DataFlex

Email Received Header Fields

Received emails will contain one or more "Received" header fields at the beginning of the email header. Each SMTP server (along the delivery path) adds a Received header to the top of the incoming message. The delivery route can be ascertained by the sequence of Received headers. There is a good summary of the Received header here.

The following explanation is taken from the reference URL above:

In theory, the value of a Received field is tokenizable. It contains

    1) optionally, a "from" atom followed by an encoded domain name;
    2) optionally, a "by" atom followed by an encoded domain name;
    3) optionally, a "via" atom followed by another atom;
    4) zero or more of the following: a "with" atom followed by another atom;
    5) optionally, an "id" atom followed by either (1) an atom or (2) a < token, an encoded address, and a > token;
    6) optionally, a "for" atom followed by an encoded address;
    7) a semicolon; and
    8) a timestamp. 

In practice, SMTP servers put all sorts of badly formatted information into Received lines. It is probably best for readers to treat everything before the final semicolon as unstructured text, purely for human consumption.

This example demonstrates iterating over each of the Recevied headers and getting the content of each.

DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoEmail
    Handle hoSbHdrName
    Integer i
    Integer iNumHeaders
    String sTemp1
    Boolean bTemp1

    Move False To iSuccess

    Get Create (RefClass(cComChilkatEmail)) To hoEmail
    If (Not(IsComObjectCreated(hoEmail))) Begin
        Send CreateComObject of hoEmail
    End

    // Load a .eml file into the email object.
    Get ComLoadEml Of hoEmail "/home/users/chilkat/eml/myEml.eml" To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoEmail To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    Get Create (RefClass(cComChilkatStringBuilder)) To hoSbHdrName
    If (Not(IsComObjectCreated(hoSbHdrName))) Begin
        Send CreateComObject of hoSbHdrName
    End

    Move 0 To i
    Get ComNumHeaderFields Of hoEmail To iNumHeaders
    While (i < iNumHeaders)
        Get ComGetHeaderFieldName Of hoEmail i To sTemp1
        Get ComSetString Of hoSbHdrName sTemp1 To iSuccess
        Get ComContentsEqual Of hoSbHdrName "Received" False To bTemp1
        If (bTemp1 = True) Begin
            Get ComGetHeaderFieldValue Of hoEmail i To sTemp1
            Showln "Received: " sTemp1
        End

        Move (i + 1) To i
    Loop



End_Procedure