func (sr SimpleRetriever) GetChunked(req *Request, cancel <-chan bool) (*Chunked, error) {
chunkCh := make(chan Chunk, 20)
var finalErr error
chunked := &Chunked{
Err: &finalErr,
Chunks: chunkCh,
}
resp, err := http.DefaultTransport.RoundTrip(proxy.UnmarshalRequest(req.HttpRequest))
if err != nil {
return nil, err
}
if resp.Header.Get("ETag") != req.Etag {
resp.Body.Close()
return nil, fmt.Errorf("ETag doesn't match expected value")
}
chunked.Header = Header{
StatusCode: resp.StatusCode,
Status: resp.Status,
ContentLength: resp.ContentLength,
Header: resp.Header,
}
go func() {
defer resp.Body.Close()
defer close(chunkCh)
offset := 0
finalErr = split.SplitFun(resp.Body, func(buf []byte) error {
digest := sha256.New()
if n, err := digest.Write(buf); err != nil || n < len(buf) {
if err == nil {
err = io.ErrShortWrite
}
return err
}
chunk := Chunk{
Offset: offset,
Length: len(buf),
Digest: digest.Sum(nil),
}
select {
case <-cancel:
return ErrCancel
default:
}
select {
case chunkCh <- chunk:
case <-cancel:
return ErrCancel
}
offset += len(buf)
return nil
})
}()
return chunked, nil
}
func getContents(req *proxy.Request, r byteRange) ([]byte, error) {
httpReq := proxy.UnmarshalRequest(req)
httpReq.Header.Set("Range", fmt.Sprintf("bytes=%d-%d", r.begin, r.end-1))
resp, err := http.DefaultTransport.RoundTrip(httpReq)
if err != nil {
return nil, err
}
defer resp.Body.Close()
if resp.Header.Get("Content-Range") == "" {
// TODO: Do something more intelligent (check earlier if supported and check Content-Range's value)
return nil, fmt.Errorf("No Content-Range in response")
}
contents, err := ioutil.ReadAll(resp.Body)
if len(contents) != int(r.end-r.begin) {
return nil, fmt.Errorf("Wrong length of range response %d %d %d", len(contents), r.end, r.begin)
}
return contents, err
}