Register encode/decode funcs instead of types

client.go

@@ -869,7 +869,7 @@ func (c *Client) ActivateSession(ctx context.Context, s *Session) error {
 		},
 		ClientSoftwareCertificates: nil,
 		LocaleIDs:                  s.cfg.LocaleIDs,
-		UserIdentityToken:          ua.NewExtensionObject(s.cfg.UserIdentityToken),
+		UserIdentityToken:          ua.NewExtensionObject(s.cfg.UserIdentityToken, extensionObjectTypeID(s.cfg.UserIdentityToken)),
 		UserTokenSignature:         s.cfg.UserTokenSignature,
 	}
 	return c.SecureChannel().SendRequest(ctx, req, s.resp.AuthenticationToken, func(v interface{}) error {
@@ -895,6 +895,23 @@ func (c *Client) ActivateSession(ctx context.Context, s *Session) error {
 	})
 }
 
+func extensionObjectTypeID(v interface{}) *ua.ExpandedNodeID {
+	switch v.(type) {
+	case *ua.AnonymousIdentityToken:
+		return ua.NewFourByteExpandedNodeID(0, id.AnonymousIdentityToken_Encoding_DefaultBinary)
+	case *ua.UserNameIdentityToken:
+		return ua.NewFourByteExpandedNodeID(0, id.UserNameIdentityToken_Encoding_DefaultBinary)
+	case *ua.X509IdentityToken:
+		return ua.NewFourByteExpandedNodeID(0, id.X509IdentityToken_Encoding_DefaultBinary)
+	case *ua.IssuedIdentityToken:
+		return ua.NewFourByteExpandedNodeID(0, id.IssuedIdentityToken_Encoding_DefaultBinary)
+	case *ua.ServerStatusDataType:
+		return ua.NewFourByteExpandedNodeID(0, id.ServerStatusDataType_Encoding_DefaultBinary)
+	default:
+		return ua.NewTwoByteExpandedNodeID(0)
+	}
+}
+
 // CloseSession closes the current session.
 //
 // See Part 4, 5.6.4

ua/activate_session_request_test.go

@@ -6,6 +6,8 @@ package ua
 
 import (
 	"testing"
+
+	"github.com/gopcua/opcua/id"
 )
 
 func TestActivateSessionRequest(t *testing.T) {
@@ -17,7 +19,7 @@ func TestActivateSessionRequest(t *testing.T) {
 				ClientSignature:            &SignatureData{},
 				ClientSoftwareCertificates: nil,
 				LocaleIDs:                  nil,
-				UserIdentityToken:          NewExtensionObject(&AnonymousIdentityToken{PolicyID: "anonymous"}),
+				UserIdentityToken:          NewExtensionObject(&AnonymousIdentityToken{PolicyID: "anonymous"}, NewFourByteExpandedNodeID(0, id.AnonymousIdentityToken_Encoding_DefaultBinary)),
 				UserTokenSignature:         &SignatureData{},
 			},
 			Bytes: flatten(

ua/cancel_request_test.go

@@ -21,7 +21,7 @@ func TestCancelRequest(t *testing.T) {
 					}),
 					Timestamp:        time.Date(2018, time.August, 10, 23, 0, 0, 0, time.UTC),
 					RequestHandle:    1,
-					AdditionalHeader: NewExtensionObject(nil),
+					AdditionalHeader: NewExtensionObject(nil, NewTwoByteExpandedNodeID(0)),
 				},
 				RequestHandle: 1,
 			},

ua/cancel_response_test.go

@@ -19,7 +19,7 @@ func TestCancelResponse(t *testing.T) {
 					RequestHandle:      1,
 					ServiceDiagnostics: &DiagnosticInfo{},
 					StringTable:        []string{},
-					AdditionalHeader:   NewExtensionObject(nil),
+					AdditionalHeader:   NewExtensionObject(nil, NewTwoByteExpandedNodeID(0)),
 				},
 				CancelCount: 1,
 			},

