Resending Messages Sample Project

This sample demonstrates all aspects of the resend functionality.

© Onix Solutions

Source code

using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Runtime.InteropServices;
using NLog.Extensions.Logging;
using OnixS.Fix;
using OnixS.Fix.Fix42;

namespace ResendingMessagesSample
{
    static class ResendingMessagesSample
    {
        const ProtocolVersion FixVersion = ProtocolVersion.Fix42;
        const int ListenPort = 10450;
        const int CounterpartyPort = ListenPort;
        const int HeartBtInt = 30;
        const string SenderCompId = "Initiator";
        const string TargetCompId = "Acceptor";
        const int OrderCount = 5;
        const int SequenceGapValue = 3;

        private static string GetLicenseStoreFolder()
        {
            string path = Path.Join(AppContext.BaseDirectory, "../../../../../license");

            if (Directory.Exists(path))
                return path;

            // expecting it run after dotnet publish using default paths
            return Path.Join(AppContext.BaseDirectory, "../../../../../../license");
        }

        static void WaitUntilEnterKey(string waitText)
        {
            if (Console.IsInputRedirected)
                return;

            System.Threading.Thread.Sleep(1000);

            Console.WriteLine("\n" + waitText);

            Console.ReadKey();
        }

        static class AcceptorListener
        {
            public static void OnInboundApplicationMsg(object sender, InboundMessageEventArgs e)
            {
                Console.WriteLine("\n[" + TargetCompId + "] - Inbound application-level message" +
                    (e.Message.GetFlag(Tag.PossDupFlag) ? " with PossDupFlag=Y:\n" : ":\n") + e.Message);
            }

            public static void OnOutboundApplicationMsg(object sender, MessageEventArgs e)
            {
                Console.WriteLine("\n[" + TargetCompId + "] - Inbound application-level message" +
                    (e.Message.GetFlag(Tag.PossDupFlag) ? " with PossDupFlag=Y:\n" : ":\n") + e.Message);
            }

            public static void OnInboundSessionMsg(object sender, InboundMessageEventArgs e)
            {
                if(e.Message.Type == OnixS.Fix.Fix44.MsgType.SequenceReset)
                {
                    Console.WriteLine("\n[" + TargetCompId + "] - Inbound <Sequence Reset> message, MsgSeqNum=" +
                        e.Message.Get(Tag.MsgSeqNum) + ", NewSeqNo=" + e.Message.Get(Tag.NewSeqNo) + ":\n" + e.Message);
                }
                else Console.WriteLine("\n[" + TargetCompId + "] - Inbound session-level message" +
                    (e.Message.GetFlag(Tag.PossDupFlag) ? " with PossDupFlag=Y:\n" : ":\n") + e.Message);
            }

            public static void OnOutboundSessionMsg(object sender, MessageEventArgs e)
            {
                if(e.Message.Type == OnixS.Fix.Fix44.MsgType.ResendRequest)
                {
                    Console.WriteLine("\n[" + TargetCompId + "] - Outbound <Resend Request> message, BeginSeqNo=" +
                        e.Message.Get(Tag.BeginSeqNo) + ", EndSeqNo=" + e.Message.Get(Tag.EndSeqNo) + ":\n" + e.Message);
                }
                else Console.WriteLine("\n[" + TargetCompId + "] - Outbound session-level message:\n" + e.Message);
            }

            public static void OnStateChange(object sender, SessionStateChangeEventArgs e)
            {
                Console.WriteLine("\n[" + TargetCompId + "] - Session's state is changed, prevState="
                + e.PrevState.ToString()
                + ", newState="
                + e.NewState.ToString());
            }

            public static void OnWarning(object sender, SessionWarningEventArgs e)
            {
                Console.WriteLine("\n[" + TargetCompId + "] - Session warning: " + e.ToString());
            }

            public static void OnError(object sender, SessionErrorEventArgs e)
            {
                Console.WriteLine("\n[" + TargetCompId + "] - Session error: " + e.ToString());
            }
        }

        static class InitiatorListener
        {
            public static void OnMessageResending(object sender, MessageResendingEventArgs e)
            {
                Console.WriteLine("\n[" + SenderCompId + "] - MessageResending event is called for message with MsgSeqNum=" +
                    e.Message.Get(Tag.MsgSeqNum) + ", AllowResending is " + ResendMode.ToString());

                e.AllowResending = ResendMode;
            }

            public static void OnWarning(object sender, SessionWarningEventArgs e)
            {
                Console.WriteLine("\n[" + SenderCompId + "] - Session warning: " + e.ToString());
            }

            public static void OnError(object sender, SessionErrorEventArgs e)
            {
                Console.WriteLine("\n[" + SenderCompId + "] - Session error: " + e.ToString());
            }

