s3: add option for "alllowEmptyFolder"

weed/s3api/s3api_objects_list_handlers.go

@@ -264,8 +264,10 @@ func (s3a *S3ApiServer) doListFilerEntries(client filer_pb.SeaweedFilerClient, d
 					}
 				} else {
 					var isEmpty bool
-					if isEmpty, err = s3a.isDirectoryAllEmpty(client, dir, entry.Name); err != nil {
-						glog.Errorf("check empty folder %s: %v", dir, err)
+					if !s3a.option.AllowEmptyFolder {
+						if isEmpty, err = s3a.isDirectoryAllEmpty(client, dir, entry.Name); err != nil {
+							glog.Errorf("check empty folder %s: %v", dir, err)
+						}
 					}
 					if !isEmpty {
 						eachEntryFn(dir, entry)

weed/s3api/s3api_server.go

@@ -20,6 +20,7 @@ type S3ApiServerOption struct {
 	DomainName       string
 	BucketsPath      string
 	GrpcDialOption   grpc.DialOption
+	AllowEmptyFolder bool
 }
 
 type S3ApiServer struct {