ua/close_secure_channel_request_test.go

@@ -21,7 +21,7 @@ func TestCloseSecureChannelRequest(t *testing.T) {
 					}),
 					Timestamp:        time.Date(2018, time.August, 10, 23, 0, 0, 0, time.UTC),
 					RequestHandle:    1,
-					AdditionalHeader: NewExtensionObject(nil),
+					AdditionalHeader: NewExtensionObject(nil, NewTwoByteExpandedNodeID(0)),
 				},
 			},
 			Bytes: []byte{

ua/close_secure_channel_response_test.go

@@ -19,7 +19,7 @@ func TestCloseSecureChannelResponse(t *testing.T) {
 					RequestHandle:      1,
 					ServiceDiagnostics: &DiagnosticInfo{},
 					StringTable:        []string{},
-					AdditionalHeader:   NewExtensionObject(nil),
+					AdditionalHeader:   NewExtensionObject(nil, NewTwoByteExpandedNodeID(0)),
 				},
 			},
 			Bytes: []byte{

ua/close_session_request_test.go

@@ -21,7 +21,7 @@ func TestCloseSessionRequest(t *testing.T) {
 					}),
 					Timestamp:        time.Date(2018, time.August, 10, 23, 0, 0, 0, time.UTC),
 					RequestHandle:    1,
-					AdditionalHeader: NewExtensionObject(nil),
+					AdditionalHeader: NewExtensionObject(nil, NewTwoByteExpandedNodeID(0)),
 				},
 				DeleteSubscriptions: true,
 			},

ua/close_session_response_test.go

@@ -19,7 +19,7 @@ func TestCloseSessionResponse(t *testing.T) {
 					RequestHandle:      1,
 					ServiceDiagnostics: &DiagnosticInfo{},
 					StringTable:        []string{},
-					AdditionalHeader:   NewExtensionObject(nil),
+					AdditionalHeader:   NewExtensionObject(nil, NewTwoByteExpandedNodeID(0)),
 				},
 			},
 			Bytes: []byte{

ua/codec_test.go

@@ -21,8 +21,7 @@ type CodecTestCase struct {
 	Bytes  []byte
 }
 
-// RunCodecTest tests encoding, decoding and length calclulation for the given
-// object.
+// RunCodecTest tests encoding, decoding and length calculation for the given object.
 func RunCodecTest(t *testing.T, cases []CodecTestCase) {
 	t.Helper()
 

ua/create_session_request_test.go

@@ -21,7 +21,7 @@ func TestCreateSessionRequest(t *testing.T) {
 					}),
 					Timestamp:        time.Date(2018, time.August, 10, 23, 0, 0, 0, time.UTC),
 					RequestHandle:    1,
-					AdditionalHeader: NewExtensionObject(nil),
+					AdditionalHeader: NewExtensionObject(nil, NewTwoByteExpandedNodeID(0)),
 				},
 				ClientDescription: &ApplicationDescription{
 					ApplicationURI:      "app-uri",

ua/create_session_response_test.go

@@ -19,7 +19,7 @@ func TestCreateSessionResponse(t *testing.T) {
 					RequestHandle:      1,
 					ServiceDiagnostics: &DiagnosticInfo{},
 					StringTable:        []string{},
-					AdditionalHeader:   NewExtensionObject(nil),
+					AdditionalHeader:   NewExtensionObject(nil, NewTwoByteExpandedNodeID(0)),
 				},
 				SessionID: NewNumericNodeID(0, 1),
 				AuthenticationToken: NewByteStringNodeID(0, []byte{

ua/create_subscription_response_test.go

@@ -19,7 +19,7 @@ func TestCreateSubscriptionResponse(t *testing.T) {
 					RequestHandle:      1,
 					ServiceDiagnostics: &DiagnosticInfo{},
 					StringTable:        []string{},
-					AdditionalHeader:   NewExtensionObject(nil),
+					AdditionalHeader:   NewExtensionObject(nil, NewTwoByteExpandedNodeID(0)),
 				},
 				SubscriptionID:            1,
 				RevisedPublishingInterval: 1000,

ua/decode.go

@@ -43,6 +43,7 @@ func decode(b []byte, val reflect.Value, name string) (n int, err error) {
 		}()
 	}
 
