implemented the blockchain, implemented the blocks propagation throught peers, implemented REST GetPeers and PostUser (address, pubK). Everything without any kind of blockchain verification. No cryptography yet.

.gitignore

@@ -0,0 +1 @@
+tests

peer/README.md

@@ -19,3 +19,53 @@ Needs the config.json file:
     "serverport": "3000"
 }
 ```
+
+
+## Peer REST API
+- GET /
+    - Returns the peer.ID (where peer.ID = hash(peer.IP + ":" + peer.Port))
+
+
+- GET /peers
+    - Returns the peer outcomingPeersList (the peers which the peer have connection)
+
+```json
+{
+    "PeerID": "VOnL-15rFsUiCnRoyGFksKvWKcwNBRz5iarRem0Ilvo=",
+    "peerslist": [
+        {
+            "id": "VOnL-15rFsUiCnRoyGFksKvWKcwNBRz5iarRem0Ilvo=",
+            "ip": "127.0.0.1",
+            "port": "3000",
+            "role": "server",
+            "conn": null
+        },
+        {
+            "id": "Lk9jEP1YcOAzl51yY61GdWADNe35_g5Teh12JeguHhA=",
+            "ip": "127.0.0.1",
+            "port": "3003",
+            "role": "client",
+            "conn": {}
+        },
+        {
+            "id": "xj78wuyN2_thFBsXOUXnwij4L8vualxQ9GnVRK6RS4c=",
+            "ip": "127.0.0.1",
+            "port": "3005",
+            "role": "client",
+            "conn": {}
+        }
+    ],
+    "date": "0001-01-01T00:00:00Z"
+}
+```
+
+- POST /register
+    - Adds the address (pubK of the user) to the blockchain
+
+
+## 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
+- 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

peer/blockchain.go

@@ -0,0 +1,69 @@
+package main
+
+import (
+	"errors"
+	"time"
+)
+
+type Block struct {
+	Hash         string    `json:"hash"`
+	Height       int64     `json:"height"`
+	Date         time.Time `json:"date"`
+	PreviousHash string    `json:"previoushash"`
+	NextHash     string    `json:"nexthash"`
+	Data         []Address `json:"data"`
+	Emitter      string    `json:"emitter"` //the ID of the peer that has emmited the block
+}
+
+type Blockchain struct {
+	GenesisBlock string    `json:"genesisblock"`
+	LastUpdate   time.Time `json:"lastupdate"`
+	Blocks       []Block   `json:"blocks"`
+}
+
+var blockchain Blockchain
+
+func (bc *Blockchain) getBlockByHash(hash string) (Block, error) {
+	for _, block := range bc.Blocks {
+		if block.Hash == hash {
+			return block, nil
+		}
+	}
+	var b Block
+	return b, errors.New("Block Hash not found")
+}
+
+func (bc *Blockchain) createBlock(address Address) Block {
+	var b Block
+	b.Height = int64(len(bc.Blocks))
+	if len(bc.Blocks) == 0 {
+		b.Height = 0
+	} else {
+		b.PreviousHash = bc.Blocks[len(bc.Blocks)-1].Hash
+	}
+	b.Date = time.Now()
+	b.Data = append(b.Data, address)
+	b.Emitter = runningPeer.ID
+
+	b.Hash = hashBlock(b)
+	return b
+}
+
+func (bc *Blockchain) blockExists(block Block) bool {
+	for _, b := range bc.Blocks {
+		if b.Hash == block.Hash {
+			return true
+		}
+	}
+	return false
+}
+func (bc *Blockchain) addBlock(block Block) error {
+	if len(bc.Blocks) > 0 {
+		bc.Blocks[len(bc.Blocks)-1].NextHash = block.Hash
+	} else {
+		bc.GenesisBlock = block.Hash
+	}
+	bc.Blocks = append(bc.Blocks, block)
+
+	return nil
+}

peer/connections.go

@@ -57,7 +57,8 @@ func handleConn(conn net.Conn, connPeer Peer) {
 	log.Println("handling conn: " + conn.RemoteAddr().String())
