(Delphi DLL) Processing a multipart/report Delivery Status Notification (Bounce Notification)

See more Email Object Examples

Note: This example requires Chilkat v11.0.0 or greater.

Chilkat for Delphi Downloads Chilkat non-ActiveX DLL for Delphi Chilkat ActiveX DLL for Delphi * The examples here use the non-ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Mime, HtmlToText, Email, JsonObject;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
email: HCkEmail;
h2t: HCkHtmlToText;
jsonDsnInfo: HCkJsonObject;
headersText: PWideChar;
mime: HCkMime;
origEmail: HCkEmail;

begin
success := False;

// Here are the MIME structures, showing the content-type and nesting of the MIME parts of three sample
// multipart/report DSN (Delivery Status Notification) emails.

// This 1st sample includes a "text/rfc822-headers" MIME subpart. 

// multipart/report
//     text/plain
//     message/delivery-status
//     text/rfc822-headers
//     message/rfc822

// This 2nd sample lacks the text/rfc-headers part, but the "report type" information
// is offered in both plain-text and HTML formats.

// multipart/report
//     multipart/alternative
//         text/plain
//         text/html
//     message/delivery-status
//     message/rfc822

// ----------------------------------------------------------------------------------------------------

// A multipart/report MIME delivery status notification follows a specific format defined by the Internet Engineering Task Force (IETF) in RFC 3464, 
// which outlines the "An Extensible Message Format for Delivery Status Notifications" standard. The format consists of multiple parts within a 
// multipart/report structure. Here's an overview of the main parts involved:
// 
// The 1st sub-part under multipart/report is the body of the DSN to be displayed by the email client (such as Outlook).
// It can be a simple text/plain body, or it can be multipart/alternative and offer a few alternative format, typically plain-text and HTML.
// HTML is best for viewing a program such as Outlook. 
// This part of the multipart/report is not structured for programmatic processing.  It's meant to be viewed by a human.

// --------------------
// The "message/delivery-status" part within a multipart/report MIME structure follows a specific format to provide details about the delivery status
// of an email message.  Here's an overview of the format and the key components within the "message/delivery-status" part:
// 
// (1) Content-Type and Reporting-UA:
// The "message/delivery-status" part begins with the Content-Type header specifying "message/delivery-status". 
// It may also include a Reporting-UA (Reporting User Agent) field that identifies the software or system generating the delivery status notification.
// 
// For example:
// 
// Content-Type: message/delivery-status
// Reporting-UA: Example Mail System 1.0
// 
// (2) Fields:
// The "message/delivery-status" part contains a series of fields, each providing specific information about the delivery status. 
// These fields are structured as key-value pairs.
// 
// Common fields include:
// 
//     Final-Recipient: Specifies the recipient for whom the delivery status is being reported.
//     Action: Describes the action performed by the reporting system (e.g., failed, delivered, delayed, etc.).
//     Status: Indicates the status code or reason for the delivery attempt result.
//     Remote-MTA: Specifies the host or system that attempted the delivery.
//     Diagnostic-Code: Provides additional diagnostic information, such as error codes or explanations.
// 
// For example:
// 
// Final-Recipient: rfc822; john.doe@example.com
// Action: failed
// Status: 5.1.1
// Remote-MTA: smtp.example.com
// Diagnostic-Code: smtp; 550 Requested action not taken: mailbox unavailable
// 
// (3) Additional Fields:
// Additional fields may be included in the "message/delivery-status" part to provide further information about the delivery attempt. 
// These fields can vary depending on the implementation or specific needs of the system generating the delivery status notification.
// For example:
// 
// X-Spam-Flag: YES
// X-Spam-Score: 7.2
// 
// Note: The specific fields and their values within the "message/delivery-status" part can vary depending on the implementation
// or the email server/application generating the delivery status notification. The structure described above represents the standard format
// as defined in RFC 3464, but variations may exist in practice.

// --------------------

// The "text/rfc822-headers" MIME part, if included, contains the headers of the original email message
// for which the delivery status notification is being generated. It provides a subset of the headers from the original message,
// typically excluding the message body and attachments.
// 
// The purpose of including the "text/rfc822-headers" part is to provide contextual information about the original message.
// It allows the recipient to review the original headers, such as the subject, sender, recipients, date, and other relevant information,
// in order to understand the context and details of the email message for which the delivery status notification is being generated.
// 
// Note that the specific headers included in the "text/rfc822-headers" part can vary based on the implementation or requirements
// of the system generating the delivery status notification.

