Re: [apps-discuss] Last Call: <draft-ietf-appsawg-mime-default-charset-03.txt> (Update to MIME regarding Charset Parameter Handling in Textual Media Types) to Proposed Standard

Ned Freed <ned.freed@mrochek.com> Fri, 11 May 2012 14:48 UTC

Return-Path: <ned.freed@mrochek.com>
X-Original-To: apps-discuss@ietfa.amsl.com
Delivered-To: apps-discuss@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 9C53121F8747 for <apps-discuss@ietfa.amsl.com>; Fri, 11 May 2012 07:48:39 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.497
X-Spam-Level:
X-Spam-Status: No, score=-2.497 tagged_above=-999 required=5 tests=[AWL=0.102, BAYES_00=-2.599]
Received: from mail.ietf.org ([12.22.58.30]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id RkV2HMaXCAPq for <apps-discuss@ietfa.amsl.com>; Fri, 11 May 2012 07:48:38 -0700 (PDT)
Received: from mauve.mrochek.com (mauve.mrochek.com [66.59.230.40]) by ietfa.amsl.com (Postfix) with ESMTP id 147EE21F8748 for <apps-discuss@ietf.org>; Fri, 11 May 2012 07:48:38 -0700 (PDT)
Received: from dkim-sign.mauve.mrochek.com by mauve.mrochek.com (PMDF V6.1-1 #35243) id <01OFCKPTTB40001J33@mauve.mrochek.com> for apps-discuss@ietf.org; Fri, 11 May 2012 07:48:26 -0700 (PDT)
Received: from mauve.mrochek.com by mauve.mrochek.com (PMDF V6.1-1 #35243) id <01OF7HODY84G0006TF@mauve.mrochek.com>; Fri, 11 May 2012 07:48:21 -0700 (PDT)
Message-id: <01OFCKPR45340006TF@mauve.mrochek.com>
Date: Fri, 11 May 2012 07:42:21 -0700
From: Ned Freed <ned.freed@mrochek.com>
In-reply-to: "Your message dated Fri, 11 May 2012 14:59:56 +0200" <00a801cd2f7a$90e429c0$4001a8c0@gateway.2wire.net>
MIME-version: 1.0
Content-type: TEXT/PLAIN
References: <20120423132812.32410.11259.idtracker@ietfa.amsl.com> <CAC4RtVDZfXi1JwGJLGwOVgsGuU-1dH-uj8bXTGCmjrva80mNhg@mail.gmail.com> <01OF8RSPPS320006TF@mauve.mrochek.com> <CALaySJLFrKSF9JPBC54j0EaTQ6SNXM2+tag2uU2SmVjWxE7Erg@mail.gmail.com> <01OF98WFXDKI0006TF@mauve.mrochek.com> <00a801cd2f7a$90e429c0$4001a8c0@gateway.2wire.net>
To: "t.petch" <ietfc@btconnect.com>
Cc: Barry Leiba <barryleiba@computer.org>, Ned Freed <ned.freed@mrochek.com>, apps-discuss@ietf.org
Subject: Re: [apps-discuss] Last Call: <draft-ietf-appsawg-mime-default-charset-03.txt> (Update to MIME regarding Charset Parameter Handling in Textual Media Types) to Proposed Standard
X-BeenThere: apps-discuss@ietf.org
X-Mailman-Version: 2.1.12
Precedence: list
List-Id: General discussion of application-layer protocols <apps-discuss.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/apps-discuss>, <mailto:apps-discuss-request@ietf.org?subject=unsubscribe>
List-Archive: <http://www.ietf.org/mail-archive/web/apps-discuss>
List-Post: <mailto:apps-discuss@ietf.org>
List-Help: <mailto:apps-discuss-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/apps-discuss>, <mailto:apps-discuss-request@ietf.org?subject=subscribe>
X-List-Received-Date: Fri, 11 May 2012 14:48:39 -0000

> What charset should be used to inspect the content?

That depends on the syntax of the content. For every syntax that supports
extraction of charset information, there are clearly defined rules for
how this is done.

> Should this be defined in this I-D?

It can't be. The rules can be syntax-specific.

> The new rules say that
> "charset" parameter is not used for the defined
>        subtype, because the charset information is transported inside
>        the payload (such as in "text/xml")

>  But a charset is needed in order to read the payload and determine that
> charset.  Catch-22?

Nope, nothing of the sort. For, say, an XML-based type, only certain sorts of
charsets are allowed. Given these constraints, you look at the first few bytes;
these determins what general sort of charset you're  dealing with (one versus
two octet, say). Then you have enough information to extract the charset label.

				Ned