/// <summary>
/// Discards the message.
/// </summary>
/// <param name="failMsg"></param>
public static async Task <bool> HandleMessageDiscardAsync(MtaQueuedMessage msg)
{
await MtaTransaction.LogTransactionAsync(msg, TransactionStatus.Discarded, string.Empty, null, null);
msg.IsHandled = true;
return(true);
}
/// <summary>
/// Discards the message.
/// </summary>
/// <param name="failMsg"></param>
public async Task <bool> HandleMessageDiscardAsync()
{
await MtaTransaction.LogTransactionAsync(this, TransactionStatus.Discarded, string.Empty, null, null);
IsHandled = true;
return(true);
}
/// <summary>
/// This method handle successful delivery.
/// Logs success
/// Deletes queued data
/// </summary>
public static async Task <bool> HandleDeliverySuccessAsync(MtaQueuedMessage msg, VirtualMTA ipAddress, MXRecord mxRecord, string response)
{
await MtaTransaction.LogTransactionAsync(msg, TransactionStatus.Success, response, ipAddress, mxRecord);
msg.IsHandled = true;
return(true);
}
/// <summary>
/// This method handle successful delivery.
/// Logs success
/// Deletes queued data
/// </summary>
public async Task <bool> HandleDeliverySuccessAsync(VirtualMta.VirtualMTA ipAddress, DNS.MXRecord mxRecord, string response)
{
await MtaTransaction.LogTransactionAsync(this, TransactionStatus.Success, response, ipAddress, mxRecord);
IsHandled = true;
return(true);
}
/// <summary>
/// Handles a service unavailable event, should be same as defer but only wait 1 minute before next retry.
/// </summary>
/// <param name="sndIpAddress"></param>
internal async Task <bool> HandleServiceUnavailableAsync(VirtualMta.VirtualMTA ipAddress)
{
// Log deferral
await MtaTransaction.LogTransactionAsync(this, TransactionStatus.Deferred, "Service Unavailable", ipAddress, null);
// Set next retry time and release the lock.
this.AttemptSendAfterUtc = DateTime.UtcNow.AddSeconds(15);
Requeue();
return(true);
}
/// <summary>
/// This method handles message throttle.
/// Logs throttle
/// Sets the next rety date time
/// </summary>
internal async Task <bool> HandleDeliveryThrottleAsync(VirtualMta.VirtualMTA ipAddress, DNS.MXRecord mxRecord)
{
// Log deferral
await MtaTransaction.LogTransactionAsync(this, TransactionStatus.Throttled, string.Empty, ipAddress, mxRecord);
// Set next retry time and release the lock.
this.AttemptSendAfterUtc = DateTime.UtcNow.AddMinutes(1);
Requeue();
return(true);
}
/// <summary>
/// Handles a service unavailable event, should be same as defer but only wait 1 minute before next retry.
/// </summary>
/// <param name="sndIpAddress"></param>
internal static async Task <bool> HandleServiceUnavailableAsync(MtaQueuedMessage msg, VirtualMTA ipAddress)
{
// Log deferral
await MtaTransaction.LogTransactionAsync(msg, TransactionStatus.Deferred, "Service Unavailable", ipAddress, null);
// Set next retry time and release the lock.
msg.AttemptSendAfterUtc = DateTime.UtcNow.AddSeconds(15);
await Requeue(msg);
return(true);
}
/// <summary>
/// This method handles message throttle.
/// Logs throttle
/// Sets the next rety date time
/// </summary>
internal static async Task <bool> HandleDeliveryThrottleAsync(MtaQueuedMessage msg, VirtualMTA ipAddress, MXRecord mxRecord)
{
// Log deferral
await MtaTransaction.LogTransactionAsync(msg, TransactionStatus.Throttled, string.Empty, ipAddress, mxRecord);
// Set next retry time and release the lock.
msg.AttemptSendAfterUtc = DateTime.UtcNow.AddMinutes(1);
await Requeue(msg);
return(true);
}
/// <summary>
/// This method handles message deferal.
