/// <summary>
/// Adds a remote application to communication layer.
/// </summary>
/// <param name="application">Remote application to add</param>
public void AddRemoteApplication(MDSRemoteApplication application)
{
lock (_remoteApplications)
{
if (!_remoteApplications.ContainsKey(application.ApplicationId))
{
_remoteApplications.Add(application.ApplicationId, application);
}
}
}
/// <summary>
/// Removes a remote application from communication layer.
/// </summary>
/// <param name="application">Remote application to remove</param>
public void RemoveRemoteApplication(MDSRemoteApplication application)
{
lock (_remoteApplications)
{
if (_remoteApplications.ContainsKey(application.ApplicationId))
{
if (application.ConnectedCommunicatorCount > 0)
{
throw new MDSException("Remote application can not be removed. It has " +
application.ConnectedCommunicatorCount + " communicators connected.");
}
_remoteApplications.Remove(application.ApplicationId);
}
}
}
/// <summary>
/// Processes MDSRegisterMessage objects.
/// </summary>
/// <param name="communicator">Sender communicator of message</param>
/// <param name="message">Message</param>
private void ProcessRegisterMessage(ICommunicator communicator, MDSRegisterMessage message)
{
//Set the communicator properties
communicator.CommunicationWay = message.CommunicationWay;
MDSRemoteApplication remoteApplication = null;
//Find remote application
lock (_remoteApplications)
{
foreach (var app in _remoteApplications.Values)
{
if (app.Name == message.Name && message.CommunicatorType == app.CommunicatorType)
{
remoteApplication = app;
break;
}
}
}
//If application is found...
if (remoteApplication != null)
{
try
{
//Add communicator to communicator list of remote application
remoteApplication.AddCommunicator(communicator);
//Remove communicator from tempoary communicators list.
RemoveFromCommunicators(communicator.ComminicatorId);
//Send success message to remote application
SendOperationResultMessage(communicator, true, communicator.ComminicatorId.ToString(), message.MessageId);
}
catch (Exception ex)
{
Logger.Warn(ex.Message, ex);
//An error occured, send failed message to remote application
SendOperationResultMessage(communicator, false, ex.Message, message.MessageId);
communicator.Stop(false);
}
}
else //application == null
{
//Stop communicator, because a remote application can not connect this server that is not defined in settings file
SendOperationResultMessage(communicator, false, "No remote application found with name: " + message.Name, message.MessageId);
communicator.Stop(false);
}
}
/// <summary>
/// To send a MDSOperationResultMessage to remote application's spesific communicator.
/// </summary>
/// <param name="senderApplication">Sender application/server</param>
/// <param name="communicator">Communicator to send message</param>
/// <param name="repliedMessage">Replied Message</param>
/// <param name="success">Operation result</param>
/// <param name="resultText">Details</param>
private static void SendOperationResultMessage(MDSRemoteApplication senderApplication, ICommunicator communicator, MDSDataTransferMessage repliedMessage, bool success, string resultText)
{
try
{
if (success)
{
//Save MessageId of acknowledged message to do not receive same message again
senderApplication.LastAcknowledgedMessageId = repliedMessage.MessageId;
}
senderApplication.SendMessage(new MDSOperationResultMessage
{
RepliedMessageId = repliedMessage.MessageId,
Success = success,
ResultText = resultText
}, communicator);
}
catch (Exception ex)
{
Logger.Warn(ex.Message, ex);
}
}
/// <summary>
/// Sends message directly to application (not stores) and waits ACK.
/// This method adds message to queue by MDSPersistentRemoteApplicationBase.AddMessageToHeadOfQueue method
/// and waits a signal/pulse from RemoteApplication_MessageReceived method to get ACK/Reject.
