Django Academy · 课时

编写自定义中间件

接入每个请求和响应

编写自定义中间件 是 CoddyKit 上的免费 Django Academy 课时。这是第 3 节课，共 4 节。你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。这是 Django Academy 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Django Academy 课程共包含 4 节课。

本课时的部分内容尚未翻译，以英文显示。

Middleware in a Sentence

Middleware is a layer that wraps every request and response, letting you run code before a view and after it returns.

The Onion Model

Think of middleware as layers of an onion around your view. A request travels inward through each layer, then the response travels back out.

The Modern Style

A modern middleware is a callable that takes get_response once at startup and returns the handler Django calls per request.

A Minimal Middleware

The factory stores get_response, and the inner function runs your code around the call. This callable shape is all Django needs.

def simple(get_response):
    def handler(request):
        # before the view
        response = get_response(request)
        # after the view
        return response
    return handler

Code Before the View

Anything before get_response runs on the way in. It is perfect for logging, timing, or attaching data to the request.

def handler(request):
    request.start = time.time()
    return get_response(request)

Code After the View

Anything after get_response runs on the way out. Here you can read or modify the response before it reaches the browser.

response = get_response(request)
response["X-App"] = "demo"
return response

The Class-Based Form

You can also write middleware as a class with __init__ and __call__. It mirrors the function form but groups related hooks neatly.

class Timer:
    def __init__(self, get_response):
        self.get_response = get_response

    def __call__(self, request):
        return self.get_response(request)

Register in MIDDLEWARE

Middleware only runs once you list its dotted path in the MIDDLEWARE setting inside settings.py.

MIDDLEWARE = [
    "django.middleware.security.SecurityMiddleware",
    "myapp.middleware.simple",
]

Short-Circuiting a Request

If middleware returns a response itself instead of calling get_response, it short-circuits the chain and the view never runs.

One Job Per Middleware

Keep each middleware focused on a single concern, like timing or auth checks. Small layers are easier to order and debug.

Common Real Uses

Teams use custom middleware for request logging, adding headers, locale handling, and lightweight auth checks across the whole site.

Quick Check

Check how a modern middleware hands off to the next layer.

Recap: Building Middleware

You built custom middleware: a callable taking get_response, with code before and after the view, registered in the MIDDLEWARE setting. ✅

常见问题解答

「编写自定义中间件」课时是免费的吗？

是的 — 「编写自定义中间件」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Django Academy 课程的其余内容，请升级到 CoddyKit PRO。 Django Academy 课程共包含 4 节课。

「编写自定义中间件」这节课中我会学到什么？

接入每个请求和响应你通过在浏览器中直接运行的动手代码来练习 Django Academy，全天候 AI 导师会在你学习这节课的过程中回答你的问题。

学习 Django Academy 需要有经验吗？

无需任何先前经验。CoddyKit 上的 Django Academy 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。这是第 3 节课，共 4 节。

「编写自定义中间件」课时需要多长时间？

大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。

我能在这节 Django Academy 课中编写并运行代码吗？

能。每节 Django Academy 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。

此课程中的所有课时

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