mime/multipart library does not support setting content-type for individual fields

[gopherbot]

by jsgoecke:

This code:

file, err := os.Open("helloWorld.wav")
buf := new(bytes.Buffer)
writer := multipart.NewWriter(buf)
audioFile, _ := writer.CreateFormFile("file", "helloWorld.wav")
_, err = io.Copy(audioFile, file)
if err != nil {
     return nil, 0, err
}
writer.Close()

Produces a Content-Type of 'application/octet-stream' when it creates the field. There
are cases where you want to set the Content-Type to something like 'audio/wav' and other
types. You may do some things by hand like this as a work around:

http://play.golang.org/p/p5U_puIvkg

It would be appropriate to have the multipart library support setting the Content-Type
by individual form field.

[bradfitz]

Comment 1:

We have to draw the line somewhere.
I think your little function is acceptable.
Others will want different headers, and we can't provide every helper method for every
combination of possible headers.

Status changed to WorkingAsIntended.