How to limit file size - multipart/form-data

[alexaleluia12]

Problem/Feature Request Summary

Limit file size using multipart/form-data
Related issue:
#66
#23

Environment Information

• koa-body: 4.1.0
• Koa: 2.7.0
• Node.js: 10.15.0

Current Behavior

Allow send file bigger than formLimit option.
Is this a bug ? If i can send a body bigger than defined value. Is this propertie affect the body only in certain conditions ?

Steps to Reproduce

git clone https://github.com/alexaleluia12/koa-upload.git
npm i
npm run start

send a txt file bigger than 1k, using multipart/form-data, pass the file through file field

Expected Behavior

Throw an error

Context (Environment)

I want to send a file to server.

[katanacrimson]

Looks like it's only for urlencoded forms.

Perhaps something for 5.0.0 (ding #139) where we hook up formLimit up to formidible's maxFieldsSize property and then better document how one can limit the actual file upload size limit (which is actually formidible's maxFileSize option.

Would def be a BC breaker though.

[MarkHerhold]

koa-body users formidable to perform file parsing so the option needs to be passed to formidable. I think this behavior is understandably confusing and should probably be addressed in a later release (ref #139).

A few other notes about your sample code:

• I recommend removing the error handler
• Math.random() isn't cryptographically secure, just FYI

I would change the options in your code to:

app.use(koaBody({
    multipart: true,
    json: true,
    formLimit: MAX_BODY,
    textLimit: MAX_BODY,
    formidable: {
        maxFileSize: MAX_BODY
    }
}));

[MarkHerhold]

@damianb ha! you beat me by seconds 😆

[katanacrimson]

Hah.

Anyways, I do think we ought to directly expose our own upload limit property (proxied to formidible's maxFileSize) for something a little easier to work with.