 	//reply to the conn, send the peerList
 	var msg Msg
-	msg = msg.construct("PeersList", "here my outcomingPeersList", outcomingPeersList)
+	msg.construct("PeersList", "here my outcomingPeersList")
+	msg.PeersList = outcomingPeersList
 	msgB := msg.toBytes()
 	_, err := conn.Write(msgB)
 	check(err)

peer/main.go

@@ -5,7 +5,6 @@ import (
 	"math/rand"
 	"net"
 	"os"
-	"strconv"
 	"time"
 
 	"github.com/fatih/color"
@@ -32,9 +31,10 @@ func main() {
 	//read configuration file
 	readConfig("config.json")
 
-	runningPeer.ID = strconv.Itoa(randInt(1, 1000)) //0 is reserved for server
+	//runningPeer.ID = strconv.Itoa(randInt(1, 1000)) //0 is reserved for server
 	runningPeer.IP = config.IP
 	runningPeer.Port = config.Port
+	runningPeer.ID = hashPeer(runningPeer)
 	runningPeer.Role = "client"
 
 	go runRestServer()
@@ -45,7 +45,8 @@ func main() {
 			color.Yellow("Running as p2p server")
 			runningPeer.Role = "server"
 			runningPeer.Port = config.ServerPort
-			runningPeer.ID = "0"
+			runningPeer.ID = hashPeer(runningPeer)
+			//runningPeer.ID = "0"
 		}
 	}
 	thisPeerID = runningPeer.ID
@@ -58,12 +59,13 @@ func main() {
 		go acceptPeers(runningPeer)
 	}
 	if runningPeer.Role == "client" {
-		var newPeer Peer
-		newPeer.ID = "0"
-		newPeer.IP = config.ServerIP
-		newPeer.Port = config.ServerPort
-		newPeer.Role = "server"
-		connectToPeer(newPeer)
+		var serverPeer Peer
+		//serverPeer.ID = "0"
+		serverPeer.IP = config.ServerIP
+		serverPeer.Port = config.ServerPort
+		serverPeer.ID = hashPeer(serverPeer)
+		serverPeer.Role = "server"
+		connectToPeer(serverPeer)
 		go acceptPeers(runningPeer)
 	}
 

peer/messages.go

@@ -14,6 +14,7 @@ type Msg struct {
 	Date      time.Time `json:"date"`
 	Content   string    `json:"content"`
 	PeersList PeersList `json:"peerslist"`
+	Block     Block     `json:"block"`
 }
 
 func messageHandler(peer Peer, msg Msg) {
@@ -57,18 +58,22 @@ func messageHandler(peer Peer, msg Msg) {
 		*/
 		printPeersList()
 		break
+	case "Block":
+		if !blockchain.blockExists(msg.Block) {
+			blockchain.addBlock(msg.Block)
+			propagateBlock(msg.Block)
+		}
+		break
 	default:
 		log.Println("Msg.Type not supported")
 		break
 	}
 
 }
-func (msg Msg) construct(msgtype string, msgcontent string, peersList PeersList) Msg {
+func (msg *Msg) construct(msgtype string, msgcontent string) {
 	msg.Type = msgtype
 	msg.Content = msgcontent
-	msg.PeersList = peersList
 	msg.Date = time.Now()
-	return msg
 }
 func (msg Msg) toBytes() []byte {
 	msgS, err := json.Marshal(msg)

peer/peersList.go → peer/peers.go

@@ -74,22 +74,16 @@ func propagatePeersList(p Peer) {
 			if peer.ID != p.ID && p.ID != "" {
 				color.Yellow(peer.ID + " - " + p.ID)
 				var msg Msg
-				msg = msg.construct("PeersList", "here my outcomingPeersList", outcomingPeersList)
+				msg.construct("PeersList", "here my outcomingPeersList")
+				msg.PeersList = outcomingPeersList
 				msgB := msg.toBytes()
 				_, err := peer.Conn.Write(msgB)
 				check(err)
 			} else {
-				//to the peer that has sent the peerList, we send our ID
-				/*
-					var msg Msg
-					var pl PeersList
-					msg = msg.construct("MyID", runningPeer.ID, pl)
-					msgB := msg.toBytes()
-					_, err := p.Conn.Write(msgB)
