BCoin is a bitcoin client which implements BIP-37. It can track transactions, public keys, and public key hashes (bitcoin addresses) without saving the entire blockchain to disk. This means you can have a wallet with a synchronized balance and send and receive payments without keeping track of a 20GB database.
BCoin is implemented in pure javascript, and is browserify-able (this means compiling a binding to an ECDSA library is not even required for node.js).
NOTE: BCoin is also in the process of supporting the original (pre-bip37) satoshi protocol, which will also optionally give the user the ability download the entire blockchain.
$ npm install bcoin
$ npm install levelup
$ npm install leveldown
var bcoin = require('bcoin');
var net = require('net');
var fs = require('fs');
// Standard bitcoin seeds
var seeds = [
'seed.bitcoin.sipa.be',
'dnsseed.bluematt.me',
'dnsseed.bitcoin.dashjr.org',
'seed.bitcoinstats.com',
'seed.bitnodes.io',
'bitseed.xf2.org'
];
var index = 0;
var pool = new bcoin.pool({
// Number of peers allowed
size: 32,
// This function must return a socket that supports the standard
// node socket model: `write()`, `destroy()` `on('data')`, etc.
createConnection: function() {
if (index >= seeds.length) {
index = 0;
}
var addr = seeds[index++];
var parts = addr.split(':');
var host = parts[0];
var port = +parts[1] || 8333;
var socket = net.connect(port, host);
socket.on('connect', function() {
console.log('Connected to %s:%d', host, port);
});
return socket;
},
// Storage DB for transactions and wallet, must support
// the levelup `put`/`del`/`createReadStream` methods.
storage: require('levelup')(process.env.HOME + '/.bcoin', {
db: require('leveldown'),
valueEncoding: 'json'
})
});
// Log connection errors to any peer
pool.on('error', function(err, peer) {
console.log(
'Connection failed to %s:%d: %s',
peer.addr.host,
peer.addr.port,
err
);
});
// Receive the address of another peer.
pool.on('addr', function(data, peer) {
var host = data.ipv4 + ':' + data.port;
if (!~seeds.indexOf(host)) {
console.log('Found new peer: %s', host);
seeds.push(host);
}
});
// Receive a block.
pool.on('block', function(block, peer) {
var hash = bcoin.utils.revHex(block.hash('hex'));
var ip = peer.socket.remoteAddress;
console.log(block);
console.log('Received block %s from %s.', hash, ip);
// Add tx hashes to our bloom filter. They're not useful if they're not our
// own, but what the hell: let's see what's going on in the world of bitcoin.
block.tx.forEach(function(hash) {
pool.watch(hash);
});
});
// Receive a transaction.
pool.on('tx', function(tx, peer) {
var hash = bcoin.utils.revHex(tx.hash('hex'));
var ip = peer.socket.remoteAddress;
console.log(tx);
console.log('Received transaction %s from %s.', hash, ip);
});
// Open our ecdsa private key (our bitcoin address is derived from this)
// `priv` can be a hex string, a binary array, or a big number (bn.js)
var privkeyfile = process.env.HOME + '/.bcoin/priv';
if (!fs.existsSync(privkeyfile)) {
try {
var privkey = bcoin.wallet().getPrivateKey('base58');
fs.writeFileSync(privkeyfile, privkey);
}
catch(err) {
console.log('Error creating private key file: '+err);
return;
}
}
var wallet = new bcoin.wallet({
priv: fs.readFileSync(privkeyfile),
storage: pool.storage
});
console.log('Opened our wallet with address: %s', wallet.getAddress());
// Make sure we keep an eye on any transactions pertaining to us.
pool.watch(wallet.getPublicKey());
pool.watch(wallet.getHash());
// Watch our balance update as we receive transactions.
wallet.on('balance', function(balance) {
// Convert satoshis to BTC.
var btc = bcoin.utils.toBTC(balance);
console.log('Your wallet balance has been updated: %s', btc);
});A bitcoin merkle block or (satoshi) block in its abstract bcoin format.
TODO...
The bloom filter used for the filterload packets, but also used for efficient
testing of existence in a collection in miscellaneous places.
TODO...
The blockchain which keeps track of block height and order.
TODO...
The peer object itself. The peer's socket resides here.
TODO...
The pool of peers, also instantiates a Chain object.
TODO...
A transaction in its abstract bcoin format.
TODO...
A pool of transactions that stores transactions based on their inputs and outputs and whether they contain certain public keys. Used by Wallet to keep track of relevant transactions.
TODO...
An object which contains an ecdsa keypair and can calculate balance for that
bitcoin address. This would be called an account in the traditional bitcoin
client.
TODO...
The low-level bitcoin protocol implementation.
The creation of outgoing packets.
TODO...
The parsing of incoming packets.
TODO...
Bitcoin constants, from the genesis block to magic number base58 prefixes.
TODO...
~3000 checkpoint blocks for the Chain to preload on instantiation.
TODO...
The bitcoin Script execution, for executing Script code in TX objects.
TODO...
Miscellaneous utilities used all throughout bcoin.
TODO...
This software is licensed under the MIT License.
Copyright Fedor Indutny, 2014.
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.