Serialization seems to contain wrong data about multipart-kit HOT 5 OPEN

Hi @dalu93, unfortunately this library's 4.0.0 version is no longer being maintained. It was merged into vapor/vapor a while ago: https://github.com/vapor/vapor/tree/master/Sources/Vapor/Multipart.

Eventually my goal is to split the package back out again and formally pitch this to the swift server work group's package index. Until then, you can access the MultipartParser and MultipartSerializer as part of the Vapor module.

That said, I'm not sure why the length is about 2x longer via MultipartKit here. Seeing the full output (attached as a .txt or something) could help. If this bug exists in the vapor/vapor version of this code I'm happy to fix it.

from multipart-kit.

Hi @tanner0101,

Vapor is not an option for us since we are planning to create a very small CLI tool and importing the whole Vapor product is going to be heavy and useless.

I created, however, an example repository where you can see the error: https://github.com/dalu93/multipartkit-issue
When running through Xcode, set the environment variable FILE_PATH to your own file path (the file is included in the project as well)

from multipart-kit.

Hi @tanner0101 have you had chance to have a look at it? Unfortunately I cannot run Vapor locally because I'm on MacOS Mojave (10.14) and Vapor only supports 10.15+.

I was anyway able to verify few things:

There is a difference in terms of bytes between the two methods, using MultipartKit the data is almost 2x the data I get from using my small helper.
So I tried to replicate as much as possible what MultipartKit is doing

1. I created my multipartData using my small helper

let multipartData = try MultipartHelper().multipart(
    from: fileUrl.path,
    partName: "file",
    boundary: boundary
)

2. I created a new ByteBuffer and I wrote the data there

var buffer = ByteBufferAllocator().buffer(capacity: 0)
buffer.writeBytes(multipartData)

3. I converted the buffer to a String

let bufferString = String(decoding: buffer.readableBytesView, as: UTF8.self)

4. I expected to have multipartData.count equal to Data(bufferString.utf8).count

print(Data(bufferString.utf8).count == multipartData.count) // got `false`

When I compare the string result of this operation (bufferString) to the string I get directly using MultipartSerializer, they are identical

let body = try MultipartSerializer().serialize(
    parts: [multipart],
    boundary: boundary
)

print(body == bufferString) // got `true`

from multipart-kit.

There are two serialization methods:

The former method you are using uses String internally so it can corrupt input data.
You have to use the latter.

from multipart-kit.

@dalu93 are you seeing this in the latest release? We've rewritten the parser in Swift so hopefully this issue has been resolved

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