Multiple file upload on express js with multer returns empty array

Question

I am building an app on Glitch with express js which requires the user to upload multiple files. Here is my code:

  var express = require('express');
var cors= require('cors');
var bodyParser= require('body-parser');
var contexts= require('./contexts');
var path= require('path');
var fileUpload= require('express-fileupload');
var multer= require('multer');
var upload = multer();

var app = express();

app.use(cors());
app.use(bodyParser.json());
app.use(fileUpload());

app.set('view engine', 'ejs');
app.set('views', 'views');
app.use(express.static('views/'));
//here express-fileuploads works fine
app.post('/getcontexts', function (req,res) {
   var context=contexts.get(req.files.file.data.toString());
   res.render('rast', {length: context.length, content : context});    
     });

//this is when I get an empty array 
   app.post('/getrast', upload.array('rastfiles'), function (req, res) {
  
     res.json({data: req.files});
     });

   var listener = app.listen(process.env.PORT, function () {
    console.log('SERVER STARTED ON PORT ' + listener.address().port);
   });

and here is the ejs form I use:

        <form action="/getrast" method="POST" enctype="multipart/form-data">
        <label for="rastfiles">Please select your Rast genome files with .txt extension</label>
        <br>
        <input type="file" id="file" name="rastfiles" class="inputFile" multiple>
        <br>
        <input type="submit" value="Run" id="sub">
      </form>

I already used express-fileupload to upload a single file and it worked just fine. However, when I use multer to upload multiple files I get and empty array when logging req,files into the console. Any idea why this might be happening?

I'd really appreciate any help. Thanks!

Daniel Hernandez · Accepted Answer · 2018-01-04 19:29:56Z

2

The reason why multer was not working is because express-fileupload was already being used as middleware for file uploading, so commenting out this line:

  app.use(fileUpload())

fixed the problem for me.

answered Jan 4, 2018 at 19:29

Daniel Hernandez

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podcastfan88 Over a year ago

This was a huge save for me. Single file upload with multer was working fine but for some reason changing it to any or array returned empty. Dueling file uploading middleware was to blame. Thanks.

YouneL · Accepted Answer · 2018-01-04 18:41:59Z

0

This is from multer doc:

Multer accepts an options object, the most basic of which is the dest property, which tells Multer where to upload the files. In case you omit the options object, the files will be kept in memory and never written to disk.

that's mean you need to define at least dest option:

var upload = multer({ dest: 'uploads/' });

answered Jan 4, 2018 at 18:41

YouneL

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1 Comment

Daniel Hernandez Over a year ago

Thanks for your response. I just added that but the problem persists. I logged req and there is nothing in the files array.

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