            static public bool ResendMode { get; set; } = false;
        }

        static void SimulateSequenceGap(Session acceptor, Session initiator, string caseName)
        {
            acceptor.InboundApplicationMessage += AcceptorListener.OnInboundApplicationMsg;
            acceptor.InboundSessionMessage += AcceptorListener.OnInboundSessionMsg;
            acceptor.OutboundApplicationMessage += AcceptorListener.OnOutboundApplicationMsg;
            acceptor.OutboundSessionMessage += AcceptorListener.OnOutboundSessionMsg;
            acceptor.StateChanged += new EventHandler<SessionStateChangeEventArgs>(AcceptorListener.OnStateChange);
            acceptor.Warning += new EventHandler<SessionWarningEventArgs>(AcceptorListener.OnWarning);
            acceptor.Error += new EventHandler<SessionErrorEventArgs>(AcceptorListener.OnError);

            acceptor.ResetLocalSequenceNumbers();
            acceptor.LogonAsAcceptor();
            initiator.ResetLocalSequenceNumbers();
            initiator.Warning += new EventHandler<SessionWarningEventArgs>(InitiatorListener.OnWarning);
            initiator.Error += new EventHandler<SessionErrorEventArgs>(InitiatorListener.OnError);

            Console.WriteLine("\nConnecting to Acceptor on host=" + IPAddress.Loopback.ToString() + " port=" + CounterpartyPort + "...");

            initiator.LogonAsInitiator(IPAddress.Loopback, CounterpartyPort, HeartBtInt);

            Console.WriteLine("\nSending " + OrderCount + " regular orders...");

            var order = new Message(OnixS.Fix.Fix44.MsgType.NewOrderSingle, initiator.Dictionary);

            int orderId = 0;

            for (int orderCounter = 0; orderCounter < OrderCount; ++orderCounter)
            {
                order.Set(Tag.ClOrdID, ++orderId);
                initiator.Send(order);
            }

            if (interactive)
            {
                WaitUntilEnterKey("Press any key to check [" + caseName + "] ...");
            }
            else
            {
                System.Threading.Thread.Sleep(100);
            }

            Console.WriteLine("\nLet's decrease the incoming sequence number of Acceptor by " + SequenceGapValue +
                " and send " + OrderCount + " orders to simulate a sequence gap.");

            acceptor.InSeqNum -= SequenceGapValue;

            for (int orderCounter = 0; orderCounter < OrderCount; ++orderCounter)
            {
                order.Set(Tag.ClOrdID, ++orderId);
                initiator.Send(order);
            }

            if (interactive)
            {
                WaitUntilEnterKey("Press any key to disconnect Initiator and complete the case...");
            }
            else
            {
                System.Threading.Thread.Sleep(100);
            }

            initiator.Logout("The session is disconnected by Initiator");
            acceptor.Logout();
        }

        static void Case1(string caseName)
        {
            using Session acceptor = new Session(TargetCompId, SenderCompId, FixVersion);
            using Session initiator = new Session(SenderCompId, TargetCompId, FixVersion);

            SimulateSequenceGap(acceptor, initiator, caseName);
        }

        static void Case2(string caseName)
        {
            using Session acceptor = new Session(TargetCompId, SenderCompId, FixVersion);
            using Session initiator = new Session(SenderCompId, TargetCompId, FixVersion);

            InitiatorListener.ResendMode = false;
            initiator.MessageResending += new EventHandler<MessageResendingEventArgs>(InitiatorListener.OnMessageResending);

            SimulateSequenceGap(acceptor, initiator, caseName);
        }

        static void Case3(string caseName)
        {
            using Session acceptor = new Session(TargetCompId, SenderCompId, FixVersion);
            using Session initiator = new Session(SenderCompId, TargetCompId, FixVersion);

            InitiatorListener.ResendMode = true;
            initiator.MessageResending += new EventHandler<MessageResendingEventArgs>(InitiatorListener.OnMessageResending);

            SimulateSequenceGap(acceptor, initiator, caseName);
        }

        static void Case4(string caseName)
        {
            using Session acceptor = new Session(TargetCompId, SenderCompId, FixVersion);
            acceptor.ResendRequestMaximumRange = SequenceGapValue - 1;

            using Session initiator = new Session(SenderCompId, TargetCompId, FixVersion);

            InitiatorListener.ResendMode = true;
            initiator.MessageResending += new EventHandler<MessageResendingEventArgs>(InitiatorListener.OnMessageResending);

            SimulateSequenceGap(acceptor, initiator, caseName);
        }

        static void Case5(string caseName)
        {
            using Session acceptor = new Session(TargetCompId, SenderCompId, FixVersion);
            using Session initiator = new Session(SenderCompId, TargetCompId, FixVersion);

            InitiatorListener.ResendMode = true;
            initiator.MessageResending += new EventHandler<MessageResendingEventArgs>(InitiatorListener.OnMessageResending);
            initiator.ResendingQueueSize = SequenceGapValue - 1;

