From 7dad281f69a316c67f7aba5599b73e7925a585d8 Mon Sep 17 00:00:00 2001
From: Michael Vines <mvines@gmail.com>
Date: Fri, 14 Sep 2018 08:27:40 -0700
Subject: [PATCH] Create TransferTokensTransaction class

---
 web3.js/src/connection.js       | 23 +++--------------------
 web3.js/src/transaction.js      | 26 +++++++++++++++++++++++++-
 web3.js/test/connection.test.js | 11 +++++++++--
 3 files changed, 37 insertions(+), 23 deletions(-)

diff --git a/web3.js/src/connection.js b/web3.js/src/connection.js
index 37fa343de3..c2fb7a6266 100644
--- a/web3.js/src/connection.js
+++ b/web3.js/src/connection.js
@@ -5,7 +5,7 @@ import fetch from 'node-fetch';
 import jayson from 'jayson/lib/client/browser';
 import {struct} from 'superstruct';
 
-import {bs58DecodePublicKey, Transaction} from './transaction';
+import {Transaction} from './transaction';
 import type {Account, PublicKey} from './account';
 import type {TransactionSignature, TransactionId} from './transaction';
 
@@ -218,30 +218,13 @@ export class Connection {
     return res.result;
   }
 
-
   /**
-   * Send tokens to another account
+   * Sign and send a transaction
    */
-  async sendTokens(from: Account, to: PublicKey, amount: number): Promise<TransactionSignature> {
-    const transaction = new Transaction();
-    transaction.fee = 0;
+  async sendTransaction(from: Account, transaction: Transaction): Promise<TransactionSignature> {
     transaction.lastId = await this.getLastId();
-    transaction.keys[0] = from.publicKey;
-    transaction.keys[1] = to;
-
-    // Forge a simple Budget Pay contract into `userdata`
-    // TODO: Clean this up
-    const userdata = Buffer.alloc(68); // 68 = serialized size of Budget enum
-    userdata.writeUInt32LE(60, 0);
-    userdata.writeUInt32LE(amount, 12);        // u64
-    userdata.writeUInt32LE(amount, 28);        // u64
-    const toData = bs58DecodePublicKey(to);
-    toData.copy(userdata, 36);
-    transaction.userdata = userdata;
-
     transaction.sign(from);
 
-    // Send it
     const wireTransaction = transaction.serialize();
     const unsafeRes = await this._rpcRequest('sendTransaction', [[...wireTransaction]]);
     const res = SendTokensRpcResult(unsafeRes);
diff --git a/web3.js/src/transaction.js b/web3.js/src/transaction.js
index 18eb2ec7bd..6ecb52ea5f 100644
--- a/web3.js/src/transaction.js
+++ b/web3.js/src/transaction.js
@@ -9,7 +9,7 @@ import type {Account, PublicKey} from './account';
 /**
  * @private
  */
-export function bs58DecodePublicKey(key: PublicKey): Buffer {
+function bs58DecodePublicKey(key: PublicKey): Buffer {
   const keyBytes = Buffer.from(bs58.decode(key));
   assert(keyBytes.length === 32);
   return keyBytes;
@@ -132,3 +132,27 @@ export class Transaction {
     return wireTransaction;
   }
 }
+
+/**
+ * A Transaction that immediately transfers tokens
+ */
+export class TransferTokensTransaction extends Transaction {
+  constructor(from: PublicKey, to: PublicKey, amount: number) {
+    super();
+
+    // Forge a simple Budget Pay contract into `userdata`
+    // TODO: Clean this up
+    const userdata = Buffer.alloc(68); // 68 = serialized size of Budget enum
+    userdata.writeUInt32LE(60, 0);
+    userdata.writeUInt32LE(amount, 12);        // u64
+    userdata.writeUInt32LE(amount, 28);        // u64
+    const toData = bs58DecodePublicKey(to);
+    toData.copy(userdata, 36);
+
+    Object.assign(this, {
+      fee: 0,
+      keys: [from, to],
+      userdata
+    });
+  }
+}
diff --git a/web3.js/test/connection.test.js b/web3.js/test/connection.test.js
index 9f5a7d53ca..94bafa1767 100644
--- a/web3.js/test/connection.test.js
+++ b/web3.js/test/connection.test.js
@@ -1,7 +1,8 @@
 // @flow
 
-import {Connection} from '../src/connection';
 import {Account} from '../src/account';
+import {Connection} from '../src/connection';
+import {TransferTokensTransaction} from '../src/transaction';
 import {mockRpc} from './__mocks__/node-fetch';
 
 const url = 'http://testnet.solana.com:8899';
@@ -272,7 +273,13 @@ test('transaction', async () => {
     }
   ]
   );
-  const signature = await connection.sendTokens(accountFrom, accountTo.publicKey, 10);
+
+  const transaction = new TransferTokensTransaction(
+    accountFrom.publicKey,
+    accountTo.publicKey,
+    10
+  );
+  const signature = await connection.sendTransaction(accountFrom, transaction);
 
   mockRpc.push([
     url,