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Re: Media types and versioning

From: Marc de Graauw <mdegraau@xs4all.nl>
Date: Thu, 17 May 2007 04:04:39 +0200 (CEST)
Message-ID: <7648.202.95.213.230.1179367479.squirrel@webmail.xs4all.nl>
To: "Mark Baker" <distobj@acm.org>
Cc: "Marc de Graauw" <marc@marcdegraauw.com>, www-tag@w3.org

Mark Baker:

> On 4/23/07, Marc de Graauw <marc@marcdegraauw.com> wrote:
>>
>> In the minutes it says:
>>
>> | Marc de Graauw wrote an article on xml.com, spurred in part
>> | by our earlier discussions. He proposes you give not a single
>> | version, but indicate each
>> | version that you believe the document conforms to.
>>
>> One correction: the gist of what I'm saying is not indicate each version
>> sender believes the document _conforms_ to, but each version (or more
>> general: language capability) the sender _requires_ the receiver to
>> understand.
>
> AFAICT, that's more or less what happens in the existing Web
> architecture.  HTTP messages carrying a document also normally include
> a media type, which is essentially a name for a series of compatible
> versions (e.g. "text/html" as a shortcut for HTML 2 + 3.2 + 4.01 + 5
> etc..).

Yes, but the list is not explicit, so it is not possible to exclude
versions (you cannot say: do not process if your version is lower than
4.01). That is not necessary for HTML, but for other languages (like
medication, which example I use in my XML.COM article) it often is, and
that is the mechanism I wanted to describe in my article.

> The difference from what you describe there is that the sender isn't
> *requiring* the receiver to understand the media type, it simply
> declares that the representation is to be interpreted using the
> semantics associated with that type.  Minor difference though, I
> think.

I did use the word "require", but that may be too strict. Partially what
to do with an incoming message is up to the receiver - wholly so for HTML,
but in other exchanges there often is a legal framework which constrains
those liberties.

Marc
Received on Thursday, 17 May 2007 10:33:51 GMT

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