Merge pull request #1005 from eordano/g7/hdkeys

HDKeys: add toBuffer/fromBuffer

lib/hdprivatekey.js

@@ -52,6 +52,8 @@ function HDPrivateKey(arg) {
       this._buildFromSerialized(arg);
     } else if (JSUtil.isValidJSON(arg)) {
       this._buildFromJSON(arg);
+    } else if (BufferUtil.isBuffer(arg) && HDPrivateKey.isValidSerialized(arg.toString())) {
+      this._buildFromSerialized(arg.toString());
     } else {
       throw HDPrivateKey.getSerializedError(arg);
     }
@@ -377,12 +379,8 @@ HDPrivateKey.prototype._buildFromBuffers = function(arg) {
   }
 
   var xprivkey;
-
-  if (!arg.xprivkey) {
-    xprivkey = Base58Check.encode(buffer.Buffer.concat(sequence));
-  } else {
-    xprivkey = arg.xprivkey;
-  }
+  xprivkey = Base58Check.encode(buffer.Buffer.concat(sequence));
+  arg.xprivkey = new Buffer(xprivkey);
 
   var privateKey = new PrivateKey(BN.fromBuffer(arg.privateKey));
   var publicKey = privateKey.toPublicKey();
@@ -480,10 +478,34 @@ HDPrivateKey.prototype.toObject = function toObject() {
   };
 };
 
+/**
+ * Returns a JSON representation of the HDPrivateKey
+ *
+ * @return {string}
+ */
 HDPrivateKey.prototype.toJSON = function toJSON() {
   return JSON.stringify(this.toObject());
 };
 
+/**
+ * Build a HDPrivateKey from a buffer
+ *
+ * @param {Buffer} arg
+ * @return {HDPrivateKey}
+ */
+HDPrivateKey.fromBuffer = function(arg) {
+  return new HDPrivateKey(arg.toString());
+};
+
+/**
+ * Returns a buffer representation of the HDPrivateKey
+ *
+ * @return {string}
+ */
+HDPrivateKey.prototype.toBuffer = function() {
+  return BufferUtil.copy(this._buffers.xprivkey);
+};
+
 HDPrivateKey.DefaultDepth = 0;
 HDPrivateKey.DefaultFingerprint = 0;
 HDPrivateKey.DefaultChildIndex = 0;

lib/hdpublickey.js

@@ -43,6 +43,8 @@ function HDPublicKey(arg) {
         return this._buildFromSerialized(arg);
       } else if (JSUtil.isValidJSON(arg)) {
         return this._buildFromJSON(arg);
+      } else if (BufferUtil.isBuffer(arg) && !HDPublicKey.getSerializedError(arg.toString())) {
+        return this._buildFromSerialized(arg.toString());
       } else {
         if (error instanceof hdErrors.ArgumentIsPrivateExtended) {
           return new HDPrivateKey(arg).hdPublicKey;
@@ -316,12 +318,8 @@ HDPublicKey.prototype._buildFromBuffers = function (arg) {
   }
 
   var xpubkey;
-
-  if (!arg.xpubkey) {
-    xpubkey = Base58Check.encode(BufferUtil.concat(sequence));
-  } else {
-    xpubkey = arg.xpubkey;
-  }
+  xpubkey = Base58Check.encode(BufferUtil.concat(sequence));
+  arg.xpubkey = new Buffer(xpubkey);
 
   var publicKey = PublicKey.fromString(arg.publicKey);
   var size = HDPublicKey.ParentFingerPrintSize;
@@ -417,6 +415,25 @@ HDPublicKey.prototype.toJSON = function toJSON() {
   return JSON.stringify(this.toObject());
 };
 
+/**
+ * Create a HDPublicKey from a buffer argument
+ *
+ * @param {Buffer} arg
+ * @return {HDPublicKey}
+ */
+HDPublicKey.fromBuffer = function(arg) {
+  return new HDPublicKey(arg);
+};
+
+/**
+ * Return a buffer representation of the xpubkey
+ *
+ * @return {Buffer}
+ */
+HDPublicKey.prototype.toBuffer = function() {
+  return BufferUtil.copy(this._buffers.xpubkey);
+};
+
 HDPublicKey.Hardened = 0x80000000;
 HDPublicKey.RootElementAlias = ['m', 'M'];
 

lib/util/buffer.js

@@ -37,6 +37,18 @@ module.exports = {
     return buffer;
   },
 
+  /**
+   * Return a copy of a buffer
+   *
+   * @param {Buffer} original
+   * @return {Buffer}
+   */
+  copy: function(original) {
+    var buffer = new Buffer(original.length);
+    original.copy(buffer);
+    return buffer;
+  },
+
   /**
    * Returns true if the given argument is an instance of a buffer. Tests for
    * both node's Buffer and Uint8Array

test/hdprivatekey.js

@@ -262,6 +262,17 @@ describe('HDPrivate key interface', function() {
     });
   });
 
+  describe('conversion to/from buffer', function() {
+    var str = 'xprv9s21ZrQH143K3QTDL4LXw2F7HEK3wJUD2nW2nRk4stbPy6cq3jPPqjiChkVvvNKmPGJxWUtg6LnF5kejMRNNU3TGtRBeJgk33yuGBxrMPHi';
+    it('should roundtrip to/from a buffer', function() {
+      var priv = new HDPrivateKey(str);
+      var toBuffer = priv.toBuffer();
+      var fromBuffer = HDPrivateKey.fromBuffer(toBuffer);
+      var roundTrip = new HDPrivateKey(fromBuffer.toBuffer());
+      roundTrip.xprivkey.should.equal(str);
+    });
+  });
+
   describe('conversion to plain object/json', function() {
     var plainObject = {
       'network':'livenet',

test/hdpublickey.js

@@ -153,6 +153,17 @@ describe('HDPublicKey interface', function() {
     pubKey.inspect().should.equal('<HDPublicKey: ' + pubKey.xpubkey + '>');
   });
 
+  describe('conversion to/from buffer', function() {
+
+    it('should roundtrip to an equivalent object', function() {
+      var pubKey = new HDPublicKey(xpubkey);
+      var toBuffer = pubKey.toBuffer();
+      var fromBuffer = HDPublicKey.fromBuffer(toBuffer);
+      var roundTrip = new HDPublicKey(fromBuffer.toBuffer());
+      roundTrip.xpubkey.should.equal(xpubkey);
+    });
+  });
+
   describe('conversion to different formats', function() {
     var plainObject = {
       'network':'livenet',