How to provide the content-type for the Upload file?

[kurennoy16]

How to set the content-type for the Upload file?

Its default value: application/octet-stream, but I would like to provide a custom one (e.g. "text/csv").

[kurennoy16]

Ok, I've found a workaround.

The client is declared as the following:
type Client struct { Transport transport.Transport extensions }

transport.Transport is a Interface.
type Transport interface { Request(req Request) Response }

So we are able to define the custom transport class to inject.
I simply copypasted the transport_http.go file with a minor replacement in the func (h *Http) formReq(gqlreq transport.Request, bodyb []byte) (*http.Request, error):

for p, f := range h.collectUploads("variables", gqlreq.Variables) {
	k := fmt.Sprintf("%v", i)

	h := make(textproto.MIMEHeader)
	h.Set("Content-Disposition", fmt.Sprintf(`form-data; name="%s"; filename="%s"`, k, f.Name))
	h.Set("Content-Type", mime.TypeByExtension(path.Ext(f.Name)))

	fw, err := w.CreatePart(h)
	if err != nil {
		return nil, err
	}

	// Write file to field
	if _, err := io.Copy(fw, f.File); err != nil {
		return nil, err
	}

	filesMap[k] = []string{p}
	i++
}