Add support for empty actions.

Author: KarlTheProgrammer

dist/golang/protocol/protocol.go

@@ -106,7 +106,8 @@ func Deserialize(script bitcoin.Script, isTest bool) (actions.Action, error) {
 			return nil, ErrNotTokenized
 		}
 
-		if msg.PayloadCount() != 3 {
+		payloadCount := msg.PayloadCount()
+		if payloadCount != 2 && payloadCount != 3 {
 			return nil, errors.Wrapf(ErrNotTokenized, "wrong payload count: %d",
 				msg.PayloadCount())
 		}
@@ -119,6 +120,17 @@ func Deserialize(script bitcoin.Script, isTest bool) (actions.Action, error) {
 			return nil, ErrUnknownVersion
 		}
 
+		if payloadCount == 2 {
+			// Action payload is not provided because it was empty.
+			result := actions.NewActionFromCode(string(msg.PayloadAt(1)))
+			if result == nil {
+				return nil, errors.Wrapf(ErrNotTokenized, "unknown action code: %s",
+					string(msg.PayloadAt(1)))
+			}
+
+			return result, nil
+		}
+
 		return actions.Deserialize(msg.PayloadAt(1), msg.PayloadAt(2))
 	}
 }
@@ -154,9 +166,9 @@ func ActionCodeForScript(script bitcoin.Script, isTest bool) (string, error) {
 			return "", ErrNotTokenized
 		}
 
-		if msg.PayloadCount() != 3 {
-			return "", errors.Wrapf(ErrNotTokenized, "wrong payload count: %d",
-				msg.PayloadCount())
+		payloadCount := msg.PayloadCount()
+		if payloadCount != 2 && payloadCount != 3 {
+			return "", errors.Wrapf(ErrNotTokenized, "wrong payload count: %d", payloadCount)
 		}
 
 		version, _, err := bitcoin.ParsePushNumberScript(msg.PayloadAt(0))
@@ -179,7 +191,12 @@ func WrapAction(action actions.Action, isTest bool) (envelope.BaseMessage, error
 	}
 
 	message := envelopeV1.NewMessage([][]byte{GetProtocolID(isTest)},
-		[][]byte{bitcoin.PushNumberScript(int64(Version)), []byte(action.Code()), payload})
+		[][]byte{bitcoin.PushNumberScript(int64(Version)), []byte(action.Code())})
+
+	if len(payload) > 0 {
+		// Only add action payload if it isn't empty.
+		message.AddPayload(payload)
+	}
 
 	return message, nil
 }

dist/golang/protocol/protocol_test.go

@@ -21,6 +21,10 @@ func Test_SerializeAction(t *testing.T) {
 			},
 			code: actions.CodeContractOffer,
 		},
+		{ // Empty action
+			action: &actions.ContractOffer{},
+			code:   actions.CodeContractOffer,
+		},
 	}
 
 	for i, test := range tests {