必须打开数据库连接才能将文件存储在 GridFSStorage._handleFile

Question

我尝试通过以下 Web 应用程序在本地 MongoDB 服务器上上传文件：

const express = require("express");
const bodyParser = require('body-parser');
const path = require('path');
const crypto = require('crypto');
const mongoose = require('mongoose');
const GridFsStorage = require('multer-gridfs-storage');
const Grid = require('gridfs-stream');
const methodOverride = require('method-override');
const multer = require('multer');

const app = express();

// Middleware
app.use(bodyParser.json());
app.use(methodOverride('_method'));
app.set('view engine', 'ejs');

// Mongo URI
const mongoURI =
    'mongodb://localhost:27017/database'

// Create mongo connection
const conn = mongoose.createConnection(mongoURI);

// Init gifs
let gfs;

conn.once('open', () => {
    // Init Stream
    gfs = Grid(conn.db, mongoose.mongo);
    gfs.collection('uploads');
})


// Create storage engine

const storage = new GridFsStorage({
  url: 'mongodb://localhost:27017/database',
  file: (req, file) => {
    return new Promise((resolve, reject) => {
      crypto.randomBytes(16, (err, buf) => {
        if (err) {
          return reject(err);
        }
        const filename = buf.toString('hex') + path.extname(file.originalname);
        const fileInfo = {
          filename: filename,
          bucketName: 'uploads'
        };
        resolve(fileInfo);
      });
    });
  }
});
const upload = multer({ storage });

// @route GET /
// @desc Loads form

app.get('/', (req, res) => {
    res.render('index');
})

// @route POST /upload
//@desc upload file to DB
app.post('/upload', upload.single('file'), (req, res) => {
res.json({ file: req.file });
});

const port = 27017;

app.listen(port, () => console.log('服务器在 ${port} 端口上启动')); 但我收到错误：“必须打开数据库连接才能存储文件 在 GridFSStorage._handleFile (/Users/payam/Desktop/mongodb-uploads/node_modules/multer-gridfs-storage/lib/gridfs.js:341:17) 在 /Users/payam/Desktop/mongodb-uploads/node_modules/multer/lib/make-middleware.js:144:17 在allowAll（/Users/.../Desktop/mongodb-uploads/node_modules/multer/index.js:8:3） 在 WrappedFileFilter (/Users/.../Desktop/mongodb-uploads/node_modules/multer/index.js:44:7) 在 Busboy。 (/Users/.../Desktop/mongodb-uploads/node_modules/multer/lib/make-middleware.js:114:7) 在 Busboy.emit (events.js:182:13) 在 Busboy.emit (/Users/.../Desktop/mongodb-uploads/node_modules/busboy/lib/main.js:38:33) 在 PartStream。 (/Users/.../Desktop/mongodb-uploads/node_modules/busboy/lib/types/multipart.js:213:13) 在 PartStream.emit (events.js:182:13) 在 HeaderParser。 (/Users/.../Desktop/mongodb-uploads/node_modules/dicer/lib/Dicer.js:51:16) 在 HeaderParser.emit (events.js:182:13) 在 HeaderParser._finish (/Users/.../Desktop/mongodb-uploads/node_modules/dicer/lib/HeaderParser.js:68:8) 在 SBMH。 (/Users/.../Desktop/mongodb-uploads/node_modules/dicer/lib/HeaderParser.js:40:12) 在 SBMH.emit (events.js:182:13) 在 SBMH._sbmh_feed (/Users/.../Desktop/mongodb-uploads/node_modules/streamsearch/lib/sbmh.js:159:14) 在 SBMH.push (/Users/.../Desktop/mongodb-uploads/node_modules/streamsearch/lib/sbmh.js:56:14)”。 任何人都可以帮助并告诉我我的代码或我的代码有什么问题吗 机器？

Answer 1

我需要做的就是为 Mongo URI 设置 useNewUrlParser: true ：

// Create mongo connection
const conn = mongoose.createConnection(mongoURI, { useNewUrlParser: true });

您可以将端口设置为 5000，如下所示：

const port = 5000;

app.listen(port, () => console.log(`server started on port ${port}`));