-					check(err)
-				*/
+				//to the peer that has sent the peerList, we send our PeersList
 				var msg Msg
-				msg = msg.construct("PeersList_Response", "here my outcomingPeersList", outcomingPeersList)
+				msg.construct("PeersList_Response", "here my outcomingPeersList")
+				msg.PeersList = outcomingPeersList
 				msgB := msg.toBytes()
 				_, err := peer.Conn.Write(msgB)
 				check(err)
@@ -123,3 +117,18 @@ func printPeersList() {
 	}
 	fmt.Println("")
 }
+
+//send the block to all the peers of the outcomingPeersList
+func propagateBlock(b Block) {
+	//prepare the msg to send to all connected peers
+	var msg Msg
+	msg.construct("Block", "new block")
+	msg.Block = b
+	msgB := msg.toBytes()
+	for _, peer := range outcomingPeersList.Peers {
+		if peer.Conn != nil {
+			_, err := peer.Conn.Write(msgB)
+			check(err)
+		}
+	}
+}

peer/restRoutes.go

@@ -0,0 +1,67 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+
+	"github.com/fatih/color"
+)
+
+type Routes []Route
+
+var routes = Routes{
+	Route{
+		"Index",
+		"GET",
+		"/",
+		Index,
+	},
+	Route{
+		"GetPeers",
+		"GET",
+		"/peers",
+		GetPeers,
+	},
+	Route{
+		"PostUser",
+		"POST",
+		"/register",
+		PostUser,
+	},
+}
+
+type Address struct {
+	Address string `json:"address"` //the pubK of the user, to perform logins
+}
+
+func Index(w http.ResponseWriter, r *http.Request) {
+	fmt.Fprintln(w, runningPeer.ID)
+}
+func GetPeers(w http.ResponseWriter, r *http.Request) {
+	jResp, err := json.Marshal(outcomingPeersList)
+	check(err)
+	fmt.Fprintln(w, string(jResp))
+}
+func PostUser(w http.ResponseWriter, r *http.Request) {
+
+	decoder := json.NewDecoder(r.Body)
+	var address Address
+	err := decoder.Decode(&address)
+	if err != nil {
+		panic(err)
+	}
+	defer r.Body.Close()
+	fmt.Println(address)
+	color.Blue(address.Address)
+
+	//TODO add the verification of the address, to decide if it's accepted to create a new Block
+	block := blockchain.createBlock(address)
+	blockchain.addBlock(block)
+
+	go propagateBlock(block)
+
+	jResp, err := json.Marshal(blockchain)
+	check(err)
+	fmt.Fprintln(w, string(jResp))
+}

peer/restServerRoutes.go

@@ -1,22 +0,0 @@
-package main
-
-import (
-	"fmt"
-	"net/http"
-)
-
-type Routes []Route
-
-var routes = Routes{
-	Route{
-		"Index",
-		"GET",
-		"/",
-		Index,
-	},
-}
-
-func Index(w http.ResponseWriter, r *http.Request) {
-	//ipFilter(w, r)
-	fmt.Fprintln(w, runningPeer.ID)
-}

peer/tests.sh

@@ -0,0 +1 @@
+curl -X POST -F address="thisisasampleaddress" http://127.0.0.1:3002/register

peer/utils.go

@@ -1,6 +1,9 @@
 package main
 
 import (
+	"crypto/sha256"
+	"encoding/base64"
+	"encoding/json"
 	"math/rand"
 	"net"
 	"strings"
@@ -27,3 +30,22 @@ func randInt(min int, max int) int {
 	r := rand.Intn(max-min) + min
 	return r
 }
+func hashPeer(p Peer) string {
+	/*peerJson, err := json.Marshal(p)
+	check(err)
+	peerString := string(peerJson)*/
+	peerString := p.IP + ":" + p.Port
+
+	h := sha256.New()
+	h.Write([]byte(peerString))
+	return base64.URLEncoding.EncodeToString(h.Sum(nil))
+}
+func hashBlock(b Block) string {
+	blockJson, err := json.Marshal(b)
+	check(err)
+	blockString := string(blockJson)
+
+	h := sha256.New()
+	h.Write([]byte(blockString))
+	return base64.URLEncoding.EncodeToString(h.Sum(nil))
+}