使用 React.js、Node.js 和 Multer，如何在服务器上控制台日志'req.file'？

Question

我正在构建一个MERN应用程序，当我尝试在服务器上控制台.log(req.file(时，我得到了未定义。我已经查看了multer github页面和其他SO文章，但我仍然无法使用React钩子和jsx找到它。我是SO的新手，所以我将添加编辑，因为我还不能发表评论。

如果你想查看所有文件，这里有一个指向GitHub分支的链接。https://github.com/BenjDG/puzzle-gallery/tree/so

我对穆尔特是个新手，所以我很感激你的帮助。

这是我的代码：

server\controllers\puzleController.js

const multer = require('multer');
const upload = multer({ dest: './uploads'});
const db = require('../models');
const fs = require('fs');
const type = upload.single('picFile');
// Defining methods for the puzzleController
module.exports = {
findAll: function (req, res) {
db.Puzzle
.find(req.query)
.then(dbModel => res.json(dbModel))
.catch(err => res.status(422).json(err));
},
save: (type, function (req, res) {
// console.log(req);
console.log(req.file);
console.log(req.body);
res.sendStatus(200);
}),
remove: function (req, res) {
db.Puzzle
.findById({ _id: req.params.id })
.then(dbModel => dbModel.remove())
.then(dbModel => res.json(dbModel))
.catch(err => res.status(422).json(err));
}
};

client\src\components\gallery\index.js

import React, { useState } from 'react';
import './styles.css';
import API from '../../services/API';

export default function Gallery () {
const [picFile, setPicFile] = useState();
const handleGetClick = async () => {
API.findAll()
.then(res => {
console.log(res)
})
.catch(err => console.error(err))
}
const handleUploadClick = async (e) => {
e.preventDefault();
// console.log(picFile);
// create new formData instance
const bodyFormData = new FormData();
// append single file to formData instance
bodyFormData.append('picFile', picFile.selectedFile);
// log items in formData object
for (const element of bodyFormData) {
console.log(element);
}
// send formData obj to axios function
API.save(bodyFormData)
.then(res => {
//console.log(res)
})
.catch(err => console.error(err))
}
const onFileChange = (e) => {
console.log(`e.target.files[0]`, e.target.files[0])
setPicFile({ selectedFile: e.target.files[0] });
}
return (
<div>
<h1>My Puzzle Gallery</h1>
<form encType='multipart/form-data'>
<input type='file' name='picFile' onChange={onFileChange} />
<br />
<br />
<button onClick={handleUploadClick}>Upload a picture</button>
</form>
<br />
<br />
<button onClick={handleGetClick}>Get pictures</button>
<br />
<br />
<img src='https://placekitten.com/640/360' alt='kitten' />
</div>
);
}

客户端\src\services\API.js

import axios from 'axios';
const API = {
login: (username, password) => {
const obj = {
username: username,
password: password
};
return axios.post('/api/auth/login', obj);
},
register: (username, password) => {
const obj = {
username: username,
password: password
};
return axios.post('/api/auth/register', obj);
},
logout: function () {
return axios.get('api/auth/logout');
},
save: function (form) {
return axios.post('api/puzzle/', form).catch(err=>console.error(err));
},
findAll: function () {
return axios.get('api/puzzle/');
},
}
export default API;

server\routes\api\pigues\index.js

const router = require('express').Router();
const puzzleController = require('../../../controllers/puzzleController');
// Matches with '/api/puzzle'
router.route('/')
.get(puzzleController.findAll)
.post(puzzleController.save);
// Matches with '/api/books/:id'
router.route('/delete/:id')
.delete(puzzleController.remove);
module.exports = router;

server\server.js

const path = require('path');
const express = require('express');
const passport = require('./config/passport');
const mongoose = require('mongoose');
const cors = require('cors');
const session = require('express-session');
const helmet = require('helmet');
const morgan = require('morgan');
const corsOptions = require('./config/cors.js');
const routes = require('./routes');
const { v1: uuidv1 } = require('uuid');
// console.log(uuidv1());
const PORT = process.env.PORT || 3001;
const app = express();
mongoose.connect(process.env.MONGODB_URI || 'mongodb://localhost/puzzlegallery', {
useNewUrlParser: true,
useUnifiedTopology: true,
useCreateIndex: true,
useFindAndModify: false
});
mongoose.set("useCreateIndex", true);
// Define middleware here
app.use(express.urlencoded({ extended: true }));
app.use(express.json());
app.use(helmet({ contentSecurityPolicy: false }));
app.use(session({ secret: 'sassy', resave: false, saveUninitialized: true }));
app.use(passport.initialize());
app.use(passport.session());
app.use(cors(corsOptions));
app.use(morgan('dev'));
app.use(routes);
// for Reactjs ##################
// Serve up static assets (usually on heroku)
if (process.env.NODE_ENV === 'production') {
app.use(express.static('client/build'));
}
// #################################################
if (process.env.NODE_ENV === 'production') {
app.get('*', (_, res) => {
res.sendFile(path.join(__dirname, '../client/build/index.html'));
});
}

app.listen(PORT, (err) => {
if (err) throw err;
console.log(
`🌎 Server is Ready and Listening on http://localhost:${PORT}`
); // eslint-disable-line no-console
});

编辑：这似乎奏效了。再次感谢！！

const path = require('path');
const router = require('express').Router();
const puzzleController = require('../../../controllers/puzzleController');
const multer = require('multer');
const { v1: uuidv1 } = require('uuid');
const storage = multer.diskStorage({
destination: function (req, file, cb) {
cb(null, path.join(__dirname, '../../../../tmp/my-uploads'))
},
filename: function (req, file, cb) {
cb(null, uuidv1())
}
})
const upload = multer({ storage: storage });
// Matches with '/api/puzzle'
router.route('/')
.get(puzzleController.findAll)
// Matches with '/api/books/:id'
router.route('/delete/:id')
.delete(puzzleController.remove);
router.use(upload.single('picFile'));
router.route('/')
.post(puzzleController.save);
module.exports = router;

Answer 1

您不能像这样调用save函数内部的中间件。

我克隆了你的repo，并在server.js中添加了以下代码，它运行良好，我在req.file.中得到了值

const multer = require('multer');
const upload = multer({ dest: 'uploads/'});
app.post('/api/puzzle/', upload.single('pictureFile'),(req,res,next)=>{
console.log("req.file22222222", req.file);
})