数据库连接必须打开以在GridFSStorage._handleFile存储文件

Question

我试图通过web应用程序将文件上载到本地MongoDB服务器上，如下所示：

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('server started port ${port}'))；但我得到了错误：“数据库连接必须打开，以便在(/Users/payam/Desktop/mongodb-uploads/node_modules/multer-gridfs-storage/lib/gridfs.js:341:17) at /Users/payam/Desktop/mongodb-uploads/node_modules/multer/lib/make-middleware.js:144:17 at allowAll (/Users/.../Desktop/mongodb-uploads/node_modules/multer/index.js:8:的GridFSStorage._handleFile存储文件。( 3)在(/Users/.../Desktop/mongodb-uploads/node_modules/multer/index.js:44:7)的wrappedFileFilter餐馆。(/Users/.../Desktop/mongodb-uploads/node_modules/multer/lib/make-middleware.js:114:7) at Busboy.emit (events.js:182:13) at Busboy.emit (/Users/.../Desktop/mongodb-uploads/node_modules/busboy/lib/main.js:38:33) at PartStream.(/Users/.../Desktop/mongodb-uploads/node_modules/busboy/lib/types/multipart.js:213:13) at PartStream.emit (events.js:182:13) at HeaderParser.(/Users/.../Desktop/mongodb-uploads/node_modules/dicer/lib/Dicer.js:51:16) at HeaderParser.emit (events.js:182:13) at HeaderParser._finish (/Users/.../Desktop/mongodb-uploads/node_modules/dicer/lib/HeaderParser.js:68:8) at SBMH.(/Users/.../Desktop/mongodb-uploads/node_modules/dicer/lib/HeaderParser.js:40:12) at SBMH.emit (events.js:182:13)在SBMH._sbmh_feed (/Users/.../Desktop/mongodb-uploads/node_modules/streamsearch/lib/sbmh.js:159:14) at SBMH.push (/Users/.../Desktop/mongodb-uploads/node_modules/streamsearch/lib/sbmh.js:56:14)".有人能帮我，告诉我我的代码或机器出了什么问题吗？

Answer 1

我所需要做的就是为Mongo设置useNewUrlParser: true：

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

对于端口，您可以设置为5000，如下所示：

const port = 5000;

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