/// </summary>
/// <param name="senderApplication">Sender application/server</param>
/// <param name="senderCommunicator">Sender communicator</param>
/// <param name="destApplication">Destination application/server</param>
/// <param name="message">Message</param>
private void SendMessageDirectly(MDSRemoteApplication senderApplication, ICommunicator senderCommunicator, MDSPersistentRemoteApplicationBase destApplication, MDSDataTransferMessage message)
{
//Create a WaitingMessage to wait and get ACK/Reject message and add it to waiting messages
var waitingMessage = new WaitingMessage();
lock (_waitingMessages)
{
_waitingMessages[message.MessageId] = waitingMessage;
}
try
{
//Add message to head of queue of remote application
destApplication.AddMessageToHeadOfQueue(message);
//Wait until thread is signalled by another thread to get response (Signalled by RemoteApplication_MessageReceived method)
waitingMessage.WaitEvent.WaitOne((int) (_settings.MessageResponseTimeout*1.2));
//Evaluate response
if (waitingMessage.ResponseMessage.Success)
{
SendOperationResultMessage(senderApplication, senderCommunicator, message, true, "Success.");
}
else
{
SendOperationResultMessage(senderApplication, senderCommunicator, message, false, "Message is not acknowledged. Reason: " + waitingMessage.ResponseMessage.ResultText);
}
}
finally
{
//Remove message from waiting messages
lock (_waitingMessages)
{
_waitingMessages.Remove(message.MessageId);
}
}
}
/// <summary>
/// Adds message to destination's send queue.
/// </summary>
/// <param name="senderApplication">Sender application/server</param>
/// <param name="senderCommunicator">Sender communicator</param>
/// <param name="destApplication">Destination application/server</param>
/// <param name="message">Message</param>
private static void EnqueueMessage(MDSRemoteApplication senderApplication, ICommunicator senderCommunicator, MDSPersistentRemoteApplicationBase destApplication, MDSDataTransferMessage message)
{
destApplication.EnqueueMessage(message);
SendOperationResultMessage(senderApplication, senderCommunicator, message, true, "Success.");
}
/// <summary>
/// This method is called by ProcessDataTransferMessage when a message must be sent to an adjacent server of this server.
/// </summary>
/// <param name="senderApplication">Sender application/server</param>
/// <param name="senderCommunicator">Sender communicator</param>
/// <param name="message">Message</param>
private void SentToAdjacentServer(MDSRemoteApplication senderApplication, ICommunicator senderCommunicator, MDSDataTransferMessage message)
{
/* On one of these conditions, message is stored:
* - TransmitRule = StoreAndForward
* - (TransmitRule = StoreOnSource OR StoreOnEndPoints) AND (This server is the source server)
*/
if (message.TransmitRule == MessageTransmitRules.StoreAndForward ||
message.TransmitRule == MessageTransmitRules.NonPersistent)
{
EnqueueMessage(
senderApplication,
senderCommunicator,
_serverGraph.AdjacentServers[message.DestinationServerName],
message
);
}
/* Else, message is not stored in these conditions:
* - TransmitRule = DirectlySend OR StoreOnDestination (this server can not be destination because message is being sent to another server right now)
* - All Other conditions
*/
else
{
SendMessageDirectly(
senderApplication,
senderCommunicator,
_serverGraph.AdjacentServers[message.DestinationServerName],
message
);
}
}
/// <summary>
/// This method is called by ProcessDataTransferMessage when a message must be sent to a server
/// that is not an adjacent of this server. Message is forwarded to next server.
/// </summary>
/// <param name="senderApplication">Sender application/server</param>
/// <param name="senderCommunicator">Sender communicator</param>
/// <param name="message">Message</param>
private void SendToNextServer(MDSRemoteApplication senderApplication, ICommunicator senderCommunicator, MDSDataTransferMessage message)
{
//If there is a path from this server to destination server...
if (_serverGraph.ThisServerNode.BestPathsToServers.ContainsKey(message.DestinationServerName))
{
//Find best path to destination server
var bestPath = _serverGraph.ThisServerNode.BestPathsToServers[message.DestinationServerName];
//If path is regular (a path must consist of 2 nodes at least)...
