express.js multiple file upload callback

Question

I'm new to node.js & express.js, so... I want to upload multiple files, and later work with them. But i need to send a response (ok or error status) after all my files have been saved on disk, or if one failed - then send an error callback.

Now I have such code:

var express = require('express');
var router = express.Router();

var multipart = require('connect-multiparty');
var multipartMiddleware = multipart();

var fs = require('fs');

router.post('/upload', multipartMiddleware, function(req, res) {
  var reqBody = req.body;
  var reqFiles = req.files;

  saveFile(reqFiles, 'main.xlsx', function(err) {
    if (err) {
      res.status(404).send('');
      return;
    }

    res.send('Multi-File File uploaded');
  }
});

function saveFile(file, name, callback) {
  fs.writeFile('./uploads/' + name, file, callback);
}

but how can i change my code to parse this:

router.post('/upload', multipartMiddleware, function(req, res) {
  var reqBody = req.body;
  var reqFiles = req.files;

  saveFile(reqFiles['files'][0], 'main.xlsx', function(err) {
    if (err) {
      res.status(404).send('');
      return;
    }
  }
  saveFile(reqFiles['files'][1], 'second.xlsx', function(err) {
    if (err) {
      res.status(404).send('');
      return;
    }
  }

  res.send(''); // only after first two fileUploaders have finished
});

function saveFile(file, name, callback) {
  fs.writeFile('./uploads/' + name, file, callback);
}

dzm · Accepted Answer · 2017-11-06 16:04:32Z

2

You need to iterate through req.files. You can use async library.

For example:

async.each(req.files, function(file, callback) {
  saveFile(file, file.name, callback)
}, function(err) {
  res.send('')
})

answered Nov 6, 2017 at 16:04

dzm

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5 Comments

byCoder Over a year ago

where should i respond with ok status?

dzm Over a year ago

In the callback for the async function. Where i have res.send('')

dzm Over a year ago

Basically what it's doing is there's the initial callback with (file, callback) this is called for each file. Once all files are processed, your final callback with res.send('') will be called, you can handle your errors in the final callback as well.

byCoder Over a year ago

var express = require('express'); var router = express.Router();  var multiparty = require('multiparty');  var fs = require('fs'); var async = require("async");

byCoder Over a year ago

router.post('/upload', function(req, res) {   var form = new multiparty.Form();    form.parse(req, function(err, fields, files) {     async.each(files, function(file, callback) {        saveFile(file[0], file[0].originalFilename, function(err) {         if (err) {           res.status(404).send('File not uploaded');           return;         }       });     }, function(err) {       res.send('');     })   }); });  function saveFile(file, name, callback) {   fs.writeFile('./' + name, file, callback); }

should be like this?

ktilcu · Accepted Answer · 2017-11-06 16:06:05Z

1

The module recommends not using this. Use the multiparty module directly.
When you have the list of files they will also have file names. you can loop through those and save each file asynchronously. Then respond. Take a peek here

answered Nov 6, 2017 at 16:06

ktilcu

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4 Comments

ktilcu Over a year ago

Exactly. The module says don't use this module.

byCoder Over a year ago

router.post('/upload', function(req, res) {   var form = new multiparty.Form();    form.parse(req, function(err, fields, files) {     async.each(files, function(file, callback) {        saveFile(file[0], file[0].originalFilename, function(err) {         if (err) {           res.status(404).send('File not uploaded');           return;         }       });     }, function(err) {       res.send('');     })   }); });  function saveFile(file, name, callback) {   fs.writeFile('./' + name, file, callback); }

should be like this?

byCoder Over a year ago

var express = require('express'); var router = express.Router();  var multiparty = require('multiparty');  var fs = require('fs'); var async = require("async");

ktilcu Over a year ago

You would need to build the middleware yourself but multiparty is pretty straightforward.

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