Why is the Formidable `form.parse` callback not running in Express?

Question

I am using the formidable package to handle file uploads on my server. This is my express.js app code:

var formidable = require("formidable"),
  http = require("http"),
  util = require("util");
app.post("/admin/uploads", function (req, res) {
  console.log(req.files, req.fields); //It prints
  var form = new formidable.IncomingForm();
  form.parse(req, function (err, fields, files) {
    console.log("Inside form parse."); //its not printing
    console.log(err, fields, files); //its not printing
  });
  form.on("file", function (name, file) {
    console.log("file=" + file);
  }); //its not printing
  form.on("error", function (err) {
    console.log(err);
  }); //its not printing
  form.on("aborted", function () {
    console.log("Aborted");
  }); //its not printing
  console.log(form); //it prints
});

In the above code, the form.parse and form.on callbacks are never run. How can I solve this issue?

Jacob · Answer 1 · 2022-08-29T01:17:42.977

30

I had the same problem when using Next.js API routes with Formidable. Like the other answer points out, you have to remove the body parser. In Next.js, you can export a config object and disable body parsing.

// /pages/api/form.js
import { IncomingForm } from "formidable";

export default function handler(req, res) {
  // formidable logic
}

// VV important VV
export const config = {
  api: {
    bodyParser: false,
  },
};

edited Aug 29 '22 at 01:17

answered Aug 30 '21 at 18:28

Jacob

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4

This answer was actually helpful for me. One thing, as a Next.js newbie I tried to export the config from my current file. You actually need to export it **from the api handler** to work – Alexander Santos Mar 20 '23 at 21:17
This worked for me! Thanks! – Andrea Roveroni Aug 29 '23 at 16:52

score 12 · Answer 2 · answered Jan 22 '13 at 13:22

12

It might be that you need to remove body parser

delete app.use(express.bodyParser());

answered Jan 22 '13 at 13:22

Marwan Roushdy

1,214
12
25

That was exactly the reason in my case. Thanks a lot! – James Jul 22 '13 at 11:18

score 1 · Answer 3 · edited Jul 25 '15 at 13:30

1

Please add the error handlers and send the error message otherwise it is hard to get an answer.

form.on('error', function(err) { console.log(err); });
form.on('aborted', function() { console.log('Aborted'); });

See the formidable documentation : doc

edited Jul 25 '15 at 13:30

Falko

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answered Nov 15 '12 at 14:13

tolgaio

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18

Nothing is printing inside form methods. – R J. Nov 16 '12 at 05:56

score 1 · Answer 4 · answered Jan 10 '15 at 11:00

Call form.parse(...) after all on(...) events.

app.post('/admin/uploads', function(req, res) {
    var form = new formidable.IncomingForm(); 
    form.on('file', function(name, file) { });
    form.on('error', function(err) { });
    form.on('aborted', function() { });
    form.parse(req, function(err, fields, files) { });
});

score 1 · Answer 5 · answered Mar 23 '20 at 20:57

1

I forgot to add enctype="multipart/form-data" to my html form, maybe this will help somebody :)

answered Mar 23 '20 at 20:57

Tim Haag

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That is a pretty general pitfall: please argue why this might well have been the problem here, given the absence of client side code. – greybeard Mar 23 '20 at 21:46

score 0 · Answer 6 · edited Jul 08 '22 at 14:44

0

Even if you remove body-parser and use express.json() etc... you will have same error.

The problem is that express.raw() is causing trouble remove it and it works!

edited Jul 08 '22 at 14:44

Tyler2P

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answered Jul 08 '22 at 08:28

Rajat Khatri

1
1

Why is the Formidable `form.parse` callback not running in Express?

6 Answers6