MBOX-Line: From mrc at CAC.Washington.EDU  Wed Nov 23 16:08:09 2005
To: imap-protocol@u.washington.edu
From: Mark Crispin <mrc@CAC.Washington.EDU>
Date: Fri Jun  8 12:34:36 2018
Subject: [Imap-protocol] IMAP capability for maximum APPEND message size?
Message-ID: <Pine.OSX.4.64.0511231556030.533@pangtzu.panda.com>

I am considering the addition of a trivial new capability to IMAP that 
would advertise the maximum size of a message in APPEND (and probably also 
CATENATE).  This has the same purpose as the SIZE capability in SMTP.

Currently, the only message size limit in IMAP is 4294967295 (2^32 - 1) 
due to IMAP's use of unsigned 32-bit integers.  Supporting that size is 
troublesome due to +1 overflow problems.  Many implementations have much 
smaller limits, such as both for administrative and technical reasons 
(many filesystems encounter problems after 2^31 - 1).

Rather than have this be a secret, I propose a capability called 
MAXAPPENDSIZE=nnn, where nnn is the size.

I considered a somewhat more complex extension might advertise the 
server's command line length.  I think that we should stick with RFC 2683 
section 3.2.1.5, since a client which is armed with more detail is much 
more likely to shoot itself in the foot.

Comments?

-- Mark --

http://panda.com/mrc
Democracy is two wolves and a sheep deciding what to eat for lunch.
Liberty is a well-armed sheep contesting the vote.

