[#106] Add chunk uploading

Signed-off-by: Artem Tataurov <a.tataurov@yadro.com>

api/handler/multipart_upload.go

@@ -232,6 +232,27 @@ func (h *handler) UploadPartHandler(w http.ResponseWriter, r *http.Request) {
 		Reader:     r.Body,
 	}
 
+	if api.IsSignedStreamingV4(r) {
+		if decodeContentSize := r.Header.Get(api.AmzDecodedContentLength); len(decodeContentSize) > 0 {
+			_, err := strconv.Atoi(decodeContentSize)
+			if err != nil {
+				h.logAndSendError(w, "cannot parse decode content length information", reqInfo,
+					errors.GetAPIError(errors.ErrMissingContentLength))
+				return
+			}
+		} else {
+			h.logAndSendError(w, "expecting decode content length information", reqInfo,
+				errors.GetAPIError(errors.ErrMissingContentLength))
+			return
+		}
+		chunkReader, err := newSignV4ChunkedReader(r)
+		if err != nil {
+			h.logAndSendError(w, "cannot initialize chunk reader", reqInfo, err)
+			return
+		}
+		p.Reader = chunkReader
+	}
+
 	p.Info.Encryption, err = formEncryptionParams(r)
 	if err != nil {
 		h.logAndSendError(w, "invalid sse headers", reqInfo, err)