/// <summary>
/// Examines an email to try to identify detailed bounce information from it.
/// </summary>
/// <param name="filename">Path and filename of the file being processed.</param>
/// <param name="message">The entire text content for an email (headers and body).</param>
/// <returns>An EmailProcessingResult value indicating whether the the email was
/// successfully processed or not.</returns>
public EmailProcessingDetails ProcessBounceEmail(string message)
{
EmailProcessingDetails bounceDetails = new EmailProcessingDetails();
MimeMessage msg = MimeMessage.Parse(message);
if (msg == null)
{
bounceDetails.ProcessingResult = EmailProcessingResult.ErrorContent;
bounceDetails.BounceIdentifier = Core.Enums.BounceIdentifier.NotIdentifiedAsABounce;
return(bounceDetails);
}
// "x-receiver" should contain what Manta originally set as the "return-path" when sending.
MessageHeader returnPath = msg.Headers.GetFirstOrDefault("x-receiver");
if (returnPath == null)
{
bounceDetails.ProcessingResult = EmailProcessingResult.ErrorNoReturnPath;
bounceDetails.BounceIdentifier = Core.Enums.BounceIdentifier.UnknownReturnPath;
return(bounceDetails);
}
string rcptTo = string.Empty;
int internalSendID = 0;
if (!ReturnPathManager.TryDecode(returnPath.Value, out rcptTo, out internalSendID))
{
// Not a valid Return-Path so can't process.
bounceDetails.ProcessingResult = EmailProcessingResult.ErrorNoReturnPath;
bounceDetails.BounceIdentifier = Core.Enums.BounceIdentifier.UnknownReturnPath;
return(bounceDetails);
}
MantaBounceEvent bounceEvent = new MantaBounceEvent();
bounceEvent.EmailAddress = rcptTo;
bounceEvent.SendID = MantaMTA.Core.DAL.SendDB.GetSend(internalSendID).ID;
// TODO: Might be good to get the DateTime found in the email.
bounceEvent.EventTime = DateTime.UtcNow;
// These properties are both set according to the SMTP code we find, if any.
bounceEvent.BounceInfo.BounceCode = MantaBounceCode.Unknown;
bounceEvent.BounceInfo.BounceType = MantaBounceType.Unknown;
bounceEvent.EventType = MantaEventType.Bounce;
// First, try to find a NonDeliveryReport body part as that's the proper way for an MTA
// to tell us there was an issue sending the email.
BouncePair bouncePair;
string bounceMsg;
BodyPart deliveryReportBodyPart;
string deliveryReport = string.Empty;
if (FindFirstBodyPartByMediaType(msg.BodyParts, "message/delivery-status", out deliveryReportBodyPart))
{
// If we've got a delivery report, check it for info.
// Abuse report content may have long lines whitespace folded.
deliveryReport = MimeMessage.UnfoldHeaders(deliveryReportBodyPart.GetDecodedBody());
if (ParseNdr(deliveryReport, out bouncePair, out bounceMsg, out bounceDetails))
{
// Successfully parsed.
bounceEvent.BounceInfo = bouncePair;
bounceEvent.Message = bounceMsg;
// Write BounceEvent to DB.
Save(bounceEvent);
bounceDetails.ProcessingResult = EmailProcessingResult.SuccessBounce;
return(bounceDetails);
}
}
// We're still here so there was either no NDR part or nothing contained within it that we could
// interpret so have to check _all_ body parts for something useful.
if (FindBounceReason(msg.BodyParts, out bouncePair, out bounceMsg, out bounceDetails))
{
bounceEvent.BounceInfo = bouncePair;
bounceEvent.Message = bounceMsg;
// Write BounceEvent to DB.
Save(bounceEvent);
bounceDetails.ProcessingResult = EmailProcessingResult.SuccessBounce;
return(bounceDetails);
}
// Nope - no clues relating to why the bounce occurred.
bounceEvent.BounceInfo.BounceType = MantaBounceType.Unknown;
bounceEvent.BounceInfo.BounceCode = MantaBounceCode.Unknown;
bounceEvent.Message = string.Empty;
bounceDetails.BounceIdentifier = Core.Enums.BounceIdentifier.NotIdentifiedAsABounce;
bounceDetails.ProcessingResult = EmailProcessingResult.Unknown;
return(bounceDetails);
}
/// <summary>
/// Examines an SMTP response message to identify detailed bounce information from it.
/// </summary>
/// <param name="response">The message that's come back from an external MTA when attempting to send an email.</param>
/// <param name="rcptTo">The email address that was being sent to.</param>
/// <param name="internalSendID">The internal Manta SendID.</param>
/// <returns>True if a bounce was found and recorded, false if not.</returns>
internal bool ProcessSmtpResponseMessage(string response, string rcptTo, int internalSendID, out EmailProcessingDetails bounceIdentification)
{
bounceIdentification = new EmailProcessingDetails();
// Check for TimedOutInQueue message first.
if (response.Equals(MtaParameters.TIMED_OUT_IN_QUEUE_MESSAGE, StringComparison.OrdinalIgnoreCase))
{
bounceIdentification = null;
MantaTimedOutInQueueEvent timeOut = new MantaTimedOutInQueueEvent
{
EventType = MantaEventType.TimedOutInQueue,
EmailAddress = rcptTo,
SendID = SendDB.GetSend(internalSendID).ID,
EventTime = DateTime.UtcNow
};
// Log to DB.
Save(timeOut);
// All done return true.
return(true);
}
BouncePair bouncePair = new BouncePair();
string bounceMessage = string.Empty;
if (ParseBounceMessage(response, out bouncePair, out bounceMessage, out bounceIdentification))
{
// Were able to find the bounce so create the bounce event.
MantaBounceEvent bounceEvent = new MantaBounceEvent
{
EventType = MantaEventType.Bounce,
EmailAddress = rcptTo,
BounceInfo = bouncePair,
SendID = SendDB.GetSend(internalSendID).ID,
// It is possible that the bounce was generated a while back, but we're assuming "now" for the moment.
// Might be good to get the DateTime found in the email at a later point.
EventTime = DateTime.UtcNow,
Message = response
};
// Log to DB.
Save(bounceEvent);
// All done return true.
return(true);
}
// Couldn't identify the bounce.
bounceIdentification.BounceIdentifier = Core.Enums.BounceIdentifier.NotIdentifiedAsABounce;
return(false);
}
