Validation pipe does not work when data is passed via multipartform-data

[uneven kite]

For context, im using multipartform-data because i need to pass some file data along with the POST request.

The json string from the body of the request is not being deserialized into the CreateProductDto

Here's an example of the issue I'm facing:
@CreateDecorators('/product') createProduct( @Body('document') createProductDto: CreateProductDto, @UploadedFiles() files: CreateFilesDto, ) { console.log(createPolymerDto.constructor.name); // <- returns string instead of CreateProductDto }

[neat herald]

Does it goes go to req.body? I guess not

[uneven kite]

Hey apologies for the late response, the json data does get extracted by the @body decorator, but the issue is that the data is not being serialized into the CreateProductDto as how i would expect it to behave

[hollow gazelle]

That sounds like multer isn't deserializing some of the data. Can you show what a request looks like? If you use just @Body() can you show that that becomes?

[uneven kite]

Here's what the object extracted from the @body without the 'document'
[Object: null prototype] { document: '{"product":{"product_name":"sad","sample":false,"product_type":"KSJL"},"measurements":[]}', tds_file: 'undefined', msds_file: 'undefined',}

[hollow gazelle]

Yeah, looks like it's a raw JSON string instead of an object. You'd probably need to JSON.parse() the document value

[uneven kite]

This is how i sent the request from the frontend:

[uneven kite]

is there a way to continue to tap on nest's inbuilt transformer?

[hollow gazelle]

What if you don't use a Blob of application/json type in your client code and just have document be a regular object?

[uneven kite]

Hmm, is this what you mean? ( I don't think I can pass a regular javascript object to formdata:

If i JSON.stringify(bodyData) , it will still not get deserialized with the @body decorator

[hollow gazelle]

Ah, okay. Well I think the blob is unnecessary but you may still need the stringified body data

[uneven kite]

Yep!

do you think there's a solution that's built into nestjs to properly deserialize the json data? Or do I just go ahead with parsing it and transforming the data into the DTO myself

[uneven kite]

I think I would need to somehow call JSON.parse before the request is being handled by the class-transformer, do you happen to know how i could do that?

[hollow gazelle]

An interceptor would work. They get called before pipes do

[uneven kite]

Ah okay

[uneven kite]

Tried to use an interceptor but seems difficult to implement (have limited knowledge on that) I decided to place a global pipe, just ontop of the validation pipe

seems to work now