From d8a47f3f41036f7a4fa9a0ba8cd7aeb44b9437bf Mon Sep 17 00:00:00 2001
From: JinnyYi <82445294+JinnyYi@users.noreply.github.com>
Date: Tue, 29 Jun 2021 09:55:26 +0800
Subject: [PATCH] Implement GSP-93, GSP-97, GSP-109 and GSP-117 (#31)

* Implement GSP-93 and GSP-109

* Implement GSP-117 Rename Service to System as the Opposite to Global

* pkg/endpoint deprecated by go-endpoint

* Implement GSP-97 Add Restrictions In Storage Metadata
---
 generated.go          | 620 ++++++++++++++++++++----------------------
 go.mod                |   5 +-
 go.sum                |  28 +-
 service.toml          |  12 +-
 storage.go            | 102 ++++++-
 tests/storage_test.go |   7 +
 tests/utils_test.go   |   3 +
 utils.go              |  28 +-
 8 files changed, 454 insertions(+), 351 deletions(-)

diff --git a/generated.go b/generated.go
index ee035fa..4fda2cd 100644
--- a/generated.go
+++ b/generated.go
@@ -21,35 +21,9 @@ var _ httpclient.Options
 // Type is the type for oss
 const Type = "oss"
 
-// Service available pairs.
-const (
-	// DefaultServicePairs set default pairs for service actions
-	pairDefaultServicePairs = "oss_default_service_pairs"
-	// DefaultStoragePairs set default pairs for storager actions
-	pairDefaultStoragePairs = "oss_default_storage_pairs"
-	// ServerSideDataEncryption specifies the encryption algorithm when server_side_encryption is KMS. Can only be set to SM4. If this is not set, AES256 will be used.
-	//
-	// For Chinese users, refer to https://help.aliyun.com/document_detail/31871.html for details.
-	//
-	// For global users, refer to https://www.alibabacloud.com/help/doc-detail/31871.htm for details, and double-check whether SM4 can be used.
-	pairServerSideDataEncryption = "oss_server_side_data_encryption"
-	// ServerSideEncryption specifies the encryption algorithm. Can be AES256, KMS or SM4.
-	//
-	// For Chinese users, refer to https://help.aliyun.com/document_detail/31871.html for details.
-	//
-	// For global users, refer to https://www.alibabacloud.com/help/doc-detail/31871.htm for details, and double-check whether SM4 can be used.
-	pairServerSideEncryption = "oss_server_side_encryption"
-	// ServerSideEncryptionKeyID is the KMS-managed user master key. Only valid when server_side_encryption is KMS.
-	pairServerSideEncryptionKeyID = "oss_server_side_encryption_key_id"
-	// ServiceFeatures set service features
-	pairServiceFeatures = "oss_service_features"
-	// StorageClass
-	pairStorageClass = "oss_storage_class"
-	// StorageFeatures set storage features
-	pairStorageFeatures = "oss_storage_features"
-)
-
 // ObjectMetadata stores service metadata for object.
+//
+// Deprecated: Use ObjectSystemMetadata instead.
 type ObjectMetadata struct {
 	// ServerSideEncryption
 	ServerSideEncryption string
@@ -63,6 +37,8 @@ type ObjectMetadata struct {
 //
 // - This function should not be called by service implementer.
 // - The returning ObjectMetadata is read only and should not be modified.
+//
+// Deprecated: Use GetObjectSystemMetadata instead.
 func GetObjectMetadata(o *Object) ObjectMetadata {
 	om, ok := o.GetServiceMetadata()
 	if ok {
@@ -74,16 +50,69 @@ func GetObjectMetadata(o *Object) ObjectMetadata {
 // setObjectMetadata will set ObjectMetadata into Object.
 //
 // - This function should only be called once, please make sure all data has been written before set.
+//
+// Deprecated: Use setObjectSystemMetadata instead.
 func setObjectMetadata(o *Object, om ObjectMetadata) {
 	o.SetServiceMetadata(om)
 }
 
+// ObjectSystemMetadata stores system metadata for object.
+type ObjectSystemMetadata struct {
+	// ServerSideEncryption
+	ServerSideEncryption string
+	// ServerSideEncryptionKeyID
+	ServerSideEncryptionKeyID string
+	// StorageClass
+	StorageClass string
+}
+
+// GetObjectSystemMetadata will get ObjectSystemMetadata from Object.
+//
+// - This function should not be called by service implementer.
+// - The returning ObjectServiceMetadata is read only and should not be modified.
+func GetObjectSystemMetadata(o *Object) ObjectSystemMetadata {
+	sm, ok := o.GetSystemMetadata()
+	if ok {
+		return sm.(ObjectSystemMetadata)
+	}
+	return ObjectSystemMetadata{}
+}
+
+// setObjectSystemMetadata will set ObjectSystemMetadata into Object.
+//
+// - This function should only be called once, please make sure all data has been written before set.
+func setObjectSystemMetadata(o *Object, sm ObjectSystemMetadata) {
+	o.SetSystemMetadata(sm)
+}
+
+// StorageSystemMetadata stores system metadata for storage meta.
+type StorageSystemMetadata struct {
+}
+
+// GetStorageSystemMetadata will get SystemMetadata from StorageMeta.
+//
+// - The returning StorageSystemMetadata is read only and should not be modified.
+func GetStorageSystemMetadata(s *StorageMeta) StorageSystemMetadata {
+	sm, ok := s.GetSystemMetadata()
+	if ok {
+		return sm.(StorageSystemMetadata)
+	}
+	return StorageSystemMetadata{}
+}
+
+// setStorageSystemMetadata will set SystemMetadata into StorageMeta.
+//
+// - This function should only be called once, please make sure all data has been written before set.
+func setStorageSystemMetadata(s *StorageMeta, sm StorageSystemMetadata) {
+	s.SetSystemMetadata(sm)
+}
+
 // WithDefaultServicePairs will apply default_service_pairs value to Options.
 //
 // DefaultServicePairs set default pairs for service actions
 func WithDefaultServicePairs(v DefaultServicePairs) Pair {
 	return Pair{
-		Key:   pairDefaultServicePairs,
+		Key:   "default_service_pairs",
 		Value: v,
 	}
 }
@@ -93,7 +122,7 @@ func WithDefaultServicePairs(v DefaultServicePairs) Pair {
 // DefaultStoragePairs set default pairs for storager actions
 func WithDefaultStoragePairs(v DefaultStoragePairs) Pair {
 	return Pair{
-		Key:   pairDefaultStoragePairs,
+		Key:   "default_storage_pairs",
 		Value: v,
 	}
 }
@@ -107,7 +136,7 @@ func WithDefaultStoragePairs(v DefaultStoragePairs) Pair {
 // For global users, refer to https://www.alibabacloud.com/help/doc-detail/31871.htm for details, and double-check whether SM4 can be used.
 func WithServerSideDataEncryption(v string) Pair {
 	return Pair{
-		Key:   pairServerSideDataEncryption,
+		Key:   "server_side_data_encryption",
 		Value: v,
 	}
 }
@@ -121,7 +150,7 @@ func WithServerSideDataEncryption(v string) Pair {
 // For global users, refer to https://www.alibabacloud.com/help/doc-detail/31871.htm for details, and double-check whether SM4 can be used.
 func WithServerSideEncryption(v string) Pair {
 	return Pair{
-		Key:   pairServerSideEncryption,
+		Key:   "server_side_encryption",
 		Value: v,
 	}
 }
@@ -131,7 +160,7 @@ func WithServerSideEncryption(v string) Pair {
 // ServerSideEncryptionKeyID is the KMS-managed user master key. Only valid when server_side_encryption is KMS.
 func WithServerSideEncryptionKeyID(v string) Pair {
 	return Pair{
-		Key:   pairServerSideEncryptionKeyID,
+		Key:   "server_side_encryption_key_id",
 		Value: v,
 	}
 }
@@ -141,7 +170,7 @@ func WithServerSideEncryptionKeyID(v string) Pair {
 // ServiceFeatures set service features
 func WithServiceFeatures(v ServiceFeatures) Pair {
 	return Pair{
-		Key:   pairServiceFeatures,
+		Key:   "service_features",
 		Value: v,
 	}
 }
@@ -151,7 +180,7 @@ func WithServiceFeatures(v ServiceFeatures) Pair {
 // StorageClass
 func WithStorageClass(v string) Pair {
 	return Pair{
-		Key:   pairStorageClass,
+		Key:   "storage_class",
 		Value: v,
 	}
 }
@@ -161,24 +190,59 @@ func WithStorageClass(v string) Pair {
 // StorageFeatures set storage features
 func WithStorageFeatures(v StorageFeatures) Pair {
 	return Pair{
-		Key:   pairStorageFeatures,
+		Key:   "storage_features",
 		Value: v,
 	}
 }
 
