///<summary>Gets the oldest Direct Ack (MDN) from the db which has not been sent yet and attempts to send it.
///If the Ack fails to send, then it remains in the database with status AckDirectNotSent, so that another attempt will be made when this function is called again.
///This function throttles the Ack responses to prevent the email host from flagging the emailAddressFrom as a spam account. The throttle speed is one Ack per 60 seconds (to mimic human behavior).
///Throws exceptions.</summary>
public static void SendOldestUnsentAck(EmailAddress emailAddressFrom) {
if(RemotingClient.RemotingRole==RemotingRole.ClientWeb) {
Meth.GetVoid(MethodBase.GetCurrentMethod());
return;
}
string command;
//Get the time that the last Direct Ack was sent for the From address.
command=DbHelper.LimitOrderBy(
"SELECT MsgDateTime FROM emailmessage "
+"WHERE FromAddress='"+POut.String(emailAddressFrom.EmailUsername.Trim())+"' AND SentOrReceived="+POut.Long((int)EmailSentOrReceived.AckDirectProcessed)+" "
+"ORDER BY MsgDateTime DESC",
1);
DateTime dateTimeLastAck=PIn.DateT(Db.GetScalar(command));//dateTimeLastAck will be 0001-01-01 if there is not yet any sent Acks.
if((DateTime.Now-dateTimeLastAck).TotalSeconds<60) {
//Our last Ack sent was less than 15 seconds ago. Abort sending Acks right now.
return;
}
//Get the oldest Ack for the From address which has not been sent yet.
command=DbHelper.LimitOrderBy(
"SELECT * FROM emailmessage "
+"WHERE FromAddress='"+POut.String(emailAddressFrom.EmailUsername.Trim())+"' AND SentOrReceived="+POut.Long((int)EmailSentOrReceived.AckDirectNotSent)+" "
+"ORDER BY EmailMessageNum",//The oldest Ack is the one that was recorded first. EmailMessageNum is better than using MsgDateTime, because MsgDateTime is only accurate down to the second.
1);
List <EmailMessage> listEmailMessageUnsentAcks=Crud.EmailMessageCrud.SelectMany(command);
if(listEmailMessageUnsentAcks.Count<1) {
return;//No Acks to send.
}
EmailMessage emailMessageAck=listEmailMessageUnsentAcks[0];
string strRawEmailAck=emailMessageAck.BodyText;//Not really body text. The entire raw Ack is saved here, and we use it to reconstruct the Ack email completely.
Health.Direct.Agent.MessageEnvelope messageEnvelopeMdn=new Health.Direct.Agent.MessageEnvelope(strRawEmailAck);
Health.Direct.Agent.OutgoingMessage outMsgDirect=new Health.Direct.Agent.OutgoingMessage(messageEnvelopeMdn);
try {
string strErrors=SendEmailDirect(outMsgDirect,emailAddressFrom);//Encryption is performed in this step. Throws an exception if unable to send (i.e. when internet down).
if(strErrors=="") {
emailMessageAck.SentOrReceived=EmailSentOrReceived.AckDirectProcessed;
emailMessageAck.MsgDateTime=DateTime.Now;//Update the time, otherwise the throttle will not work properly.
Update(emailMessageAck);
}
}
catch {
}
}
///<summary>Encrypts the message, verifies trust, locates the public encryption key for the To address (if already stored locally), etc. emailMessage.
///Use this polymorphism when the attachments have already been saved to the email attachments folder in file form. patNum can be 0.
///Returns an empty string upon success, or an error string if there were errors. It is possible that the email was sent to some trusted recipients and not sent to untrusted recipients (in which case there would be errors but some recipients would receive successfully).
///Surround with a try catch.</summary>
public static string SendEmailDirect(EmailMessage emailMessage,EmailAddress emailAddressFrom) {
//No need to check RemotingRole; no call to db.
emailMessage.FromAddress=emailAddressFrom.EmailUsername.Trim();//Cannot be emailAddressFrom.SenderAddress, or else will not find the correct encryption certificate. Used in ConvertEmailMessageToMessage().
//Start by converting the emailMessage to an unencrypted message using the Direct libraries. The email must be in this form to carry out encryption.
Health.Direct.Common.Mail.Message msgUnencrypted=ConvertEmailMessageToMessage(emailMessage,true);
Health.Direct.Agent.MessageEnvelope msgEnvelopeUnencrypted=new Health.Direct.Agent.MessageEnvelope(msgUnencrypted);
Health.Direct.Agent.OutgoingMessage outMsgUnencrypted=new Health.Direct.Agent.OutgoingMessage(msgEnvelopeUnencrypted);
string strErrors=SendEmailDirect(outMsgUnencrypted,emailAddressFrom);
return strErrors;
}
///<summary>Used for creating encrypted Message Disposition Notification (MDN) ack messages for Direct.
///An ack must be sent when a message is received/processed, and other acks are supposed be sent when other events occur (but are not required).
///For example, when the user reads a decrypted message we must send an ack with notification type of Displayed (not required).</summary>
private static string SendAckDirect(Health.Direct.Agent.IncomingMessage inMsg,EmailAddress emailAddressFrom,long patNum) {
//No need to check RemotingRole; no call to db.
