bitcoin Thin Clients Request a merkle block with bitcore-p2p


Example

In this example we will ask the bitcoin network for the merkle block number 442603.

In order to do this we need to send a filterload message and then we have to send a getdata message using the inventory type MSG_MERKLEBLOCK.

The peers should reply with a merkleblock message for the requested block and a tx message for any transactions in the requested block that matched the filter.

In bitcore-p2p we need to register an event for each message's type that we want recive.

let Pool = require('bitcore-p2p').Pool;
let BloomFilter = require('bitcore-p2p').BloomFilter;
let NetworksData = require('bitcore-lib').Networks;
let Messages = require('bitcore-p2p').Messages;

let network = 'livenet';  // Network can be livenet or testnet
let txs = []; // Here we store the transactions
let filteredBlocks = []; // Here we store the merkleblocks

// Date that we are loocking for
let data = {
  code: '88adcf0215d5fcbca5c6532aaecffb48128cf1a6',  // 1DTh7XPb42PgCFnuMHSitMPWxCfNNFej8n in hex fromat
  format: 'hex',
};

// Isatnciate and connect a node Pool
let pool = new Pool({network: NetworksData[network]});
pool.connect();

// Create a filter and a bitcoin message with the filter
let filter = BloomFilter.create(1000, 0.1).insert(new Buffer(data.code, data.format));
let filterLoad = new Messages({network: NetworksData[network]}).FilterLoad(filter);

// Create a bitcoin message for require a merkleblock
let blockHashRequested = '0000000000000000004f8325a66388e22c10e6de9f0f6e5809eaf1e0393efe02';
let getDataForFilteredBlock = new Messages({network: NetworksData[network]}).GetData.forFilteredBlock(blockHashRequested);

// Transactions and merkleblock are sent in different messages
pool.on('peertx', function(peer, message) {
  txs.push({
    peer: peer,
    message: message,
  });

  console.log('Recived from: ', peer.host);
  console.log('The transaction: ', message.transaction.hash);
});

pool.on('peermerkleblock', function(peer, message) {
  filteredBlocks.push({
    peer: peer,
    message: message,
  });

  console.log('Recived from: ', peer.host);
  console.log('The merkleBlock: ', message.merkleBlock.header.hash);
});

// Wait for pool to connect
setTimeout(function(){
  pool.sendMessage(filterLoad);
  pool.sendMessage(getDataForFilteredBlock);
}, 5000);

//Recived from:  138.68.111.63
//The merkleBlock:  0000000000000000004f8325a66388e22c10e6de9f0f6e5809eaf1e0393efe02
//Recived from:  138.68.111.63
//The transaction:  9aec6cc42ddcf5900d280f3fa598f5cdb101f00614785165f777a6856314f4d9
//Recived from:  103.3.61.48
//The merkleBlock:  0000000000000000004f8325a66388e22c10e6de9f0f6e5809eaf1e0393efe02
//Recived from:  103.3.61.48
//The transaction:  9aec6cc42ddcf5900d280f3fa598f5cdb101f00614785165f777a6856314f4d9