Subject: [lemonade] Interaction between IMAP NOTIFY and METADATA (draft-daboo-imap-annotatemore-15.txt)

From: Alexey Melnikov <[email-masked]>
Date: Sat, 08 Nov 2008 16:43:50 +0000

Hi,
I've been thinking about interaction between METADATA-UNSOLICITED 
capability (defined in draft-daboo-imap-annotatemore-15.txt) and IMAP 
NOTIFY. The METADATA-UNSOLICITED capability can be used by the client to 
enable unsolicited METADATA responses.

I don't think that a client that is using MailboxMetadataChange and/or 
ServerMetadataChange event type with IMAP NOTIFY also needs to issue 
ENABLE METADATA-UNSOLICITED. I think the latter should just be implied 
by use of the NOTIFY command. I also think this would make it slightly 
easier for clients to deal with.

If people agree, then a short note on this should be added to IMAP NOTIFY.

Alexey

P.S. As a side note: I am a little bit concerned about adding 
METADATA-UNSOLICITED capability. All other extensions are just using 
ENABLE on the "base" capability (such as METADATA-SERVER or METADATA) in 
this case.
The only case when this new capability would be needed if we want to 
allow servers that can support METADATA/METADATA-SERVER, but can't send 
unsolicited METADATA responses. I am not entirely convinced that that 
would be useful.

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From: Arnt Gulbrandsen <[email-masked]>
Date: Fri, 14 Nov 2008 11:05:24 +0100

Alexey Melnikov writes:
> NOTIFY. The METADATA-UNSOLICITED capability can be used by the client 
> to enable unsolicited METADATA responses.
>
> ENABLE METADATA-UNSOLICITED. I think the latter should just be 
> implied by use of the NOTIFY command. I also think this would make it 
> slightly easier for clients to deal with.
>

I am uncomfortable with this.

This gives us two ways to ask for unsolicited METADATA responses, and I 
have real problems understanding why that is necessary.

Sometimes we have two ways because one was added first and something 
more generic added later. Consider 3348 vs. listext, or RFC822.HEADER 
vs. BODY[HEADER.FIELDS (...)]. But in this case, both are added at the 
same time, and I don't see justification for having two.

> ENABLE on the "base" capability (such as METADATA-SERVER or METADATA) 
> in this case.
> allow servers that can support METADATA/METADATA-SERVER, but can't 
> send unsolicited METADATA responses. I am not entirely convinced that 
> that would be useful.

I quite agree.

Arnt

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From: Timo Sirainen <[email-masked]>
Date: Fri, 14 Nov 2008 14:28:52 +0200

> have real problems understanding why that is necessary.

But I think it's also confusing if a client issues MailboxMetadataChange
and it doesn't do anything if ENABLE METADATA-UNSOLICITED hasn't been
done.

I don't think I really like any of the solutions for this.

> > send unsolicited METADATA responses. I am not entirely convinced that 

Same here. Capability bloat is annoying.
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---

From: Alexey Melnikov <[email-masked]>
Date: Fri, 14 Nov 2008 12:36:55 +0000

Arnt Gulbrandsen wrote:

>> I don't think that a client that is using MailboxMetadataChange 
>> and/or ServerMetadataChange event type with IMAP NOTIFY also needs to 
>> issue ENABLE METADATA-UNSOLICITED. I think the latter should just be 
> This gives us two ways to ask for unsolicited METADATA responses, and 
> I have real problems understanding why that is necessary.
>

Are you suggesting that any client willing to MailboxMetadataChange 
and/or ServerMetadataChange event in IMAP NOTIFY must issue ENABLE 
METADATA-<something> first?

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From: Alexey Melnikov <[email-masked]>
Date: Fri, 14 Nov 2008 12:42:40 +0000

>and it doesn't do anything if ENABLE METADATA-UNSOLICITED hasn't been
This is exactly the point I was trying to make.

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From: Alexey Melnikov <[email-masked]>
Date: Sat, 15 Nov 2008 17:35:53 -0600

Alexey Melnikov wrote:

>>>> capability (defined in draft-daboo-imap-annotatemore-15.txt) and 
>>>> IMAP NOTIFY. The METADATA-UNSOLICITED capability can be used by the 
>>>> client to enable unsolicited METADATA responses.
>>>>
>>>> and/or ServerMetadataChange event type with IMAP NOTIFY also needs 
>>>> to issue ENABLE METADATA-UNSOLICITED. I think the latter should 
>>>> just be implied by use of the NOTIFY command. I also think this 
>>>> would make it slightly easier for clients to deal with.
>>>>
>>> This gives us two ways to ask for unsolicited METADATA responses, 
>>> and I have real problems understanding why that is necessary.
>>

I've just talked to Chris about that and his personal opinion is that 
ENABLE METADATA... shouldn't be required when MailboxMetadataChange 
and/or ServerMetadataChange event type is used.
So I think we have [week] consensus for adding such RFC editor note.