flocore-node/lib/services/block.js
2015-07-07 13:28:47 -04:00

528 lines
15 KiB
JavaScript

'use strict';
var config = require('config');
var LevelUp = require('levelup');
var Promise = require('bluebird');
var RPC = require('bitcoind-rpc');
var bitcore = require('bitcore');
var BufferUtil = bitcore.util.buffer;
var Block = bitcore.Block;
var errors = require('../errors');
var BlockChain = require('../blockchain');
var genesisBlocks = require('../data/genesis');
var TransactionService = require('./transaction');
var $ = bitcore.util.preconditions;
var JSUtil = bitcore.util.js;
var _ = bitcore.deps._;
var helper = function(index) {
return function(maybeHash) {
if (_.isString(maybeHash)) {
return index + maybeHash;
} else if (bitcore.util.buffer.isBuffer(maybeHash)) {
return index + maybeHash.toString('hex');
} else if (maybeHash instanceof bitcore.Block) {
return index + maybeHash.id;
} else {
throw new bitcore.errors.InvalidArgument();
}
};
};
var Index = {
timestamp: 'bts-', // bts-<timestamp> -> hash for the block that was mined at this TS
prev: 'prev-', // prev-<hash> -> parent hash
next: 'nxt-', // nxt-<hash> -> hash for the next block in the main chain that is a child
height: 'bh-', // bh-<hash> -> height (-1 means disconnected)
tip: 'tip', // tip -> { hash: hex, height: int }, the latest tip
work: 'wk-', // wk-<hash> -> amount of work for block
header: 'header-', // header-<hash> -> JSON for block header
blockchain: 'bc-'
};
_.extend(Index, {
getNextBlock: helper(Index.next),
getPreviousBlock: helper(Index.prev),
getBlockHeight: helper(Index.height),
getBlockWork: helper(Index.work),
getBlockByTs: function(block) {
return Index.timestamp + block.header.time;
},
getBlockHeader: helper(Index.header),
});
function BlockService(opts) {
opts = _.extend({}, opts);
this.database = opts.database || Promise.promisifyAll(new LevelUp(config.get('LevelUp')));
this.rpc = opts.rpc || Promise.promisifyAll(new RPC(config.get('RPC')));
this.transactionService = opts.transactionService || new TransactionService({
database: this.database,
rpc: this.rpc
});
}
/**
* Transforms data as received from an RPC result structure for `getblock`,
* plus a list of transactions, and build a block based on thosė.
*
* @param {Object} blockData
* @param {Number} blockData.version a 32 bit number with the version of the block
* @param {string} blockData.previousblockhash a string of length 64 with the hexa encoding of the
* hash for the previous block
* @param {Number} blockData.time a 32 bit number with the timestamp when this block was created
* @param {Number} blockData.nonce a 32 bit number with a random number
* @param {string} blockData.bits a 32 bit "varint" encoded number with the length of the block
* @param {string} blockData.merkleroot an hex string of length 64 with the hash of the block
* @param {Array} transactions an array of bitcore.Transaction objects, in the order that forms the
* merkle root hash
* @return {bitcore.Block}
*/
BlockService.blockRPCtoBitcore = function(blockData) {
$.checkArgument(blockData, 'blockData is required');
var block = new bitcore.Block({
header: new bitcore.BlockHeader({
version: blockData.version,
prevHash: blockData.previousblockhash ?
bitcore.util.buffer.reverse(
new bitcore.deps.Buffer(blockData.previousblockhash, 'hex')
) : bitcore.util.buffer.emptyBuffer(32),
time: blockData.time,
nonce: blockData.nonce,
bits: new bitcore.deps.bnjs(
new bitcore.deps.Buffer(blockData.bits, 'hex')
).toNumber(),
merkleRoot: bitcore.util.buffer.reverse(
new bitcore.deps.Buffer(blockData.merkleroot, 'hex')
)
}),
transactions: blockData.transactions
});
block.height = blockData.height;
return block;
};
/**
* A helper function to return an error when a block couldn't be found
*
* @param {*} err an error message or the block hash
* @return {Promise} a promise that will always be rejected
*/
var blockNotFound = function(err) {
if (err.message === 'Block not found' ||
err.message === 'Block height out of range') {
throw new errors.Blocks.NotFound();
}
throw err;
};
/**
* Fetch a block using the hash of that block
*
* @param {string} blockHash the hash of the block to be fetched
* @return {Promise<Block>}
*/
BlockService.prototype.getBlock = function(blockHash, opts) {
$.checkArgument(
JSUtil.isHexa(blockHash) || bitcore.util.buffer.isBuffer(blockHash),
'Block hash must be a buffer or hexa'
);
if (bitcore.util.buffer.isBuffer(blockHash)) {
blockHash = bitcore.util.buffer.reverse(blockHash).toString('hex');
}
opts = opts || {};
var self = this;
return Promise.try(function() {
return self.rpc.getBlockAsync(blockHash, false);
})
.catch(blockNotFound)
.then(function(res) {
return bitcore.Block.fromString(res.result);
});
};
/**
* Fetch the block that is currently taking part of the main chain at a given height
*
* @param {Number} height the height of the block
* @return {Promise<Block>}
*/
BlockService.prototype.getBlockByHeight = function(height) {
$.checkArgument(_.isNumber(height), 'Block height must be a number');
var self = this;
if (height === 0) {
return Promise.resolve(
Block.fromBuffer(genesisBlocks[bitcore.Networks.defaultNetwork])
);
}
return Promise.try(function() {
return self.rpc.getBlockHashAsync(height);
})
.catch(blockNotFound)
.then(function(result) {
var blockHash = result.result;
return self.getBlock(blockHash);
});
};
/**
* Returns a list of blocks given certain required query options.
