中间件

¥Middleware

我们将返回 Response 的原语称为 "处理程序"。"中间件" 在 Handler 之前和之后执行，并处理 Request 和 Response。它就像一个洋葱结构。

¥We call the primitive that returns Response as "Handler". "Middleware" is executed before and after the Handler and handles the Request and Response. It's like an onion structure.

例如，我们可以编写中间件来添加 "X-Response-Time" 标头，如下所示。

¥For example, we can write the middleware to add the "X-Response-Time" header as follows.

app.use(async (c, next) => {
  const start = Date.now()
  await next()
  const end = Date.now()
  c.res.headers.set('X-Response-Time', `${end - start}`)
})

使用这种简单的方法，我们可以编写自己的自定义中间件，并且可以使用内置或第三方中间件。

¥With this simple method, we can write our own custom middleware and we can use the built-in or third party middleware.