1 files changed, 9 insertions, 23 deletions
diff --git a/whisper/whisperv5/topic.go b/whisper/whisperv5/topic.go
index 54d7422d1..d1996c460 100644
--- a/whisper/whisperv5/topic.go
+++ b/whisper/whisperv5/topic.go
@@ -19,10 +19,8 @@
 package whisperv5
 
 import (
-	"fmt"
-	"strings"
-
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
 )
 
 // Topic represents a cryptographically secure, probabilistic partial
@@ -46,24 +44,12 @@ func (topic *TopicType) String() string {
 	return string(common.ToHex(topic[:]))
 }
 
-// UnmarshalJSON parses a hex representation to a topic.
-func (t *TopicType) UnmarshalJSON(input []byte) error {
-	length := len(input)
-	if length >= 2 && input[0] == '"' && input[length-1] == '"' {
-		input = input[1 : length-1]
-	}
-	// strip "0x" for length check
-	if len(input) > 1 && strings.ToLower(string(input[:2])) == "0x" {
-		input = input[2:]
-	}
-	// validate the length of the input
-	if len(input) != TopicLength*2 {
-		return fmt.Errorf("unmarshalJSON failed: topic must be exactly %d bytes", TopicLength)
-	}
-	b := common.FromHex(string(input))
-	if b == nil {
-		return fmt.Errorf("unmarshalJSON failed: wrong topic format")
-	}
-	*t = BytesToTopic(b)
-	return nil
+// MarshalText returns the hex representation of t.
+func (t TopicType) MarshalText() ([]byte, error) {
+	return hexutil.Bytes(t[:]).MarshalText()
+}
+
+// UnmarshalText parses a hex representation to a topic.
+func (t *TopicType) UnmarshalText(input []byte) error {
+	return hexutil.UnmarshalFixedText("Topic", input, t[:])
 }