/// <summary>
/// This implementation of the ReleaseSession method is
/// invoked to simultaneously release any locks that are
/// currently being held on a session and update the info
/// for the session in the database.
/// </summary>
/// <param name="sessionId">
/// The session id of the session being released.
/// </param>
/// <param name="record">
/// The updated record for the session being released.
/// </param>
public void ReleaseSession(string sessionId, VfxFixDatabaseRecord record)
{
string sessionPath = Path.Combine(_rootPath, sessionId);
string sessionFile = Path.Combine(sessionPath, "Session.xml");
// REC: Write the updated session details out to
// the session record file:
XmlFixDatabaseRecord xmlRecord = new XmlFixDatabaseRecord();
xmlRecord.TxSequence = record.TxSequence;
xmlRecord.RxSequence = record.RxSequence;
FileStream fsSession = new FileStream(sessionFile, FileMode.Create, FileAccess.Write, FileShare.None);
XmlSerializer xsSession = new XmlSerializer(typeof(XmlFixDatabaseRecord));
xsSession.Serialize(fsSession, xmlRecord);
fsSession.Close();
// REC: Close the index and message database files since
// they are no longer needed:
SessionDetails sessionDetails = _mapSessions[sessionId];
sessionDetails.IdxWriter.Close();
sessionDetails.MsgWriter.Close();
// REC: Delete the session's lock file:
string lockPath = Path.Combine(_rootPath, sessionId);
string lockFile = Path.Combine(lockPath, "Locked.txt");
if (File.Exists(lockFile))
{
File.Delete(lockFile);
}
// REC: Remove the session details from the map:
_mapSessions.Remove(sessionId);
}
/// <summary>
/// The HandleSession_Logon method is invoked to handle
/// a logon message that has been received from the peer
/// session that this session is communicating with.
/// </summary>
/// <param name="msg">
/// The FIX logon message received from the peer.
/// </param>
private void HandleSession_Logon(FixMessage msg)
{
// REC: Ensure that we're in the appropriate state
// to handle a logon message:
if (_currentState == SessionStates.Session_Pending || _currentState == SessionStates.Session_Closed)
{
// REC: Retrieve the FIX SenderCompID of the peer
// from the logon message:
FixField fldSenderCompID = msg.Header.GetField(49);
if (fldSenderCompID != null)
{
// REC: The SenderCompID from the peer becomes the
// session's TargetCompID for outgoing messages:
_fixTargetCompID = fldSenderCompID.Content;
// REC: Now that the FIX SenderCompID of the peer
// session is known, it is used to construct the
// identifier for the session - used to retrieve
// the session's details from the database:
_sessionId = string.Format("{0}-{1}", _fixSenderCompID, _fixTargetCompID);
// REC: Attempt to retrieve the session details
// from the session database:
if (_fixDatabase != null)
{
// REC: Note that once a session record is acquired
// from the database, it must be released when it is
// no longer needed by the session instance...
_sessionRecord = _fixDatabase.AcquireSession(_sessionId);
if (this._resetSequence == true)
{
_sessionRecord.RxSequence = 1;
_sessionRecord.TxSequence = 1;
}
}
// REC: Register the peer session's SenderCompID as
// the TargetCompID for outgoing messages:
_fixAssembler.SetField(new FixField(56, _fixTargetCompID));
// REC: Assemble the response message:
FixMessage response = _fixAssembler.CreateMessage(_sxVersion, _axVersion, "A");
// REC: Handle the sequence number reset flag
// if it is present in the logon message:
FixField fieldReset = msg.GetField(141);
if (fieldReset != null)
{
response.AddField(new FixField(141, "Y"));
}
// REC: Transition to the opened state:
_currentState = SessionStates.Session_Opened;
// REC: Notify the session's owner that the peer
// session has sent the logon request:
_handler.OnSessionLogon(this, msg);
// REC: Dispatch the administrative message out
// to the session's owner:
Dispatch_AdmMessage(response);
}
else
{
// REC: Throw an exception since the session has not
// yet been established and there will be no handler
// at the application level that can deal with this:
throw new ArgumentException("Logon message missing required field - SenderCompID.");
}
}
else
{
// REC: Notify the session handler that an
// administrative message has been received
// from the peer session:
_handler.OnSessionRxAdmMessage(this, msg);
// REC: Throw an exception that indicates the
// session is not in the appropriate state to
// handle the received message:
//throw new InvalidOperationException("Session state invalid for received message.");
}
}
/// <summary>
/// The HandleConnect_Entrypoint method is the asynchronous
/// entrypoint for the session's connect handling logic.
