Re: [IMAP] APPEND Command Usage

Inline comments

On 12/12/14 5:24 AM, Alexey Melnikov wrote:
> Hi Stuart,
>
> On 10/12/2014 19:58, Stuart Brandt wrote:
>> From a server perspective, the proposal solves my concern. From a
>> client perspective, I'm not sure whether the addition of [SP
>> nz-number] to the TOOBIG response would present problems for clients
>> that only implement CATENATE and not APPENDLIMIT. I too would like to
>> see others chime in on that part.
>>
>> From what I see, most IMAP sessions either precede an APPEND with a
>> SELECT/EXAMINE or LIST...likely to confirm the existence of the target
>> mailbox into which they're going to append.  The proposal already
>> covers SELECT/EXAMINE, so would it be reasonable to add the
>> APPENDLIMIT=x as an attribute to the LIST response data in order to
>> reflect any per-mailbox limit and avoid trying to convey the limit as
>> part of the TOOBIG response code to APPEND? Something along the line of:
>>
>> C: t1 LIST "" "%"
>> S: * LIST (\Marked \HasNoChildren) "/" Inbox
>> S: * LIST (\HasNoChildren) "/" ToDo
>> S: * LIST (\HasChildren) "/" Projects
>> S: * LIST (\Sent \HasNoChildren) "/" SentMail
>> S: * LIST (\Marked \Drafts \HasNoChildren \APPENDLIMIT=257890) "/"
>> MyDrafts
>> S: * LIST (\Trash \HasNoChildren) "/" Trash
> All mailbox attributes are typically checked for equality, so this this
> a departure from this principle. (I know we started to violate this rule
> in CAPABILITY response)
> So personally, I prefer if we add a new STATUS item for APPEND limit.
> Then we can use STATUS-in-LIST bridge
> (https://tools.ietf.org/html/rfc5819) to return this information.
>
> As clients that want to obey APPENDLIMIT would need to be modified
> anyway, they might as well be modified to support RFC 5819 syntax.

And same goes for the server, because the client will want to query 
*every* server that supports APPENDLIMIT just in case it has per-mailbox 
limits. Unless I'm way off base here, a server with a simple 
mailbox-wide APPEND limit would need to implement APPENDLIMIT *plus* 
5819 and 5258 to support the client asking about per-mailbox limits -- 
unless we have the client assume that lack of support for 5819/5258 
implies that the server has no per-mailbox limits. Seems pretty involved.

>
> But otherwise I am Ok with being able to return this information in LIST.
>> S: t1 OK done
>>
>> Comments?
>>
>> - Stuart
>>
>> On 12/10/14 11:20 AM, Jayantheesh S B wrote:
>>> Yes, I agree with your comments. Existing functionality should be
>>> broken with this new proposal.
>>>
>>> But the TOOBIG response syntax does not convey the size supported by
>>> the server
>>>
>>> resp-text-code =/ toobig-response-code / badurl-response-code
>>> toobig-response-code = "TOOBIG"
>>>
>>> Reusing the TOOBIG response code with updated syntax like below
>>> solves the issue
>>>
>>> toobig-response-code = " TOOBIG " [SP nz-number]
>>> resp-text-code /=  toobig-response-code
>>>
>>> Please share your comments.
>>>
>>> Regards,
>>> Jay
>>>
>>> -----Original Message-----
>>> From: Stuart Brandt [mailto:[email protected]]
>>> Sent: Tuesday, December 09, 2014 8:25 PM
>>> To: Jayantheesh S B; 'Alexey Melnikov'
>>> Cc: '[email protected]'
>>> Subject: Re: [imapext] [IMAP] APPEND Command Usage
>>>
>>> If I'm understanding the proposal correctly, a server that has
>>> already implemented CATENATE and now implements APPENDLIMIT is left
>>> in an ambiguous state whenever the limit is exceeded. If it returns
>>> [TOOBIG], then it's not compliant with the APPENDLIMIT
>>> recommendation. If it returns [APPENDLIMIT x] then it's returning an
>>> unexpected response to clients that have yet to implement
>>> APPENDLIMIT, thereby "breaking"
>>> existing functionality.
>>>
>>>
>>> On 12/9/14 5:16 PM, Jayantheesh S B wrote:
>>>> Hi All,
>>>>
>>>> Thanks for your response.
>>>>
>>>> New response code APPENDLIMIT will be returned as part of SELECT
>>>> response to convey per mailbox limit
>>>>    and APPEND command response, if the APPENTLIMIT size is exceeded.
>>>>
>>>> C: t2 SELECT INBOX
>>>> S: * 172 EXISTS
>>>> S: * OK [APPENDLIMIT 257890] Maximum upload limit
>>>> S: [...]
>>>> S: t2 OK [READ-WRITE] SELECT completed
>>>>
>>>> C: t1 APPEND "Draft" (\SEEN \DRAFT) {98994952}
>>>> S: t1 NO [APPENDLIMIT 257890] Exceeds the maximum allowed size
>>>>
>>>> Whereas TOOBIG response, does not covey the size restriction applied
>>>> by the server.
>>>>
>>>>    resp-text-code =/ toobig-response-code / badurl-response-code
>>>>    toobig-response-code = "TOOBIG"
>>>>
>>>> We feel APPENDLIMIT response can convey per mailbox size restriction
>>>> and it can overcome the limitation of TOOBIG response.
>>>>
>>>> Please share your thoughts.
>>>>
>>>> Regards,
>>>> Jay
>

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