public static void Main(string[] args)
{
// get the subscription handler ready (tracks websocket clients and their subscriptions)
_subscriptionHandler = new SubscriptionHandler();
// get the dataHandler ready (handles incoming blocks and transactions, compares to client subscriptions using the subscription handler)
_dataHandler = new DataHandler(_subscriptionHandler);
// start with a ZMQ connection for blocks
var blockConsumer = new BlockConsumer(_dataHandler.HandleBlock);
var zmqBlockClient = new ZMQClient(Config.GetConfigString("ZMQBlockHostname"),
Config.GetConfigInt("ZMQBlockPort"), "rawblock",
(frameHeader, data, frameCounter) => blockConsumer.EnqueueTask(data, frameCounter));
// start a ZMQ subscription for transactions
var transactionConsumer = new TransactionConsumer(_dataHandler.HandleTransaction);
var zmqTxClient = new ZMQClient(Config.GetConfigString("ZMQTxHostname"),
Config.GetConfigInt("ZMQTxPort"), "rawtx",
(frameHeader, data, frameCounter) => transactionConsumer.EnqueueTask(data, frameCounter));
// initialize websocket server
// TODO: we need an x509 certificate including key to use secure (wss) - add to application config options
_server = new WebsocketServer(IPAddress.Parse(Config.GetConfigString("WebsocketBindIP")),
Config.GetConfigInt("WebsocketBindPort"), false, false)
// restart websocket listener automatically
{
RestartAfterListenError = true
};
// start the websocket server, and add callbacks to track active sockets
_server.Start(socket =>
{
socket.OnOpen = () =>
{
// track the connection
_subscriptionHandler.AddSocket(socket);
};
socket.OnClose = () =>
{
// stop tracking this connection
_subscriptionHandler.RemoveSocket(socket);
};
socket.OnMessage = message =>
{
// process incoming message
MessageHandler.HandleMessage(socket, message, _subscriptionHandler);
};
socket.OnError = exception =>
{
// TODO: handle websocket exceptions
};
});
}
/// <summary>
/// Handles json messages:
/// {"op": "block"}
/// {"op": "transaction"}
/// {"op": "address", "address": "[CASH_ADDRESS]"}
/// {"op": "opreturn", "prefix": "[PREFIX(HEX)]"}
/// {"op": "rm_block"}
/// {"op": "rm_transaction"}
/// {"op": "rm_address", "address": "[CASH_ADDRESS]"}
/// {"op": "rm_opreturn", "prefix": "[PREFIX(HEX)]"}
/// - Validates json
/// - Validates parameters
/// - Sends response (error or ok)
/// - Adds valid subscriptions to subscription handler
/// </summary>
/// <param name="socket"></param>
/// <param name="message"></param>
/// <param name="subscriptionHandler"></param>
public static void HandleMessage(IWebsocketConnection socket, string message, SubscriptionHandler subscriptionHandler)
{
message = message.Trim();
// check if the message is valid json
if ((!message.StartsWith("{") || !message.EndsWith("}")) &&
(!message.StartsWith("[") || !message.EndsWith("]")))
{
return;
}
JToken jToken;
try
{
jToken = JToken.Parse(message);
}
catch (JsonReaderException jex)
{
socket.Send("{ \"op\": \"error\", \"error\": \"Unable to parse JSON request. " + JsonConvert.ToString(jex.Message) + "\" }");
return;
}
catch (Exception ex)
{
socket.Send("{ \"op\": \"error\", \"error\": \"Exception while parsing JSON request. " + JsonConvert.ToString(ex.Message) + "\" }");
return;
}
if (jToken.Type != JTokenType.Object)
{
socket.Send("{ \"op\": \"error\", \"error\": \"Error while parsing JSON request. Expected Object, but encountered " + jToken.Type + "\" }");
return;
}
var jObject = jToken.ToObject <JObject>();
if (!jObject.ContainsKey("op") || jObject["op"].Type != JTokenType.String)
{
socket.Send("{ \"op\": \"error\", \"error\": \"Error while parsing JSON request. Expected 'op' parameter as string.\" }");
return;
}
// block subscriptions
if (jObject["op"].ToString().Equals("block", StringComparison.CurrentCultureIgnoreCase))
{
subscriptionHandler.AddSubscription(socket, new BlockSubscription());
socket.Send("{ \"op\": \"block\", \"result\": \"ok\" }");
}
// block un-subscribe
else if (jObject["op"].ToString().Equals("rm_block", StringComparison.CurrentCultureIgnoreCase))
