问使用multer处理包含表单数据的POST请求时，req.body为[Object: null prototype] {}，req.files为空

EN

import * as functions from 'firebase-functions';
import express = require('express');
import * as bodyParser from 'body-parser';
import formMiddlware from "./formMiddleware";

const app = express();

app.use(bodyParser.json());
app.use(bodyParser.urlencoded({extended: true}));

app.post('/upload', formMiddlware, (req: any, res: any) => {

    console.log(req.body);
    console.log(req.files);

    res.sendStatus(200);


});

export const server = functions.https.onRequest(app);

import * as Busboy from "busboy";
import os from "os";
import fs from "fs";
import path from "path";

type Dict = {
    [key: string]: any
}

function formMiddlware (req: any , res: any, next: any) {
    // See https://cloud.google.com/functions/docs/writing/http#multipart_data
    const busboy = new Busboy.default({
      headers: req.headers,
      limits: {
        // Cloud functions impose this restriction anyway
        fileSize: 10 * 1024 * 1024,
      }
    });
  
    const fields: Dict = {};
    const files: any[] = [];
    const fileWrites: any[] = [];
    // Note: os.tmpdir() points to an in-memory file system on GCF
    // Thus, any files in it must fit in the instance's memory.
    const tmpdir = os.tmpdir();
  
    busboy.on('field', (key: string, value: any) => {
      // You could do additional deserialization logic here, values will just be
      // strings
      fields[key] = value;
    });
  
    busboy.on('file', (fieldname, file, filename, encoding, mimetype) => {
      const filepath = path.join(tmpdir, filename);
      console.log(`Handling file upload field ${fieldname}: ${filename} (${filepath})`);
      const writeStream = fs.createWriteStream(filepath);
      file.pipe(writeStream);
  
      fileWrites.push(new Promise((resolve, reject) => {
        file.on('end', () => writeStream.end());
        writeStream.on('finish', () => {
          fs.readFile(filepath, (err, buffer) => {
            const size = Buffer.byteLength(buffer);
            console.log(`${filename} is ${size} bytes`);
            if (err) {
              return reject(err);
            }
  
            files.push({
              fieldname,
              originalname: filename,
              encoding,
              mimetype,
              buffer,
              size,
            });
  
            try {
              fs.unlinkSync(filepath);
            } catch (error) {
              return reject(error);
            }
  
            resolve();
          });
        });
        writeStream.on('error', reject);
      }));
    });
  
    busboy.on('finish', () => {
      Promise.all(fileWrites)
        .then(() => {
          req.body = fields;
          req.files = files;
          next();
        })
        .catch(next);
    });
  
    busboy.end(req.rawBody);
}
export default formMiddlware;