+	// fmt.Printf("decode: %s is a %s\n", name, val.Kind())
 	buf := NewBuffer(b)
 	switch {
 	case isBinaryDecoder(val):
@@ -51,7 +52,6 @@ func decode(b []byte, val reflect.Value, name string) (n int, err error) {
 	case isTime(val):
 		val.Set(reflect.ValueOf(buf.ReadTime()).Convert(val.Type()))
 	default:
-		// fmt.Printf("decode: %s is a %s\n", name, val.Kind())
 		switch val.Kind() {
 		case reflect.Bool:
 			val.SetBool(buf.ReadBool())

ua/extension_object.go

@@ -5,21 +5,33 @@
 package ua
 
 import (
+	"fmt"
+	"reflect"
+
 	"github.com/gopcua/opcua/debug"
-	"github.com/gopcua/opcua/id"
 )
 
 // eotypes contains all known extension objects.
-var eotypes = NewTypeRegistry()
+var eotypes = NewFuncRegistry()
 
 // RegisterExtensionObject registers a new extension object type.
 // It panics if the type or the id is already registered.
 func RegisterExtensionObject(typeID *NodeID, v interface{}) {
-	if err := eotypes.Register(typeID, v); err != nil {
+	RegisterExtensionObjectFunc(typeID, DefaultEncodeExtensionObject, DefaultDecodeExtensionObject(v))
+}
+
+// RegisterExtensionObjectFunc registers a new extension object type using encode and decode functions
+// It panics if the type or the id is already registered.
+func RegisterExtensionObjectFunc(typeID *NodeID, ef encodefunc, df decodefunc) {
+	if err := eotypes.Register(typeID, ef, df); err != nil {
 		panic("Extension object " + err.Error())
 	}
 }
 
+func Deregister(typeID *NodeID) {
+	eotypes.Deregister(typeID)
+}
+
 // These flags define the value type of an ExtensionObject.
 // They cannot be combined.
 const (
@@ -28,6 +40,9 @@ const (
 	ExtensionObjectXML    = 2
 )
 
+type encodefunc func(v interface{}) ([]byte, error)
+type decodefunc func(b []byte, v interface{}) error
+
 // ExtensionObject is encoded as sequence of bytes prefixed by the NodeId of its DataTypeEncoding
 // and the number of bytes encoded.
 //
@@ -38,15 +53,16 @@ type ExtensionObject struct {
 	Value        interface{}
 }
 
-func NewExtensionObject(value interface{}) *ExtensionObject {
+func NewExtensionObject(value interface{}, typeID *ExpandedNodeID) *ExtensionObject {
 	e := &ExtensionObject{
-		TypeID: ExtensionObjectTypeID(value),
+		TypeID: typeID,
 		Value:  value,
 	}
 	e.UpdateMask()
 	return e
 }
 
+// Decode fails if there is no decode func registered for e
 func (e *ExtensionObject) Decode(b []byte) (int, error) {
 	buf := NewBuffer(b)
 	e.TypeID = new(ExpandedNodeID)
@@ -74,21 +90,57 @@ func (e *ExtensionObject) Decode(b []byte) (int, error) {
 	}
 
 	typeID := e.TypeID.NodeID
-	e.Value = eotypes.New(typeID)
-	if e.Value == nil {
+	decode := eotypes.DecodeFunc(typeID)
+	if decode == nil {
 		debug.Printf("ua: unknown extension object %s", typeID)
 		return buf.Pos(), buf.Error()
 	}
-
-	body.ReadStruct(e.Value)
+	err := decode(body.Bytes(), &e.Value)
+	if err != nil {
+		// TODO: we are losing Pos by creating new buf in decode?
+		return buf.Pos(), err
+	}
+	// TODO: we are losing Pos by creating new buf in decode?
 	return buf.Pos(), body.Error()
 }
 
