Multer not adding file extension

Question

I'm working on a Node.js/MongoDB based website and i'm trying to upload images directly on server using Express, Jade, and Multer, but no matter what i do, i can't achive to upload the file with extension.

I've got this on my app.js file:

var express = require('express');
var mongoose = require('mongoose');
var bodyParser = require('body-parser');
var multer = require('multer');

var storage = multer.diskStorage({
    destination: function (req, file, cb) {
        cb(null, './uploads')
    },
    filename: function (req, file, cb) {
        cb(null, file.originalname)
    }
});

var upload = multer({ storage: storage });


var app = express();

mongoose.connect("mongodb://localhost/primera_pagina");

app.use(bodyParser.json());
app.use(bodyParser.urlencoded({extended: true}));
app.use(multer({dest: "./uploads"}).single("image_avatar"));


var productSchema = {
    title:String,
    description:String,
    imageURL:String,
    pricing:Number
};

var Product = mongoose.model("Product", productSchema);

app.set("view engine","jade");

app.use(express.static("public"));

app.get("/",function(req,res){

    res.render("index");

});

app.post("/productos",function(req,res){
    if(req.body.password == "123"){
        var data = {
            title: req.body.title,
            description: req.body.description,
            imageURL: "image_avatar",
            pricing: req.body.pricing
        }

        var product = new Product(data);

        console.log(req.file)

    }else{
        res.render("index");
    }


});

app.get("/productos/new",function(req,res){
    res.render("productos/new");
});


app.listen(8080);

Any idea? I've search on Internet and tried every single method to add file extension with multer, but none has worked.

Answer 1

Multer strips the file extension for both security and collision reasons. For a workaround, try this:

var path = require('path')
var multer = require('multer')
var mime = require('mime-types')

var storage = multer.diskStorage({
  destination: './uploads/',
  filename: function (req, file, cb) {
    crypto.pseudoRandomBytes(16, function (err, raw) {
      if (err) return cb(err)

      cb(null, raw.toString('hex') + mime.extension(file.mimetype))
    })
  }
})

var upload = multer({ storage: storage })

(from https://github.com/expressjs/multer/issues/170#issuecomment-123402678)

It assigns a random file name, but keeps the file extension in tact.

---

You should also be using the authorize field in multer, since it looks like you only want files when the user has the correct password. Do something like this:

var upload = multer({ storage: storage }, limits : { fileFilter: authorize }); 

function authorize(req, file, cb) {
    if (req.body.password == PASS) {
        cb(null, true); //accept
    } else { 
        cb(null, false); //reject
    }
}

This will only save the file to disk if the user has inputted the correct password.

Answer 2

You can pass the right parameters for Multer like this in order to save the file extension:

var multer = require('multer');
var path = require('path')

var storage = multer.diskStorage({
  destination: function (req, file, cb) {
    cb(null, 'uploads/')
  },
  filename: function (req, file, cb) {
    cb(null, Date.now() + path.extname(file.originalname)) 
  }
})

var upload = multer({ storage: storage });