+var pairMap = map[string]string{
+	"content_md5":                   "string",
+	"content_type":                  "string",
+	"context":                       "context.Context",
+	"continuation_token":            "string",
+	"credential":                    "string",
+	"default_service_pairs":         "DefaultServicePairs",
+	"default_storage_pairs":         "DefaultStoragePairs",
+	"endpoint":                      "string",
+	"expire":                        "int",
+	"http_client_options":           "*httpclient.Options",
+	"interceptor":                   "Interceptor",
+	"io_callback":                   "func([]byte)",
+	"list_mode":                     "ListMode",
+	"location":                      "string",
+	"multipart_id":                  "string",
+	"name":                          "string",
+	"object_mode":                   "ObjectMode",
+	"offset":                        "int64",
+	"server_side_data_encryption":   "string",
+	"server_side_encryption":        "string",
+	"server_side_encryption_key_id": "string",
+	"service_features":              "ServiceFeatures",
+	"size":                          "int64",
+	"storage_class":                 "string",
+	"storage_features":              "StorageFeatures",
+	"work_dir":                      "string",
+}
 var (
 	_ Servicer = &Service{}
 )
 
 type ServiceFeatures struct {
-	LooseOperationAll    bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
+	LooseOperationAll bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
 	LooseOperationCreate bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
 	LooseOperationDelete bool
-	LooseOperationGet    bool
-	LooseOperationList   bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
+	LooseOperationGet bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
+	LooseOperationList bool
 
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
 	VirtualOperationAll bool
 
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
 	VirtualPairAll bool
 }
 
@@ -216,7 +280,7 @@ func parsePairServiceNew(opts []Pair) (pairServiceNew, error) {
 			result.HasCredential = true
 			result.Credential = v.Value.(string)
 		// Optional pairs
-		case pairDefaultServicePairs:
+		case "default_service_pairs":
 			if result.HasDefaultServicePairs {
 				continue
 			}
@@ -234,7 +298,7 @@ func parsePairServiceNew(opts []Pair) (pairServiceNew, error) {
 			}
 			result.HasHTTPClientOptions = true
 			result.HTTPClientOptions = v.Value.(*httpclient.Options)
-		case pairServiceFeatures:
+		case "service_features":
 			if result.HasServiceFeatures {
 				continue
 			}
@@ -269,23 +333,10 @@ func (s *Service) parsePairServiceCreate(opts []Pair) (pairServiceCreate, error)
 	}
 
 	for _, v := range opts {
-		// isUnsupportedPair records whether current pair is unsupported.
-		isUnsupportedPair := false
-
 		switch v.Key {
 		default:
-			isUnsupportedPair = true
+			return pairServiceCreate{}, services.PairUnsupportedError{Pair: v}
 		}
-
-		if !isUnsupportedPair {
-			continue
-		}
-
-		// If user enables the loose operation feature, we will ignore PairUnsupportedError.
-		if s.features.LooseOperationAll || s.features.LooseOperationCreate {
-			continue
-		}
-		return pairServiceCreate{}, services.PairUnsupportedError{Pair: v}
 	}
 
 	// Check required pairs.
@@ -305,23 +356,10 @@ func (s *Service) parsePairServiceDelete(opts []Pair) (pairServiceDelete, error)
 	}
 
 	for _, v := range opts {
-		// isUnsupportedPair records whether current pair is unsupported.
-		isUnsupportedPair := false
-
 		switch v.Key {
 		default:
-			isUnsupportedPair = true
+			return pairServiceDelete{}, services.PairUnsupportedError{Pair: v}
 		}
-
-		if !isUnsupportedPair {
-			continue
-		}
-
-		// If user enables the loose operation feature, we will ignore PairUnsupportedError.
-		if s.features.LooseOperationAll || s.features.LooseOperationDelete {
-			continue
-		}
-		return pairServiceDelete{}, services.PairUnsupportedError{Pair: v}
 	}
 
 	// Check required pairs.
@@ -341,23 +379,10 @@ func (s *Service) parsePairServiceGet(opts []Pair) (pairServiceGet, error) {
 	}
 
 	for _, v := range opts {
-		// isUnsupportedPair records whether current pair is unsupported.
-		isUnsupportedPair := false
-
 		switch v.Key {
 		default:
-			isUnsupportedPair = true
+			return pairServiceGet{}, services.PairUnsupportedError{Pair: v}
 		}
-
-		if !isUnsupportedPair {
-			continue
-		}
-
-		// If user enables the loose operation feature, we will ignore PairUnsupportedError.
-		if s.features.LooseOperationAll || s.features.LooseOperationGet {
-			continue
-		}
-		return pairServiceGet{}, services.PairUnsupportedError{Pair: v}
 	}
 
 	// Check required pairs.
@@ -377,23 +402,10 @@ func (s *Service) parsePairServiceList(opts []Pair) (pairServiceList, error) {
 	}
 
 	for _, v := range opts {
-		// isUnsupportedPair records whether current pair is unsupported.
-		isUnsupportedPair := false
-
 		switch v.Key {
 		default:
-			isUnsupportedPair = true
+			return pairServiceList{}, services.PairUnsupportedError{Pair: v}
 		}
-
-		if !isUnsupportedPair {
-			continue
-		}
-
-		// If user enables the loose operation feature, we will ignore PairUnsupportedError.
-		if s.features.LooseOperationAll || s.features.LooseOperationList {
-			continue
-		}
-		return pairServiceList{}, services.PairUnsupportedError{Pair: v}
 	}
 
 	// Check required pairs.
@@ -504,30 +516,57 @@ func (s *Service) ListWithContext(ctx context.Context, pairs ...Pair) (sti *Stor
 
 var (
 	_ Appender    = &Storage{}
+	_ Direr       = &Storage{}
 	_ Multiparter = &Storage{}
 	_ Storager    = &Storage{}
 )
 
 type StorageFeatures struct {
-	LooseOperationAll               bool
-	LooseOperationCommitAppend      bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
+	LooseOperationAll bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
+	LooseOperationCommitAppend bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
 	LooseOperationCompleteMultipart bool
-	LooseOperationCreate            bool
-	LooseOperationCreateAppend      bool
-	LooseOperationCreateMultipart   bool
-	LooseOperationDelete            bool
-	LooseOperationList              bool
-	LooseOperationListMultipart     bool
-	LooseOperationMetadata          bool
-	LooseOperationRead              bool
-	LooseOperationStat              bool
-	LooseOperationWrite             bool
-	LooseOperationWriteAppend       bool
-	LooseOperationWriteMultipart    bool
-
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
+	LooseOperationCreate bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
+	LooseOperationCreateAppend bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
+	LooseOperationCreateDir bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
+	LooseOperationCreateMultipart bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
+	LooseOperationDelete bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
+	LooseOperationList bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
+	LooseOperationListMultipart bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
+	LooseOperationMetadata bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
+	LooseOperationRead bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
+	LooseOperationStat bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
+	LooseOperationWrite bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
+	LooseOperationWriteAppend bool
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
+	LooseOperationWriteMultipart bool
+
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
 	VirtualOperationAll bool
 
+	// Deprecated: This field has been deprecated by GSP-109, planned be removed in v4.3.0.
 	VirtualPairAll bool
+	// VirtualDir virtual_dir feature is designed for a service that doesn't have native dir support but wants to provide simulated operations.
+	//
+	// - If this feature is disabled (the default behavior), the service will behave like it doesn't have any dir support.
+	// - If this feature is enabled, the service will support simulated dir behavior in create_dir, create, list, delete, and so on.
+	//
+	// This feature was introduced in GSP-109.
+	VirtualDir bool
 }
 