            SimulateSequenceGap(acceptor, initiator, caseName);
        }

        static void Case6(string caseName)
        {
            using Session acceptor = new Session(TargetCompId, SenderCompId, FixVersion);
            acceptor.RequestOnlyMissedMessages = true;

            using Session initiator = new Session(SenderCompId, TargetCompId, FixVersion);

            InitiatorListener.ResendMode = true;
            initiator.MessageResending += new EventHandler<MessageResendingEventArgs>(InitiatorListener.OnMessageResending);

            SimulateSequenceGap(acceptor, initiator, caseName);
        }

        static void Case7(string caseName)
        {
            using Session acceptor = new Session(TargetCompId, SenderCompId, FixVersion);
            acceptor.RequestOnlyMissedMessages = true;
            acceptor.ResendRequestMaximumRange = SequenceGapValue - 1;

            using Session initiator = new Session(SenderCompId, TargetCompId, FixVersion);

            InitiatorListener.ResendMode = true;
            initiator.MessageResending += new EventHandler<MessageResendingEventArgs>(InitiatorListener.OnMessageResending);

            SimulateSequenceGap(acceptor, initiator, caseName);
        }

        public delegate void Case(string caseName);

        static bool interactive;

        /// <summary>
        /// The main entry point for the application.
        /// </summary>
        static int Main(string[] args)
        {
            try
            {
                Console.WriteLine("ResendingMessages sample");

                var settings = new EngineSettings()
                {
                    LicenseStore = GetLicenseStoreFolder(),
                    LoggerProvider = new NLogLoggerProvider()
                };
                settings.ListenPorts.Add(ListenPort);

                Engine.Init(settings);

                var menuItems = new Dictionary<int, KeyValuePair<Case, string>>
                {
                    { 1, new KeyValuePair<Case, string>(Case1, "Default resend functionality without using any specific settings and MessageResending events in the Initiator") },
                    { 2, new KeyValuePair<Case, string>(Case2, "Default resend functionality with using the MessageResending event which sets AllowResending to false") },
                    { 3, new KeyValuePair<Case, string>(Case3, "Default resend functionality with using the MessageResending event which sets AllowResending to true") },
                    { 4, new KeyValuePair<Case, string>(Case4, "Default resend functionality with a limitation of the resend request range") },
                    { 5, new KeyValuePair<Case, string>(Case5, "Default resend functionality with a limitation of the resending queue size") },
                    { 6, new KeyValuePair<Case, string>(Case6, "Second option of resend functionality (RequestOnlyMissedMessages=true) with using the MessageResending event which sets AllowResending to true") },
                    { 7, new KeyValuePair<Case, string>(Case7, "Second option of resend functionality (RequestOnlyMissedMessages=true) with a limitation of the resend request range") }
                };

                interactive = 0 == args.Length;

                if (interactive)
                {
                    while (true)
                    {
                        Console.WriteLine("\nSelect resend functionality case you want to perform or press <Enter> to exit: \n");

                        for (int index = 1; index <= menuItems.Count; ++index)
                        {
                            Console.WriteLine(index.ToString() + ") " + menuItems[index].Value);
                        }

                        ConsoleKeyInfo key = Console.ReadKey();

                        if (key.Key == ConsoleKey.Enter)
                            break;

                        bool r = int.TryParse(key.KeyChar.ToString(), out int selectedItemNumber);

                        if (r && selectedItemNumber > 0 && selectedItemNumber <= menuItems.Count)
                        {
                            menuItems[selectedItemNumber].Key(menuItems[selectedItemNumber].Value);
                        }
                        else
                        {
                            Console.WriteLine("\nInvalid command requested. Repeat your choice.");
                        }
                    }
                }
                else
                {
                    Case1("Default resend functionality without using any specific settings and MessageResending events in the Initiator");
                }

                Engine.Shutdown();
            }
            catch(Exception ex)
            {
                Console.WriteLine("Exception: " + ex);

                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows) && ex.Message.Contains("ErrorCode=10013"))
                {
                    Console.WriteLine("The socket is already in use, or access to the port is restricted on this OS. Please try to change the listen port in EngineSettings.ListenPorts to another one.");
                    Console.WriteLine("You can view a list of which ports are excluded from your user by running this command: 'netsh interface ipv4 show excludedportrange protocol=tcp'");
                }

                return 1;
            }
            finally
            {
                // From https://github.com/NLog/NLog/wiki/Tutorial:
                // NET Application running on Mono / Linux are required to stop threads / timers before entering application shutdown phase.
                // Failing to do this will cause unhandled exceptions and segmentation faults, and other unpredictable behavior.
                NLog.LogManager.Shutdown(); // Flush and close down internal threads and timers
            }

            return 0;
        }
    }
}