*
* @param {Number} from block height as lower limit
* @param {Number} to ditto, but for the upper limit, non inclusive
* @param {Number} offset skip the first offset blocks
* @param {Number} limit max amount of blocks returned
* @return {Array} a list of blocks
*
*/
BlockService.prototype.listBlocks = function(from, to, offset, limit) {
$.checkArgument(_.isNumber(from), 'from is required, and must be a number');
$.checkArgument(_.isNumber(to), 'to is required, and must be a number');
$.checkArgument(_.isNumber(offset), 'offset is required, and must be a number');
$.checkArgument(_.isNumber(limit), 'limit is required, and must be a number');
$.checkArgument(from <= to, 'from must be <= to');
var self = this;
var start = from + offset;
var end = Math.min(to, start + limit);
var blocks = [];
// TODO: optimize: precompute heights and fetch all blocks in parallel?
var fetchBlock = function(height) {
if (height >= end) {
return Promise.resolve();
}
return self.getBlockByHeight(height)
.then(function(block) {
blocks.push(block);
return fetchBlock(height + 1);
})
.catch(function(err) {
// block not found, ignore
});
};
return fetchBlock(start)
.then(function() {
return blocks;
});
};
BlockService.prototype._getLatestHash = function() {
var self = this;
return Promise.try(function() {
return self.database.getAsync(Index.tip);
}).catch(LevelUp.errors.NotFoundError, function() {
return null;
});
};
/**
* Fetch the block that is currently the tip of the blockchain
*
* @return {Promise<Block>}
*/
BlockService.prototype.getLatest = function() {
var self = this;
return this._getLatestHash().then(function(blockHash) {
if (!blockHash) {
return null;
}
return self.getBlock(blockHash);
});
};
/**
* Handle a block from the network
*
* @param {bitcore.Block} block
* @return a list of events back to the event bus
*/
BlockService.prototype.onBlock = function(block) {
var events = [];
return this.save(block)
.then(function(block) {
console.log('block', block.id, 'saved with height', block.height);
block.transactions.forEach(function(tx) {
events.push(tx);
});
return events;
});
};
/**
* Set a block as the current tip of the blockchain
*
* @param {bitcore.Block} block
* @param {Array=} ops
* @return {Promise<Block>} a promise of the same block, for chaining
*/
BlockService.prototype.confirm = function(block, ops) {
$.checkArgument(block instanceof bitcore.Block);
var self = this;
ops = ops || [];
return Promise.try(function() {
self._setHeader(ops, block);
self._setNextBlock(ops, block.header.prevHash, block);
self._setBlockHeight(ops, block);
self._setBlockWork(ops, block);
self._setBlockByTs(ops, block);
self._setTip(ops, block);
return Promise.all(block.transactions.map(function(transaction) {
return self.transactionService._confirmTransaction(ops, block, transaction);
}));
})
.then(function() {
return self.database.batchAsync(ops);
})
.then(function() {
return block;
});
};
BlockService.prototype._setHeader = function(ops, block) {
ops.push({
type: 'put',
key: Index.getBlockHeader(block.hash),
value: block.header.toJSON(),
});
};
BlockService.prototype._setNextBlock = function(ops, prevBlockHash, block) {
if (bitcore.util.buffer.isBuffer(prevBlockHash)) {
prevBlockHash = bitcore.util.buffer.reverse(prevBlockHash).toString('hex');
}
ops.push({
type: 'put',
key: Index.getNextBlock(prevBlockHash),
value: block.hash
});
ops.push({
type: 'put',
key: Index.getPreviousBlock(block.hash),
value: prevBlockHash
});
};
BlockService.prototype._setBlockHeight = function(ops, block) {
ops.push({
type: 'put',
key: Index.getBlockHeight(block),
value: block.height
});
};
BlockService.prototype._setTip = function(ops, block) {
ops.push({
type: 'put',
key: Index.tip,
value: block.hash
});
};
BlockService.prototype._setBlockWork = function(ops, block) {
ops.push({
type: 'put',
key: Index.getBlockWork(block),
value: block.work
});
};
BlockService.prototype._setBlockByTs = function(ops, block) {
// TODO: uncomment this
/*
var self = this;
var key = Index.timestamp + block.header.time;
return Promise.try(function() {
return self.database.getAsync(key);
})
.then(function(result) {
