educational node bitcoin getwork pool cpu mining

miner.js

// educational node bitcoin getwork pool cpu mining

var request = require('request');
var crypto = require('crypto');

var json_rpc_id = 1;

function sha256(buf) {
	var sha = crypto.createHash('sha256');
	sha.update(buf);
	return sha.digest();
}

function reverse_hex(str) {
	var out = "";
	for(var i = 0; i < str.length; i += 2) {
		out = str.substr(i, 2) + out;
	}
	return out;
}

function swap32(buf) {
	if(buf.length % 4) throw "what";
	for(var i = 0; i < buf.length; i += 4) {
		buf.writeUInt32BE(buf.readUInt32LE(i), i);
	}
	return buf;
}

var BlockHeader = function() {};
BlockHeader.deserialize = function(buf) {
	var blockheader = new BlockHeader();
	blockheader.ver = buf.readUInt32LE(0);
	blockheader.prev_block = reverse_hex(buf.slice(4, 4+32).toString('hex'));
	blockheader.mrkl_root = reverse_hex(buf.slice(36, 36+32).toString('hex'));
	blockheader.time = buf.readUInt32LE(68);
	blockheader.bits = buf.readUInt32LE(72);
	blockheader.nonce = buf.readUInt32LE(76);
	return blockheader;
}
BlockHeader.prototype.serialize = function() {
	var buf = new Buffer(80);
	buf.writeUInt32LE(this.ver, 0);
	buf.write(reverse_hex(this.prev_block), 4, 32, 'hex');
	buf.write(reverse_hex(this.mrkl_root), 36, 32, 'hex');
	buf.writeUInt32LE(this.time, 68);
	buf.writeUInt32LE(this.bits, 72);
	buf.writeUInt32LE(this.nonce, 76);
	return buf;
};
BlockHeader.prototype.hash = function() {
	return reverse_hex(sha256(sha256(this.serialize())).toString('hex'));
};

var Work = function() {};
Work.get = function(url, cb) {
	var work = new Work();
	work.url = url;
	request({
		url: url,
		method: 'POST',
		body: JSON.stringify({
			"method": "getwork",
			"params": [],
			"id": (json_rpc_id++)
		})
	}, function(e, r, body) {
		console.log("RESPONSE1:", body);
		var result = JSON.parse(body);
		work.data = result.result.data;
		work.target = result.result.target;
		work.current_nonce = work.getBlockHeader().nonce; // usually 0
		setImmediate(cb.bind(this, work));
	});
};
Work.prototype.getBlockHeader = function() {
	var buf = new Buffer(this.data, 'hex');
	buf = swap32(buf);
	return BlockHeader.deserialize(buf);
};
Work.prototype.submit = function(blockheader) {
	var url = this.url;
	var data = swap32(blockheader.serialize()).toString('hex');
	data += this.data.substr(160);
	var body = JSON.stringify({
		"method": "getwork",
		"params": [data],
		"id": (json_rpc_id++)
	});
	console.log("SUBMIT:", body);
	request({
		url: url,
		method: 'POST',
		body: body
	}, function(e, r, body) {
		console.log("RESPONSE2:", body);
	});
};
Work.prototype.do = function(hashes, cb) {
	var blockheader = this.getBlockHeader();
	for(var i = 0; i < hashes; i++) {
		blockheader.nonce = ++this.current_nonce;
		var hash = blockheader.hash();
		if(hash.indexOf("00000000") == 0) {
			// todo: real target comparison
			this.submit(blockheader);
		}
	}
};



var url = 'http://user.worker:password@api.bitcoin.cz:8332';

var get_new_work = false;

var do_work = function(work) {
	work.do(10000);
	setImmediate(function() {
		if(get_new_work) {
			get_new_work = false;
			Work.get(url, do_work);
		} else {
			do_work(work);
		}
	});
};

Work.get(url, do_work);
setInterval(function() {
	get_new_work = true;
}, 1000 * 60 * 5); // 5 minutes...