W3C home > Mailing lists > Public > www-tag@w3.org > July 2003

Re: httpRange-14

From: Roy T. Fielding <fielding@apache.org>
Date: Thu, 24 Jul 2003 21:51:58 -0700
Cc: www-tag@w3.org
To: Norman Walsh <Norman.Walsh@Sun.COM>
Message-Id: <B93AE384-BE5B-11D7-A195-000393753936@apache.org>

> It isn't illegal or illogical or wrong to use http URIs to identify
> things that aren't documents. But it is potentially misleading, is
> likely to introduce ambiguity that it would be better to avoid, and is
> not obviously superior to mechanisms that don't have these defects.
> (Or, more accurately, if it is superior, I don't see how.)
> Progress?

No.  You have left out all of the HTTP-based services that are not
documents, by any stretch of the imagination, and yet still are
identified by "http" URIs.  "almost all" is not ALL.  I see no
reason why the web architecture document should claim something
that is obviously false, particularly when it is used within
millions of transactions every day.

The fact is that "most users" don't know that the target of a submit
button is a URI that usually begins with "http".  It is also a fact
that most users of automated tools based on libwww-perl never see
the URI.  It is reasonable to expect the same will be true of WSA.
If most users think that "http" means document, then all I can say
is that most users are not developers of WWW technology.

http URIs identify resources via the http naming convention.  That
is all that ever needs to be said, anywhere, for any system that
makes use of http URIs (semantic or otherwise).  The only way you
can start to make assumptions about the kind of resource associated
with a URI (any scheme) is to see it in use: <a href="..."> is a
context for a resource that responds to retrieval requests, whereas
<foo xmln="..."> is not.

In any case, making claims about resources by examining their
scheme completely fails when considering all of the other schemes,
especially "urn".  As such, this claim does not help the SW
architecture at all, and in fact is actively harmful to it
because it is used as an excuse not to fix the fundamental
problems of associating identity with a bare URI.

There are no special categories of "information resource". Any URI
provided within a retrieval context is assumed to be an information
resource.  The scheme is irrelevant to such assumptions.  The right
solution is to fix the Semantic Web so that it doesn't throw away
method semantics, as it does currently by assuming a URI denotes
what is obtained by a response to GET.

None of this has any impact on the principle that it is unwise to
use the same URI to identify multiple resources.  That argument
is and always has been a red herring, and is not solved by
claiming that "http" means document.

Received on Friday, 25 July 2003 02:46:28 UTC

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