if (bestPath.Count > 1)
{
//Next server
var nextServerName = bestPath[1].Name;
/* On one of these conditions, message is stored:
* - TransmitRule = StoreAndForward
* - (TransmitRule = StoreOnSource OR StoreOnEndPoints) AND (This server is the source server)
*/
if (message.TransmitRule == MessageTransmitRules.StoreAndForward ||
message.TransmitRule == MessageTransmitRules.NonPersistent)
{
EnqueueMessage(
senderApplication,
senderCommunicator,
_serverGraph.AdjacentServers[nextServerName],
message
);
}
/* Else, message is not stored in these conditions:
* - TransmitRule = DirectlySend OR StoreOnDestination (this server can not be destination because message is being sent to another server right now)
* - All Other conditions
*/
else
{
SendMessageDirectly(
senderApplication,
senderCommunicator,
_serverGraph.AdjacentServers[nextServerName],
message
);
}
}
//Server graph may be wrong (this is just for checking case, normally this situation must not become)
else
{
SendOperationResultMessage(senderApplication, senderCommunicator, message, false, "Server graph is wrong.");
}
}
//No path from this server to destination server
else
{
SendOperationResultMessage(senderApplication, senderCommunicator, message, false, "There is no path from this server to destination.");
}
}
/// <summary>
/// Checks a MDSDataTransferMessage and fills it's empty fields by default values.
/// </summary>
/// <param name="dataTransferMessage">Message</param>
/// <param name="senderApplication">Sender application</param>
/// <param name="communicator">Sender communicator of application</param>
private void FillEmptyMessageFields(MDSDataTransferMessage dataTransferMessage, MDSRemoteApplication senderApplication, ICommunicator communicator)
{
//Default SourceApplicationName: Name of the sender application.
if (string.IsNullOrEmpty(dataTransferMessage.SourceApplicationName))
{
dataTransferMessage.SourceApplicationName = senderApplication.Name;
}
//Default SourceServerName: Name of this server.
if (string.IsNullOrEmpty(dataTransferMessage.SourceServerName))
{
dataTransferMessage.SourceServerName = _settings.ThisServerName;
}
//Default DestinationApplicationName: Name of the sender application.
if (string.IsNullOrEmpty(dataTransferMessage.DestinationApplicationName))
{
dataTransferMessage.DestinationApplicationName = senderApplication.Name;
}
//Default DestinationServerName: Name of this server.
if (string.IsNullOrEmpty(dataTransferMessage.DestinationServerName))
{
dataTransferMessage.DestinationServerName = _settings.ThisServerName;
}
if (dataTransferMessage.SourceServerName == _settings.ThisServerName)
{
//Sender communicator id is being set.
dataTransferMessage.SourceCommunicatorId = communicator.ComminicatorId;
}
}
/// <summary>
/// This method is called by ProcessDataTransferMessage when a message must be sent to a aclient application
/// that is running on this server.
/// </summary>
/// <param name="senderApplication">Sender application/server</param>
/// <param name="senderCommunicator">Sender communicator</param>
/// <param name="message">Message</param>
private void SentToClientApplication(MDSRemoteApplication senderApplication, ICommunicator senderCommunicator, MDSDataTransferMessage message)
{
MDSClientApplication destinationApplication = null;
//If application exists on this server, get it
lock (_clientApplicationList.Applications)
{
if (_clientApplicationList.Applications.ContainsKey(message.DestinationApplicationName))
{
destinationApplication = _clientApplicationList.Applications[message.DestinationApplicationName];
}
}
//If application doesn't exist on this server...
if (destinationApplication == null)
{
SendOperationResultMessage(senderApplication, senderCommunicator, message, false, "Application does not exists on this server (" + _settings.ThisServerName + ").");
return;
}
//Send message according TransmitRule
switch (message.TransmitRule)
{
case MessageTransmitRules.DirectlySend:
SendMessageDirectly(
senderApplication,
senderCommunicator,
destinationApplication,
message
);
break;
default:
// case MessageTransmitRules.StoreAndForward:
// case MessageTransmitRules.NonPersistent:
EnqueueMessage(
senderApplication,
senderCommunicator,
destinationApplication,
message
);
break;
}
}
/// <summary>
/// This method is used to process a MDSDataTransferMessage that is gotten from a mds server or client application.
