func (rx *ResumableUpload) transferChunks(ctx context.Context) (*http.Response, error) {
var start int64
var err error
res := &http.Response{}
if rx.started {
start, res, err = rx.transferStatus(ctx)
if err != nil || res.StatusCode != statusResumeIncomplete {
return res, err
}
}
rx.started = true
for {
select { // Check for cancellation
case <-ctx.Done():
res.StatusCode = http.StatusRequestTimeout
return res, ctx.Err()
default:
}
reqSize := rx.ContentLength - start
if reqSize > chunkSize {
reqSize = chunkSize
}
r := io.NewSectionReader(rx.Media, start, reqSize)
req, _ := http.NewRequest("POST", rx.URI, r)
req.ContentLength = reqSize
req.Header.Set("Content-Range", fmt.Sprintf("bytes %v-%v/%v", start, start+reqSize-1, rx.ContentLength))
req.Header.Set("Content-Type", rx.MediaType)
req.Header.Set("User-Agent", rx.UserAgent)
res, err = ctxhttp.Do(ctx, rx.Client, req)
start += reqSize
if err == nil && (res.StatusCode == statusResumeIncomplete || res.StatusCode == http.StatusOK) {
rx.mu.Lock()
rx.progress = start // keep track of number of bytes sent so far
rx.mu.Unlock()
if rx.Callback != nil {
rx.Callback(start, rx.ContentLength)
}
}
if err != nil || res.StatusCode != statusResumeIncomplete {
break
}
}
return res, err
}
func (rx *ResumableUpload) transferStatus(ctx context.Context) (int64, *http.Response, error) {
req, _ := http.NewRequest("POST", rx.URI, nil)
req.ContentLength = 0
req.Header.Set("User-Agent", rx.UserAgent)
req.Header.Set("Content-Range", fmt.Sprintf("bytes */%v", rx.ContentLength))
res, err := ctxhttp.Do(ctx, rx.Client, req)
if err != nil || res.StatusCode != statusResumeIncomplete {
return 0, res, err
}
var start int64
if m := rangeRE.FindStringSubmatch(res.Header.Get("Range")); len(m) == 2 {
start, err = strconv.ParseInt(m[1], 10, 64)
if err != nil {
return 0, nil, fmt.Errorf("unable to parse range size %v", m[1])
}
start += 1 // Start at the next byte
}
return start, res, nil
}