PureBasic

Create a Delivery Status Notification (DSN)

Demonstrates the Chilkat Email.ToDsn method, which creates a new Delivery Status Notification (DSN) email in the format specified by RFC 3464, based on this email. The generated DSN is returned in the last argument, and the source email is not modified. The first argument is the human-readable explanation, the second is the delivery-status fields, and the third indicates whether to include headers only. This example builds a DSN for a received message.

Background: A DSN is the formal "bounce" a mail system returns when a message cannot be delivered. It is a multipart/report containing a human-readable explanation plus a machine-readable message/delivery-status part (with fields like Action and Status). ToDsn generates that structured report for you — useful when building a mail server or gateway that must issue standards-compliant bounces. After generating it, populate the sender/recipient fields and send.

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IncludeFile "CkEmail.pb"

Procedure ChilkatExample()

    success.i = 0

    ;  Demonstrates the ToDsn method, which creates a new Delivery Status Notification (DSN)
    ;  email (RFC 3464) based on this email.  The generated DSN is returned in the last argument.
    ;  The source email is not modified.

    email.i = CkEmail::ckCreate()
    If email.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkEmail::ckLoadEml(email,"qa_data/eml/received.eml")
    If success = 0
        Debug CkEmail::ckLastErrorText(email)
        CkEmail::ckDispose(email)
        ProcedureReturn
    EndIf

    ;  Create a DSN for the received message.  The 1st argument is the human-readable
    ;  explanation, the 2nd is the delivery-status fields, and the 3rd (headerOnly) is false.
    dsn.i = CkEmail::ckCreate()
    If dsn.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkEmail::ckToDsn(email,"The message could not be delivered to the recipient.","Action: failed; Status: 5.1.1",0,dsn)
    If success = 0
        Debug CkEmail::ckLastErrorText(email)
        CkEmail::ckDispose(email)
        CkEmail::ckDispose(dsn)
        ProcedureReturn
    EndIf

    ;  Populate additional sender/recipient fields on the DSN before sending, then send it.
    Debug CkEmail::ckGetMime(dsn)

    ;  Note: The path "qa_data/..." is a relative local filesystem path,
    ;  relative to the current working directory of the running application.


    CkEmail::ckDispose(email)
    CkEmail::ckDispose(dsn)


    ProcedureReturn
EndProcedure