// --------------------

// If the message/rfc822 part is present, it contains the full MIME of the email that was not delivered.
// In Chilkat terminology, this is an attached message.

// OK, let's write code to process a multipart/report email.

email := CkEmail_Create();
success := CkEmail_LoadEml(email,'qa_data/eml/deliveryStatus.eml');
// success = email.LoadEml("qa_data/eml/sample_multipart_report.eml");
if (success = False) then
  begin
    Memo1.Lines.Add(CkEmail__lastErrorText(email));
    Exit;
  end;

// Verify this is a multipart/report email..
if (CkEmail_IsMultipartReport(email) = False) then
  begin
    Memo1.Lines.Add('Not a multipart/report email.');
    Exit;
  end;

// Get the body that is to be displayed to a human in an email program (such as Outlook).
if (CkEmail_HasPlainTextBody(email) = True) then
  begin
    Memo1.Lines.Add('Plain text body:');
    // println email.GetPlainTextBody();
  end
else
  begin
    if (CkEmail_HasHtmlBody(email) = True) then
      begin
        // Convert HTML to plain-text..
        h2t := CkHtmlToText_Create();
        Memo1.Lines.Add('HTML body converted to plain-text:');
        Memo1.Lines.Add(CkHtmlToText__toText(h2t,CkEmail__getHtmlBody(email)));
      end
    else
      begin
        Memo1.Lines.Add('Has no plain-text or HTML body...');
      end;
  end;
Memo1.Lines.Add('---------------------------------');

// Now get information from the message/delivery-status part (or the message/disposition-notification part)
Memo1.Lines.Add('--- Delivery Status Information:');
Memo1.Lines.Add('Status: ' + CkEmail__getDeliveryStatusInfo(email,'Status'));
Memo1.Lines.Add('Action: ' + CkEmail__getDeliveryStatusInfo(email,'Action'));
Memo1.Lines.Add('Reporting-MTA: ' + CkEmail__getDeliveryStatusInfo(email,'Reporting-MTA'));

jsonDsnInfo := CkJsonObject_Create();
CkEmail_GetDsnInfo(email,jsonDsnInfo);
CkJsonObject_putEmitCompact(jsonDsnInfo,False);
Memo1.Lines.Add(CkJsonObject__emit(jsonDsnInfo));

Memo1.Lines.Add('---------------------------------');

// If the multipart/report contains a text/rfc822-headers, it can be retrieved like this:
headersText := CkEmail__getNthTextPartOfType(email,0,'text/rfc822-headers',False,False);
if (CkEmail_getLastMethodSuccess(email) = True) then
  begin
    Memo1.Lines.Add('The text/rfc822-headers part exists..');
    Memo1.Lines.Add('');
    Memo1.Lines.Add(headersText);

    // If you wish to process the headers, you can load them into a MIME object and use the Chilkat MIME functionality to examine the headers.
    mime := CkMime_Create();
    CkMime_LoadMime(mime,headersText);

    // Do whatever you want.. 
    // For example, look at the "To" header.
    Memo1.Lines.Add('MIME To header:');
    Memo1.Lines.Add(CkMime__getHeaderField(mime,'To'));
  end;

Memo1.Lines.Add('---------------------------------');

// Finally, if the original email was attached, you can load it into another Chilkat Email object instance and
// do what you want with it..

if (CkEmail_getNumAttachedMessages(email) > 0) then
  begin
    // Get the 1st attachment message (assume we don't have more than one attached message)
    origEmail := CkEmail_Create();
    success := CkEmail_GetAttachedEmail(email,0,origEmail);
    if (success = True) then
      begin
        Memo1.Lines.Add('Attached message subject: ' + CkEmail__subject(origEmail));
        // Do whatever else you want..
      end;
  end;

CkEmail_Dispose(email);
        CkHtmlToText_Dispose(h2t);
CkJsonObject_Dispose(jsonDsnInfo);
    CkMime_Dispose(mime);
    CkEmail_Dispose(origEmail);

end;