//The CreateAcks() function handles the case where the incoming message is an MDN, in which case we do not reply with anything.
//The CreateAcks() function also takes care of figuring out where to send the MDN, because the rules are complicated.
//According to http://wiki.directproject.org/Applicability+Statement+for+Secure+Health+Transport+Working+Version#x3.0%20Message%20Disposition%20Notification,
//The MDN must be sent to the first available of: Disposition-Notification-To header, MAIL FROM SMTP command, Sender header, From header.
Health.Direct.Common.Mail.Notifications.MDNStandard.NotificationType notificationType=Health.Direct.Common.Mail.Notifications.MDNStandard.NotificationType.Failed;
notificationType=Health.Direct.Common.Mail.Notifications.MDNStandard.NotificationType.Processed;
IEnumerable<Health.Direct.Common.Mail.Notifications.NotificationMessage> notificationMsgs=inMsg.CreateAcks("OpenDental "+Assembly.GetExecutingAssembly().GetName().Version,"",notificationType);
if(notificationMsgs==null) {
return "";
}
string strErrorsAll="";
foreach(Health.Direct.Common.Mail.Notifications.NotificationMessage notificationMsg in notificationMsgs) {
string strErrors="";
try {
//According to RFC3798, section 3 - Format of a Message Disposition Notification http://tools.ietf.org/html/rfc3798#page-3
//A message disposition notification is a MIME message with a top-level
//content-type of multipart/report (defined in [RFC-REPORT]). When
//multipart/report content is used to transmit an MDN:
//(a) The report-type parameter of the multipart/report content is "disposition-notification".
//(b) The first component of the multipart/report contains a human-readable explanation of the MDN, as described in [RFC-REPORT].
//(c) The second component of the multipart/report is of content-type message/disposition-notification, described in section 3.1 of this document.
//(d) If the original message or a portion of the message is to be returned to the sender, it appears as the third component of the multipart/report.
// The decision of whether or not to return the message or part of the message is up to the MUA generating the MDN. However, in the case of
// encrypted messages requesting MDNs, encrypted message text MUST be returned, if it is returned at all, only in its original encrypted form.
Health.Direct.Agent.OutgoingMessage outMsgDirect=new Health.Direct.Agent.OutgoingMessage(notificationMsg);
if(notificationMsg.ToValue.Trim().ToLower()==notificationMsg.FromValue.Trim().ToLower()) {
continue;//Do not send an ack to self.
}
EmailMessage emailMessage=ConvertMessageToEmailMessage(outMsgDirect.Message,false);
emailMessage.PatNum=patNum;
//First save the ack message to the database in case their is a failure sending the email. This way we can remember to try and send it again later, based on SentOrRecieved.
emailMessage.SentOrReceived=EmailSentOrReceived.AckDirectNotSent;
MemoryStream ms=new MemoryStream();
notificationMsg.Save(ms);
byte[] arrayMdnMessageBytes=ms.ToArray();
emailMessage.BodyText=Encoding.UTF8.GetString(arrayMdnMessageBytes);
ms.Dispose();
Insert(emailMessage);
}
catch(Exception ex) {
strErrors=ex.Message;
}
if(strErrorsAll!="") {
strErrorsAll+="\r\n";
}
strErrorsAll+=strErrors;
}
try {
SendOldestUnsentAck(emailAddressFrom);//Send the ack(s) we created above.
}
catch {
//Not critical to send the acks here, because they will be sent later if they failed now.
}
return strErrorsAll;
}
///<summary>Throws exceptions. Uses the Direct library to sign the message, so that our unencrypted/signed messages are built the same way as our encrypted/signed messages.
///The provided certificate must contain a private key, or else the signing will fail (exception) when computing the signature digest.</summary>
public static void SendEmailUnsecureWithSig(EmailMessage emailMessage,EmailAddress emailAddressFrom,X509Certificate2 certPrivate) {
if(emailAddressFrom.IsImplicitSsl) {
throw new Exception(Lans.g("EmailMessages","Digitally signed messages cannot be sent over implicit SSL."));//See detailed comments in the private version of SendEmailUnsecure().
}
//No need to check RemotingRole; no call to db.
emailMessage.FromAddress=emailAddressFrom.EmailUsername.Trim();//Cannot be emailAddressFrom.SenderAddress, or else will not find the correct signing certificate. Used in ConvertEmailMessageToMessage().
Health.Direct.Common.Mail.Message msg=ConvertEmailMessageToMessage(emailMessage,true);
Health.Direct.Agent.MessageEnvelope msgEnvelope=new Health.Direct.Agent.MessageEnvelope(msg);
Health.Direct.Agent.OutgoingMessage msgOut=new Health.Direct.Agent.OutgoingMessage(msgEnvelope);
Health.Direct.Agent.DirectAgent directAgent=GetDirectAgentForEmailAddress(emailMessage.FromAddress);
Health.Direct.Common.Cryptography.SignedEntity signedEntity=directAgent.Cryptographer.Sign(msgOut.Message,certPrivate);//Compute the signature digest. A hash of the certificate against the raw email content.
msgOut.Message.UpdateBody(signedEntity);//Modify the relevant message headers as well as the entire message body to include the signature digest.
WireEmailUnsecure(msgOut,emailAddressFrom,emailMessage.PatNum);
}
