get the undeliverable email address with mimekit/mailkit library

问题

I started using @jstedfast Mimekit/Mailkit library, which is great by the way, to pull undeliverables using its subject line for search. I tried using the message.to, message.resentto.

how do i get that information. My first try today. I was able to get the list and the body but I just need the email. I tried using s22.imap but there's no support anymore then I discovered this. I know you're active here @jstedfast I need you help..there's no discussion tab in your github.

Thanks in advance

回答1:

If you look at the raw message source, does the value of the Content-Type header match something along the lines of multipart/report; report-type=delivery-status? If so, it is very likely that this message will have a sub-part with a Content-Type header with a value of message/delivery-status. It should be the second child part of the multipart/report (the first part should be a human-readable explanation).

If so, you can cast the message/delivery-status MimeEntity to an instance of a MessageDeliveryStatus. You'll notice that the MessageDeliveryStatus class has a property called StatusGroups which is a list of multiple collections of headers (e.g. a list of HeaderList objects).

Each HeaderList contains information about a particular recipient that failed. I think what you want to do is look at the Final-Recipient header which will contain 2 pieces of information:

The address-type (should typically be "rfc822")
The mailbox of the recipient (which is what you want)

Unfortunately, MimeKit does not have any tools to parse the Final-Recipient header, but it should be trivial to locate the end of the address-type parameter in the header value by using IndexOf (';') and then you can use something like MailboxAddress.TryParse() to parse it (or you could probably just Substring() the value w/o parsing).

So, the way this might look in code is this:

string[] GetUndeliverableAddresses (MimeMessage message)
{
    var report = message.Body as MultipartReport;

    if (report == null)
        throw new ArgumentException ("This is not a multipart/report!");

    MessageDeliveryStatus status = null;

    for (int i = 0; i < report.Count; i++) {
        status = report[i] as MessageDeliveryStatus;
        if (status != null)
            break;
    }

    if (status == null)
        throw new ArgumentException ("Did not contain a message/delivery-status!");

    var undeliverables = new List<string> ();
    for (int i = 0; i < status.StatusGroups.Count; i++) {
        var recipient = status.StatusGroups[i]["Final-Recipient"];
        int semicolon = recipient.IndexOf (';');

        var undeliverable = recipient.Substring (semicolon + 1).Trim ();
        undeliverables.Add (undeliverable);
    }

    return undeliverables.ToArray ();
}

For more information on message/delivery-status, see https://tools.ietf.org/html/rfc3464

Hope that helps.

回答2:

this is what I did

 foreach (var uid in inbox.Search(query))
        {
            var message = inbox.GetMessage(uid);
           // Console.WriteLine("Subject: {0}", message.Subject);
            //Console.WriteLine("Subject: {0}", message.Headers);
           // Console.WriteLine("Subject: {0}", message.BodyParts);
            var text = message.BodyParts;
            string src = text.ElementAt(1).ToString();
            int srcStart = src.IndexOf("RFC822;",0); << i used final-recipient intially
            int srcEnd   = src.IndexOf("Action", 0);
            Console.WriteLine("Email:" + src.Substring(srcStart + 8, srcEnd - (srcStart + 8)));
            Console.WriteLine(src);


            //foreach (var part in message.BodyParts)
            //{
            //    Console.WriteLine(part);
            //    // do something
            //}

        }

let me know if there could be a problem..will I get the rfc822 if the recipient inbox is full? there's no way i can test that.. I tested with emails with nonexistent domain, mailbox does not exist..with live.com, randomdomain.com,yahoo.com and gmail. gmail, on the other hand does not return any undeliverables.

来源：https://stackoverflow.com/questions/42128889/get-the-undeliverable-email-address-with-mimekit-mailkit-library

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mailkit