private void ReliablyInsertMessage(MessageForDelivery message, DbContext context)
{
context.Database.ExecuteSqlCommand(this.insertQuery,
new SqlParameter("@Body", message.Body),
new SqlParameter("@DeliveryDate", message.DeliveryDate.HasValue ? (object)message.DeliveryDate.Value : DBNull.Value),
new SqlParameter("@CorrelationId", (object)message.CorrelationId ?? DBNull.Value));
}
/// <summary>
/// Sends the specified message.
/// </summary>
public void Send(MessageForDelivery message)
{
using (var connection = this.connectionFactory.CreateConnection(this.connectionString))
{
connection.Open();
this.InsertMessage(message, connection);
}
}
private void InsertMessage(MessageForDelivery message, DbConnection connection)
{
using (var command = (SqlCommand)connection.CreateCommand())
{
command.CommandText = this.insertQuery;
command.CommandType = CommandType.Text;
command.Parameters.Add("@Body", SqlDbType.NVarChar).Value = message.Body;
command.Parameters.Add("@DeliveryDate", SqlDbType.DateTime).Value = message.DeliveryDate.HasValue ? (object)message.DeliveryDate.Value : DBNull.Value;
command.Parameters.Add("@CorrelationId", SqlDbType.NVarChar).Value = (object)message.CorrelationId ?? DBNull.Value;
command.ExecuteNonQuery();
}
}
public MessageReceivedEventArgs(MessageForDelivery message)
{
this.Message = message;
}
protected bool ReceiveMessage(DbConnection connection, DbTransaction transaction)
{
var currentDate = this.GetCurrentDate();
long messageId = -1;
MessageForDelivery message = null;
try
{
using (var command = connection.CreateCommand())
{
command.Transaction = transaction;
command.CommandType = CommandType.Text;
command.CommandText = this.readQuery;
((SqlCommand)command).Parameters.Add("@CurrentDate", SqlDbType.DateTime).Value = currentDate;
using (var reader = command.ExecuteReader())
{
if (!reader.Read())
{
return(false);
}
// Delegate message receiving to another process as fast as possible
this.delegateMessageReceiving.Invoke();
var body = (string)reader["Body"];
var deliveryDateValue = reader["DeliveryDate"];
var deliveryDate = deliveryDateValue == DBNull.Value ? (DateTime?)null : new DateTime?((DateTime)deliveryDateValue);
var correlationIdValue = reader["CorrelationId"];
var correlationId = (string)(correlationIdValue == DBNull.Value ? null : correlationIdValue);
message = new MessageForDelivery(body, correlationId, deliveryDate);
messageId = (long)reader["Id"];
}
}
this.MessageReceived(this, new MessageReceivedEventArgs(message));
using (var command = connection.CreateCommand())
{
command.Transaction = transaction;
command.CommandType = CommandType.Text;
command.CommandText = this.deleteQuery;
((SqlCommand)command).Parameters.Add("@Id", SqlDbType.BigInt).Value = messageId;
command.ExecuteNonQuery();
}
transaction.Commit();
}
catch (Exception e)
{
try
{
// Dead Lettering
using (var command = connection.CreateCommand())
{
command.Transaction = transaction;
command.CommandType = CommandType.Text;
command.CommandText = this.setDeadLetterQuery;
((SqlCommand)command).Parameters.Add("@Id", SqlDbType.BigInt).Value = messageId;
((SqlCommand)command).Parameters.Add("@TraceInfo", SqlDbType.NVarChar).Value =
string.Format("Exception Type: {0}. Exception Message: {1} Inner Exception Type: {2}. Inner Exception Message: {3} StackTrace: {4}",
e.GetType().Name, e.Message, e.InnerException.GetType(), e.InnerException.Message, e.StackTrace);
command.ExecuteNonQuery();
}
transaction.Commit();
}
catch (Exception)
{
try
{
transaction.Rollback();
}
catch (Exception)
{
// NOTE: we catch ANY exceptions. This implementation
// supports retries and dead-lettering.
}
}
}
return(true);
}