an error if it doesn't exist
4. Renders the view template and passes the post data to it

Tips for Working with Controllers

• Keep controllers lean: Don't put too much logic directly in controllers. Use models or services for heavy lifting.
• Use filters for common tasks like authentication: Yii supports filters like accessControl and verbControl .
• Organize actions logically: Group related actions into the same controller.
• Use controller namespaces properly: Especially when working with modules or advanced templates.
• Return proper HTTP status codes: Helps with SEO and APIs.

Controllers are essential in any MVC framework like Yii because they manage how users interact with your app. While it's possible to write everything in one place, using controllers keeps your code clean, maintainable, and scalable.

基本上就這些。

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