 // pairStorageNew is the parsed struct
@@ -562,13 +601,13 @@ func parsePairStorageNew(opts []Pair) (pairStorageNew, error) {
 			result.HasName = true
 			result.Name = v.Value.(string)
 		// Optional pairs
-		case pairDefaultStoragePairs:
+		case "default_storage_pairs":
 			if result.HasDefaultStoragePairs {
 				continue
 			}
 			result.HasDefaultStoragePairs = true
 			result.DefaultStoragePairs = v.Value.(DefaultStoragePairs)
-		case pairStorageFeatures:
+		case "storage_features":
 			if result.HasStorageFeatures {
 				continue
 			}
@@ -595,6 +634,7 @@ type DefaultStoragePairs struct {
 	CompleteMultipart []Pair
 	Create            []Pair
 	CreateAppend      []Pair
+	CreateDir         []Pair
 	CreateMultipart   []Pair
 	Delete            []Pair
 	List              []Pair
@@ -619,23 +659,10 @@ func (s *Storage) parsePairStorageCommitAppend(opts []Pair) (pairStorageCommitAp
 	}
 
 	for _, v := range opts {
-		// isUnsupportedPair records whether current pair is unsupported.
-		isUnsupportedPair := false
-
 		switch v.Key {
 		default:
-			isUnsupportedPair = true
-		}
-
-		if !isUnsupportedPair {
-			continue
-		}
-
-		// If user enables the loose operation feature, we will ignore PairUnsupportedError.
-		if s.features.LooseOperationAll || s.features.LooseOperationCommitAppend {
-			continue
+			return pairStorageCommitAppend{}, services.PairUnsupportedError{Pair: v}
 		}
-		return pairStorageCommitAppend{}, services.PairUnsupportedError{Pair: v}
 	}
 
 	// Check required pairs.
@@ -655,23 +682,10 @@ func (s *Storage) parsePairStorageCompleteMultipart(opts []Pair) (pairStorageCom
 	}
 
 	for _, v := range opts {
-		// isUnsupportedPair records whether current pair is unsupported.
-		isUnsupportedPair := false
-
 		switch v.Key {
 		default:
-			isUnsupportedPair = true
+			return pairStorageCompleteMultipart{}, services.PairUnsupportedError{Pair: v}
 		}
-
-		if !isUnsupportedPair {
-			continue
-		}
-
-		// If user enables the loose operation feature, we will ignore PairUnsupportedError.
-		if s.features.LooseOperationAll || s.features.LooseOperationCompleteMultipart {
-			continue
-		}
-		return pairStorageCompleteMultipart{}, services.PairUnsupportedError{Pair: v}
 	}
 
 	// Check required pairs.
@@ -684,6 +698,8 @@ type pairStorageCreate struct {
 	pairs          []Pair
 	HasMultipartID bool
 	MultipartID    string
+	HasObjectMode  bool
+	ObjectMode     ObjectMode
 }
 
 // parsePairStorageCreate will parse Pair slice into *pairStorageCreate
@@ -693,9 +709,6 @@ func (s *Storage) parsePairStorageCreate(opts []Pair) (pairStorageCreate, error)
 	}
 
 	for _, v := range opts {
-		// isUnsupportedPair records whether current pair is unsupported.
-		isUnsupportedPair := false
-
 		switch v.Key {
 		case "multipart_id":
 			if result.HasMultipartID {
@@ -704,19 +717,16 @@ func (s *Storage) parsePairStorageCreate(opts []Pair) (pairStorageCreate, error)
 			result.HasMultipartID = true
 			result.MultipartID = v.Value.(string)
 			continue
-		default:
-			isUnsupportedPair = true
-		}
-
-		if !isUnsupportedPair {
-			continue
-		}
-
-		// If user enables the loose operation feature, we will ignore PairUnsupportedError.
-		if s.features.LooseOperationAll || s.features.LooseOperationCreate {
+		case "object_mode":
+			if result.HasObjectMode {
+				continue
+			}
+			result.HasObjectMode = true
+			result.ObjectMode = v.Value.(ObjectMode)
 			continue
+		default:
+			return pairStorageCreate{}, services.PairUnsupportedError{Pair: v}
 		}
-		return pairStorageCreate{}, services.PairUnsupportedError{Pair: v}
 	}
 
 	// Check required pairs.
@@ -746,9 +756,6 @@ func (s *Storage) parsePairStorageCreateAppend(opts []Pair) (pairStorageCreateAp
 	}
 
 	for _, v := range opts {
-		// isUnsupportedPair records whether current pair is unsupported.
-		isUnsupportedPair := false
-
 		switch v.Key {
 		case "content_type":
 			if result.HasContentType {
@@ -757,28 +764,28 @@ func (s *Storage) parsePairStorageCreateAppend(opts []Pair) (pairStorageCreateAp
 			result.HasContentType = true
 			result.ContentType = v.Value.(string)
 			continue
-		case pairServerSideDataEncryption:
+		case "server_side_data_encryption":
 			if result.HasServerSideDataEncryption {
 				continue
 			}
 			result.HasServerSideDataEncryption = true
 			result.ServerSideDataEncryption = v.Value.(string)
 			continue
-		case pairServerSideEncryption:
+		case "server_side_encryption":
 			if result.HasServerSideEncryption {
 				continue
 			}
 			result.HasServerSideEncryption = true
 			result.ServerSideEncryption = v.Value.(string)
 			continue
-		case pairServerSideEncryptionKeyID:
+		case "server_side_encryption_key_id":
 			if result.HasServerSideEncryptionKeyID {
 				continue
 			}
 			result.HasServerSideEncryptionKeyID = true
 			result.ServerSideEncryptionKeyID = v.Value.(string)
 			continue
-		case pairStorageClass:
+		case "storage_class":
 			if result.HasStorageClass {
 				continue
 			}
@@ -786,18 +793,40 @@ func (s *Storage) parsePairStorageCreateAppend(opts []Pair) (pairStorageCreateAp
 			result.StorageClass = v.Value.(string)
 			continue
 		default:
-			isUnsupportedPair = true
+			return pairStorageCreateAppend{}, services.PairUnsupportedError{Pair: v}
 		}
+	}
 
-		if !isUnsupportedPair {
-			continue
-		}
+	// Check required pairs.
+
+	return result, nil
+}
+
+// pairStorageCreateDir is the parsed struct
+type pairStorageCreateDir struct {
+	pairs           []Pair
+	HasStorageClass bool
+	StorageClass    string
+}
+
+// parsePairStorageCreateDir will parse Pair slice into *pairStorageCreateDir
+func (s *Storage) parsePairStorageCreateDir(opts []Pair) (pairStorageCreateDir, error) {
+	result := pairStorageCreateDir{
+		pairs: opts,
+	}
 
-		// If user enables the loose operation feature, we will ignore PairUnsupportedError.
-		if s.features.LooseOperationAll || s.features.LooseOperationCreateAppend {
+	for _, v := range opts {
+		switch v.Key {
+		case "storage_class":
+			if result.HasStorageClass {
+				continue
+			}
+			result.HasStorageClass = true
+			result.StorageClass = v.Value.(string)
 			continue
+		default:
+			return pairStorageCreateDir{}, services.PairUnsupportedError{Pair: v}
 		}
-		return pairStorageCreateAppend{}, services.PairUnsupportedError{Pair: v}
 	}
 
