The small test provided returned the expected filename with multer@1.4.4, and changed with multer@1.4.4-lts.1.

Same problem after update from 1.4.4 on 1.4.5-lts.1

Multer has nothing to do with it, Busboy has changed something.
mscdex/busboy#20

This solved my problem:

file.originalname = Buffer.from(file.originalname, 'latin1').toString('utf8')

Multer has something to do about this, since it definitely changed behavior in an arguably incompatible way in what looks like a patch revision.

What to do however I'm not sure; either way would be fine (interpreting the utf-8 to be consistent with previous behavior or passing the raw string to not make assumptions about encoding), but I believe this kind of change in a patch is troublesome to users.

Multer has nothing to do with it, Busboy has changed something. mscdex/busboy#20

This solved my problem:

file.originalname = Buffer.from(file.originalname, 'latin1').toString('utf8')

God bless you.

I've managed to make a bodge in my app

    const fileName = Buffer.from(el.originalname, 'latin1').toString('utf8');

because in my case invalid £$ file.txt was becoming invalid £$ file.txt.
Ideally we have this fixed when busboy is fixing that end.
Thanks a lot.

HI, I faced same issue with the filename in Korean. I found out that the issue is relevant to "busboy', especially config property of "defParanCharset." The default value of that property is 'latin1', which means some parameters like non-latin filename in input-form is misdecoded on nodejs side without proper configuration. However, in the "multer" we don't have option to change the config properties of busboy.

I hope the line 28 in '/lib/make-middleware.js' will be changed such as:
busboy = Busboy({ headers: req.headers, limits: limits, preservePath: preservePath, defParamCharset: 'utf8' })

At least, some way to configure busboy through multer module would be required.

This issue is still relevant. Multer should not deviate from utf-8 default. An multer option should be created so that we can influence busboy defParamCharset.

I published a multer-utf8 package on npm that read files as utf8 charset by default.

https://www.npmjs.com/package/multer-utf8

The problem still exists, please fix it quickly

Just to clarify, in Multer 1.4.4 the name was parsed as utf-8, and in Multer 1.4.5-lts.1 it's parsed as latin1?

In that case it seems straight forward to add defParamCharset: 'utf8' so that the new version behaves the same as the previous...

1. Tried both defParamCharset and defCharset - has no effect

multer({
	storage,
	defParamCharset: 'utf8',
	defCharset: 'utf8',
})

2. As far as I see, only selected options are passed from the config to busboy
   https://github.com/expressjs/multer/blob/25794553989a674f4998b32a061dfc9287b23188/index.js#LL11C1-L23C2

@CleyFaye @dvantage thank you very much

why the default Postman is right?

@TiuBen

Postman uses “filename*”, so filename problems do not occur.
But browsers do not use it.

see #1104 (comment)

I've seen another issue related to using "filename*", but there is two problem with that: the browser's formdata does not use this

where can I use filename*

Is this solved ? I still got this issue and Buffer.from(file.originalname, 'latin1').toString('utf8') solves it...