Node.js 当try 将 formData 转换为 express js 时，服务器无法识别 multipartformdata

我需要在我的Express服务器上设置什么才能接收 表格数据？

Yes, To handle multipart/form-data in your Express server, you must configure a middleware.
For instance multer library.

演示:

Server.js个

const express = require("express");
app = express();
const multer = require("multer");
const upload = multer({ dest: "uploads/" });
//----------------------vvvvvvvvvvvvvvvvvvvvvv <------- middleware
app.post("/uploads/:id", upload.single("file"), function (req, res) {
  const title = req.body.title;
  console.log(req.file);
/*
Output of req.file:
{
  fieldname: 'file',
  originalname: 'test.jpg',
  encoding: '7bit',
  mimetype: 'image/jpeg',
  destination: 'uploads/',
  filename: '61d00f21b9813bdcb326082b41b58eb3',
  path: 'uploads\\61d00f21b9813bdcb326082b41b58eb3',
  size: 0
}
*/
  res.json({ msg: `file ${title} uploaded successfully!` });
});
app.listen(1234, () => {
  console.log("app is running on 1234");
});

Upload.js个

var fs = require("fs");
const fetch = require("node-fetch");
var FormData = require("form-data");

const form = new FormData();
const title = "Test";
const file = fs.createReadStream(`./test.jpg`);
form.append("title", title);
form.append("file", file);

(async () => {
  try {
    const response = await fetch("http://localhost:1234/uploads/1234", {
      method: "POST",
      //   headers: {
      //     "Content-Type": "multipart/form-data",
      //   },
      body: form,
    });
    const responseData = await response.json();
    console.log(responseData); // you got { msg: 'file Test uploaded successfully!' }
  } catch (error) {
    console.error(error);
  }
})();

Note:获取将自动设置标题，因此只需删除标题"Content-Type": "multipart/form-data".

如果您想要将上传到特定文件夹"Uploads/"的文件保存到标题为req.body.title的文件夹中，请将此配置添加到multer:

const path = require("path");
const storage = multer.diskStorage({
  destination: (req, file, cb) => {
    cb(null, "uploads/");
  },
  filename: (req, file, cb) => {
    const title = req.body.title;
    cb(null, title + path.extname(file.originalname));
  },
});
const upload = multer({ storage: storage });