QuickFIX/n FIX协议Acceptor能否动态对接未知Initiator并创建会话？

我刚接触FIX协议，使用版本为1.11.0的QuickFIX/n库，同时使用同版本的QuickFIXn.FIX5.0SP2和QuickFIXn.FIXT1.1组件。

Acceptor配置 #

[DEFAULT]
BeginString=FIXT.1.1
DefaultApplVerID=FIX.5.0SP2
HeartBtInt=20
AppDataDictionary=../../../ApplicationData/FIXRTv1.xml
TransportDataDictionary=../../../ApplicationData/FIXT11.xml

FileLogPath=log
SocketAcceptPort=9823 
SocketAcceptHost = 127.0.0.1
ConnectionType=acceptor
UseDataDictionary=Y
ResetOnLogon=Y
ResetOnLogout=Y
ResetOnDisconnect=Y

SenderCompID=TEST
StartTime=00:00:00
EndTime=23:59:00
FileStorePath=store

Initiator配置 #

[DEFAULT]
BeginString=FIXT.1.1
DefaultApplVerID=FIX.5.0SP2
ConnectionType=initiator
HeartBtInt=20
AppDataDictionary=../../spec/fix/FIXRTv1.xml
TransportDataDictionary=../../spec/fix/FIXT11.xml
UseDataDictionary=Y

ResetOnLogon=Y
ResetOnLogout=Y
ResetOnDisconnect=Y
FileStorePath=store
FileLogPath=log

[SESSION]
SenderCompID=USER
TargetCompID=TEST
SocketConnectHost=127.0.0.1 
SocketConnectPort=9823 

StartTime=00:00:00
EndTime=23:59:00

目前Acceptor配置仅含DEFAULT段时，Initiator会报错：Connection failed: The connection was not established because The destination computer rejected the connection request. 127.0.0.1:9823，只有给Acceptor添加对应Initiator的SESSION段后才能正常连接。

请问Acceptor能否对接预先未知的Initiator并动态创建会话？

QuickFIX/n的Acceptor支持对接预先未知的Initiator并动态创建会话，无需在配置文件中预先定义所有SESSION段，具体实现方式如下：

• 自定义会话工厂
  实现IAcceptorSessionFactory接口，在收到未知Initiator的登录请求时，根据登录消息里的SenderCompID、TargetCompID等字段，动态生成对应会话的配置参数，再创建会话实例。这种方式能灵活控制每个动态会话的参数，是官方推荐的实现方式。

• 关闭严格会话校验
  默认情况下QuickFIX/n会校验连接的会话是否存在于配置中，你可以通过代码或配置关闭该校验逻辑，允许未知会话连接。但这种方式灵活性较低，不如自定义会话工厂可控。

• 保持参数一致性
  动态创建会话时，需确保会话核心参数（如心跳间隔、数据字典路径、存储/日志路径）与DEFAULT段配置一致，或根据业务需求调整；同时要处理好会话的持久化，避免服务重启后丢失动态会话信息。

以下是简单的C#代码示例：

public class DynamicAcceptorSessionFactory : IAcceptorSessionFactory
{
    private readonly SessionSettings _settings;
    private readonly IMessageStoreFactory _storeFactory;
    private readonly ILogFactory _logFactory;
    private readonly IApplication _application;

    public DynamicAcceptorSessionFactory(SessionSettings settings, IMessageStoreFactory storeFactory, ILogFactory logFactory, IApplication application)
    {
        _settings = settings;
        _storeFactory = storeFactory;
        _logFactory = logFactory;
        _application = application;
    }

    public Session CreateSession(SessionID sessionID)
    {
        // 检查会话是否已配置，未配置则动态生成
        if (!_settings.HasSession(sessionID))
        {
            // 读取DEFAULT段的基础配置
            var defaultConfig = _settings.Get();
            // 构建新会话的配置
            var sessionConfig = new Dictionary<string, string>(defaultConfig)
            {
                ["SenderCompID"] = sessionID.SenderCompID,
                ["TargetCompID"] = sessionID.TargetCompID
            };
            // 将新会话配置加入全局设置
            _settings.Set(sessionID, sessionConfig);
        }
        return SessionFactory.Create(sessionID, _application, _storeFactory, _logFactory, _settings);
    }
}

初始化Acceptor时使用自定义工厂：

var settings = new SessionSettings("acceptor.cfg");
var application = new YourCustomApplication();
var storeFactory = new FileStoreFactory(settings);
var logFactory = new FileLogFactory(settings);
var sessionFactory = new DynamicAcceptorSessionFactory(settings, storeFactory, logFactory, application);
var acceptor = new ThreadedSocketAcceptor(application, storeFactory, settings, logFactory, sessionFactory);
acceptor.Start();

通过上述实现，Acceptor即可接收预先未知的Initiator连接，并动态创建对应的会话。

内容的提问来源于stack exchange，提问作者rapetum228