MBOX-Line: From guenther+imap at sendmail.com  Thu Mar  8 15:59:59 2007
To: imap-protocol@u.washington.edu
From: Philip Guenther <guenther+imap@sendmail.com>
Date: Fri Jun  8 12:34:38 2018
Subject: [Imap-protocol] question on BODY[n.MIME]? 
In-Reply-To: <alpine.WNT.0.83.0703081500000.4212@Tomobiki-Cho.CAC.Washington.EDU>
References: <07Mar8.112542pst."57996"@synergy1.parc.xerox.com>
	<alpine.OSX.0.83.0703081129120.11046@pangtzu.panda.com>
	<07Mar8.141232pst."57996"@synergy1.parc.xerox.com>
	<alpine.WNT.0.83.0703081500000.4212@Tomobiki-Cho.CAC.Washington.EDU>
Message-ID: <Pine.BSO.4.64.0703081647110.2904@vanye.mho.net>

On Thu, 8 Mar 2007, Mark Crispin wrote:
...
> Extension fields (those in body-ext-1part and body-ext-mpart) MAY be omitted 
> IF no subsequent extension field is non-NIL.  Thus, if you have a "body 
> language", you MUST have a "body MD5" and "body disposition" because they 
> occur earlier in the list, but you MAY omit the "body location" or anything 
> after that.
>
> In addition, you may send NIL instead of omitting a field.  This is what my 
> server does.

Note that there's a difference between omitting a trailing field and 
returning it as NIL: in the latter case, the client knows that the 
associated header field isn't present.  If the server leaves it off 
entirely then the client doesn't know whether the field exists or not and 
will have to do a direct fetch of the missing fields if it's interested in 
them.


Philip Guenther

