Parse a Delivery Status Notification (DSN) Email

Download: Chilkat .NET Assemblies

This C# example program demonstrates how to parse a DSN message using the Chilkat Email component.

// How to parse a DSN Email
// (Parsing a Delivery Status Notification Email)

// Unlock the components that are needed for this example:
Chilkat.MailMan mailman0 = new Chilkat.MailMan();
mailman0.UnlockComponent("30-day trial");

Chilkat.Mime mime0 = new Chilkat.Mime();
mime0.UnlockComponent("30-day trial");

// Load a .eml file into the email object.
// A zip containing 10 DSN sample emails can be found at:
// http://www.chilkatsoft.com/dsn_samples/DSN_Samples.zip
Chilkat.Email email = new Chilkat.Email();
email.LoadEml("dsnSample10.eml");

// The email should be a multipart/report.  If not, exit.
if (!email.IsMultipartReport()) {
    MessageBox.Show("Not a DSN!");
    return;
}

// The overall format of a DSN is described here:
// http://www.chilkatsoft.com/braindump/email_headers/mime_format_dsn.html
//
// In summary, the outermost MIME layer is a multipart/report,
// and 3 parts are contained within:
// 1) A human-readable explanation of the DSN (content-type is text/plain)
// 2) A message/delivery-status part.
// 3) The original email (message/rfc822) or the headers of the original
//    email (text/rfc822-headers)

// The human-readable part of the DSN is accessible via the email's Body property:
textBox1.Text = email.Body;

// To parse the message/delivery-status part, we need Chilkat Mime.
// Get the email as a MIME object:
Chilkat.Mime mime = email.GetMimeObject();

// Now get the message/delivery-status part.
// It is the 2nd sub-part, so the index is 1.
Chilkat.Mime dstat = mime.GetPart(1);

// Do we have what we expect?
if (dstat.ContentType.Equals("message/delivery-status")) {

    // The body of the message/delivery-status contains MIME headers.
    // There is a single per-message header set, and 1 or more
    // per-recipient header sets.
    // For example, this one has 2 recipients:
    //
    //Reporting-MTA: dns; comcast.net
    //Arrival-Date: 13 Sep 2006 23:28:50 +0000
    //
    //Final-Recipient: rfc822; <ajsfdlkjasdglkjadsg@blah.com>
    //Action: failed
    //Status: 5.0.0 550_Requested_action_not_taken:_mailbox_unavailable_or_not_local
    //Diagnostic-Code: smtp; Permanent Failure: Other undefined Status
    //Last-Attempt-Date: Wed, 13 Sep 2006 23:28:51 -0000
    //
    //Final-Recipient: rfc822; <asgfafdsga8fgsfdgk@blah.com>
    //Action: failed
    //Status: 5.0.0 550_Requested_action_not_taken:_mailbox_unavailable_or_not_local
    //Diagnostic-Code: smtp; Permanent Failure: Other undefined Status
    //Last-Attempt-Date: Wed, 13 Sep 2006 23:28:51 -0000
    
    // How do we parse it???
    // We'll let ChilkatMime do the work.  First, we'll get the body and then
    // split it into separate chunks where each is then treated as a separate
    // MIME message with an empty body.
            
    string body = dstat.GetBodyDecoded();
    
    // The Chilkat.StringArray class includes the SplitAndAppend method to
    // split a string using boundary strings.  If we split at double-CRLF's
    // we can get each chunk.
    // Note: The SplitAndAppend is new to Chilkat.NET (14-Sep-2006).  If it is not present
    // in your existing DLL, download the latest from http://www.chilkatsoft.com/downloads.asp
    Chilkat.StringArray sa = new Chilkat.StringArray();
    sa.SplitAndAppend(body, "\r\n\r\n");
    
    MessageBox.Show(Convert.ToString(sa.Count));
    
    // Display each set of headers...
    int i;
    for (i=0; i<sa.Count; i++)
    {
	MessageBox.Show("[" + sa.GetString(i) + "]");
    }
    
    // The 1st header-set contains the Reporting-MTA.
    // Load it and
    Chilkat.Mime mTemp = new Chilkat.Mime();
    mTemp.LoadMime(sa.GetString(0) + "\r\n\r\n");
    
    // Display the Reporting-MTA
    listBox1.Items.Add("Reporting-MTA: " + mTemp.GetHeaderField("Reporting-MTA"));
    // Display the Arrival-Date
    listBox1.Items.Add("Arrival-Date: " + mTemp.GetHeaderField("Arrival-Date"));
    listBox1.Items.Add("--");
    
    // Display information for each Final-Recipient
    for (i=1; i<sa.Count; i++) {
    
	mTemp.LoadMime(sa.GetString(i));
        
	// (Not all of these fields may be present.)
        