/// Logs deferral
/// Fails the message if timed out
/// or
/// Sets the next rety date time
/// </summary>
/// <param name="defMsg">The deferal message from the SMTP server.</param>
/// <param name="ipAddress">IP Address that send was attempted from.</param>
/// <param name="mxRecord">MX Record of the server tried to send too.</param>
/// <param name="isServiceUnavailable">If false will backoff the retry, if true will use the MtaParameters.MtaRetryInterval,
/// this is needed to reduce the tail when sending as a message could get multiple try again laters and soon be 1h+ before next retry.</param>
public static async Task <bool> HandleDeliveryDeferralAsync(MtaQueuedMessage msg, string defMsg, VirtualMTA ipAddress, MXRecord mxRecord, bool isServiceUnavailable = false, int?overrideTimeminutes = null)
{
// Log the deferral.
await MtaTransaction.LogTransactionAsync(msg, TransactionStatus.Deferred, defMsg, ipAddress, mxRecord);
// This holds the maximum interval between send retries. Should be put in the database.
int maxInterval = 3 * 60;
// Increase the defered count as the queued messages has been deferred.
msg.DeferredCount++;
// Hold the minutes to wait until next retry.
double nextRetryInterval = MtaParameters.MtaRetryInterval;
if (overrideTimeminutes.HasValue)
{
nextRetryInterval = overrideTimeminutes.Value;
}
else
{
if (!isServiceUnavailable)
{
// Increase the deferred wait interval by doubling for each retry.
for (int i = 1; i < msg.DeferredCount; i++)
{
nextRetryInterval = nextRetryInterval * 2;
}
// If we have gone over the max interval then set to the max interval value.
if (nextRetryInterval > maxInterval)
{
nextRetryInterval = maxInterval;
}
}
else
{
nextRetryInterval = 1; // For service unavalible use 1 minute between retries.
}
}
// Set next retry time and release the lock.
msg.AttemptSendAfterUtc = DateTime.UtcNow.AddMinutes(nextRetryInterval);
await Requeue(msg);
return(true);
}
/// <summary>
/// This method handles failure of delivery.
/// Logs failure
/// Deletes queued data
/// </summary>
/// <param name="failMsg"></param>
public static async Task <bool> HandleDeliveryFailAsync(MtaQueuedMessage msg, string failMsg, VirtualMTA ipAddress, MXRecord mxRecord)
{
await MtaTransaction.LogTransactionAsync(msg, TransactionStatus.Failed, failMsg, ipAddress, mxRecord);
try
{
// Send fails to Manta.Core.Events
for (int i = 0; i < msg.RcptTo.Length; i++)
{
EmailProcessingDetails processingInfo = null;
EventsManager.Instance.ProcessSmtpResponseMessage(failMsg, msg.RcptTo[i], msg.InternalSendID, out processingInfo);
}
}
catch (Exception)
{
}
msg.IsHandled = true;
return(true);
}
private async Task <bool> SendMessageAsync(MtaQueuedMessage msg)
{
// Check that the message next attempt after has passed.
if (msg.AttemptSendAfterUtc > DateTime.UtcNow)
{
RabbitMqOutboundQueueManager.Enqueue(msg);
await Task.Delay(50); // To prevent a tight loop within a Task thread we should sleep here.
return(false);
}
if (await MtaTransaction.HasBeenHandledAsync(msg.ID))
{
msg.IsHandled = true;
return(true);
}
// Get the send that this message belongs to so that we can check the send state.
Send snd = await SendManager.Instance.GetSendAsync(msg.InternalSendID);
switch (snd.SendStatus)
{
// The send is being discarded so we should discard the message.
case SendStatus.Discard:
await msg.HandleMessageDiscardAsync();
return(false);
// The send is paused, the handle pause state will delay, without deferring, the message for a while so we can move on to other messages.
case SendStatus.Paused:
msg.HandleSendPaused();
return(false);
// Send is active so we don't need to do anything.
case SendStatus.Active:
break;
// Unknown send state, requeue the message and log error. Cannot send!
default:
msg.AttemptSendAfterUtc = DateTime.UtcNow.AddMinutes(1);
RabbitMqOutboundQueueManager.Enqueue(msg);
Logging.Error("Failed to send message. Unknown SendStatus[" + snd.SendStatus + "]!");
return(false);
}
bool result;
// Check the message hasn't timed out. If it has don't attempt to send it.
// Need to do this here as there may be a massive backlog on the server
// causing messages to be waiting for ages after there AttemptSendAfter
// before picking up. The MAX_TIME_IN_QUEUE should always be enforced.
if (msg.AttemptSendAfterUtc - msg.QueuedTimestampUtc > new TimeSpan(0, MtaParameters.MtaMaxTimeInQueue, 0))
{
await msg.HandleDeliveryFailAsync(MtaParameters.TIMED_OUT_IN_QUEUE_MESSAGE, null, null);
result = false;
}
else
{
MailAddress mailAddress = new MailAddress(msg.RcptTo[0]);
MailAddress mailFrom = new MailAddress(msg.MailFrom);
MXRecord[] mXRecords = DNSManager.GetMXRecords(mailAddress.Host);
// If mxs is null then there are no MX records.
if (mXRecords == null || mXRecords.Length < 1)
{
await msg.HandleDeliveryFailAsync("550 Domain Not Found.", null, null);
result = false;
}
else if (IsMxBlacklisted(mXRecords))
{
await msg.HandleDeliveryFailAsync("550 Domain blacklisted.", null, mXRecords[0]);
result = false;
}
else
{
// The IP group that will be used to send the queued message.
