[#227] Add versionID header after complete multipart

Signed-off-by: Marina Biryukova <m.biryukova@yadro.com>

api/handler/multipart_upload.go

@@ -3,7 +3,6 @@ package handler
 import (
 	"encoding/xml"
 	"fmt"
-	"io"
 	"net/http"
 	"net/url"
 	"strconv"
@@ -399,6 +398,12 @@ func (h *handler) CompleteMultipartUploadHandler(w http.ResponseWriter, r *http.
 		return
 	}
 
+	settings, err := h.obj.GetBucketSettings(r.Context(), bktInfo)
+	if err != nil {
+		h.logAndSendError(w, "could not get bucket settings", reqInfo, err)
+		return
+	}
+
 	var (
 		uploadID   = r.URL.Query().Get(uploadIDHeaderName)
 		uploadInfo = &layer.UploadInfoParams{
@@ -425,29 +430,12 @@ func (h *handler) CompleteMultipartUploadHandler(w http.ResponseWriter, r *http.
 		Parts: reqBody.Parts,
 	}
 
-	// Next operations might take some time, so we want to keep client's
-	// connection alive. To do so, gateway sends periodic white spaces
-	// back to the client the same way as Amazon S3 service does.
-	stopPeriodicResponseWriter := periodicXMLWriter(w, h.cfg.CompleteMultipartKeepalive())
-
 	// Start complete multipart upload which may take some time to fetch object
 	// and re-upload it part by part.
 	objInfo, err := h.completeMultipartUpload(r, c, bktInfo, reqInfo)
 
-	// Stop periodic writer as complete multipart upload is finished
-	// successfully or not.
-	headerIsWritten := stopPeriodicResponseWriter()
-
-	responseWriter := middleware.EncodeToResponse
-	errLogger := h.logAndSendError
-	// Do not send XML and HTTP headers if periodic writer was invoked at this point.
-	if headerIsWritten {
-		responseWriter = middleware.EncodeToResponseNoHeader
-		errLogger = h.logAndSendErrorNoHeader
-	}
-
 	if err != nil {
-		errLogger(w, "complete multipart error", reqInfo, err, additional...)
+		h.logAndSendError(w, "complete multipart error", reqInfo, err, additional...)
 		return
 	}
 
@@ -457,12 +445,12 @@ func (h *handler) CompleteMultipartUploadHandler(w http.ResponseWriter, r *http.
 		ETag:   objInfo.ETag(h.cfg.MD5Enabled()),
 	}
 
-	// Here we previously set api.AmzVersionID header for versioned bucket.
-	// It is not possible after #60, because of periodic white
-	// space XML writer to keep connection with the client.
+	if settings.VersioningEnabled() {
+		w.Header().Set(api.AmzVersionID, objInfo.VersionID())
+	}
 
-	if err = responseWriter(w, response); err != nil {
-		errLogger(w, "something went wrong", reqInfo, err, additional...)
+	if err = middleware.EncodeToResponse(w, response); err != nil {
+		h.logAndSendError(w, "something went wrong", reqInfo, err, additional...)
 	}
 }
 
@@ -730,53 +718,3 @@ func encodeListPartsToResponse(info *layer.ListPartsInfo, params *layer.ListPart
 		StorageClass:     api.DefaultStorageClass,
 	}
 }
-
-// periodicXMLWriter creates go routine to write xml header and whitespaces
-// over time to avoid connection drop from the client. To work properly,
-// pass `http.ResponseWriter` with implemented `http.Flusher` interface.
-// Returns stop function which returns boolean if writer has been used
-// during goroutine execution. To disable writer, pass 0 duration value.
-func periodicXMLWriter(w io.Writer, dur time.Duration) (stop func() bool) {
-	if dur == 0 { // 0 duration disables periodic writer
-		return func() bool { return false }
-	}
-
-	whitespaceChar := []byte(" ")
-	closer := make(chan struct{})
-	done := make(chan struct{})
-	headerWritten := false
-
-	go func() {
-		defer close(done)
-
-		tick := time.NewTicker(dur)
-		defer tick.Stop()
-
-		for {
-			select {
-			case <-tick.C:
-				if !headerWritten {
-					_, err := w.Write([]byte(xml.Header))
-					headerWritten = err == nil
-				}
-				_, err := w.Write(whitespaceChar)
-				if err != nil {
-					return // is there anything we can do better than ignore error?
-				}
-				if buffered, ok := w.(http.Flusher); ok {
-					buffered.Flush()
-				}
-			case <-closer:
-				return
-			}
-		}
-	}()
-
-	stop = func() bool {
-		close(closer)
-		<-done // wait for goroutine to stop
-		return headerWritten
-	}
-
-	return stop
-}