func guessMimeType(res cmds.Response) (string, error) {
// Try to guess mimeType from the encoding option
enc, found, err := res.Request().Option(cmds.EncShort).String()
if err != nil {
return "", err
}
if !found {
return "", errors.New("no encoding option set")
}
return mimeTypes[enc], nil
}
func sendResponse(w http.ResponseWriter, r *http.Request, res cmds.Response, req cmds.Request) {
mime, err := guessMimeType(res)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
status := http.StatusOK
// if response contains an error, write an HTTP error status code
if e := res.Error(); e != nil {
if e.Code == cmds.ErrClient {
status = http.StatusBadRequest
} else {
status = http.StatusInternalServerError
}
// NOTE: The error will actually be written out by the reader below
}
out, err := res.Reader()
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
h := w.Header()
if res.Length() > 0 {
h.Set(contentLengthHeader, strconv.FormatUint(res.Length(), 10))
}
if _, ok := res.Output().(io.Reader); ok {
// we don't set the Content-Type for streams, so that browsers can MIME-sniff the type themselves
// we set this header so clients have a way to know this is an output stream
// (not marshalled command output)
mime = ""
h.Set(streamHeader, "1")
}
// if output is a channel and user requested streaming channels,
// use chunk copier for the output
_, isChan := res.Output().(chan interface{})
if !isChan {
_, isChan = res.Output().(<-chan interface{})
}
streamChans, _, _ := req.Option("stream-channels").Bool()
if isChan {
h.Set(channelHeader, "1")
if streamChans {
// streaming output from a channel will always be json objects
mime = applicationJson
}
}
if mime != "" {
h.Set(contentTypeHeader, mime)
}
h.Set(transferEncodingHeader, "chunked")
if r.Method == "HEAD" { // after all the headers.
return
}
if err := writeResponse(status, w, out); err != nil {
if strings.Contains(err.Error(), "broken pipe") {
// log.Info("client disconnect while writing stream ", err)
return
}
// log.Error("error while writing stream ", err)
}
}