zooko-spv.js

'use strict';

const assert = require('assert');
const {SPVNode, Namestate, Rules, resource} = require('hsd');

const argv = process.argv;
assert(argv.length === 3, 'Usage:\n $ node zooko-spv.js <name>');
assert(Rules.verifyName(argv[2], 'Invalid name.'));
const nameHash = Rules.hashName(argv[2]);

const node = new SPVNode({
  network: 'main',
  memory: true,
  workers: true
});

async function resolveAt(nameHash, root) {
  const peer = node.pool.pickProver(nameHash);

  // NameRequest class not exported from pool.js
  const item = {root};

  node.pool.nameMap.set(nameHash, item);
  peer.nameMap.set(nameHash, Date.now());
  peer.sendGetProof(root, nameHash);

  return new Promise((resolve, reject) => {
    item.resolve = resolve;
    item.reject = reject;
  });
}

const queue = [];

(async() => {
  node.on('connect', async (entry) => {
    if (entry.height % 100 === 0)
      console.log(`SPV headers chain height: ${entry.height}`);

    if (entry.height % 36 !== 0)
      return;

    const {treeRoot} = entry;
    queue.push({height: entry.height, root: treeRoot});
  });

  console.log('Opening in-memory SPV node...');
  await node.open();
  await node.connect();
  node.startSync();

  for(;;) {
    if (!queue.length) {
      await new Promise(r => setImmediate(r));
      continue;
    }

    const {height, root} = queue.shift();

    let records = null;
    try {
      const data = await resolveAt(nameHash, root);

      if (data) {
        const ns = Namestate.decode(data);
        if (ns.data.length > 0) {
          const res = resource.Resource.decode(ns.data);
          records = JSON.stringify(res.toJSON());
        }
      }

      console.log(
        ' ' +
        `height: ${height} ` +
        `tree root: ${root.toString('hex')} `+
        `records: ${records}`
      );
    } catch (e) {
      // Probably a peer timed out getting proof, retry...
      queue.unshift({height, root});
    } finally {
      await new Promise(r => setTimeout(r, 100));
    }
  }
})();


// Example output snippet:

// SPV headers chain height: 16700
// SPV headers chain height: 16800
// SPV headers chain height: 16900
// SPV headers chain height: 17000
// SPV headers chain height: 17100
// Error (Timed out.) retrying...
//  height: 4392 tree root: d88bbfd5c5d20035ce3d7b71579732a02b4105a8afdad9ef09e2b155b1a3a222 records: null
//  height: 4428 tree root: 2e1a8c84b182b85f8a072b95b3a42d21a55fb13c227e271153b72a0f681f7246 records: null
//  height: 4464 tree root: f0ab4c73fa171e1ab6fa48281b86b44a0f94e425a1ce0f96dc1eaa73f2419912 records: null
//  height: 4500 tree root: bdf23fdbe9796a10957e348aaf1b86be949a1fb3df725e94607f7270456ffc2e records: null
// SPV headers chain height: 17200
//  height: 4536 tree root: cabce5e0c39f2f76f81983dd7fd436329eb330426fa780ff44cfbec4fa17bcaa records: {"records":[{"type":"NS","ns":"a.dns.park.io."}]}
//  height: 4572 tree root: 42a1dddd8c50174dbd8b2897ab984f00c7d4c5cba5fa4da483c7528306fb5da3 records: {"records":[{"type":"NS","ns":"a.dns.park.io."}]}
//  height: 4608 tree root: 2c80023af98b1f21ca29cd992ca0c4a786ddf13253e0e2b478d05f88bab278ca records: {"records":[{"type":"NS","ns":"a.dns.park.io."}]}
//  height: 4644 tree root: c4ac14b925f8a742ccbf93f098b26762a6bd5719413031eecb98cc9cb187b147 records: {"records":[{"type":"NS","ns":"a.dns.park.io."}]}
// SPV headers chain height: 17300
//  height: 4680 tree root: af81df51f70494c60179f3bd1ecdc7871a542bffa09b37e928aa03f4dcea598c records: {"records":[{"type":"NS","ns":"a.dns.park.io."}]}
// SPV headers chain height: 17400