/// </summary>
/// <param name="state">
/// Ignored parameter; required for the method to meet the
/// required signature for use with the sequencer.
/// </param>
private void HandleConnect_Entrypoint(object state)
{
// REC: Transition the session to the active state so
// that it can begin handling messages:
_currentState = SessionStates.Session_Pending;
// REC: Reset the receive timestamp:
this._lastRxTicks = DateTime.Now.Ticks;
// REC: Reset the transmit timestamp:
this._lastTxTicks = DateTime.Now.Ticks;
// REC: Acquire the session's persisted session
// state from the database:
if (_fixDatabase != null)
{
_sessionRecord = _fixDatabase.AcquireSession(_sessionId);
}
// REC: The session's timer is started in order
// to drive the heartbeat and timeout logic:
this._fixTimer.Start();
_handler.OnSessionOpened(this);
// REC: The client session needs to dispatch a logon
// message to the peer as soon as it connects:
FixMessage msgLogon = _fixAssembler.CreateMessage(_sxVersion, _axVersion, "A");
if (msgLogon != null)
{
Dispatch_AdmMessage(msgLogon);
}
}
/// <summary>
/// The AcquireSession method is invoked to request exclusive
/// access to a session's information in the database.
/// </summary>
/// <param name="sessionId">
/// The session's unique identifier.
/// </param>
/// <returns>
/// The persisted information that is maintained for
/// the specified session identifier.
/// </returns>
public VfxFixDatabaseRecord AcquireSession(string sessionId)
{
VfxFixDatabaseRecord result = new VfxFixDatabaseRecord();
// REC: Determine if the session's file path exists:
string sessionPath = Path.Combine(_rootPath, sessionId);
if (!Directory.Exists(sessionPath))
{
Directory.CreateDirectory(sessionPath);
}
// REC: Attempt to open and load the database entry
// for the specified session:
string sessionFile = Path.Combine(sessionPath, "Session.xml");
if (!File.Exists(sessionFile))
{
ResetSession(sessionId);
}
// REC: Attempt to read the session's details from
// the persisted information in the session file:
FileStream fsSession = new FileStream(sessionFile, FileMode.Open, FileAccess.Read, FileShare.None);
XmlSerializer xsSession = new XmlSerializer(typeof(XmlFixDatabaseRecord));
XmlFixDatabaseRecord sessionRecord = xsSession.Deserialize(fsSession) as XmlFixDatabaseRecord;
result.TxSequence = sessionRecord.TxSequence;
result.RxSequence = sessionRecord.RxSequence;
fsSession.Close();
// REC: Create the session's lock file:
string lockFile = Path.Combine(sessionPath, "Locked.txt");
FileStream fs = new FileStream(lockFile, FileMode.Create, FileAccess.ReadWrite, FileShare.None);
fs.Close();
// REC: Create a new instance of the SessionDetails class
// that will be used to maintain the session's information:
SessionDetails sessionDetails = new SessionDetails();
// REC: Attempt to open the index file for the session:
string idxFile = Path.Combine(sessionPath, "Index.xml");
FileStream idxStream = new FileStream(idxFile, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.None);
// REC: Maintain a reference to the index file stream
// in the session's details record:
sessionDetails.IdxWriter = new StreamWriter(idxStream);
// REC: Read all of the index entries from the index file
// and store them in the session's details structure:
StreamReader idxReader = new StreamReader(idxStream);
while (idxReader.EndOfStream == false)
{
string idxLine = idxReader.ReadLine();
string[] idxTokens = idxLine.Split(new char[] { ':' });
IndexEntry idxEntry = new IndexEntry();
idxEntry.msgOffset = int.Parse(idxTokens[1]);
idxEntry.msgLength = int.Parse(idxTokens[2]);
idxEntry.msgSequence = int.Parse(idxTokens[0]);
sessionDetails.Index.Add(idxEntry);
}
// REC: Attempt to open the message file for the session:
string msgFile = Path.Combine(sessionPath, "Messages.txt");
FileStream msgStream = new FileStream(msgFile, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.None);
// REC: Maintain a reference to the message file stream
// in the session's details record:
sessionDetails.MsgWriter = new StreamWriter(msgStream);
// REC: Add the session details record to the internal
// map, keyed by the session identifier:
_mapSessions.Add(sessionId, sessionDetails);
// REC: Return the session's specifics to the caller:
return(result);
}