{
socket.Send(subscriptionHandler.RemoveSubscription(socket, new BlockSubscription())
? "{ \"op\": \"rm_block\", \"result\": \"ok\" }"
: "{ \"op\": \"rm_block\", \"result\": \"failed\" }");
}
// transaction subscriptions
else if (jObject["op"].ToString().Equals("transaction", StringComparison.CurrentCultureIgnoreCase))
{
subscriptionHandler.AddSubscription(socket, new TransactionSubscription());
socket.Send("{ \"op\": \"transaction\", \"result\": \"ok\" }");
}
// transaction un-subscribe
else if (jObject["op"].ToString().Equals("rm_transaction", StringComparison.CurrentCultureIgnoreCase))
{
socket.Send(subscriptionHandler.RemoveSubscription(socket, new TransactionSubscription())
? "{ \"op\": \"rm_transaction\", \"result\": \"ok\" }"
: "{ \"op\": \"rm_transaction\", \"result\": \"failed\" }");
}
// address subscriptions
else if (jObject["op"].ToString().Equals("address", StringComparison.CurrentCultureIgnoreCase) ||
jObject["op"].ToString().Equals("rm_address", StringComparison.CurrentCultureIgnoreCase))
{
if (!jObject.ContainsKey("address") || jObject["address"].Type != JTokenType.String)
{
socket.Send("{ \"op\": \"error\", \"error\": \"Error while parsing JSON request. Expected 'address' parameter as string.\" }");
return;
}
// attempt to decode cash address
try
{
var decoded = CashAddress.DecodeCashAddress(jObject["address"].ToString());
if (jObject["op"].ToString().Equals("address", StringComparison.CurrentCultureIgnoreCase))
{
subscriptionHandler.AddSubscription(socket, new AddressSubscription(decoded));
socket.Send("{ \"op\": \"address\", \"result\": \"ok\" }");
}
else if (jObject["op"].ToString().Equals("rm_address", StringComparison.CurrentCultureIgnoreCase))
{
socket.Send(!subscriptionHandler.RemoveSubscription(socket, new AddressSubscription(decoded))
? "{ \"op\": \"rm_address\", \"result\": \"failed\" }"
: "{ \"op\": \"rm_address\", \"result\": \"ok\" }");
}
}
catch (CashAddress.CashAddressException e)
{
socket.Send("{ \"op\": \"error\", \"error\": \"" + JsonConvert.ToString(e.Message) + " ... " + JsonConvert.ToString(e.InnerException.Message) + "\" }");
}
}
// op return subscriptions
else if (jObject["op"].ToString().Equals("opreturn", StringComparison.CurrentCultureIgnoreCase) ||
jObject["op"].ToString().Equals("rm_opreturn", StringComparison.CurrentCultureIgnoreCase))
{
if (!jObject.ContainsKey("prefix") || jObject["prefix"].Type != JTokenType.String)
{
socket.Send("{ \"op\": \"error\", \"error\": \"Error while parsing JSON request. Expected 'prefix' parameter as string.\" }");
return;
}
if (!IsValidHexString(jObject["prefix"].ToString()))
{
socket.Send("{ \"op\": \"error\", \"error\": \"Error while parsing JSON request. Expected 'prefix' parameter to be valid hex.\" }");
return;
}
if (jObject["prefix"].ToString().Length > 32)
{
socket.Send("{ \"op\": \"error\", \"error\": \"Error while parsing JSON request. Expected 'prefix' parameter to be less than 32 hex characters long.\" }");
return;
}
var prefix = ByteHexConverter.StringToByteArray(jObject["prefix"].ToString());
if (jObject["op"].ToString().Equals("opreturn", StringComparison.CurrentCultureIgnoreCase))
{
subscriptionHandler.AddSubscription(socket, new OpReturnSubscription(prefix));
socket.Send("{ \"op\": \"opreturn\", \"result\": \"ok\" }");
}
else if (subscriptionHandler.RemoveSubscription(socket,
new OpReturnSubscription(prefix)))
{
socket.Send(!subscriptionHandler.RemoveSubscription(socket, new OpReturnSubscription(prefix))
? "{ \"op\": \"rm_opreturn\", \"result\": \"failed\" }"
: "{ \"op\": \"rm_opreturn\", \"result\": \"ok\" }");
}
}
else
{
// unrecognized op command
socket.Send("{ \"op\": \"error\", \"error\": \"Error while parsing JSON request. Expected valid 'op' parameter.\" }");
}
}
/// <summary>
/// Constructor
/// </summary>
/// <param name="subscriptionHandler">initialized subscription handler</param>
public DataHandler(SubscriptionHandler subscriptionHandler)
{
_subscriptionHandler = subscriptionHandler;
}