VirtualMtaGroup virtualMtaGroup = VirtualMtaManager.GetVirtualMtaGroup(msg.VirtualMTAGroupID);
VirtualMTA sndIpAddress = virtualMtaGroup.GetVirtualMtasForSending(mXRecords[0]);
SmtpOutboundClientDequeueResponse dequeueResponse = await SmtpClientPool.Instance.DequeueAsync(sndIpAddress, mXRecords);
switch (dequeueResponse.DequeueResult)
{
case SmtpOutboundClientDequeueAsyncResult.Success:
case SmtpOutboundClientDequeueAsyncResult.NoMxRecords:
case SmtpOutboundClientDequeueAsyncResult.FailedToAddToSmtpClientQueue:
case SmtpOutboundClientDequeueAsyncResult.Unknown:
break; // Don't need to do anything for these results.
case SmtpOutboundClientDequeueAsyncResult.FailedToConnect:
await msg.HandleFailedToConnectAsync(sndIpAddress, mXRecords[0]);
break;
case SmtpOutboundClientDequeueAsyncResult.ServiceUnavalible:
await msg.HandleServiceUnavailableAsync(sndIpAddress);
break;
case SmtpOutboundClientDequeueAsyncResult.Throttled:
await msg.HandleDeliveryThrottleAsync(sndIpAddress, mXRecords[0]);
break;
case SmtpOutboundClientDequeueAsyncResult.FailedMaxConnections:
msg.AttemptSendAfterUtc = DateTime.UtcNow.AddSeconds(2);
RabbitMqOutboundQueueManager.Enqueue(msg);
break;
}
SmtpOutboundClient smtpClient = dequeueResponse.SmtpOutboundClient;
// If no client was dequeued then we can't currently send.
// This is most likely a max connection issue. Return false but don't
// log any deferal or throttle.
if (smtpClient == null)
{
result = false;
}
else
{
try
{
Action <string> failedCallback = delegate(string smtpResponse)
{
// If smtpRespose starts with 5 then perm error should cause fail
if (smtpResponse.StartsWith("5"))
{
msg.HandleDeliveryFailAsync(smtpResponse, sndIpAddress, smtpClient.MXRecord).Wait();
}
else
{
// If the MX is actively denying use service access, SMTP code 421 then we should inform
// the ServiceNotAvailableManager manager so it limits our attepts to this MX to 1/minute.
if (smtpResponse.StartsWith("421"))
{
ServiceNotAvailableManager.Add(smtpClient.SmtpStream.LocalAddress.ToString(), smtpClient.MXRecord.Host, DateTime.UtcNow);
msg.HandleDeliveryDeferral(smtpResponse, sndIpAddress, smtpClient.MXRecord, true);
}
else
{
// Otherwise message is deferred
msg.HandleDeliveryDeferral(smtpResponse, sndIpAddress, smtpClient.MXRecord, false);
}
}
throw new SmtpTransactionFailedException();
};
// Run each SMTP command after the last.
await smtpClient.ExecHeloOrRsetAsync(failedCallback);
await smtpClient.ExecMailFromAsync(mailFrom, failedCallback);
await smtpClient.ExecRcptToAsync(mailAddress, failedCallback);
await smtpClient.ExecDataAsync(msg.Message, failedCallback, async (response) => {
await msg.HandleDeliverySuccessAsync(sndIpAddress, smtpClient.MXRecord, response);
});
SmtpClientPool.Instance.Enqueue(smtpClient);
result = true;
}
catch (SmtpTransactionFailedException)
{
// Exception is thrown to exit transaction, logging of deferrals/failers already handled.
result = false;
}
catch (Exception ex)
{
Logging.Error("MessageSender error.", ex);
if (msg != null)
{
msg.HandleDeliveryDeferral("Connection was established but ended abruptly.", sndIpAddress, smtpClient.MXRecord, false);
}
result = false;
}
finally
{
if (smtpClient != null)
{
smtpClient.IsActive = false;
smtpClient.LastActive = DateTime.UtcNow;
}
}
}
}
}
return(result);
}
