Subject: Review of new HTTPbis text for 303 See Other

From: Jonathan Rees <[email-masked]>
Date: Mon, 15 Jun 2009 09:47:50 -0400

Quoting from http://tools.ietf.org/html/draft-ietf-httpbis-p2-semantics-06#page-24
:

   A 303 response to a GET request indicates that the requested resource
   does not have a representation of its own that can be transferred by
   the server over HTTP.  ...  Note that answers to
   the questions of what can be represented, what representations are
   adequate, and what might be a useful description are outside the
   scope of HTTP and thus entirely determined by the resource owner(s).

1. I think the first sentence makes too strong a commitment. Some
sites are using 303 for resources that *do* have perfectly good
representations that can be transferred by the server over HTTP; they
just don't want to do so because they consider the 303 redirect to a
description of the resource to be more valuable than providing
representations. Perhaps when LRDD comes on line the need to use 303
to provide metadata will decrease, but I see no reason to restrict 303
to representationless resources. In addition, the TAG's httpRange-14
rule [1] does not restrict the resource in the 303 case in any way at
all, so saying that it does would introduce an incompatibility that
would have to be resolved.

It is easy to imagine other cases where one uses a 303 because one has
a description (e.g. an article abstract) of the resource but the
resource itself, while having perfectly good "representations", is
protected or offline.

I recommend changing this to something weaselly like

   A 303 response to a GET request *may indicate* that the requested resource
   does not have a representation of its own that can be transferred by ...

2. The last sentence is also incorrect - to say that these decisions
are up to the resource's owner is also too strong a commitment. For
example, if I create a URI meant to "identify" my neighbor's car, it
is not necessarily up to my neighbor to determine what a useful
description of it is.

Even if you say that "what representations are adequate" and so on are
up to the URI owner (a term defined not by HTTP but rather by AWWW),
as opposed to the resource owner, you are making a very strong
architectural commitment that is certainly not in the scope of HTTP.

I advise that you simply remove the phrase " and thus entirely
determined by the resource owner(s)".

Best
Jonathan Rees

[1] http://lists.w3.org/Archives/Public/www-tag/2005Jun/0039.html

---

From: Julian Reschke <[email-masked]>
Date: Wed, 01 Jul 2009 06:56:03 +0200

> description of the resource to be more valuable than providing

Could you please provide an example for a resource like that? My 
understanding of the 303/information resource issue always was that if 
the resource can be represented with a bag of bits then it *is* an 
information resource.

 > ...
> ...

Assuming we did want to change it, it would still to be phrased in a way 
that explains what 303 means, not what it "may" mean...

> is not necessarily up to my neighbor to determine what a useful

 From HTTP's point of view, the owner of the URI is the owner of the 
resource. It just doesn't care about the case where you use an HTTP URI 
to identify somebody's car.

> ...

BR, Julian