emailrelay-set-from.js

//
// SPDX-FileCopyrightText: 2026 Graeme Walker <graeme_walker@users.sourceforge.net>
// SPDX-License-Identifier: FSFAP
//
// Copyright (c) 2026 Graeme Walker <graeme_walker@users.sourceforge.net>
//
// Copying and distribution of this file, with or without modification,
// are permitted in any medium without royalty provided the copyright
// notice and this notice are preserved.  This file is offered as-is,
// without any warranty.
// ===
//
// emailrelay-set-from.js
//
// An example E-MailRelay filter script that edits the
// content originator fields (ie. From, Sender and Reply-To)
// to a fixed value.
//
// This does not set the envelope-from field in the envelope
// file by default. If the remote server expects the SMTP
// MAIL-FROM address to match the "From:" header then set
// 'edit_envelope' to true.
//
// See also: emailrelay-set-from.pl, RFC-2822
//
try
{
    var edit_envelope = false ; // <= set true to also edit the envelope
    var new_from = 'noreply@example.com' ; // <= edit this
    var new_sender = '' ;
    var new_reply_to = new_from ;

    var content = WScript.Arguments( 0 ) ;
    var envelope = WScript.Arguments( 1 ) ;

    var fs = WScript.CreateObject( "Scripting.FileSystemObject" ) ;
    var in_ = fs.OpenTextFile( content , 1 , false ) ;
    var out_ = fs.OpenTextFile( content + ".tmp" , 8 , true ) ;

    var re_from = /^From:/i ;
    var re_sender = /^Sender:/i ;
    var re_reply_to = /^Reply-To:/i ;
    var re_fold = /^[ \t]/ ;

    var in_edit = 0 ;
    while( !in_.AtEndOfStream )
    {
            var line = in_.ReadLine() ;
            if( line === "" )
            {
                    out_.WriteLine( line ) ;
                    break ;
            }

            if( line.match(re_from) && new_from !== null )
            {
                    in_edit = 1 ;
                    line = "From: " + new_from ;
                    out_.WriteLine( line ) ;
            }
            else if( line.match(re_sender) && new_sender !== null )
            {
                    in_edit = 1 ;
                    line = "Sender: " + new_sender ;
                    if( new_sender !== "" )
                    {
                            out_.WriteLine( line ) ;
                    }
            }
            else if( line.match(re_reply_to) && new_reply_to !== null )
            {
                    in_edit = 1 ;
                    line = "Reply-To: " + new_reply_to ;
                    out_.WriteLine( line ) ;
            }
            else if( in_edit && line.match(re_fold) )
            {
            }
            else
            {
                    in_edit = 0 ;
                    out_.WriteLine( line ) ;
            }
    }
    while( !in_.AtEndOfStream )
    {
            var body_line = in_.ReadLine() ;
            out_.WriteLine( body_line ) ;
    }

    in_.Close() ;
    out_.Close() ;
    fs.DeleteFile( content ) ;
    fs.MoveFile( content + ".tmp" , content ) ;

    if( edit_envelope )
    {
            var ts = fs.OpenTextFile( envelope , 1 , false ) ;
            var txt = ts.ReadAll() ;
            ts.Close() ;
            var re = new RegExp( "X-MailRelay-From: *\\S*" ) ;
            txt = txt.replace( re , "X-MailRelay-From: " + new_from ) ;
            ts = fs.OpenTextFile( envelope , 2 , false ) ;
            ts.Write( txt ) ;
            ts.Close() ;
    }

    WScript.Quit( 0 ) ;
}
catch( e )
{
    WScript.StdOut.WriteLine( "<<edit failed>>" ) ;
    WScript.StdOut.WriteLine( "<<" + e + ">>" ) ;
    WScript.Quit( 1 ) ;
}