 	// Check required pairs.
@@ -827,9 +856,6 @@ func (s *Storage) parsePairStorageCreateMultipart(opts []Pair) (pairStorageCreat
 	}
 
 	for _, v := range opts {
-		// isUnsupportedPair records whether current pair is unsupported.
-		isUnsupportedPair := false
-
 		switch v.Key {
 		case "content_type":
 			if result.HasContentType {
@@ -838,28 +864,28 @@ func (s *Storage) parsePairStorageCreateMultipart(opts []Pair) (pairStorageCreat
 			result.HasContentType = true
 			result.ContentType = v.Value.(string)
 			continue
-		case pairServerSideDataEncryption:
+		case "server_side_data_encryption":
 			if result.HasServerSideDataEncryption {
 				continue
 			}
 			result.HasServerSideDataEncryption = true
 			result.ServerSideDataEncryption = v.Value.(string)
 			continue
-		case pairServerSideEncryption:
+		case "server_side_encryption":
 			if result.HasServerSideEncryption {
 				continue
 			}
 			result.HasServerSideEncryption = true
 			result.ServerSideEncryption = v.Value.(string)
 			continue
-		case pairServerSideEncryptionKeyID:
+		case "server_side_encryption_key_id":
 			if result.HasServerSideEncryptionKeyID {
 				continue
 			}
 			result.HasServerSideEncryptionKeyID = true
 			result.ServerSideEncryptionKeyID = v.Value.(string)
 			continue
-		case pairStorageClass:
+		case "storage_class":
 			if result.HasStorageClass {
 				continue
 			}
@@ -867,18 +893,8 @@ func (s *Storage) parsePairStorageCreateMultipart(opts []Pair) (pairStorageCreat
 			result.StorageClass = v.Value.(string)
 			continue
 		default:
-			isUnsupportedPair = true
-		}
-
-		if !isUnsupportedPair {
-			continue
-		}
-
-		// If user enables the loose operation feature, we will ignore PairUnsupportedError.
-		if s.features.LooseOperationAll || s.features.LooseOperationCreateMultipart {
-			continue
+			return pairStorageCreateMultipart{}, services.PairUnsupportedError{Pair: v}
 		}
-		return pairStorageCreateMultipart{}, services.PairUnsupportedError{Pair: v}
 	}
 
 	// Check required pairs.
@@ -891,6 +907,8 @@ type pairStorageDelete struct {
 	pairs          []Pair
 	HasMultipartID bool
 	MultipartID    string
+	HasObjectMode  bool
+	ObjectMode     ObjectMode
 }
 
 // parsePairStorageDelete will parse Pair slice into *pairStorageDelete
@@ -900,9 +918,6 @@ func (s *Storage) parsePairStorageDelete(opts []Pair) (pairStorageDelete, error)
 	}
 
 	for _, v := range opts {
-		// isUnsupportedPair records whether current pair is unsupported.
-		isUnsupportedPair := false
-
 		switch v.Key {
 		case "multipart_id":
 			if result.HasMultipartID {
@@ -911,19 +926,16 @@ func (s *Storage) parsePairStorageDelete(opts []Pair) (pairStorageDelete, error)
 			result.HasMultipartID = true
 			result.MultipartID = v.Value.(string)
 			continue
-		default:
-			isUnsupportedPair = true
-		}
-
-		if !isUnsupportedPair {
-			continue
-		}
-
-		// If user enables the loose operation feature, we will ignore PairUnsupportedError.
-		if s.features.LooseOperationAll || s.features.LooseOperationDelete {
+		case "object_mode":
+			if result.HasObjectMode {
+				continue
+			}
+			result.HasObjectMode = true
+			result.ObjectMode = v.Value.(ObjectMode)
 			continue
+		default:
+			return pairStorageDelete{}, services.PairUnsupportedError{Pair: v}
 		}
-		return pairStorageDelete{}, services.PairUnsupportedError{Pair: v}
 	}
 
 	// Check required pairs.
@@ -945,9 +957,6 @@ func (s *Storage) parsePairStorageList(opts []Pair) (pairStorageList, error) {
 	}
 
 	for _, v := range opts {
-		// isUnsupportedPair records whether current pair is unsupported.
-		isUnsupportedPair := false
-
 		switch v.Key {
 		case "list_mode":
 			if result.HasListMode {
@@ -957,18 +966,8 @@ func (s *Storage) parsePairStorageList(opts []Pair) (pairStorageList, error) {
 			result.ListMode = v.Value.(ListMode)
 			continue
 		default:
-			isUnsupportedPair = true
+			return pairStorageList{}, services.PairUnsupportedError{Pair: v}
 		}
-
-		if !isUnsupportedPair {
-			continue
-		}
-
-		// If user enables the loose operation feature, we will ignore PairUnsupportedError.
-		if s.features.LooseOperationAll || s.features.LooseOperationList {
-			continue
-		}
-		return pairStorageList{}, services.PairUnsupportedError{Pair: v}
 	}
 
 	// Check required pairs.
@@ -988,23 +987,10 @@ func (s *Storage) parsePairStorageListMultipart(opts []Pair) (pairStorageListMul
 	}
 
 	for _, v := range opts {
-		// isUnsupportedPair records whether current pair is unsupported.
-		isUnsupportedPair := false
-
 		switch v.Key {
 		default:
-			isUnsupportedPair = true
-		}
-
-		if !isUnsupportedPair {
-			continue
-		}
-
-		// If user enables the loose operation feature, we will ignore PairUnsupportedError.
-		if s.features.LooseOperationAll || s.features.LooseOperationListMultipart {
-			continue
+			return pairStorageListMultipart{}, services.PairUnsupportedError{Pair: v}
 		}
-		return pairStorageListMultipart{}, services.PairUnsupportedError{Pair: v}
 	}
 
 	// Check required pairs.
@@ -1024,23 +1010,10 @@ func (s *Storage) parsePairStorageMetadata(opts []Pair) (pairStorageMetadata, er
 	}
 
 	for _, v := range opts {
-		// isUnsupportedPair records whether current pair is unsupported.
-		isUnsupportedPair := false
-
 		switch v.Key {
 		default:
-			isUnsupportedPair = true
+			return pairStorageMetadata{}, services.PairUnsupportedError{Pair: v}
 		}
-
-		if !isUnsupportedPair {
-			continue
-		}
-
-		// If user enables the loose operation feature, we will ignore PairUnsupportedError.
-		if s.features.LooseOperationAll || s.features.LooseOperationMetadata {
-			continue
-		}
-		return pairStorageMetadata{}, services.PairUnsupportedError{Pair: v}
 	}
 
 	// Check required pairs.
@@ -1066,9 +1039,6 @@ func (s *Storage) parsePairStorageRead(opts []Pair) (pairStorageRead, error) {
 	}
 
 	for _, v := range opts {
-		// isUnsupportedPair records whether current pair is unsupported.
-		isUnsupportedPair := false
-
 		switch v.Key {
 		case "io_callback":
 			if result.HasIoCallback {
@@ -1092,18 +1062,8 @@ func (s *Storage) parsePairStorageRead(opts []Pair) (pairStorageRead, error) {
 			result.Size = v.Value.(int64)
 			continue
 		default:
-			isUnsupportedPair = true
+			return pairStorageRead{}, services.PairUnsupportedError{Pair: v}
 		}
-
-		if !isUnsupportedPair {
-			continue
-		}
-
-		// If user enables the loose operation feature, we will ignore PairUnsupportedError.
-		if s.features.LooseOperationAll || s.features.LooseOperationRead {
-			continue
-		}
-		return pairStorageRead{}, services.PairUnsupportedError{Pair: v}
 	}
 
 	// Check required pairs.
@@ -1116,6 +1076,8 @@ type pairStorageStat struct {
 	pairs          []Pair
 	HasMultipartID bool
 	MultipartID    string
+	HasObjectMode  bool
+	ObjectMode     ObjectMode
 }
 
 // parsePairStorageStat will parse Pair slice into *pairStorageStat
@@ -1125,9 +1087,6 @@ func (s *Storage) parsePairStorageStat(opts []Pair) (pairStorageStat, error) {
 	}
 
 	for _, v := range opts {
-		// isUnsupportedPair records whether current pair is unsupported.
-		isUnsupportedPair := false
-
 		switch v.Key {
 		case "multipart_id":
 			if result.HasMultipartID {
@@ -1136,19 +1095,16 @@ func (s *Storage) parsePairStorageStat(opts []Pair) (pairStorageStat, error) {
 			result.HasMultipartID = true
 			result.MultipartID = v.Value.(string)
 			continue
-		default:
-			isUnsupportedPair = true
-		}
-
-		if !isUnsupportedPair {
-			continue
-		}
-
-		// If user enables the loose operation feature, we will ignore PairUnsupportedError.
-		if s.features.LooseOperationAll || s.features.LooseOperationStat {
+		case "object_mode":
+			if result.HasObjectMode {
+				continue
+			}
+			result.HasObjectMode = true
+			result.ObjectMode = v.Value.(ObjectMode)
 			continue
+		default:
+			return pairStorageStat{}, services.PairUnsupportedError{Pair: v}
 		}
-		return pairStorageStat{}, services.PairUnsupportedError{Pair: v}
 	}
 
