Re: [Extra] I-D Action: draft-ietf-extra-imap-fetch-preview-07.txt

Alexey Melnikov <> Wed, 11 December 2019 13:15 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 9118F120119 for <>; Wed, 11 Dec 2019 05:15:49 -0800 (PST)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -1.999
X-Spam-Status: No, score=-1.999 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: (amavisd-new); dkim=pass (1024-bit key)
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id kZOWkTMkGzCJ for <>; Wed, 11 Dec 2019 05:15:48 -0800 (PST)
Received: from ( []) by (Postfix) with ESMTP id CF1D212011C for <>; Wed, 11 Dec 2019 05:15:47 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1576070147;; s=june2016;; bh=Np7hm6rw+iCKRBvzVpsFvvrKIidz147QXijok7dvSGg=; h=From:Sender:Reply-To:Subject:Date:Message-ID:To:Cc:MIME-Version: In-Reply-To:References:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description; b=r1fXxePAEJ1rLnMVEmwjk6fgtPazh3x+POEK1Yr+AndebcjT/7uW1fXN22S7D9ZK2rHGRU MqRfmDwAil+cUoxQ7fhQWynJAA+34xRRY3W8hmL2Z1QFLPlizDzpHRdRaGkzEjVUKsVxrI 7JkPdGn3M9hFwug0r5YmbSJ3uF7R2HI=;
Received: from [] ( []) by (submission channel) via TCP with ESMTPSA id <>; Wed, 11 Dec 2019 13:15:47 +0000
To: Michael Slusarz <>,
References: <> <>
From: Alexey Melnikov <>
Message-ID: <>
Date: Wed, 11 Dec 2019 13:15:30 +0000
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.0
In-Reply-To: <>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Content-Language: en-GB
Archived-At: <>
Subject: Re: [Extra] I-D Action: draft-ietf-extra-imap-fetch-preview-07.txt
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Email mailstore and eXtensions To Revise or Amend <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Wed, 11 Dec 2019 13:15:50 -0000

Hi Michael,

On 11/12/2019 01:21, Michael Slusarz wrote:
> Sorry for the delay on this.
> Per discussion in Singapore, the PREVIEW draft has been altered to replace "named algorithms" with media types.  The "FUZZY" algorithm was therefore renamed to "text/imap-fetch-preview" so that the semantics could be identified using the new media type method.
> As part of this, it was necessary to clarify that the default algorithm, if either no algorithm list was provided or no algorithm was associated with a LAZY modifier, MUST be text/imap-fetch-preview.  Now that there is not a way for a client to determine which algorithms a server supports ("PREVIEW=" capability detection was removed), this seems to be the only rational choice - allowing every server to potentially specify a different default algorithm would lead to an inconsistent IMAP experience across installations.
> I think this covers everything that was discussed at the last meeting.

This is a move in the right direction, but we are not quite there yet. I 
have a few questions that might affect my specific suggestions:

1) The document says to use media type syntax, but not necessarily media 
types. If you want the former, you probably need a new registry (I 
recommend against that). If you want the latter, then why not just use 
text/plain, as a registered media type?

2) If there is a good reason not to use "text/plain", you need to 
registered "text/imap-fetch-preview" with IANA.

3) For unsupported media types, it would be good to define a new IMAP 
response code, similar to BADCHARSET.

Best Regards,


> michael
>> On 12/10/2019 6:07 PM wrote:
>> A New Internet-Draft is available from the on-line Internet-Drafts directories.
>> This draft is a work item of the Email mailstore and eXtensions To Revise or Amend WG of the IETF.
>>          Title           : IMAP4 Extension: Message Preview Generation
>>          Author          : Michael M. Slusarz
>> 	Filename        : draft-ietf-extra-imap-fetch-preview-07.txt
>> 	Pages           : 15
>> 	Date            : 2019-12-10
>> Abstract:
>>     This document specifies an Internet Message Access Protocol (IMAP)
>>     protocol extension allowing a client to request a server-generated
>>     abbreviated representation of message data useful as a contextual
>>     preview of the entire message.
>> The IETF datatracker status page for this draft is:
>> There are also htmlized versions available at:
>> A diff from the previous version is available at:
>> Please note that it may take a couple of minutes from the time of submission
>> until the htmlized version and diff are available at
>> Internet-Drafts are also available by anonymous FTP at:
>> _______________________________________________
>> Extra mailing list
> _______________________________________________
> Extra mailing list