layer: Return unsupported error if meta parameter is empty

Closes #846.

Signed-off-by: Evgenii Baidakov <[email protected]>

CHANGELOG.md

@@ -4,6 +4,9 @@ This document outlines major changes between releases.
 
 ## [Unreleased]
 
+### Added
+- Passing an empty meta parameter value raises "Your metadata headers are not supported." error.
+
 ## [0.29.0] - 2023-09-28
 
 ### Added

api/handler/util.go

@@ -39,6 +39,10 @@ func transformToS3Error(err error) error {
 		return s3errors.GetAPIError(s3errors.ErrAccessDenied)
 	}
 
+	if errorsStd.Is(err, layer.ErrMetaEmptyParameterValue) {
+		return s3errors.GetAPIError(s3errors.ErrUnsupportedMetadata)
+	}
+
 	return s3errors.GetAPIError(s3errors.ErrInternalError)
 }
 

api/layer/neofs.go

@@ -127,6 +127,9 @@ type PrmObjectDelete struct {
 // ErrAccessDenied is returned from NeoFS in case of access violation.
 var ErrAccessDenied = errors.New("access denied")
 
+// ErrMetaEmptyParameterValue describes situation when meta parameter was passed but with empty value.
+var ErrMetaEmptyParameterValue = errors.New("meta empty parameter value")
+
 // NeoFS represents virtual connection to NeoFS network.
 type NeoFS interface {
 	// CreateContainer creates and saves parameterized container in NeoFS.

api/layer/object.go

@@ -183,6 +183,8 @@ func ParseCompletedPartHeader(hdr string) (*Part, error) {
 }
 
 // PutObject stores object into NeoFS, took payload from io.Reader.
+//
+// Returns [ErrMetaEmptyParameterValue] error if any attribute parameter is empty.
 func (n *layer) PutObject(ctx context.Context, p *PutObjectParams) (*data.ExtendedObjectInfo, error) {
 	owner := n.Owner(ctx)
 
@@ -240,6 +242,10 @@ func (n *layer) PutObject(ctx context.Context, p *PutObjectParams) (*data.Extend
 	prm.Attributes = make([][2]string, 0, len(p.Header))
 
 	for k, v := range p.Header {
+		if v == "" {
+			return nil, ErrMetaEmptyParameterValue
+		}
+
 		prm.Attributes = append(prm.Attributes, [2]string{k, v})
 	}
 

docs/aws_s3_compat.md

@@ -255,3 +255,9 @@ See also `GetObject` and other method parameters.
 | 🔵 | DeleteBucketWebsite |          |
 | 🔵 | GetBucketWebsite    |          |
 | 🔵 | PutBucketWebsite    |          |
+
+
+## Metadata
+
+Each meta parameter value must be non-empty. If any parameter value is an empty,
+then "Your metadata headers are not supported." error will be returned on the object put operation.