	// Information about Final-Recipient is located here:
	// http://chilkatsoft.com/braindump/email_headers/Final-Recipient_header.html
	listBox1.Items.Add("Final-Recipient: " + mTemp.GetHeaderField("Final-Recipient"));
        
	// Information about the Action header field is located at:
	// http://chilkatsoft.com/braindump/email_headers/action_dsn_header_field.html
	listBox1.Items.Add("Action: " + mTemp.GetHeaderField("Action"));
        
	// Information about the Status header field is located at:
	// http://chilkatsoft.com/braindump/email_headers/status_dsn_header_field.html
	listBox1.Items.Add("Status: " + mTemp.GetHeaderField("Status"));
        
	// Information about the Diagnostic-Code header field is located at:
	// http://chilkatsoft.com/braindump/email_headers/diagnostic-code_header_field.html
	listBox1.Items.Add("Diagnostic-Code: " + mTemp.GetHeaderField("Diagnostic-Code"));
        
	listBox1.Items.Add("Last-Attempt-Date: " + mTemp.GetHeaderField("Last-Attempt-Date"));
	listBox1.Items.Add("Remote-MTA: " + mTemp.GetHeaderField("Remote-MTA"));
        
	listBox1.Items.Add("--");
	} 
    }
    else {
    MessageBox.Show("Unexpected delivery status, content-type = " + dstat.ContentType);
}

// The original email is available as an embedded message:
Chilkat.Email originalEmail = email.GetAttachedMessage(0);

// If the original email is Nothing, then the DSN only included the original
// email headers as a text/rfc822-headers
if (originalEmail != null) {
    // We got the original email.  Because it is a ChilkatEmail2 object,
    // the headers, bodies, attachments, etc, are all accessible.
    // This example will simply save the original email to a file.
    originalEmail.SaveEml("originalEmail.eml");
    }
else {
    // The DSN did not have the complete message/rfc822 attached.
    // Use Chilkat Mime to see what we have...
    // (The DSN samples at http://www.chilkatsoft.com/dsn_samples/DSN_Samples.zip
    // include a DSN (sampleEml10.eml) that uses a text/rfc822-headers.)
    
    // Access the email via the ChilkatMime API:
    mime = email.GetMimeObject();
    
    // Now get the 3rd sub-part, which is at index 2.
    Chilkat.Mime part3 = mime.GetPart(2);
    
    // Make sure we have it...
    if (part3 == null) {
	MessageBox.Show("Did not get sub-part #3!");
	return;
    }
    
    // Is this a text/rfc822-headers part?
    if (part3.ContentType.Equals("text/rfc822-headers")) {
	// OK, the body of this part is a collection of headers.
	// If we get the body, we can append a few blank lines
	// and then read it as a MIME message and access any
	// header.
	string msg = part3.GetBodyDecoded() + "\r\n\r\n";
        
	// Load it into a MIME object.
	Chilkat.Mime mime2 = new Chilkat.Mime();
	mime2.LoadMime(msg);
        
	// Fetch some of the headers:
	listBox1.Items.Add("From: " + mime2.GetHeaderField("from"));
	listBox1.Items.Add("Subject: " + mime2.GetHeaderField("subject"));
	listBox1.Items.Add("To: " + mime2.GetHeaderField("to"));
    }  
    else {
	MessageBox.Show("Unexpected content-type: " + part3.ContentType);
    }
    
}

Important: The download for this example does not contain the ChilkatDotNet.dll which
must be downloaded and installed separately at http://www.chilkatsoft.com/downloads.asp.
Once installed, add a reference to the DLL in the project by following the instructions at
http://www.example-code.com/vbdotnet/step2.asp