 	// Check required pairs.
@@ -1182,9 +1138,6 @@ func (s *Storage) parsePairStorageWrite(opts []Pair) (pairStorageWrite, error) {
 	}
 
 	for _, v := range opts {
-		// isUnsupportedPair records whether current pair is unsupported.
-		isUnsupportedPair := false
-
 		switch v.Key {
 		case "content_md5":
 			if result.HasContentMd5 {
@@ -1207,28 +1160,28 @@ func (s *Storage) parsePairStorageWrite(opts []Pair) (pairStorageWrite, error) {
 			result.HasIoCallback = true
 			result.IoCallback = v.Value.(func([]byte))
 			continue
-		case pairServerSideDataEncryption:
+		case "server_side_data_encryption":
 			if result.HasServerSideDataEncryption {
 				continue
 			}
 			result.HasServerSideDataEncryption = true
 			result.ServerSideDataEncryption = v.Value.(string)
 			continue
-		case pairServerSideEncryption:
+		case "server_side_encryption":
 			if result.HasServerSideEncryption {
 				continue
 			}
 			result.HasServerSideEncryption = true
 			result.ServerSideEncryption = v.Value.(string)
 			continue
-		case pairServerSideEncryptionKeyID:
+		case "server_side_encryption_key_id":
 			if result.HasServerSideEncryptionKeyID {
 				continue
 			}
 			result.HasServerSideEncryptionKeyID = true
 			result.ServerSideEncryptionKeyID = v.Value.(string)
 			continue
-		case pairStorageClass:
+		case "storage_class":
 			if result.HasStorageClass {
 				continue
 			}
@@ -1236,18 +1189,8 @@ func (s *Storage) parsePairStorageWrite(opts []Pair) (pairStorageWrite, error) {
 			result.StorageClass = v.Value.(string)
 			continue
 		default:
-			isUnsupportedPair = true
+			return pairStorageWrite{}, services.PairUnsupportedError{Pair: v}
 		}
-
-		if !isUnsupportedPair {
-			continue
-		}
-
-		// If user enables the loose operation feature, we will ignore PairUnsupportedError.
-		if s.features.LooseOperationAll || s.features.LooseOperationWrite {
-			continue
-		}
-		return pairStorageWrite{}, services.PairUnsupportedError{Pair: v}
 	}
 
 	// Check required pairs.
@@ -1271,9 +1214,6 @@ func (s *Storage) parsePairStorageWriteAppend(opts []Pair) (pairStorageWriteAppe
 	}
 
 	for _, v := range opts {
-		// isUnsupportedPair records whether current pair is unsupported.
-		isUnsupportedPair := false
-
 		switch v.Key {
 		case "content_md5":
 			if result.HasContentMd5 {
@@ -1290,18 +1230,8 @@ func (s *Storage) parsePairStorageWriteAppend(opts []Pair) (pairStorageWriteAppe
 			result.IoCallback = v.Value.(func([]byte))
 			continue
 		default:
-			isUnsupportedPair = true
+			return pairStorageWriteAppend{}, services.PairUnsupportedError{Pair: v}
 		}
-
-		if !isUnsupportedPair {
-			continue
-		}
-
-		// If user enables the loose operation feature, we will ignore PairUnsupportedError.
-		if s.features.LooseOperationAll || s.features.LooseOperationWriteAppend {
-			continue
-		}
-		return pairStorageWriteAppend{}, services.PairUnsupportedError{Pair: v}
 	}
 
 	// Check required pairs.
@@ -1323,9 +1253,6 @@ func (s *Storage) parsePairStorageWriteMultipart(opts []Pair) (pairStorageWriteM
 	}
 
 	for _, v := range opts {
-		// isUnsupportedPair records whether current pair is unsupported.
-		isUnsupportedPair := false
-
 		switch v.Key {
 		case "content_md5":
 			if result.HasContentMd5 {
@@ -1335,18 +1262,8 @@ func (s *Storage) parsePairStorageWriteMultipart(opts []Pair) (pairStorageWriteM
 			result.ContentMd5 = v.Value.(string)
 			continue
 		default:
-			isUnsupportedPair = true
-		}
-
-		if !isUnsupportedPair {
-			continue
-		}
-
-		// If user enables the loose operation feature, we will ignore PairUnsupportedError.
-		if s.features.LooseOperationAll || s.features.LooseOperationWriteMultipart {
-			continue
+			return pairStorageWriteMultipart{}, services.PairUnsupportedError{Pair: v}
 		}
-		return pairStorageWriteMultipart{}, services.PairUnsupportedError{Pair: v}
 	}
 
 	// Check required pairs.
@@ -1414,6 +1331,11 @@ func (s *Storage) CompleteMultipartWithContext(ctx context.Context, o *Object, p
 
 // Create will create a new object without any api call.
 //
+// ## Behavior
+//
+// - Create SHOULD NOT send any API call.
+// - Create SHOULD accept ObjectMode pair as object mode.
+//
 // This function will create a context by default.
 func (s *Storage) Create(path string, pairs ...Pair) (o *Object) {
 	pairs = append(pairs, s.defaultPairs.Create...)
@@ -1450,6 +1372,31 @@ func (s *Storage) CreateAppendWithContext(ctx context.Context, path string, pair
 	return s.createAppend(ctx, path, opt)
 }
 
+// CreateDir will create a new dir object.
+//
+// This function will create a context by default.
+func (s *Storage) CreateDir(path string, pairs ...Pair) (o *Object, err error) {
+	ctx := context.Background()
+	return s.CreateDirWithContext(ctx, path, pairs...)
+}
+
+// CreateDirWithContext will create a new dir object.
+func (s *Storage) CreateDirWithContext(ctx context.Context, path string, pairs ...Pair) (o *Object, err error) {
+	defer func() {
+		err = s.formatError("create_dir", err, path)
+	}()
+
+	pairs = append(pairs, s.defaultPairs.CreateDir...)
+	var opt pairStorageCreateDir
+
+	opt, err = s.parsePairStorageCreateDir(pairs)
+	if err != nil {
+		return
+	}
+
+	return s.createDir(ctx, path, opt)
+}
+
 // CreateMultipart will create a new multipart.
 //
 // This function will create a context by default.
@@ -1475,7 +1422,17 @@ func (s *Storage) CreateMultipartWithContext(ctx context.Context, path string, p
 	return s.createMultipart(ctx, path, opt)
 }
 
-// Delete will delete an Object from service.
+// Delete will delete an object from service.
+//
+// ## Behavior
+//
+// - Delete only delete one and only one object.
+//   - Service DON'T NEED to support remove all.
+//   - User NEED to implement remove_all by themself.
+// - Delete is idempotent.
+//   - Successful delete always return nil error.
+//   - Delete SHOULD never return `ObjectNotExist`
+//   - Delete DON'T NEED to check the object exist or not.
 //
 // This function will create a context by default.
 func (s *Storage) Delete(path string, pairs ...Pair) (err error) {
@@ -1483,7 +1440,17 @@ func (s *Storage) Delete(path string, pairs ...Pair) (err error) {
 	return s.DeleteWithContext(ctx, path, pairs...)
 }
 
-// DeleteWithContext will delete an Object from service.
+// DeleteWithContext will delete an object from service.
+//
+// ## Behavior
+//
+// - Delete only delete one and only one object.
+//   - Service DON'T NEED to support remove all.
+//   - User NEED to implement remove_all by themself.
+// - Delete is idempotent.
+//   - Successful delete always return nil error.
+//   - Delete SHOULD never return `ObjectNotExist`
+//   - Delete DON'T NEED to check the object exist or not.
 func (s *Storage) DeleteWithContext(ctx context.Context, path string, pairs ...Pair) (err error) {
 	defer func() {
 		err = s.formatError("delete", err, path)
@@ -1594,6 +1561,12 @@ func (s *Storage) ReadWithContext(ctx context.Context, path string, w io.Writer,
 
