From bcdb352ae08f4249fd9f03a0998e5b9c4694bdbf Mon Sep 17 00:00:00 2001
From: Rongjian Lan <rongjian.lan@gmail.com>
Date: Mon, 18 Jun 2018 17:25:54 -0700
Subject: [PATCH] Add RequestTransactionsMessage for requesting missing
 transactions in a node

---
 node/message.go | 16 ++++++++++++++--
 node/node.go    | 32 +++++++++++++++++++++-----------
 2 files changed, 35 insertions(+), 13 deletions(-)

diff --git a/node/message.go b/node/message.go
index dc537b1b3..3910eb85c 100644
--- a/node/message.go
+++ b/node/message.go
@@ -7,14 +7,15 @@ import (
 	"harmony-benchmark/common"
 )
 
+// The types of messages used for NODE/TRANSACTION
 type TransactionMessageType int
-
 const (
 	SEND TransactionMessageType = iota
+	REQUEST
 )
 
+// The types of messages used for NODE/CONTROL
 type ControlMessageType int
-
 const (
 	STOP ControlMessageType = iota
 )
@@ -29,6 +30,17 @@ func ConstructTransactionListMessage(transactions []blockchain.Transaction) []by
 	return byteBuffer.Bytes()
 }
 
+//ConstructTransactionListMessage constructs serialized transactions
+func ConstructRequestTransactionsMessage(transactionIds [][]byte) []byte {
+	byteBuffer := bytes.NewBuffer([]byte{byte(common.NODE)})
+	byteBuffer.WriteByte(byte(common.TRANSACTION))
+	byteBuffer.WriteByte(byte(REQUEST))
+	for _, txId := range transactionIds {
+		byteBuffer.Write(txId)
+	}
+	return byteBuffer.Bytes()
+}
+
 //ConstructStopMessage is  STOP message
 func ConstructStopMessage() []byte {
 	byteBuffer := bytes.NewBuffer([]byte{byte(common.NODE)})
diff --git a/node/node.go b/node/node.go
index 062e17a85..c9a9e2e93 100644
--- a/node/node.go
+++ b/node/node.go
@@ -1,8 +1,6 @@
 package node
 
 import (
-	"bytes"
-	"encoding/gob"
 	"harmony-benchmark/blockchain"
 	"harmony-benchmark/consensus"
 	"harmony-benchmark/common"
@@ -11,6 +9,8 @@ import (
 	"net"
 	"os"
 	"time"
+	"bytes"
+	"encoding/gob"
 )
 
 // A node represents a program (machine) participating in the network
@@ -105,15 +105,7 @@ func (node *Node) NodeHandler(conn net.Conn) {
 		actionType := common.NodeMessageType(msgType)
 		switch actionType {
 		case common.TRANSACTION:
-			txDecoder := gob.NewDecoder(bytes.NewReader(msgPayload[1:])) // skip the SEND messge type
-
-			txList := new([]blockchain.Transaction)
-			err := txDecoder.Decode(&txList)
-			if err != nil {
-				log.Println("Failed deserializing transaction list")
-			}
-			node.pendingTransactions = append(node.pendingTransactions, *txList...)
-			log.Println(len(node.pendingTransactions))
+			node.transactionMessageHandler(msgPayload)
 		case common.CONTROL:
 			controlType := msgPayload[0]
 			if ControlMessageType(controlType) == STOP {
@@ -125,6 +117,24 @@ func (node *Node) NodeHandler(conn net.Conn) {
 	}
 }
 
+func (node *Node) transactionMessageHandler(msgPayload []byte) {
+	txMessageType := TransactionMessageType(msgPayload[0])
+
+	switch txMessageType {
+	case SEND:
+		txDecoder := gob.NewDecoder(bytes.NewReader(msgPayload[1:])) // skip the SEND messge type
+
+		txList := new([]blockchain.Transaction)
+		err := txDecoder.Decode(&txList)
+		if err != nil {
+			log.Println("Failed deserializing transaction list")
+		}
+		node.pendingTransactions = append(node.pendingTransactions, *txList...)
+	case REQUEST:
+		// TODO: fill in logic to return the request transactions
+	}
+}
+
 func (node *Node) WaitForConsensusReady(readySignal chan int) {
 	for { // keep waiting for consensus ready
 		<-readySignal