`emailrelay-set-from.js <emailrelay-set-from.js>`_
--------------------------------------------------

.. code:: javascript

    //
    // 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 ) ;
    }

.. _../examples/emailrelay-set-from.js: emailrelay-set-from_js.html