 // Stat will stat a path to get info of an object.
 //
+// ## Behavior
+//
+// - Stat SHOULD accept ObjectMode pair as hints.
+//   - Service COULD have different implementations for different object mode.
+//   - Service SHOULD check if returning ObjectMode is match
+//
 // This function will create a context by default.
 func (s *Storage) Stat(path string, pairs ...Pair) (o *Object, err error) {
 	ctx := context.Background()
@@ -1601,6 +1574,12 @@ func (s *Storage) Stat(path string, pairs ...Pair) (o *Object, err error) {
 }
 
 // StatWithContext will stat a path to get info of an object.
+//
+// ## Behavior
+//
+// - Stat SHOULD accept ObjectMode pair as hints.
+//   - Service COULD have different implementations for different object mode.
+//   - Service SHOULD check if returning ObjectMode is match
 func (s *Storage) StatWithContext(ctx context.Context, path string, pairs ...Pair) (o *Object, err error) {
 	defer func() {
 		err = s.formatError("stat", err, path)
@@ -1703,4 +1682,5 @@ func (s *Storage) WriteMultipartWithContext(ctx context.Context, o *Object, r io
 func init() {
 	services.RegisterServicer(Type, NewServicer)
 	services.RegisterStorager(Type, NewStorager)
+	services.RegisterSchema(Type, pairMap)
 }
diff --git a/go.mod b/go.mod
index 3df7fdf..99804fc 100644
--- a/go.mod
+++ b/go.mod
@@ -5,8 +5,9 @@ go 1.14
 require (
 	github.com/aliyun/aliyun-oss-go-sdk v2.1.8+incompatible
 	github.com/baiyubin/aliyun-sts-go-sdk v0.0.0-20180326062324-cfa1a18b161f // indirect
-	github.com/beyondstorage/go-integration-test/v4 v4.0.0
-	github.com/beyondstorage/go-storage/v4 v4.0.1-0.20210530044854-1c928ddbe52d
+	github.com/beyondstorage/go-endpoint v1.0.1
+	github.com/beyondstorage/go-integration-test/v4 v4.1.1
+	github.com/beyondstorage/go-storage/v4 v4.2.0
 	github.com/google/uuid v1.2.0
 	github.com/satori/go.uuid v1.2.0 // indirect
 	golang.org/x/time v0.0.0-20191024005414-555d28b269f0 // indirect
diff --git a/go.sum b/go.sum
index fe9c273..2839254 100644
--- a/go.sum
+++ b/go.sum
@@ -4,22 +4,23 @@ github.com/aliyun/aliyun-oss-go-sdk v2.1.8+incompatible h1:hLUNPbx10wawWW7DeNExv
 github.com/aliyun/aliyun-oss-go-sdk v2.1.8+incompatible/go.mod h1:T/Aws4fEfogEE9v+HPhhw+CntffsBHJ8nXQCwKr0/g8=
 github.com/baiyubin/aliyun-sts-go-sdk v0.0.0-20180326062324-cfa1a18b161f h1:ZNv7On9kyUzm7fvRZumSyy/IUiSC7AzL0I1jKKtwooA=
 github.com/baiyubin/aliyun-sts-go-sdk v0.0.0-20180326062324-cfa1a18b161f/go.mod h1:AuiFmCCPBSrqvVMvuqFuk0qogytodnVFVSN5CeJB8Gc=
-github.com/beyondstorage/go-integration-test/v4 v4.0.0 h1:tdXQV9yxQ3Q6p9xfyQKzK3MEo9r9j9g3uT5+3sbVtnQ=
-github.com/beyondstorage/go-integration-test/v4 v4.0.0/go.mod h1:26/JF4b0XxRN0pL4kihpnVNhbbw+QWvmmvgxfnFJDfA=
-github.com/beyondstorage/go-storage/v4 v4.0.0/go.mod h1:oa2dYco+xplPj99WSBnYVw/xXvRkIKWSSVDQKNZ5Kz8=
-github.com/beyondstorage/go-storage/v4 v4.0.1-0.20210530044854-1c928ddbe52d h1:s9t6VNNRDqmg+PXyXtVEsxIM7xZQIJOYlma28IpkbNQ=
-github.com/beyondstorage/go-storage/v4 v4.0.1-0.20210530044854-1c928ddbe52d/go.mod h1:kXMu07IDZaKtxbqI1ufuhqo0FjYe0nH7zPCbBanln/Y=
-github.com/beyondstorage/specs/go v0.0.0-20210521044836-3d41c1d9c97f/go.mod h1:f5VvmLHc/dNJwl+/yAv/TOHdev3phvuEswx8DIXiSQQ=
-github.com/beyondstorage/specs/go v0.0.0-20210530044123-3ff75e192bc9 h1:YSiF27cAHlDZk9q+oaEHQbA8dH8XTvYxeTOoPzNCwOQ=
-github.com/beyondstorage/specs/go v0.0.0-20210530044123-3ff75e192bc9/go.mod h1:f5VvmLHc/dNJwl+/yAv/TOHdev3phvuEswx8DIXiSQQ=
+github.com/beyondstorage/go-endpoint v1.0.1 h1:F8x2dGLMu9je6g7zPbKoxCXDlug97K26SeCx7KEHgyg=
+github.com/beyondstorage/go-endpoint v1.0.1/go.mod h1:P2hknaGrziOJJKySv/XnAiVw/d3v12/LZu2gSxEx4nM=
+github.com/beyondstorage/go-integration-test/v4 v4.1.1 h1:9bSXKbr6hLb4+ZsmAhWE32fvqhyrpub4U4qgBGeth4A=
+github.com/beyondstorage/go-integration-test/v4 v4.1.1/go.mod h1:ihtCaOJvaHGE0v+IhY6ZUF5NU1IND6xmdrJI9Lq/jhc=
+github.com/beyondstorage/go-storage/v4 v4.2.0 h1:J0xqqy4qEQRtIS2zUWMA5wRXVHx/cxX5fHsU2ezA3+I=
+github.com/beyondstorage/go-storage/v4 v4.2.0/go.mod h1:rUNzOXcikYk5w0ewvNsKbztg7ndQDyDvjDuP0bznSLU=
+github.com/beyondstorage/specs/go v0.0.0-20210623065218-d1c2d7d81259 h1:mW9XpHLc6pdXBRnsha1VlqF0rNsB/Oc+8l+5UYngmRA=
+github.com/beyondstorage/specs/go v0.0.0-20210623065218-d1c2d7d81259/go.mod h1:vF/Q0P1tCvhVAUrxg7i6NvrARRMQVTAuQdDNqpSzR1w=
 github.com/dave/dst v0.26.2 h1:lnxLAKI3tx7MgLNVDirFCsDTlTG9nKTk7GcptKcWSwY=
 github.com/dave/dst v0.26.2/go.mod h1:UMDJuIRPfyUCC78eFuB+SV/WI8oDeyFDvM/JR6NI3IU=
 github.com/dave/gopackages v0.0.0-20170318123100-46e7023ec56e/go.mod h1:i00+b/gKdIDIxuLDFob7ustLAVqhsZRk2qVZrArELGQ=
 github.com/dave/jennifer v1.2.0/go.mod h1:fIb+770HOpJ2fmN9EPPKOqm1vMGhB+TwXKMZhrIygKg=
 github.com/dave/kerr v0.0.0-20170318121727-bc25dd6abe8e/go.mod h1:qZqlPyPvfsDJt+3wHJ1EvSXDuVjFTK0j2p/ca+gtsb8=
 github.com/dave/rebecca v0.9.1/go.mod h1:N6XYdMD/OKw3lkF3ywh8Z6wPGuwNFDNtWYEMFWEmXBA=
-github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/golang/mock v1.5.0 h1:jlYHihg//f7RRwuPfptm04yp4s7O6Kw8EZiVYIGcH0g=
 github.com/golang/mock v1.5.0/go.mod h1:CWnOUgYIOo4TcNZ0wHX3YZCqsaM1I1Jvs6v3mP3KVu8=
 github.com/google/pprof v0.0.0-20181127221834-b4f47329b966/go.mod h1:zfwlbNMJ+OItoe0UupaVj+oy1omPYYDuagoSzA8v9mc=
@@ -37,19 +38,22 @@ github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORN
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
-github.com/pelletier/go-toml v1.9.1 h1:a6qW1EVNZWH9WGI6CsYdD8WAylkoXBS5yv0XHlh17Tc=
-github.com/pelletier/go-toml v1.9.1/go.mod h1:u1nR/EPcESfeI/szUZKdtJ0xRNbUoANCkoOuaOx1Y+c=
+github.com/pelletier/go-toml v1.9.3 h1:zeC5b1GviRUyKYd6OJPvBU/mcVDVoL1OhT17FCt5dSQ=
+github.com/pelletier/go-toml v1.9.3/go.mod h1:u1nR/EPcESfeI/szUZKdtJ0xRNbUoANCkoOuaOx1Y+c=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/satori/go.uuid v1.2.0 h1:0uYX9dsZ2yD7q2RtLRtPSdGDWzjeM3TbMJP9utgA0ww=
 github.com/satori/go.uuid v1.2.0/go.mod h1:dA0hQrYB0VpLJoorglMZABFdXlWrHn1NEOzdhQKdks0=
 github.com/sergi/go-diff v1.0.0 h1:Kpca3qRNrduNnOQeazBd0ysaKrUJiIuISHxogkT9RPQ=
 github.com/sergi/go-diff v1.0.0/go.mod h1:0CfEIISq7TuYL3j771MWULgwwjU+GofnZX9QAmXWZgo=
+github.com/sirupsen/logrus v1.8.1 h1:dJKuHgqk1NNQlqoA6BTlM1Wf9DOH3NBjQyu0h9+AZZE=
+github.com/sirupsen/logrus v1.8.1/go.mod h1:yWOB1SBYBC5VeMP7gHvWumXLIWorT60ONWic61uBYv0=
 github.com/smartystreets/assertions v0.0.0-20180927180507-b2de0cb4f26d h1:zE9ykElWQ6/NYmHa3jpm/yHnI4xSofP+UP6SpjHcSeM=
 github.com/smartystreets/assertions v0.0.0-20180927180507-b2de0cb4f26d/go.mod h1:OnSkiWE9lh6wB0YB77sQom3nweQdgAjqCqsofrRNTgc=
 github.com/smartystreets/goconvey v1.6.4 h1:fv0U8FUIMPNf1L9lnHLvLhgicrIVChEkdzIKYqbNC9s=
 github.com/smartystreets/goconvey v1.6.4/go.mod h1:syvi0/a8iFYH4r/RixwvyeAJjdLS9QV7WQ/tjFTllLA=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY=
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
@@ -68,6 +72,8 @@ golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJ
 golang.org/x/sys v0.0.0-20180903190138-2b024373dcd9/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20191026070338-33540a1f6037 h1:YyJpGZS1sBuBCzLAR1VEpK193GlqGZbnPFnPV/5Rsb4=
+golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/time v0.0.0-20191024005414-555d28b269f0 h1:/5xXl8Y5W96D+TtHSlonuFqGHIWVuyCkGJLwGh9JJFs=
 golang.org/x/time v0.0.0-20191024005414-555d28b269f0/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
diff --git a/service.toml b/service.toml
index 99a737c..6f04c56 100644
--- a/service.toml
+++ b/service.toml
@@ -7,20 +7,24 @@ required = ["credential"]
 optional = ["service_features", "default_service_pairs", "endpoint", "http_client_options"]
 
