index.js

// @ts-check
// Required imports
const { ApiPromise, WsProvider } = require('@polkadot/api');

const https = require('https');
const fs = require('fs');

var express = require('express');
var app = express();

var mysql = require('mysql');

// Local Polkadot node
var wsProviderUrl = 'ws://127.0.0.1:9944';

// CORS
app.use((req, res, next) => {
  res.header('Access-Control-Allow-Origin', '*');
  res.header('Access-Control-Allow-Headers', 'Authorization, X-API-KEY, Origin, X-Requested-With, Content-Type, Accept, Access-Control-Allow-Request-Method');
  res.header('Access-Control-Allow-Methods', 'GET, POST, OPTIONS, PUT, DELETE');
  res.header('Allow', 'GET, POST, OPTIONS, PUT, DELETE');
  next();
});

app.get('/system', async function (req, res) {
  
  //
  // Initialise the provider to connect to the local polkadot node
  //
  const provider = new WsProvider(wsProviderUrl);

  //
  // Create the API and wait until ready
  //
  const api = await ApiPromise.create(provider);

  // Retrieve chain, node name and node version
  const [chain, nodeName, nodeVersion] = await Promise.all([
    api.rpc.system.chain(),
    api.rpc.system.name(),
    api.rpc.system.version()
  ]);

  //
  // Disconnect. TODO: Reuse websocket connection
  //
  provider.disconnect();

  //
  // Outputs JSON
  //
  res.json({
    'chain': chain,
    'nodeName': nodeName,
    'nodeVersion': nodeVersion
  });

});


app.get('/session', async function (req, res) {
  
  //
  // Initialise the provider to connect to the local polkadot node
  //
  const provider = new WsProvider(wsProviderUrl);

  //
  // Create the API and wait until ready
  //
  const api = await ApiPromise.create(provider);

  //
  // Get session info
  //
  const session = await api.derive.session.info();

  //
  // Disconnect. TODO: Reuse websocket connection
  //
  provider.disconnect();

  //
  // Outputs JSON
  //
  res.json(session);

});

app.get('/bestblocknumber', async function (req, res) {
  
  //
  // Initialise the provider to connect to the local polkadot node
  //
  const provider = new WsProvider(wsProviderUrl);

  //
  // Create the API and wait until ready
  //
  const api = await ApiPromise.create(provider);

  //
  // Get best block number
  //
  const blockNumber = await api.derive.chain.bestNumber();

  //
  // Disconnect. TODO: Reuse websocket connection
  //
  provider.disconnect();

  //
  // Outputs JSON
  //
  res.json(blockNumber);

});


app.get('/validators', async function (req, res) {
  
  //
  // Initialise the provider to connect to the local polkadot node
  //
  const provider = new WsProvider(wsProviderUrl);

  //
  // Create the API and wait until ready
  //
  const api = await ApiPromise.create(provider);

  //
  // Retrieve active validators
  //
  const [validators] = await Promise.all([
    api.query.session.validators()
  ]);

  //
  // Map validator authorityId to staking info object
  //
  const validatorStaking = await Promise.all(
    validators.map(authorityId => api.derive.staking.info(authorityId))
  );

  //
  // Disconnect. TODO: Reuse websocket connection
  //
  provider.disconnect();

  //
  // Outputs JSON
  //
  res.json(validatorStaking);

});

app.get('/validator/:accountId', async function (req, res) {
  
  //
  // Initialise the provider to connect to the local polkadot node
  //
  const provider = new WsProvider(wsProviderUrl);

  //
  // Create the API and wait until ready
  //
  const api = await ApiPromise.create(provider);

  //
  // Retrieve validator staking info
  //
  const [validator] = await Promise.all([
    api.derive.staking.info(req.params.accountId)
  ]);

  //
  // Disconnect. TODO: Reuse websocket connection
  //
  provider.disconnect();

  //
  // Outputs JSON
  //
  res.json(validator);

});


app.get('/validator/graph/daily/:accountId', function (req, res, next) {

  // Connect to MySQL
  var con = mysql.createConnection({
    host: "localhost",
    user: "stats",
    password: "stats",
    database: 'validators'
  });
  // Last 24 hours
  con.query('SELECT id, accountId, timestamp, amount FROM bonded WHERE accountId = \'' + req.params.accountId + '\' ORDER BY id DESC LIMIT 288;', function(err, rows, fields) {
    if (err) throw err;
    
    res.json(rows);

  });

});

app.get('/validator/graph/weekly/:accountId', function (req, res, next) {

  // Connect to MySQL
  var con = mysql.createConnection({
    host: "localhost",
    user: "stats",
    password: "stats",
    database: 'validators'
  });
  // Last 7 days
  con.query('SELECT id, accountId, timestamp, amount FROM bonded WHERE accountId = \'' + req.params.accountId + '\' AND DATE_FORMAT(FROM_UNIXTIME(`timestamp`), "%d/%m/%Y %H:%i:%s") LIKE "%00:00:%" ORDER BY id DESC LIMIT 7;', function(err, rows, fields) {
    if (err) throw err;
    
    res.json(rows);

  });

});

app.get('/validator/graph/monthly/:accountId', function (req, res, next) {

  // Connect to MySQL
  var con = mysql.createConnection({
    host: "localhost",
    user: "stats",
    password: "stats",
    database: 'validators'
  });
  // Last month (30 days)
  con.query('SELECT id, accountId, timestamp, amount FROM bonded WHERE accountId = \'' + req.params.accountId + '\' AND DATE_FORMAT(FROM_UNIXTIME(`timestamp`), "%d/%m/%Y %H:%i:%s") LIKE "%00:00:%" ORDER BY id DESC LIMIT 720;', function(err, rows, fields) {

    if (err) throw err;
    
    res.json(rows);

  });

});



app.get('/offline', async function (req, res) {
  
  //
  // Initialise the provider to connect to the local polkadot node
  //
  const provider = new WsProvider(wsProviderUrl);

  //
  // Create the API and wait until ready
  //
  const api = await ApiPromise.create(provider);

  //
  // Get validator outages
  //
  const offlineEvents = await api.query.staking.recentlyOffline();

  //
  // Disconnect. TODO: Reuse websocket connection
  //
  provider.disconnect();

  //
  // Outputs JSON
  //
  res.json(offlineEvents);

});

// Certificate
const privateKey = fs.readFileSync('/etc/letsencrypt/live/alexander.polkastats.io/privkey.pem', 'utf8');
const certificate = fs.readFileSync('/etc/letsencrypt/live/alexander.polkastats.io/cert.pem', 'utf8');
const ca = fs.readFileSync('/etc/letsencrypt/live/alexander.polkastats.io/chain.pem', 'utf8');

const credentials = {
	key: privateKey,
	cert: certificate,
	ca: ca
};

// Starting https server
const httpsServer = https.createServer(credentials, app);

httpsServer.listen(8443, () => {
	console.log('HTTPS Server running on port 8443');
});