reconstructBlockchainFromBlock, deletePeerFromPeersList when conn is closed, REST routes: GenesisBlock, NextBlock, LastBlock

peer/README.md

@@ -64,8 +64,9 @@ Needs the config.json file:
 
 
 ## TODO
-- When a peer connects to the network, sends his last Block, and receives the new Blocks from this last Block
-- Delete the peer from the peers list when the connection is closed
+- When a peer connects to the network, sends his last Block, and receives the new Blocks from this last Block --> DONE with REST petitions, maybe is better with tcp conn
+- Delete the peer from the peers list when the connection is closed --> DONE
 - REST:
     - endpoint to get if the address is in the blockchain (to verify users)
 - parameters Date or LastUpdate on the structs needs to be updated values
+- implement rsa encryption between peers

peer/blockchain.go

@@ -1,8 +1,14 @@
 package main
 
 import (
+	"encoding/json"
 	"errors"
+	"fmt"
+	"io/ioutil"
+	"net/http"
 	"time"
+
+	"github.com/fatih/color"
 )
 
 type Block struct {
@@ -57,7 +63,11 @@ func (bc *Blockchain) blockExists(block Block) bool {
 	}
 	return false
 }
+
 func (bc *Blockchain) addBlock(block Block) error {
+	if blockchain.blockExists(block) {
+		return errors.New("[Error adding Block]: Block already exists in the Blockchain")
+	}
 	if len(bc.Blocks) > 0 {
 		bc.Blocks[len(bc.Blocks)-1].NextHash = block.Hash
 	} else {
@@ -67,3 +77,48 @@ func (bc *Blockchain) addBlock(block Block) error {
 
 	return nil
 }
+
+func reconstructBlockchainFromBlock(urlAPI string, h string) {
+	color.Yellow("reconstructing the blockchain from last block in memory")
+	var block Block
+	if h == "" {
+		//no genesis block yet
+		color.Green(urlAPI + "/blocks/genesis")
+		res, err := http.Get(urlAPI + "/blocks/genesis")
+		check(err)
+		body, err := ioutil.ReadAll(res.Body)
+		check(err)
+		err = json.Unmarshal(body, &block)
+		check(err)
+		color.Yellow("[New Block]: " + block.Hash)
+		err = blockchain.addBlock(block)
+		check(err)
+	} else {
+		block.NextHash = h
+	}
+
+	for block.NextHash != "" {
+		res, err := http.Get(urlAPI + "/blocks/next/" + block.Hash)
+		check(err)
+		body, err := ioutil.ReadAll(res.Body)
+		check(err)
+		err = json.Unmarshal(body, &block)
+		check(err)
+		color.Yellow("[New Block]: " + block.Hash)
+		err = blockchain.addBlock(block)
+		check(err)
+	}
+	blockchain.print()
+}
+
+func (bc *Blockchain) print() {
+	color.Green("Printing Blockchain stored in memory")
+	color.Green("Genesis Block: " + bc.GenesisBlock)
+	for _, b := range bc.Blocks {
+		color.Green("Block height:")
+		fmt.Println(b.Height)
+		color.Green("Hash: " + b.Hash)
+		color.Green("Date: " + b.Date.String())
+		color.Green("---")
+	}
+}

peer/config.json

@@ -4,5 +4,6 @@
     "restip": "127.0.0.1",
     "restport": "3002",
     "serverip": "127.0.0.1",
-    "serverport": "3000"
+    "serverport": "3000",
+    "serverrestport": "3002"
 }

peer/connections.go

@@ -88,4 +88,7 @@ func handleConn(conn net.Conn, connPeer Peer) {
 	log.Println("Peer: " + conn.RemoteAddr().String() + " connection closed")
 	conn.Close()
 	//TODO delete the peer from the outcomingPeersList
+	deletePeerFromPeersList(connPeer, &outcomingPeersList)
+	color.Yellow("peer deleted, current peerList:")
+	printPeersList()
 }

peer/main.go

@@ -11,11 +11,12 @@ import (
 )
 
 type Peer struct {
-	ID   string   `json:"id"` //in the future, this will be the peer hash
-	IP   string   `json:"ip"`
-	Port string   `json:"port"`
-	Role string   `json:"role"` //client or server
-	Conn net.Conn `json:"conn"`
+	ID       string   `json:"id"` //in the future, this will be the peer hash
+	IP       string   `json:"ip"`
+	Port     string   `json:"port"`
+	RESTPort string   `json:"restport"`
+	Role     string   `json:"role"` //client or server
+	Conn     net.Conn `json:"conn"`
 }
 
 var running bool
@@ -34,6 +35,7 @@ func main() {
 	//runningPeer.ID = strconv.Itoa(randInt(1, 1000)) //0 is reserved for server
 	runningPeer.IP = config.IP
 	runningPeer.Port = config.Port
+	runningPeer.RESTPort = config.RESTPort
 	runningPeer.ID = hashPeer(runningPeer)
 	runningPeer.Role = "client"
 