 [namespace.storage]
-implement = ["appender", "multiparter"]
+features = ["virtual_dir"]
+implement = ["appender", "direr", "multiparter"]
 
 [namespace.storage.new]
 required = ["name"]
 optional = ["storage_features", "default_storage_pairs", "work_dir"]
 
 [namespace.storage.op.create]
-optional = ["multipart_id"]
+optional = ["multipart_id", "object_mode"]
+
+[namespace.storage.op.create_dir]
+optional = ["storage_class"]
 
 [namespace.storage.op.delete]
-optional = ["multipart_id"]
+optional = ["multipart_id", "object_mode"]
 
 [namespace.storage.op.stat]
-optional = ["multipart_id"]
+optional = ["multipart_id", "object_mode"]
 
 [namespace.storage.op.list]
 optional = ["list_mode"]
diff --git a/storage.go b/storage.go
index 56cd316..42c6108 100644
--- a/storage.go
+++ b/storage.go
@@ -2,12 +2,14 @@ package oss
 
 import (
 	"context"
+	"fmt"
 	"io"
 	"strconv"
 	"time"
 
 	"github.com/aliyun/aliyun-oss-go-sdk/oss"
 
+	ps "github.com/beyondstorage/go-storage/v4/pairs"
 	"github.com/beyondstorage/go-storage/v4/pkg/headers"
 	"github.com/beyondstorage/go-storage/v4/pkg/iowrap"
 	"github.com/beyondstorage/go-storage/v4/services"
@@ -46,16 +48,27 @@ func (s *Storage) completeMultipart(ctx context.Context, o *Object, parts []*Par
 }
 
 func (s *Storage) create(path string, opt pairStorageCreate) (o *Object) {
+	rp := s.getAbsPath(path)
+
 	// Handle create multipart object separately.
 	if opt.HasMultipartID {
 		o = s.newObject(true)
 		o.Mode = ModePart
 		o.SetMultipartID(opt.MultipartID)
 	} else {
-		o = s.newObject(false)
-		o.Mode = ModeRead
+		if opt.HasObjectMode && opt.ObjectMode.IsDir() {
+			if !s.features.VirtualDir {
+				return
+			}
+			rp += "/"
+			o = s.newObject(true)
+			o.Mode = ModeDir
+		} else {
+			o = s.newObject(false)
+			o.Mode = ModeRead
+		}
 	}
-	o.ID = s.getAbsPath(path)
+	o.ID = rp
 	o.Path = path
 	return o
 }
@@ -94,6 +107,35 @@ func (s *Storage) createAppend(ctx context.Context, path string, opt pairStorage
 	return o, nil
 }
 
+func (s *Storage) createDir(ctx context.Context, path string, opt pairStorageCreateDir) (o *Object, err error) {
+	if !s.features.VirtualDir {
+		err = NewOperationNotImplementedError("create_dir")
+		return
+	}
+	rp := s.getAbsPath(path)
+
+	// Add `/` at the end of path to simulate directory.
+	// ref: https://help.aliyun.com/document_detail/31978.html#title-gkg-amg-aes
+	rp += "/"
+
+	options := make([]oss.Option, 0)
+	options = append(options, oss.ContentLength(0))
+	if opt.HasStorageClass {
+		options = append(options, oss.StorageClass(oss.StorageClassType(opt.StorageClass)))
+	}
+
+	err = s.bucket.PutObject(rp, nil, options...)
+	if err != nil {
+		return
+	}
+
+	o = s.newObject(true)
+	o.Path = path
+	o.ID = rp
+	o.Mode |= ModeDir
+	return
+}
+
 func (s *Storage) createMultipart(ctx context.Context, path string, opt pairStorageCreateMultipart) (o *Object, err error) {
 	rp := s.getAbsPath(path)
 
@@ -124,10 +166,6 @@ func (s *Storage) createMultipart(ctx context.Context, path string, opt pairStor
 	o.Path = path
 	o.Mode |= ModePart
 	o.SetMultipartID(output.UploadID)
-	// set multipart restriction
-	o.SetMultipartNumberMaximum(multipartNumberMaximum)
-	o.SetMultipartNumberMaximum(multipartSizeMaximum)
-	o.SetMultipartSizeMinimum(multipartSizeMinimum)
 
 	return o, nil
 }
@@ -152,6 +190,15 @@ func (s *Storage) delete(ctx context.Context, path string, opt pairStorageDelete
 		return
 	}
 
+	if opt.HasObjectMode && opt.ObjectMode.IsDir() {
+		if !s.features.VirtualDir {
+			err = services.PairUnsupportedError{Pair: ps.WithObjectMode(opt.ObjectMode)}
+			return
+		}
+
+		rp += "/"
+	}
+
 	// OSS DeleteObject is idempotent, so we don't need to check NoSuchKey error.
 	//
 	// References
@@ -201,6 +248,14 @@ func (s *Storage) metadata(opt pairStorageMetadata) (meta *StorageMeta) {
 	meta = NewStorageMeta()
 	meta.Name = s.bucket.BucketName
 	meta.WorkDir = s.workDir
+	// set write restriction
+	meta.SetWriteSizeMaximum(writeSizeMaximum)
+	// set append restriction
+	meta.SetAppendTotalSizeMaximum(appendTotalSizeMaximum)
+	// set multipart restrictions
+	meta.SetMultipartNumberMaximum(multipartNumberMaximum)
+	meta.SetMultipartNumberMaximum(multipartSizeMaximum)
+	meta.SetMultipartSizeMinimum(multipartSizeMinimum)
 	return
 }
 
