chainhash: JSON Unmarshal hash from appropriate string.

chaincfg/chainhash/hash.go

@@ -116,6 +116,21 @@ func (hash Hash) MarshalJSON() ([]byte, error) {
 	return json.Marshal(hash.String())
 }
 
+// UnmarshalJSON parses the hash with JSON appropriate string value.
+func (hash *Hash) UnmarshalJSON(input []byte) error {
+	var sh string
+	err := json.Unmarshal(input, &sh)
+	if err != nil {
+		return err
+	}
+	newHash, err := NewHashFromStr(sh)
+	if err != nil {
+		return err
+	}
+
+	return hash.SetBytes(newHash[:])
+}
+
 // NewHash returns a new Hash from a byte slice.  An error is returned if
 // the number of bytes passed in is not HashSize.
 func NewHash(newHash []byte) (*Hash, error) {

chaincfg/chainhash/hash_test.go

@@ -7,6 +7,7 @@ package chainhash
 import (
 	"bytes"
 	"encoding/hex"
+	"encoding/json"
 	"testing"
 )
 
@@ -194,3 +195,28 @@ func TestNewHashFromStr(t *testing.T) {
 		}
 	}
 }
+
+// TestHashJsonMarshal tests json marshal and unmarshal.
+func TestHashJsonMarshal(t *testing.T) {
+	hashStr := "000000000003ba27aa200b1cecaad478d2b00432346c3f1f3986da1afd33e506"
+
+	hash, err := NewHashFromStr(hashStr)
+	if err != nil {
+		t.Errorf("NewHashFromStr error:%v, hashStr:%s", err, hashStr)
+	}
+
+	hashBytes, err := json.Marshal(hash)
+	if err != nil {
+		t.Errorf("Marshal json error:%v, hash:%v", err, hashBytes)
+	}
+
+	var newHash Hash
+	err = json.Unmarshal(hashBytes, &newHash)
+	if err != nil {
+		t.Errorf("Unmarshal json error:%v, hash:%v", err, hashBytes)
+	}
+
+	if !hash.IsEqual(&newHash) {
+		t.Errorf("String: wrong hash string - got %v, want %v", newHash.String(), hashStr)
+	}
+}