[#619] Filter system metadata

Signed-off-by: Angira Kekteeva <kira@nspcc.ru>

api/headers.go

@@ -3,6 +3,7 @@ package api
 // Standard S3 HTTP request/response constants.
 const (
 	MetadataPrefix            = "X-Amz-Meta-"
+	NeoFSSystemMetadataPrefix = "S3-"
 	AmzMetadataDirective      = "X-Amz-Metadata-Directive"
 	AmzVersionID              = "X-Amz-Version-Id"
 	AmzTaggingCount           = "X-Amz-Tagging-Count"
@@ -88,3 +89,13 @@ var ResponseModifiers = map[string]string{
 	"response-content-disposition": ContentDisposition,
 	"response-content-encoding":    ContentEncoding,
 }
+
+var SystemMetadata = map[string]struct{}{
+	Date:               {},
+	CacheControl:       {},
+	ContentDisposition: {},
+	ContentLength:      {},
+	ContentType:        {},
+	LastModified:       {},
+	ETag:               {},
+}

api/layer/object.go

@@ -613,7 +613,8 @@ func (n *layer) getAllObjectsVersions(ctx context.Context, bkt *data.BucketInfo,
 }
 
 func IsSystemHeader(key string) bool {
-	return strings.HasPrefix(key, "S3-")
+	_, ok := api.SystemMetadata[key]
+	return ok || strings.HasPrefix(key, api.NeoFSSystemMetadataPrefix)
 }
 
 func shouldSkip(node *data.NodeVersion, p allObjectParams, existed map[string]struct{}) bool {