我在提交表单时遇到错误

Posted 2023-03-10

【中文标题】我在提交表单时遇到错误

【英文标题】：I am getting error on submitting the form

【发布时间】：2019-10-09 14:41:10

【问题描述】：

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:[e-mail]/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

【参考方案1】：

//连接

var mongoURI='mongodb+srv://charanpuli:Charan@[e-mail]/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') )

【讨论】：

我收到此错误 - C:\Users\charan puli\Desktop\upload\node_modules\gridfs-stream\lib\index.js:25 if (!db) throw new Error('missing db 参数\nnew Grid(db, mongo)'); ^ 错误：缺少 db 参数 new Grid(db, mongo)

【参考方案2】：

这应该对你有用，我已经测试过了：

//connection

const mongoURI = 'mongodb+srv://user:[e-mail]/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。

【讨论】：

C:\Users\charan puli\Desktop\upload\node_modules\gridfs-stream\lib\index.js:25 if (!db) throw new Error('missing db argument\nnew Grid(分贝，蒙戈）'）； ^ 错误：缺少 db 参数 new Grid(db, mongo)

我想我犯了一个小错误。而不是：gfs = Grid(conn.db, mongoose.mongo);它应该是：gfs = Grid(conn, mongoose.mongo);