fileUpload directive does not respect Content-Transfer-Encoding header

[satorg]

Consider the example:

(post & path("upload")) {
  fileUpload("myFile") { case (FileInfo(fieldName, fileName, contentType), fileSource) =>
    // handle this request somehow
  }
}

and this curl request:

curl -F 'myFile=@path/to/some/file.dat;encoder=base64' http://localhost/upload

It creates an HTTP request which looks like the following:

POST /upload HTTP/1.1
Host: localhost
Content-Length: ???
Content-Type: multipart/form-data; boundary=------------------------abcdefghijk

--------------------------abcdefghijk
Content-Disposition: form-data; name="myFile"; filename="file.dat"
Content-Transfer-Encoding: base64

GuCpMEOL1qXwbDU9e4gqdz6EO9czFKzGV2b+i7dOzZZeAmQpyQBkM7hFXzPmZx4o
es0i0I5jWjReuvAWq25AKeK4XkgRIv7pOWPMFrX8wE4QyVPBLVoNz9uRBW81GSUb
NMnzYWQ9QdCcLOvzqwGdHWbCn64/h2ASX2QGoSP6KQ0=
--------------------------abcdefghijk--

The fileUpload ignores the Content-Transfer-Encoding scheme and provides the body part data as base64-encoded bytes. However, it does not let the client code know which encoding scheme was actually used upon the request.

If different encoding schemes can be used for a single route backed by the fileUpload directive, then there's no way to handle uploading files correctly.