/// <summary>
/// Gets raw transaction data for a given txid
/// </summary>
/// <param name="txid">transaction id in hex</param>
/// <returns>raw transaction byte data</returns>
public byte[] GetRawTransaction(string txid)
{
var ret = SendCommand("getrawtransaction", txid);
var transactionHex = ret.GetValue("result").ToObject <string>();
return(ByteToHex.StringToByteArray(transactionHex));
}
private static void Main(string[] args)
{
// get internal litedb database filename from app settings
var databaseFileName = ConfigurationManager.AppSettings["LiteDBFileName"];
// init the database
Database = new DatabaseConsumer(databaseFileName);
// get saved subscriptions
Subscriptions = Database.GetSubscriptions().ToList();
// get RPC connection params from app settings
var rpcURL = ConfigurationManager.AppSettings["RPCURI"];
var rpcUsername = ConfigurationManager.AppSettings["RPCUsername"];
var rpcPassword = ConfigurationManager.AppSettings["RPCPassword"];
// init RPC connection
RPCClient = new RPCClient(new Uri(rpcURL), rpcUsername, rpcPassword);
// get info for the last block that was processed
var lastBlock = Database.GetLastBlock();
var blockCount = RPCClient.GetBlockCount();
// write out of the current block height, and last processed block height
Console.Write("Current block: " + blockCount + ". " + (lastBlock == null ? " No previous block data found." : " Last block processed: " + lastBlock.Height));
// if we already have block data, fetch transactions since the last seen block
if (lastBlock != null && lastBlock.Height < blockCount)
{
Console.WriteLine(". processing " + (blockCount - lastBlock.Height) + " blocks...");
// record how long it takes to process the block data
var stopWatch = new Stopwatch();
stopWatch.Start();
// look at all blocks from the last block that was processed until the current height
for (var blockIndex = lastBlock.Height; blockIndex <= blockCount; blockIndex++)
{
// fetch raw block data by height
var blockHash = RPCClient.GetBlockHash(blockIndex);
var blockData = RPCClient.GetBlockData(blockHash);
// decode the block
var block = new Block(ByteToHex.StringToByteArray(blockData))
{
FirstSeen = DateTimeOffset.UtcNow.ToUnixTimeSeconds()
};
// add the block to the database
Database.EnqueueTask(new DatabaseWrite(block), 0);
// process all transactions that occured in the block
foreach (var transaction in block.Transactions)
{
// does this transaction contain an output we are watching?
SubscriptionCheck.CheckForSubscription(transaction);
}
}
stopWatch.Stop();
var elapsed = stopWatch.Elapsed;
Console.Write("Processed blocks in " + $"{elapsed.Hours:00}:{elapsed.Minutes:00}:{elapsed.Seconds:00}.{elapsed.Milliseconds / 10:00}");
}
Console.WriteLine();
// get websocket listen address/port from app settings
var websocketListen = ConfigurationManager.AppSettings["WebSocketListen"];
// start websocket server
WebSocketServer = new WebSocket.Server(websocketListen);
// get ZMQ server address from app settings
var zmqServerTX = ConfigurationManager.AppSettings["ZMQPublisherRawTX"];
var zmqServerBlock = ConfigurationManager.AppSettings["ZMQPublisherRawBlock"];
// start ZMQ subscribers
new ZMQ.Subscriber(zmqServerTX, "rawtx", new TXConsumer());
new ZMQ.Subscriber(zmqServerBlock, "rawblock", new BlockConsumer());
// skip scanning the mempool if there is no saved block data yet (TODO: maybe it should still scan?)
if (lastBlock != null)
{
// fetch the mempool
var memPool = RPCClient.GetMemPool();
Console.WriteLine("Mempool contains " + memPool.Length + " transactions; processing...");
// record how long it takes to process the mempool
var stopWatch2 = new Stopwatch();
stopWatch2.Start();
// process all mempool transactions
foreach (var txid in memPool)
{
var rawTransaction = RPCClient.GetRawTransaction(txid);
var transaction = new Transaction(rawTransaction)
{
FirstSeen = DateTimeOffset.UtcNow.ToUnixTimeSeconds(),
LastUpdated = DateTimeOffset.UtcNow.ToUnixTimeSeconds()
};
// does this transaction contain an output we are watching?
