Renaming an uploaded file using Multer doesn't work (Express.js)

The usage for Multer has changed.

Currently Multer constructor accepts only three options:

1. dist/storage
2. fileFilter
3. limits

now rename, onFileUploadStart, onFileUploadComplete would not work.

however renaming can be done using DiskStorage

var storage = multer.diskStorage({    destination: function (req, file, cb) {        cb(null, '/tmp/my-uploads')    },    filename: function (req, file, cb) {        cb(null, file.fieldname + '-' + Date.now())  }})var upload = multer({ storage: storage })

have a look at these links:

• https://github.com/expressjs/multer
• multer callbacks not working ?

I know this post is dated. I want to contribute to those who may arrive later. Below is a full functional server script to handle multiple uploaded pictures with random saved pictures names and file extension.

var express = require("express");var multer = require("multer");var app = express();var path = require("path");var uuid = require("uuid");// Allow cross origin resource sharing (CORS) within our applicationapp.use(function(req, res, next) {    res.header("Access-Control-Allow-Origin", "*");    res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");    next();});var storage = multer.diskStorage({  destination: function (req, file, cb) {    cb(null, 'uploadedimages/')  },  filename: function (req, file, cb) {    cb(null, uuid.v4() + path.extname(file.originalname));  }})var upload = multer({ storage: storage })// "files" should be the same name as what's coming from the field name on the client side.app.post("/upload", upload.array("files", 12), function(req, res) {    res.send(req.files);    console.log("files = ", req.files);});var server = app.listen(3000, function() {    console.log("Listening on port %s...", server.address().port);});

try this way which i'm using

  var storage = multer.diskStorage({    destination: function (req, file, cb) {      cb(null, 'uploads/')    },    filename: function (req, file, cb) {      console.log(file);      var fileObj = {        "image/png": ".png",        "image/jpeg": ".jpeg",        "image/jpg": ".jpg"      };      if (fileObj[file.mimetype] == undefined) {        cb(new Error("file format not valid"));      } else {        cb(null, file.fieldname + '-' + Date.now() + fileObj[file.mimetype])      }    }  })  var upload = multer({ storage: storage })