if (result === block.hash) {
return Promise.resolve();
} else {
// TODO: Retry or provide a strategy to insert correctly the block
throw new Error('Found blocks that have same timestamp');
}
})
.error(function(err) {
console.log('err', err);
// TODO: Check if err is not found
return ops.push({
type: 'put',
key: Index.getBlockByTs(block),
value: block.hash
});
});
*/
};
/**
* Unconfirm a block
*
* @param {bitcore.Block} block
* @param {Array=} ops
* @return {Promise<Block>} a promise of the same block, for chaining
*/
BlockService.prototype.unconfirm = function(block, ops) {
ops = ops || [];
var self = this;
return Promise.try(function() {
self._removeNextBlock(ops, block.header.prevHash, block);
self._unsetBlockHeight(ops, block, block.height);
self._dropBlockByTs(ops, block);
return Promise.all(block.transactions.map(function(transaction) {
return self.transactionService._unconfirmTransaction(ops, block, transaction);
}));
}).then(function() {
return self.database.batchAsync(ops);
});
};
BlockService.prototype._removeNextBlock = function(ops, prevHash, block) {
if (bitcore.util.buffer.isBuffer(prevHash)) {
prevHash = bitcore.util.buffer.reverse(prevHash).toString('hex');
}
ops.push({
type: 'del',
key: Index.getNextBlock(prevHash)
});
ops.push({
type: 'del',
key: Index.getPreviousBlock(block.hash)
});
};
BlockService.prototype._unsetBlockHeight = function(ops, block) {
ops.push({
type: 'del',
key: Index.getBlockHeight(block)
});
};
BlockService.prototype._dropBlockByTs = function(ops, block) {
// TODO
};
/**
* Retrieve the block hash that forms part of the current main chain that confirmed a given
* transaction.
*
* @param {bitcore.Transaction} transaction
* @return {Promise<string>} a promise of the hash of the block
*/
BlockService.prototype.getBlockHashForTransaction = function(transaction) {
return this.database.getAsync(Index.getBlockForTransaction(transaction))
.error(function(error) {
// TODO: Handle error
});
};
/**
* Retrieve the block that forms part of the current main chain that confirmed a given transaction.
*
* @param {bitcore.Transaction} transaction
* @return {Promise<Block>} a promise of a block
*/
BlockService.prototype.getBlockForTransaction = function(transaction) {
if (transaction instanceof bitcore.Transaction) {
transaction = transaction.id;
}
$.checkArgument(_.isString(transaction));
var self = this;
return self.getBlockHashForTransaction(transaction).then(function(hash) {
return self.getBlock(hash);
});
};
BlockService.prototype.getBlockchain = function() {
var self = this;
var blockchain = new BlockChain();
var headers = [];
console.log('Fetching hashes from db...');
return self.database.getAsync(Index.blockchain, {valueEncoding: 'json'})
.catch(function(err) {
if(err instanceof LevelUp.errors.NotFoundError) {
return [];
}
throw err;
})
.then(function(blockchainCache) {
console.log(blockchainCache.length + ' headers cached');
var fetchHeader = function(blockHash) {
if (blockHash === BlockChain.NULL) {
console.log('All headers fetched, total =', headers.length);
return Promise.resolve();
} else if(blockchainCache.length && blockchainCache[blockchainCache.length - 1].hash === blockHash) {
console.log(headers.length + ' non-cached headers loaded');
return Promise.resolve();
}
var headerKey = Index.getBlockHeader(blockHash);
return self.database.getAsync(headerKey)
.then(function(json) {
return bitcore.Block.BlockHeader.fromJSON(json);
})
.then(function(header) {
headers.push(header);
return fetchHeader(BufferUtil.reverse(header.prevHash).toString('hex'));
});
};
return self._getLatestHash()
.then(function(tip) {
if (!tip) {
console.log('No tip found, syncing blockchain from genesis block');
return null;
}
console.log('Tip is', tip);
return fetchHeader(tip)
.then(function() {
blockchain.loadFromCache(blockchainCache);
while (headers.length !== 0) {
var header = headers.pop();
blockchain.proposeNewHeader(header);
}
return blockchain;
});
})
});
};
BlockService.prototype.saveBlockchainCache = function(cache) {
return this.database.putAsync(Index.blockchain, JSON.stringify(cache));
}
module.exports = BlockService;