[#307] Filter system metadata

Signed-off-by: Denis Kirillov <denis@nspcc.ru>

api/handler/get.go

@@ -77,6 +77,9 @@ func writeHeaders(h http.Header, info *data.ObjectInfo, tagSetLength int) {
 	h.Set(api.AmzTaggingCount, strconv.Itoa(tagSetLength))
 
 	for key, val := range info.Headers {
+		if layer.IsSystemHeader(key) {
+			continue
+		}
 		h[api.MetadataPrefix+key] = []string{val}
 	}
 }

api/layer/layer.go

@@ -444,7 +444,6 @@ func (n *layer) GetBucketTagging(ctx context.Context, bucketName string) (map[st
 	}
 
 	objInfo, err := n.headSystemObject(ctx, bktInfo, formBucketTagObjectName(bucketName))
-
 	if err != nil && !errors.IsS3Error(err, errors.ErrNoSuchKey) {
 		return nil, err
 	}

api/layer/object.go

@@ -546,6 +546,10 @@ func isSystem(obj *data.ObjectInfo) bool {
 		len(obj.Headers[attrVersionsIgnore]) > 0
 }
 
+func IsSystemHeader(key string) bool {
+	return strings.HasPrefix(key, "S3-")
+}
+
 func trimAfterObjectName(startAfter string, objects []*data.ObjectInfo) []*data.ObjectInfo {
 	if len(objects) != 0 && objects[len(objects)-1].Name <= startAfter {
 		return nil

api/layer/system_object.go

@@ -88,7 +88,10 @@ func (n *layer) putSystemObjectIntoNeoFS(ctx context.Context, p *PutSystemObject
 
 	for k, v := range p.Metadata {
 		attr := object.NewAttribute()
-		attr.SetKey(p.Prefix + k)
+		if !IsSystemHeader(k) {
+			k = p.Prefix + k
+		}
+		attr.SetKey(k)
 		if p.Prefix == tagPrefix && v == "" {
 			v = tagEmptyMark
 		}