+// Encode falls back to defaultencode if there is no encode func registered for e
 func (e *ExtensionObject) Encode() ([]byte, error) {
-	buf := NewBuffer(nil)
 	if e == nil {
 		e = &ExtensionObject{TypeID: NewTwoByteExpandedNodeID(0), EncodingMask: ExtensionObjectEmpty}
 	}
+
+	typeID := e.TypeID.NodeID
+	encode := eotypes.EncodeFunc(typeID)
+	if encode == nil {
+		debug.Printf("ua: unknown extension object %s", typeID)
+		return DefaultEncodeExtensionObject(e)
+	}
+	return encode(e)
+}
+
+// DefaultDecode creates a new instance of v and decodes into it
+func DefaultDecodeExtensionObject(v interface{}) func([]byte, interface{}) error {
+	return func(b []byte, vv interface{}) error {
+		rv := reflect.ValueOf(vv)
+		if rv.Kind() != reflect.Pointer || rv.IsNil() {
+			return fmt.Errorf("incorrect type to decode into")
+		}
+		r := reflect.New(reflect.TypeOf(v).Elem()).Interface()
+		buf := NewBuffer(b)
+		buf.ReadStruct(r)
+		reflect.Indirect(rv).Set(reflect.ValueOf(r))
+		return nil
+	}
+}
+
+// DefaultEncode encodes into bytes based on the go struct
+func DefaultEncodeExtensionObject(v interface{}) ([]byte, error) {
+	e, ok := v.(*ExtensionObject)
+	if !ok {
+		return nil, fmt.Errorf("expected ExtensionObject")
+	}
+	buf := NewBuffer(nil)
 	buf.WriteStruct(e.TypeID)
 	buf.WriteByte(e.EncodingMask)
 	if e.EncodingMask == ExtensionObjectEmpty {
@@ -114,23 +166,3 @@ func (e *ExtensionObject) UpdateMask() {
 		e.EncodingMask = ExtensionObjectBinary
 	}
 }
-
-func ExtensionObjectTypeID(v interface{}) *ExpandedNodeID {
-	switch v.(type) {
-	case *AnonymousIdentityToken:
-		return NewFourByteExpandedNodeID(0, id.AnonymousIdentityToken_Encoding_DefaultBinary)
-	case *UserNameIdentityToken:
-		return NewFourByteExpandedNodeID(0, id.UserNameIdentityToken_Encoding_DefaultBinary)
-	case *X509IdentityToken:
-		return NewFourByteExpandedNodeID(0, id.X509IdentityToken_Encoding_DefaultBinary)
-	case *IssuedIdentityToken:
-		return NewFourByteExpandedNodeID(0, id.IssuedIdentityToken_Encoding_DefaultBinary)
-	case *ServerStatusDataType:
-		return NewFourByteExpandedNodeID(0, id.ServerStatusDataType_Encoding_DefaultBinary)
-	default:
-		if id := eotypes.Lookup(v); id != nil {
-			return &ExpandedNodeID{NodeID: id}
-		}
-		return NewTwoByteExpandedNodeID(0)
-	}
-}

ua/extension_object_test.go

@@ -6,13 +6,15 @@ package ua
 
 import (
 	"testing"
+
+	"github.com/gopcua/opcua/id"
 )
 
 func TestExtensionObject(t *testing.T) {
 	cases := []CodecTestCase{
 		{
 			Name:   "anonymous-user-identity-token",
-			Struct: NewExtensionObject(&AnonymousIdentityToken{PolicyID: "anonymous"}),
+			Struct: NewExtensionObject(&AnonymousIdentityToken{PolicyID: "anonymous"}, NewFourByteExpandedNodeID(0, id.AnonymousIdentityToken_Encoding_DefaultBinary)),
 			Bytes: []byte{
 				// TypeID
 				0x01, 0x00, 0x41, 0x01,