@@ -66,6 +68,7 @@ func main() {
 		serverPeer.ID = hashPeer(serverPeer)
 		serverPeer.Role = "server"
 		connectToPeer(serverPeer)
+		reconstructBlockchainFromBlock("http://"+config.IP+":"+config.ServerRESTPort, blockchain.GenesisBlock)
 		go acceptPeers(runningPeer)
 	}
 

peer/messages.go

@@ -44,20 +44,6 @@ func messageHandler(peer Peer, msg Msg) {
 		updateNetworkPeersList(peer.Conn, msg.PeersList)
 		printPeersList()
 		break
-	case "MyID":
-		color.Blue("MyID")
-		fmt.Println(msg.Content)
-		color.Green(peer.Conn.RemoteAddr().String())
-		peer.ID = msg.Content
-		searchPeerAndUpdate(peer)
-
-		//time.Sleep(1000 * time.Millisecond)
-		/*
-			updatePeersList(peer.Conn, msg.PeersList)
-			propagatePeersList(peer)
-		*/
-		printPeersList()
-		break
 	case "Block":
 		if !blockchain.blockExists(msg.Block) {
 			blockchain.addBlock(msg.Block)

peer/peers.go

@@ -35,6 +35,14 @@ func peerIsInPeersList(p Peer, pl []Peer) int {
 	}
 	return r
 }
+
+func deletePeerFromPeersList(p Peer, pl *PeersList) {
+	i := peerIsInPeersList(p, pl.Peers)
+	if i != -1 {
+		//delete peer from pl.Peers
+		pl.Peers = append(pl.Peers[:i], pl.Peers[i+1:]...)
+	}
+}
 func appendPeerIfNoExist(pl PeersList, p Peer) PeersList {
 	i := peerIsInPeersList(p, pl.Peers)
 	if i == -1 {

peer/readConfig.go

@@ -7,12 +7,13 @@ import (
 
 //Config reads the config
 type Config struct {
-	IP         string `json:"ip"`
-	Port       string `json:"port"`
-	RestIP     string `json:"restip"`
-	RestPort   string `json:"restport"`
-	ServerIP   string `json:"serverip"`
-	ServerPort string `json:"serverport"`
+	IP             string `json:"ip"`
+	Port           string `json:"port"`
+	RestIP         string `json:"restip"`
+	RESTPort       string `json:"restport"`
+	ServerIP       string `json:"serverip"`
+	ServerPort     string `json:"serverport"`
+	ServerRESTPort string `json:"serverrestport"`
 }
 
 var config Config

peer/restRoutes.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 
 	"github.com/fatih/color"
+	"github.com/gorilla/mux"
 )
 
 type Routes []Route
@@ -29,6 +30,24 @@ var routes = Routes{
 		"/register",
 		PostUser,
 	},
+	Route{
+		"GenesisBlock",
+		"GET",
+		"/blocks/genesis",
+		GenesisBlock,
+	},
+	Route{
+		"NextBlock",
+		"GET",
+		"/blocks/next/{blockhash}",
+		NextBlock,
+	},
+	Route{
+		"LastBlock",
+		"GET",
+		"/blocks/last",
+		LastBlock,
+	},
 }
 
 type Address struct {
@@ -65,3 +84,39 @@ func PostUser(w http.ResponseWriter, r *http.Request) {
 	check(err)
 	fmt.Fprintln(w, string(jResp))
 }
+
+func GenesisBlock(w http.ResponseWriter, r *http.Request) {
+	var genesis Block
+	if len(blockchain.Blocks) >= 0 {
+		genesis = blockchain.Blocks[0]
+	}
+
+	jResp, err := json.Marshal(genesis)
+	check(err)
+	fmt.Fprintln(w, string(jResp))
+}
+
+func NextBlock(w http.ResponseWriter, r *http.Request) {
+	vars := mux.Vars(r)
+	blockhash := vars["blockhash"]
+
+	currBlock, err := blockchain.getBlockByHash(blockhash)
+	check(err)
+	nextBlock, err := blockchain.getBlockByHash(currBlock.NextHash)
+	check(err)
+
+	jResp, err := json.Marshal(nextBlock)
+	check(err)
+	fmt.Fprintln(w, string(jResp))
+}
+
+func LastBlock(w http.ResponseWriter, r *http.Request) {
+	var genesis Block
+	if len(blockchain.Blocks) > 0 {
+		genesis = blockchain.Blocks[len(blockchain.Blocks)-1]
+	}
+
+	jResp, err := json.Marshal(genesis)
+	check(err)
+	fmt.Fprintln(w, string(jResp))
+}

peer/restServer.go

@@ -11,10 +11,10 @@ func runRestServer() {
 	//run API
 	log.Println("server running")
 	log.Print("port: ")
-	log.Println(config.RestPort)
+	log.Println(config.RESTPort)
 	router := NewRouter()
 	headersOk := handlers.AllowedHeaders([]string{"X-Requested-With", "Access-Control-Allow-Origin"})
 	originsOk := handlers.AllowedOrigins([]string{"*"})
 	methodsOk := handlers.AllowedMethods([]string{"GET", "HEAD", "POST", "PUT", "OPTIONS"})
-	log.Fatal(http.ListenAndServe(":"+config.RestPort, handlers.CORS(originsOk, headersOk, methodsOk)(router)))
+	log.Fatal(http.ListenAndServe(":"+config.RESTPort, handlers.CORS(originsOk, headersOk, methodsOk)(router)))
 }