SubscriptionCheck.CheckForSubscription(transaction);
}
stopWatch2.Stop();
var elapsed2 = stopWatch2.Elapsed;
Console.WriteLine("Processed mempool in " +
$"{elapsed2.Hours:00}:{elapsed2.Minutes:00}:{elapsed2.Seconds:00}.{elapsed2.Milliseconds / 10:00}");
}
else
{
Console.WriteLine("Skipping mempool scan on first run.");
}
}
private void HandleBlock(Block block)
{
// have we seen this block before?
var blockSearch = _blocks.FindOne(x => x.BlockHash == block.BlockHash);
if (blockSearch != null)
{
// yes; we've seen the block before. So, no need to handle it.
return;
}
// is this the first block we've stored?
blockSearch = _blocks.FindOne(x => x.IsChainTip);
if (blockSearch == null)
{
// yes; so, just store it without PrevHash check
// use JSON RPC to fetch block height
var blockHeight = Program.RPCClient.GetBlockHeight(block.BlockHash);
block.Height = blockHeight;
// mark as best known chain tip
_chainTipHash = block.BlockHash;
block.IsChainTip = true;
// save to db
_blocks.Insert(block);
return;
}
// no; so, check if we have the previous block in the chain
blockSearch = _blocks.FindOne(x => x.BlockHash == block.Header.PrevBlockHash);
if (blockSearch == null)
{
// we are missing the prev block; this shouldn't happen...
// queue blocks backwards until we find a prev-block we have, and track the missing blocks
var missingBlocks = new List <Block> {
block
};
var prevBlockHash = block.Header.PrevBlockHash;
// loop until we have already have the previous block
while (!_blocks.Exists(x => x.BlockHash == prevBlockHash))
{
var prevBlockData = Program.RPCClient.GetBlockData(block.Header.PrevBlockHash);
var prevBlock = new Block(ByteToHex.StringToByteArray(prevBlockData));
missingBlocks.Add(prevBlock);
prevBlockHash = prevBlock.Header.PrevBlockHash;
}
// missingBlocks is now an ordered list of blocks we are missing - queue them in reverse
missingBlocks.Reverse();
foreach (var missingBlock in missingBlocks)
{
Program.Database.EnqueueTask(new DatabaseWrite(missingBlock), 0);
}
// discard (don't save) this block, as it will be re-processed in order
return;
}
// we already have the previous block in the chain...
// so, this new block's height is prevblock height + 1
block.Height = blockSearch.Height + 1;
var chainTipBlock = _blocks.FindOne(x => x.IsChainTip);
// check if the prevHash block is our chaintip
if (_chainTipHash != block.Header.PrevBlockHash)
{
// no; so, there was a re-org!
// we need to invalidate transaction inclusions, back to the forking block
var orphanedBlock = chainTipBlock;
var newChainBlock = block;
var orphanedBlocks = new List <Block> {
orphanedBlock
};
var newChainBlocks = new List <Block> {
newChainBlock
};
// step backwards on each chain in turn until the two sides of the fork are at the same height
while (orphanedBlock.Height > newChainBlock.Height)
{
orphanedBlock = _blocks.FindOne(x => x.BlockHash == orphanedBlock.Header.PrevBlockHash);
orphanedBlocks.Add(orphanedBlock);
}
while (orphanedBlock.Height < newChainBlock.Height)
{
newChainBlock = _blocks.FindOne(x => x.BlockHash == newChainBlock.Header.PrevBlockHash);
newChainBlocks.Add(newChainBlock);
}
// orphaned chain and new chain are the same height now
// step back both chains at the same time until we have a matching prevBlockHash
while (orphanedBlock.Header.PrevBlockHash != newChainBlock.Header.PrevBlockHash)
{
orphanedBlock = _blocks.FindOne(x => x.BlockHash == orphanedBlock.Header.PrevBlockHash);
orphanedBlocks.Add(orphanedBlock);
newChainBlock = _blocks.FindOne(x => x.BlockHash == newChainBlock.Header.PrevBlockHash);
newChainBlocks.Add(newChainBlock);
}
// prevBlockHash is now the forking block;
// roll-back transaction inclusions
var transactions = _transactions.Find(x => x.IncludedAtBlockHeight >= orphanedBlock.Height);
foreach (var transaction in transactions)
{
transaction.IncludedAtBlockHeight = 0;
transaction.IncludedInBlockHex = "";
}
// mark all blocks on the orphaned side as orphaned, and vice-versa
foreach (var blk in orphanedBlocks)
{
blk.Orphaned = true;
}
// this is needed in the case of re-re-orgs
foreach (var blk in newChainBlocks)
{
blk.Orphaned = false;
}
// we need to re-scan transactions in higher blocks
// (skip the transactions in this block itself, as they will be queued behind this insert)
// for most re-orgs, this won't actually have anything to process
foreach (var blk in newChainBlocks.Where(x => x.BlockHash != block.BlockHash))
{
// check all transactions in the block
foreach (var transaction in block.Transactions)
{
SubscriptionCheck.CheckForSubscription(transaction);
}
}
// re-org is handled, and this is the new chaintip, so fall thru to insert the block normally
}
// this is a regular block insert - we have previous block, and the previous block is our last known chaintip
chainTipBlock.IsChainTip = false;
_blocks.Update(chainTipBlock);
block.IsChainTip = true;
_chainTipHash = block.BlockHash;
// save to db
_blocks.Insert(block);
}