Nestjs-form-data not serializing.

[crimson violet]

Hello,
I've implemented nestjs-form-data for managing files and validations but it actually doesn't work .

[brazen comet]

try with raw, json

[crimson violet]

I will upload a file sometimes

[wary flame]

multer doesn't automatically parse the data the same way json will. You'll need some custom @Transform()s for that

[crimson violet]

yeah but nestjs-form-data package provides that feature, does not?

[wary flame]

Not sure honestly. Looks like it uses append-field, so it might depend on how that librarty works. Never worked with nestjs-form-data to be honest

[toxic gate]

i've been using nestjs- form-data in my project as well and what i've figured is that when doing the request as multipart/form-data all values will be received as strings and you have to use @Transform() to handle them in your DTO.

i'm not sure if thats an issue with the library or if its just how multipart/form-data works tbh

[crimson violet]

Thanks, I'm trying this, but how to transform an array?

[wary flame]

How do you send it, how does it come in?

[wary flame]

Remove the validation momentarily to see what the data looks like after busboy parses it

[wary flame]

I believe a JSON.parse() will do for that

[crimson violet]

It's done, thanks for help.

But how it's usually manages file uploads with other types of data. In a single request or multiple (json)?

[wary flame]

Most people I know try to avoid multi file uploads for the complexity of it, but it is a valid use case, so it all just depends

[crimson violet]

is there any option to upload files?

[wary flame]

What do you mean?

[crimson violet]

that it is easier for validations

[wary flame]

Your issue is with how multipart/form-data is parsed. These parsers really exist to handle the binary data of forms and treat absolutely everything as strings. I've not looked into if there is a parser that treats binary as binary and everything else parsed into a JS type like you're wanting

But good news, this workaround exists, and it's honestly not too complex

[crimson violet]

ah okay I understand, thanks for help.

[toxic gate]

@wary flame kinda related to this, how would you recommend dealing with an album picture type thing where a user could upload one or more files?

avoid doing multi file upload on one request and instead do one request for each file?

[wary flame]

It depends on how you want to do the files. Does each file have it's own name and description? Are you just adding a name and description for the album instead? Uploading multiple files at once isn't impossible, nor is it bad, the "difficult" thing is bulk upload of multiple objects with multiple files, because of the way multipart data is formed

[toxic gate]

i see
in this scenario the album would have its own name and description and the files don't have their own info. im currently doing it with nestjs-form-data and uploading multiple files at once but was just curious if there was a better/more recommended way of dealing with these situations