p2p-server.js

const Websocket = require("ws");

const P2P_PORT = process.env.P2P_PORT || 5001;
const peers = process.env.PEERS ? process.env.PEERS.split(',') : [];
const MESSAGE_TYPES = {
    chain: "CHAIN",
    transaction: "TRANSACTION",
    clear_transactions: "CLEAR_TRANSACTIONS"
};

class P2pServer {
    constructor(blockchain, transactionPool) {
        this.blockchain = blockchain;
        this.transactionPool = transactionPool;
        this.sockets = [];
    }

    listen() {
        const server = new Websocket.Server({ port: P2P_PORT });
        server.on('connection', socket => this.connectSocket(socket));
        this.connectToPeers();
        console.log(`listening for peer to peer connections on Port: ${P2P_PORT}`)
    }

    connectSocket(socket) {
        this.sockets.push(socket);
        console.log('socket connected');
        this.messageHandler(socket);
        this.sendChain(socket);
    }

    connectToPeers() {
        peers.forEach(peer => {
            //ws://localhost:5001
            const socket = new Websocket(peer);
            socket.on('open', () => this.connectSocket(socket));
            socket.onerror = function (error) {
                setTimeout(() => {
                    console.error(`ERROR: close connection to ${peer}`);
                    //connectToPeers();
                    socket.close();
                }, 5000);
            };
        });
    }

    messageHandler(socket) {
        socket.on('message', message => {
            const data = JSON.parse(message);
            switch (data.type) {
                case MESSAGE_TYPES.chain:
                    this.blockchain.replaceChain(data.chain);
                    break;
                case MESSAGE_TYPES.transaction:
                    this.transactionPool.updateOrAddTransaction(data.transaction);
                    break;
                case MESSAGE_TYPES.clear_transactions:
                    this.transactionPool.clear();
                    break;
            }
        });
    }

    sendChain(socket) {
        socket.send(JSON.stringify({
            type: MESSAGE_TYPES.chain,
            chain: this.blockchain.chain
        }));
    }

    sendTransaction(socket, transaction) {
        socket.send(JSON.stringify({
            type: MESSAGE_TYPES.transaction,
            transaction: transaction
        }));
    }

    syncChains() {
        this.sockets.forEach(socket => this.sendChain(socket));
    }

    broadcastTransaction(transaction) {
        this.sockets.forEach(socket => this.sendTransaction(socket, transaction));
    }

    broadcastClearTransactions() {
        this.sockets.forEach(socket => socket.send(JSON.stringify(
            { type: MESSAGE_TYPES.clear_transactions }
        )));
    }
}

module.exports = P2pServer;