form-data file is empty with node version 14.1.0

[chwo]

Description

I am doing a multipart/form-data POST Request with fields and a file in the body.

When I try to access the file in the form.parse function, the files property is empty.

const form = new multiparty.Form();
form.parse(req, (error, fields, files) => {
    console.log(files) // -> is empty: {}
});

I tried debugging it and noticed that

multiparty/index.js

Line 134 in f4c2ea6

self.on('close', function() {

is called before

multiparty/index.js

Line 130 in f4c2ea6

self.on('file', function(name, file) {

This order occurs with node version 14.1.0 whereas for example with node version 12.0.0 the order is the opposite and the files property contains the file.

Environment

• multiparty version 4.2.1
• node version 14.1.0

[dougwilson]

Hi @chwo thank you for the report. It is indeed a bug due to some streams changes in Node.js 14. I am working to get it all fixed up. You can look though expressjs/connect-multiparty#29 if you wanted to know about some of the background, but otherwise I'll use this issue as the tracker for the Node.js 14 fix in multiparty itself 👍

[hkumar4]

Hi, Can someone please update when this issue would be fixed? I see that the form.on('close') fires twice since node 14. Once with empty files and then with files populated. Thank you for looking into this.

[barisusakli]

Hi @dougwilson, looks like you fixed this, any eta on a new release for this and connect-multiparty?

[dougwilson]

Hi @barisusakli indeed, I fixed both issues with the Node.js changes: max size limit broken and files empty. The first change was an issue with a dependency being broken and it looks like it will just never be fixed, so that was a bit more involved change to test. I think it is working well, but if not we'll just field any reported bugs. I'm going to land them here now, sorry for the delay.

[dougwilson]

The fix is merged into master. Please feel free to test ahead of time. I try not to release and then go to sleep, so will release first thing in the morning.

[barisusakli]

@dougwilson from my testing our upload tests pass by using the latest code from multiparty with node 14.6.0 and connect-multiparty 2.2.0

[dougwilson]

Published as patch version 4.2.2

[barisusakli]

👍 waiting on connect-multiparty

[dougwilson]

@barisusakli it is picked up automatically as the package.json is ~4.2.1