代理助手

🌐 Proxy Helper

当使用 Hono 应用作为（反向）代理时，Proxy Helper 提供了有用的功能。

🌐 Proxy Helper provides useful functions when using Hono application as a (reverse) proxy.

导入

🌐 Import

import { Hono } from 'hono'
import { proxy } from 'hono/proxy'

proxy()

proxy() 是用于代理的 fetch() API 封装。参数和返回值与 fetch() 相同（除了特定于代理的选项之外）。

Accept-Encoding 头被替换为当前运行时可以处理的编码。多余的响应头被移除，并返回一个 Response 对象，该对象可以由处理程序发送。

🌐 The Accept-Encoding header is replaced with an encoding that the current runtime can handle. Unnecessary response headers are removed, and a Response object is returned that can be sent from the handler.

示例

🌐 Examples

简单用法：

🌐 Simple usage:

app.get('/proxy/:path', (c) => {
  return proxy(`http://${originServer}/${c.req.param('path')}`)
})

复杂用法:

🌐 Complicated usage:

app.get('/proxy/:path', async (c) => {
  const res = await proxy(
    `http://${originServer}/${c.req.param('path')}`,
    {
      headers: {
        ...c.req.header(), // optional, specify only when forwarding all the request data (including credentials) is necessary.
        'X-Forwarded-For': '127.0.0.1',
        'X-Forwarded-Host': c.req.header('host'),
        Authorization: undefined, // do not propagate request headers contained in c.req.header('Authorization')
      },
    }
  )
  res.headers.delete('Set-Cookie')
  return res
})

或者你可以将 c.req 作为参数传递。

🌐 Or you can pass the c.req as a parameter.

app.all('/proxy/:path', (c) => {
  return proxy(`http://${originServer}/${c.req.param('path')}`, {
    ...c.req, // optional, specify only when forwarding all the request data (including credentials) is necessary.
    headers: {
      ...c.req.header(),
      'X-Forwarded-For': '127.0.0.1',
      'X-Forwarded-Host': c.req.header('host'),
      Authorization: undefined, // do not propagate request headers contained in c.req.header('Authorization')
    },
  })
})

你可以使用 customFetch 选项覆盖默认的全局 fetch 函数：

🌐 You can override the default global fetch function with the customFetch option:

app.get('/proxy', (c) => {
  return proxy('https://example.com/', {
    customFetch,
  })
})

连接头处理

🌐 Connection Header Processing

默认情况下，proxy() 会忽略 Connection 头，以防止逐跳头注入攻击。你可以使用 strictConnectionProcessing 选项启用严格的 RFC 9110 兼容性：

🌐 By default, proxy() ignores the Connection header to prevent Hop-by-Hop Header Injection attacks. You can enable strict RFC 9110 compliance with the strictConnectionProcessing option:

// Default behavior (recommended for untrusted clients)
app.get('/proxy/:path', (c) => {
  return proxy(`http://${originServer}/${c.req.param('path')}`, c.req)
})

// Strict RFC 9110 compliance (use only in trusted environments)
app.get('/internal-proxy/:path', (c) => {
  return proxy(`http://${internalServer}/${c.req.param('path')}`, {
    ...c.req,
    strictConnectionProcessing: true,
  })
})

ProxyFetch

proxy() 的类型定义为 ProxyFetch，具体如下

🌐 The type of proxy() is defined as ProxyFetch and is as follows

interface ProxyRequestInit extends Omit<RequestInit, 'headers'> {
  raw?: Request
  customFetch?: (request: Request) => Promise<Response>
  strictConnectionProcessing?: boolean
  headers?:
    | HeadersInit
    | [string, string][]
    | Record<RequestHeader, string | undefined>
    | Record<string, string | undefined>
}

interface ProxyFetch {
  (
    input: string | URL | Request,
    init?: ProxyRequestInit
  ): Promise<Response>
}