我在提交表单时遇到错误

Question

在连接到 mongodb 时，我收到警告

"DeprecationWarning: 当前的 URL 字符串解析器已被弃用，并将 在未来的版本中被删除。要使用新的解析器，请传递选项 { useNewUrlParser: true } 到 MongoClient.connect。”

提交表单时 - 我收到了

必须打开数据库连接才能存储文件 在 GridFSStorage._handleFile (C:\Users\charan puli\Desktop\upload\node_modules\multer-gridfs-storage\lib\gridfs.js:341:17) 在 C:\Users\charan puli\Desktop\upload\node_modules\multer\lib\make-middleware.js:144:17 在allowAll (C:\Users\charan puli\Desktop\upload\node_modules\multer\index.js:8:3) 在 WrappedFileFilter (C:\Users\charan puli\Desktop\upload\node_modules\multer\index.js:44:7) 在 Busboy。 (C:\Users\charan puli\Desktop\upload\node_modules\multer\lib\make-middleware.js:114:7) 在 Busboy.emit (events.js:182:13)

//////////////////app.js///////////////////////

//middle wares

app.use(bodyparser.json())

app.use(methodOverride('_method'))


app.set("view engine","ejs")

//connection

var mongoURI='mongodb+srv://user:password@clusterpuli-xs9yc.mongodb.net/test?retryWrites=true'


mongoose.connect(mongoURI,{useNewUrlParser:true})
        .then(()=>{console.log('connected successfully');
        })
        .catch(err=>{console.log(err);
        })

var conn=mongoose.connection
var gfs
conn.once('open',() =>{
gfs = Grid(conn.db, mongoose.mongo);

  gfs.collection('questions')
})
//create storage object

var storage = new GridFsStorage({
    url: mongoURI,
    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: 'questions'
          };
          resolve(fileInfo);
        });
      });
    }
  });
  const upload = multer({ storage });
//@route /upload POST

app.post('/upload',upload.single('file'),(req,res)=>{
    res.json({'file':req.file})
})


 var port= 3000
app.get("/",(req,res)=>{
    res.render('index')
})

app.listen(port,()=>{
    console.log(`app is running at ${port}`);

})


////////////////////////////////////

预期 - json 文件对象，连接成功

实际 - 必须打开数据库连接

Answer 1

//连接

var mongoURI='mongodb+srv://charanpuli:Charan@1999@clusterpuli-xs9yc.mongodb.net/test?retryWrites=true'

var conn = mongoose.connection

MongoClient.connect(db, { useNewUrlParser: true })

    .then(()=>{console.log('connected successfully');
    })
    .catch(err=>{console.log(err);
    })

var gfs conn.once('open',() =>{ gfs = Grid(conn.db, mongoose.mongo);

gfs.collection('问题') })

Answer 2

这应该对你有用，我已经测试过了：

//connection

const mongoURI = 'mongodb+srv://user:password@clusterpuli-xs9yc.mongodb.net/test?retryWrites=true';

const promise = mongoose.connect(mongoURI, { useNewUrlParser: true });

const conn = mongoose.connection;
let gfs;

conn.once('open',() => {
  gfs = Grid(conn, mongoose.mongo);
  gfs.collection('questions');
});

//create storage object
const storage = new GridFsStorage({
  db: promise,
  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: 'questions'
        };
        resolve(fileInfo);
      });
    });
  }
});
const upload = multer({ storage });

请在此处查看此参考以获取更多信息： Multer's GridFS storage engine

这与 Node.js MongoDB Driver API 的新 mongo 客户端的新 url 解析器有关。请参阅此参考：MongoClient

我遇到了同样的问题，这就是我最终回答您的问题的原因。