如何在TypeScript中正确扩展请求（Request）头

Question

我需要在req.headers中获取userId，但我无法正确地输入它，我该如何做？

首先我尝试了以下方法：

  interface ISpot{
    thumbnail: File,
    company: string,
    price: number,
    techs: string
  }

  interface IReqCustom<T> extends Request{
    body: T,
  }

  export default {
    async store (req: IReqCustom<ISpot>, res: Response): Promise<Response> {
      const { filename } = req.file
      const { company, techs, price } = req.body
      const { userId } = req.headers

      const user = await User.findById(userId)

      if (!user) {
        return res.status(400).json({ error: 'User doesn\'t exist' })
      }

      const spot = await Spot.create({
        user: userId,
        thumbnail: filename,
        company,
        techs: techs.split(',').map(tech => tech.trim()),
        price
      })

      return res.json(spot)
    }

}

第34行的用户键必须是一个字符串，但它从userId接收到的值可能是string | string [] | undefined。

我也尝试过这个：

interface UserHeader{
  userId: string
}

interface IReqCustom<T, P> extends Request{
  body: T,
  headers: P
}

async store (req: IReqCustom<ISpot, UserHeader>, res: Response): Promise<Response>{}

用户分配错误已消失，但接口 IReqCustom 出现了另一个错误。

Interface 'IReqCustom<T, P>' incorrectly extends interface 'Request<ParamsDictionary, any, any, ParsedQs>'.
  Types of property 'headers' are incompatible.
    Type 'P' is not assignable to type 'IncomingHttpHeaders'.

我该如何使这些属性识别其各自的类型？

- Jose Carlos Filho

---

这是 express 吗？ - gurisko

是的，我使用import { Request, Response } from 'express'。 - Jose Carlos Filho

Answer 1

你需要使用 IncomingHttpHeaders（它是由express.Request.headers返回的类型）并将其与你的自定义头部类型进行扩展或交叉：

import {Request, Response} from 'express';
import {IncomingHttpHeaders} from 'http';

interface ISpot{
  thumbnail: File,
  company: string,
  price: number,
  techs: string
}

interface CustomHeaders {
  userId: string;
}

interface IReqCustom<TBody, THeader> extends Request {
  body: TBody;
  headers: IncomingHttpHeaders & THeader;
}

export const handler = (req: IReqCustom<ISpot, CustomHeaders>, res: Response) => {
  const {userId} = req.headers; // `userId` is now `string`
  return res.status(200);
}

- gurisko