maxFiles options doesn't work

[bottom-up-ai]

Support plan

• Which support plan is this issue covered by? (Community, Sponsor, Enterprise): Community
• Currently blocking your project/work? (yes/no): yes
• Affecting a production system? (yes/no): no

Context

• Node.js version: v16.17.0
• Release Line of Formidable (Legacy, Current, Next): Current
• Formidable exact version: ^2.0.1
• Environment (node, browser, native, OS): node
• Used with (popular names of modules): express

What are you trying to achieve or the steps to reproduce?

I try to limit the maxFiles option to 1, but when I upload 3 files, the 3 get uploaded in the corresponding folder.

const form = formidable({
        uploadDir: `${__dirname}/uploads`,
        maxFiles: 1
});
   
form.parse(req, (err, fields, files) => {
        console.log('ERR', err)
        console.log('FIELDS', fields)
        console.log('FILES', files)
});

What was the result you got?

3 files uploaded in folder

What result did you expect?

1 file uploaded in folder

[bottom-up-ai]

Temporary fix :

let countFileUploaded = 0;

const form = formidable({
        uploadDir: `${__dirname}/uploads`,
        keepExtensions: true,
        // maxFiles: 1,
        filter: () => {
            if (countFileUploaded === 1) return false;

            countFileUploaded += 1;

            return true;
        }
});

[GrosSacASac]

Try again with version 3

[bottom-up-ai]

It breaks my application with version 3, as I'm using CommonJS instead of ESModule.

Will you add support for both CJS & ESM ?

EDIT :

I created another project for testing purposes.

It doesn't seem to work perfectly though.

Scenario 1 :

const form = formidable({
        uploadDir: `./uploads`,
        maxFiles: 1
});

I try to upload 4 files, only 1 gets uploaded : Success.

Scenario 2 :

const form = formidable({
        uploadDir: `./uploads`,
        maxFiles: 2
});

I try to upload 4 files, only 1 gets uploaded : Failure.

Scenario 3 :

const form = formidable({
        uploadDir: `./uploads`,
        maxFiles: 3
});

I try to upload 4 files, only 2 get uploaded : Failure.

Scenario 4 :

const form = formidable({
        uploadDir: `./uploads`,
        maxFiles: 4
});

I try to upload 4 files, only 4 get uploaded : Success.

Scenario 5 :

const form = formidable({
        uploadDir: `./uploads`,
        maxFiles: 5
});

I try to upload 5 files, only 4 get uploaded : Failure.

[tunnckoCore]

@bottom-up-ai ha, that looks very weird, definitely.

As about CJS support... I don't want to, but unfortunately seems like we should and we will...

[GrosSacASac]

If the number of files uploaded is greater than the max, the whole form is going to error. By the time that happens there maybe a lower number of files written to disk. The files that are ongoing are cancelled.

That is why
Scenario 2 :

const form = formidable({
uploadDir: ./uploads,
maxFiles: 2
});

I try to upload 4 files, only 1 gets uploaded : Failure.
When formidable received the 3rd file the second one still being written to disk is cancelled.

As for scenario 5 I was not able to reproduce it. Please provide a repro case.

[GrosSacASac]

To make formidable not error use the filter option instead. If it does not error it will not cancel ongoing write operations, which means you will have exactly the maximum files uploaded