index.js

const express = require('express');
const request = require('request');
const bodyParser = require('body-parser');
const Blockchain = require('./blockchain');
const PubSub = require('./pubsub.js');

const app = express();
const blockchain = new Blockchain();
const pubsub = new PubSub({ blockchain });

const DEFAULT_PORT = 3000;
const ROOT_NODE_ADDRESS = `http://localhost:${DEFAULT_PORT}`;

// setTimeout(() => pubsub.broadcastChain(), 1000);

app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));

app.get('/', (req, res) => res.send('Welcome to Scriptcoin Blockchain'));

app.get('/api/blocks', (req, res) => {
  res.json(blockchain.chain);
});

app.post('/api/mine', (req, res) => {
  const { data } = req.body;

  blockchain.addBlock({ data });

  pubsub.broadcastChain();
  res.redirect('/api/blocks');
});

const syncBlockchains = () => {
  request(
    {
      url: `${ROOT_NODE_ADDRESS}/api/blocks`
    },
    (error, response, body) => {
      if (!error && response.statusCode === 200) {
        const rootChain = JSON.parse(body);
        blockchain.replaceChain(rootChain);
      }
    }
  );
};

let PEER_PORT;

if (process.env.GENERATE_PEER_PORT === 'true') {
  PEER_PORT = DEFAULT_PORT + Math.ceil(Math.random() * 1000);
}
const PORT = PEER_PORT || DEFAULT_PORT;

app.listen(PORT, () => {
  console.log(`The blockchain app is listening on port ${PORT}!`);

  if (PORT !== DEFAULT_PORT) {
    syncBlockchains();
  }
});