/// <summary>
/// Main loop for listener task.
/// </summary>
private void NotificationLoop()
{
while (IsListening())
{
List <NotificationMessage> messages = new List <NotificationMessage>();
try
{
messages = SqlProcedures.ReceiveSubscription(AppName);
}
catch (Exception ex)
{
try
{
ErrorMessageHandler.Invoke(new NotificationMessage(ex.Message));
}
catch (Exception)
{ }
}
foreach (NotificationMessage message in messages)
{
try
{
switch (message.MessageType)
{
case NotificationMessageType.Error:
ErrorMessageHandler.Invoke(message);
break;
case NotificationMessageType.NotImplementedType:
ErrorMessageHandler.Invoke(message);
break;
case NotificationMessageType.Unsubscribed:
UnsubscribedMessageHandler.Invoke(message);
break;
case NotificationMessageType.Empty:
break;
default:
MessageHandler.Invoke(message);
break;
}
}
catch (Exception ex)
{
try
{
message.AddError(ex);
ErrorMessageHandler.Invoke(message);
}
catch (Exception)
{ }
}
}
}
}
/// <summary>
/// Creates new receiver witch specified properies.
/// </summary>
/// <param name="appName"> Application name for which messages listener will be listening. </param>
/// <param name="connectionString"> Connection string used to connect to DB. </param>
/// <param name="messageHandler"> Handler used to handle typical NotificationMessage. Default: no handler is specified. </param>
/// <param name="unsubscribedMessageHandler"> Handler used to handle unsubscribe NotificationMessage. Default: messageHandler handler is used. </param>
/// <param name="errorMessageHandler"> Handler used to handle unsubscribe NotificationMessage. Default: unsubscribedMessageHandler handler is used. </param>
/// <param name="sqlTimeout"> Timeout in seconds used for query. Default value uses value set in constructor. 0 indicates infinite. Default: 30. </param>
public Receiver(
string appName,
string connectionString,
HandleMessage messageHandler = null,
HandleMessage unsubscribedMessageHandler = null,
HandleMessage errorMessageHandler = null,
int sqlTimeout = 30)
{
AppName = appName;
SqlProcedures = new SqlProcedures(connectionString, sqlTimeout);
MessageHandler += messageHandler;
UnsubscribedMessageHandler += unsubscribedMessageHandler ?? messageHandler;
ErrorMessageHandler += errorMessageHandler ?? unsubscribedMessageHandler ?? messageHandler;
}
/// <summary>
/// UnSubscribe from notification.
/// </summary>
/// <param name="subscription"> Subscription used to unsubscribe. </param>
public void UnSubscribe(Subscription subscription)
{
SqlProcedures.UninstallSubscription(subscription);
}
/// <summary>
/// Subscribes for notification.
/// </summary>
/// <param name="subscription"> Subscription used to subscribe. </param>
public void Subscribe(Subscription subscription)
{
SqlProcedures.InstallSubscription(subscription);
}