/// Message is sent to destination or next server in one of these three conditions:
/// - Destination server is this server and application exists on this server
/// - Destination server is an adjacent server of this server
/// - Destination server in server graph and there is a path from this server to destination server
/// </summary>
/// <param name="senderApplication">Sender application/server</param>
/// <param name="senderCommunicator">Sender communicator</param>
/// <param name="message">Message</param>
private void ProcessDataTransferMessage(MDSRemoteApplication senderApplication, ICommunicator senderCommunicator, MDSDataTransferMessage message)
{
//Check for duplicate messages
if (senderApplication.LastAcknowledgedMessageId == message.MessageId)
{
SendOperationResultMessage(senderApplication, senderCommunicator, message, true, "Duplicate message.");
return;
}
try
{
AddThisServerToPassedServerList(message);
FillEmptyMessageFields(message, senderApplication, senderCommunicator);
_routingTable.ApplyRouting(message);
//If Destination server is this server then deliver message to the destination application
if (message.DestinationServerName.Equals(_settings.ThisServerName, StringComparison.OrdinalIgnoreCase))
{
SentToClientApplication(senderApplication, senderCommunicator, message);
}
//Else, if destination server is an adjacent of this server (so they can communicate directly)
else if (_serverGraph.AdjacentServers.ContainsKey(message.DestinationServerName))
{
SentToAdjacentServer(senderApplication, senderCommunicator, message);
}
//Else, if destination server is not adjacent but in server graph (so, send message to next server)
else if (_serverGraph.ServerNodes.ContainsKey(message.DestinationServerName))
{
SendToNextServer(senderApplication, senderCommunicator, message);
}
else
{
//return error to sender
SendOperationResultMessage(senderApplication, senderCommunicator, message, false, "Destination does not exists.");
}
}
catch (Exception ex)
{
SendOperationResultMessage(senderApplication, senderCommunicator, message, false, ex.Message);
}
}
/// <summary>
/// Constructor.
/// </summary>
/// <param name="remoteApplication">Reference to the MDSRemoteApplication object that is used with this MessageDeliverer</param>
public MessageDeliverer(MDSRemoteApplication remoteApplication)
{
_remoteApplication = remoteApplication;
_asynchronMessageControlTimer = new Timer(AsynchronMessageControlTimer_Elapsed, null, Timeout.Infinite, Timeout.Infinite);
}
/// <summary>
/// Constructor.
/// </summary>
/// <param name="remoteApplication">Reference to the MDSRemoteApplication object that is used with this MessageDeliverer</param>
public MessageDeliverer(MDSRemoteApplication remoteApplication)
{
_remoteApplication = remoteApplication;
_asynchronMessageControlTimer = new Timer(AsynchronMessageControlTimer_Elapsed, null, Timeout.Infinite, Timeout.Infinite);
}
/// <summary>
/// Removes a remote application from communication layer.
/// </summary>
/// <param name="application">Remote application to remove</param>
public void RemoveRemoteApplication(MDSRemoteApplication application)
{
lock (_remoteApplications)
{
if (_remoteApplications.ContainsKey(application.ApplicationId))
{
if(application.ConnectedCommunicatorCount > 0)
{
throw new MDSException("Remote application can not be removed. It has " +
application.ConnectedCommunicatorCount + " communicators connected.");
}
_remoteApplications.Remove(application.ApplicationId);
}
}
}
/// <summary>
/// Adds a remote application to communication layer.
/// </summary>
/// <param name="application">Remote application to add</param>
public void AddRemoteApplication(MDSRemoteApplication application)
{
lock (_remoteApplications)
{
if (!_remoteApplications.ContainsKey(application.ApplicationId))
{
_remoteApplications.Add(application.ApplicationId, application);
}
}
}