ua/find_servers_on_network_request_test.go

@@ -21,7 +21,7 @@ func TestFindServersOnNetworkRequest(t *testing.T) {
 					}),
 					Timestamp:        time.Date(2018, time.August, 10, 23, 0, 0, 0, time.UTC),
 					RequestHandle:    1,
-					AdditionalHeader: NewExtensionObject(nil),
+					AdditionalHeader: NewExtensionObject(nil, NewTwoByteExpandedNodeID(0)),
 				},
 				StartingRecordID:       1000,
 				MaxRecordsToReturn:     0,
@@ -34,7 +34,7 @@ func TestFindServersOnNetworkRequest(t *testing.T) {
 			//			0xa6, 0x43, 0xf8, 0x77, 0x7b, 0xc6, 0x2f, 0xc8,
 			//		}),
 			//		time.Date(2018, time.August, 10, 23, 0, 0, 0, time.UTC),
-			//		1, 0, 0, "", NewExtensionObject(nil),
+			//		1, 0, 0, "", NewExtensionObject(nil,nil),
 			//	),
 			//	1000,
 			//	0,

ua/find_servers_on_network_response_test.go

@@ -19,7 +19,7 @@ func TestFindServersOnNetworkResponse(t *testing.T) {
 					RequestHandle:      1,
 					ServiceDiagnostics: &DiagnosticInfo{},
 					StringTable:        []string{},
-					AdditionalHeader:   NewExtensionObject(nil),
+					AdditionalHeader:   NewExtensionObject(nil, NewTwoByteExpandedNodeID(0)),
 				},
 				LastCounterResetTime: time.Date(2018, time.August, 10, 23, 0, 0, 0, time.UTC),
 				Servers: []*ServerOnNetwork{
@@ -72,7 +72,7 @@ func TestFindServersOnNetworkResponse(t *testing.T) {
 					RequestHandle:      1,
 					ServiceDiagnostics: &DiagnosticInfo{},
 					StringTable:        []string{},
-					AdditionalHeader:   NewExtensionObject(nil),
+					AdditionalHeader:   NewExtensionObject(nil, NewTwoByteExpandedNodeID(0)),
 				},
 				LastCounterResetTime: time.Date(2018, time.August, 10, 23, 0, 0, 0, time.UTC),
 				Servers: []*ServerOnNetwork{

ua/find_servers_request_test.go

@@ -21,7 +21,7 @@ func TestFindServersRequest(t *testing.T) {
 					}),
 					Timestamp:        time.Date(2018, time.August, 10, 23, 0, 0, 0, time.UTC),
 					RequestHandle:    1,
-					AdditionalHeader: NewExtensionObject(nil),
+					AdditionalHeader: NewExtensionObject(nil, NewTwoByteExpandedNodeID(0)),
 				},
 				EndpointURL: "opc.tcp://wow.its.easy:11111/UA/Server",
 			},

ua/find_servers_response_test.go

@@ -19,7 +19,7 @@ func TestFindServersResponse(t *testing.T) {
 					RequestHandle:      1,
 					ServiceDiagnostics: &DiagnosticInfo{},
 					StringTable:        []string{},
-					AdditionalHeader:   NewExtensionObject(nil),
+					AdditionalHeader:   NewExtensionObject(nil, NewTwoByteExpandedNodeID(0)),
 				},
 				Servers: []*ApplicationDescription{
 					{

ua/get_endpoints_request_test.go

@@ -21,7 +21,7 @@ func TestGetEndpointsRequest(t *testing.T) {
 					}),
 					Timestamp:        time.Date(2018, time.August, 10, 23, 0, 0, 0, time.UTC),
 					RequestHandle:    1,
-					AdditionalHeader: NewExtensionObject(nil),
+					AdditionalHeader: NewExtensionObject(nil, NewTwoByteExpandedNodeID(0)),
 				},
 				EndpointURL: "opc.tcp://wow.its.easy:11111/UA/Server",
 			},

ua/get_endpoints_response_test.go

@@ -19,7 +19,7 @@ func TestGetEndpointsResponse(t *testing.T) {
 					RequestHandle:      1,
 					ServiceDiagnostics: &DiagnosticInfo{},
 					StringTable:        []string{},
-					AdditionalHeader:   NewExtensionObject(nil),
+					AdditionalHeader:   NewExtensionObject(nil, NewTwoByteExpandedNodeID(0)),
 				},
 				Endpoints: []*EndpointDescription{
 					{