@@ -390,6 +445,15 @@ func (s *Storage) stat(ctx context.Context, path string, opt pairStorageStat) (o
 		return o, nil
 	}
 
+	if opt.HasObjectMode && opt.ObjectMode.IsDir() {
+		if !s.features.VirtualDir {
+			err = services.PairUnsupportedError{Pair: ps.WithObjectMode(opt.ObjectMode)}
+			return
+		}
+
+		rp += "/"
+	}
+
 	output, err := s.bucket.GetObjectMeta(rp)
 	if err != nil {
 		return nil, err
@@ -398,7 +462,11 @@ func (s *Storage) stat(ctx context.Context, path string, opt pairStorageStat) (o
 	o = s.newObject(true)
 	o.ID = rp
 	o.Path = path
-	o.Mode |= ModeRead
+	if opt.HasObjectMode && opt.ObjectMode.IsDir() {
+		o.Mode |= ModeDir
+	} else {
+		o.Mode |= ModeRead
+	}
 
 	if v := output.Get(headers.ContentLength); v != "" {
 		size, err := strconv.ParseInt(v, 10, 64)
@@ -427,7 +495,7 @@ func (s *Storage) stat(ctx context.Context, path string, opt pairStorageStat) (o
 		o.SetContentType(v)
 	}
 
-	var sm ObjectMetadata
+	var sm ObjectSystemMetadata
 	if v := output.Get(storageClassHeader); v != "" {
 		sm.StorageClass = v
 	}
@@ -437,12 +505,17 @@ func (s *Storage) stat(ctx context.Context, path string, opt pairStorageStat) (o
 	if v := output.Get(serverSideEncryptionKeyIdHeader); v != "" {
 		sm.ServerSideEncryptionKeyID = v
 	}
-	o.SetServiceMetadata(sm)
+	o.SetSystemMetadata(sm)
 
 	return o, nil
 }
 
 func (s *Storage) write(ctx context.Context, path string, r io.Reader, size int64, opt pairStorageWrite) (n int64, err error) {
+	if size > writeSizeMaximum {
+		err = fmt.Errorf("size limit exceeded: %w", services.ErrRestrictionDissatisfied)
+		return
+	}
+
 	if opt.HasIoCallback {
 		r = iowrap.CallbackReader(r, opt.IoCallback)
 	}
@@ -500,6 +573,15 @@ func (s *Storage) writeAppend(ctx context.Context, o *Object, r io.Reader, size
 }
 
 func (s *Storage) writeMultipart(ctx context.Context, o *Object, r io.Reader, size int64, index int, opt pairStorageWriteMultipart) (n int64, part *Part, err error) {
+	if index < 0 || index >= multipartNumberMaximum {
+		err = fmt.Errorf("multipart number limit exceeded: %w", services.ErrRestrictionDissatisfied)
+		return
+	}
+	if size > multipartSizeMaximum {
+		err = fmt.Errorf("size limit exceeded: %w", services.ErrRestrictionDissatisfied)
+		return
+	}
+
 	imur := oss.InitiateMultipartUploadResult{
 		Bucket:   s.bucket.BucketName,
 		Key:      o.ID,
diff --git a/tests/storage_test.go b/tests/storage_test.go
index 4cbd418..0b0776c 100644
--- a/tests/storage_test.go
+++ b/tests/storage_test.go
@@ -27,3 +27,10 @@ func TestMultiparter(t *testing.T) {
 	}
 	tests.TestMultiparter(t, setupTest(t))
 }
+
+func TestDirer(t *testing.T) {
+	if os.Getenv("STORAGE_OSS_INTEGRATION_TEST") != "on" {
+		t.Skipf("STORAGE_OSS_INTEGRATION_TEST is not 'on', skipped")
+	}
+	tests.TestDirer(t, setupTest(t))
+}
diff --git a/tests/utils_test.go b/tests/utils_test.go
index 6574b98..c803638 100644
--- a/tests/utils_test.go
+++ b/tests/utils_test.go
@@ -18,6 +18,9 @@ func setupTest(t *testing.T) types.Storager {
 		ps.WithName(os.Getenv("STORAGE_OSS_NAME")),
 		ps.WithEndpoint(os.Getenv("STORAGE_OSS_ENDPOINT")),
 		ps.WithWorkDir("/"+uuid.New().String()+"/"),
+		oss.WithStorageFeatures(oss.StorageFeatures{
+			VirtualDir: true,
+		}),
 	)
 	if err != nil {
 		t.Errorf("new storager: %v", err)
diff --git a/utils.go b/utils.go
index 04e1d25..ff70c71 100644
--- a/utils.go
+++ b/utils.go
@@ -6,9 +6,9 @@ import (
 
 	"github.com/aliyun/aliyun-oss-go-sdk/oss"
 
+	"github.com/beyondstorage/go-endpoint"
 	ps "github.com/beyondstorage/go-storage/v4/pairs"
 	"github.com/beyondstorage/go-storage/v4/pkg/credential"
-	"github.com/beyondstorage/go-storage/v4/pkg/endpoint"
 	"github.com/beyondstorage/go-storage/v4/pkg/httpclient"
 	"github.com/beyondstorage/go-storage/v4/services"
 	typ "github.com/beyondstorage/go-storage/v4/types"
@@ -42,6 +42,7 @@ type Storage struct {
 	typ.UnimplementedStorager
 	typ.UnimplementedAppender
 	typ.UnimplementedMultiparter
+	typ.UnimplementedDirer
 }
 
 // String implements Storager.String
@@ -96,12 +97,22 @@ func newServicer(pairs ...typ.Pair) (srv *Service, err error) {
 		return nil, err
 	}
 
+	var url string
+	switch ep.Protocol() {
+	case endpoint.ProtocolHTTP:
+		url, _, _ = ep.HTTP()
+	case endpoint.ProtocolHTTPS:
+		url, _, _ = ep.HTTPS()
+	default:
+		return nil, services.PairUnsupportedError{Pair: ps.WithEndpoint(opt.Endpoint)}
+	}
+
 	var copts []oss.ClientOption
 	if opt.HasHTTPClientOptions {
 		copts = append(copts, oss.HTTPClient(httpclient.New(opt.HTTPClientOptions)))
 	}
 
-	srv.service, err = oss.New(ep.String(), ak, sk, copts...)
+	srv.service, err = oss.New(url, ak, sk, copts...)
 	if err != nil {
 		return nil, err
 	}
@@ -259,11 +270,11 @@ func (s *Storage) formatFileObject(v oss.ObjectProperties) (o *typ.Object, err e
 		o.SetEtag(v.ETag)
 	}
 
-	var sm ObjectMetadata
+	var sm ObjectSystemMetadata
 	if value := v.Type; value != "" {
 		sm.StorageClass = value
 	}
-	o.SetServiceMetadata(sm)
+	o.SetSystemMetadata(sm)
 
 	return
 }
@@ -311,3 +322,12 @@ const (
 	// multipartSizeMinimum is the minimum size for each part, 100KB.
 	multipartSizeMinimum = 100 * 1024
 )
+
+const (
+	// writeSizeMaximum is the maximum size for each object with a single PUT operation, 5GB.
+	// ref: https://help.aliyun.com/document_detail/31978.html#title-gkg-amg-aes
+	writeSizeMaximum = 5 * 1024 * 1024 * 1024
+	// appendSizeMaximum is the total maximum size for an append object, 5GB.
+	// ref: https://help.aliyun.com/document_detail/31981.html?spm=a2c4g.11186623.6.1684.479a3ea7S8dRgB#title-22f-5c3-0sv
+	appendTotalSizeMaximum = 5 * 1024 * 1024 * 1024
+)