Use Marshal and UnmarshalJSON for HexBytes

libs/bytes/bytes.go

@@ -69,3 +69,28 @@ func (bz HexBytes) Format(s fmt.State, verb rune) {
 		s.Write([]byte(fmt.Sprintf("%X", []byte(bz))))
 	}
 }
+
+// Matches the hexbytes MarshalJSON of tendermint/tendermint. Overrides the
+// default []byte Marshal implementation. This is basically the point of hex bytes.
+func (bz HexBytes) MarshalJSON() ([]byte, error) {
+	s := strings.ToUpper(hex.EncodeToString(bz))
+	jbz := make([]byte, len(s)+2)
+	jbz[0] = '"'
+	copy(jbz[1:], s)
+	jbz[len(jbz)-1] = '"'
+	return jbz, nil
+}
+
+// Matches the hexbytes UnmarshalJSON of tendermint/tendermint. Overrides the
+// default []byte Marshal implementation. This is basically the point of hex bytes.
+func (bz *HexBytes) UnmarshalJSON(data []byte) error {
+	if len(data) < 2 || data[0] != '"' || data[len(data)-1] != '"' {
+		return fmt.Errorf("invalid hex string: %s", data)
+	}
+	bz2, err := hex.DecodeString(string(data[1 : len(data)-1]))
+	if err != nil {
+		return err
+	}
+	*bz = bz2
+	return nil
+}

libs/bytes/bytes_test.go

@@ -72,3 +72,41 @@ func TestHexBytes_String(t *testing.T) {
 		t.Fatal(err)
 	}
 }
+
+// Define a struct to match the JSON structure
+type ValidatorsHash struct {
+	NextValidatorsHash HexBytes `json:"next_validators_hash"`
+}
+
+func TestMarshalBasic(t *testing.T) {
+	var vh ValidatorsHash
+	vh.NextValidatorsHash = []byte("abc")
+	bz, err := json.Marshal(vh)
+	if err != nil {
+		t.Fatal(err)
+	}
+	assert.Equal(t, string(bz), "{\"next_validators_hash\":\"616263\"}")
+}
+
+func TestUnmarshalBasic(t *testing.T) {
+	jsonData := []byte(`{"next_validators_hash":"616263"}`)
+	var vh ValidatorsHash
+	err := json.Unmarshal(jsonData, &vh)
+	if err != nil {
+		t.Fatalf("Error unmarshalling JSON: %v", err)
+		return
+	}
+	assert.Equal(t, string(vh.NextValidatorsHash), "abc")
+}
+
+func TestUnmarshalExample(t *testing.T) {
+	jsonData := []byte(`{"next_validators_hash":"20021C2FB4B2DDFF6E8C484A2ED5862910E3AD7074FC6AD1C972AD34891AE3A4"}`)
+	expectedLength := 32
+	var vh ValidatorsHash
+	err := json.Unmarshal(jsonData, &vh)
+	if err != nil {
+		t.Fatalf("Error unmarshalling JSON: %v", err)
+		return
+	}
+	assert.Equal(t, expectedLength, len(vh.NextValidatorsHash))
+}