W3C home > Mailing lists > Public > public-html@w3.org > May 2009

Re: HTML interpreter vs. HTML user agent

From: Anne van Kesteren <annevk@opera.com>
Date: Thu, 28 May 2009 15:57:59 +0200
To: "Sam Ruby" <rubys@intertwingly.net>
Cc: "Maciej Stachowiak" <mjs@apple.com>, "Roy T. Fielding" <fielding@gbiv.com>, "Larry Masinter" <masinter@adobe.com>, "HTML WG" <public-html@w3.org>
Message-ID: <op.uum7qxww64w2qv@annevk-t60>
On Thu, 28 May 2009 15:41:36 +0200, Sam Ruby <rubys@intertwingly.net> wrote:
> I don't understand the "conformance with HTTP" part of the question.  I  
> believe that the current spec'ed behavior constitutes "a willful  
> violation of the HTTP specification, which requires that the  
> Content-Type headers be honored, despite implementation experience  
> showing that this is not pratical in many cases."

Currently they completely violate HTTP. By following the rules layed out in HTML5 they could get much closer. (I agree that it is probably better for this part of HTML5 to end up with the IETF, but I still think it would make sense for feed readers to adhere to the rules as well.)

When sniffing was discussed a while ago I remember that technorati.com and a feed library gsnedders was working on made their code much stricter. They're not browsers.

> The actual observed behavior of user agents designed to (primarily)  
> process content of a certain media type (either in general, or in the  
> specific context) is to make every effort to parse the content according  
> to those rules, and only if such rules fail to produce meaningful  
> results will they investigate alternatives.
> Browsers will first attempt to process content as HTML.
> FeedReaders will first attempt to process content as a feed.
> Media plays will first attempt to process content as media.
> Browsers, when chasing an image tag, will make different assumptions  
> than when presented with a raw uri from the chrome.
> All are equally "right" or "wrong".

While it is certainly true that different contexts have different sniffing rules, reducing that to a minimum would be good I think. Or are you saying the attempt is futile?

> None of this is meant to imply that the behavior that is being settled  
> upon by browser manufacturers isn't worth specifying or standardizing.


Anne van Kesteren
Received on Thursday, 28 May 2009 13:58:50 UTC

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