Re: Issue-57

On Wed, Jun 22, 2011 at 10:44 PM, Tim Berners-Lee <timbl@w3.org> wrote:
>
> If the client can gather nothing from the 200 code at all, the there is not
> much point  in doing the operation.  In the web architecture, it is the 200 that allows
> the client to in future point others too the web page using the same URI
> and expect them to get the same document. (not any document about the same
> thing, or any document by the same author or any document of the same length)
> (You can nit-pick about the definitions, but it is not very constructive).

Hi Tim,

I think this is a nice idea in theory and might have been true at some
point, but it doesn't seem to be true anymore. And even the example in
the AWWW seem to contradict this. If a server responds with a 200 for
the weather report for Oaxaca, on subsequent days it is not returning
the "same" document in any sense that "same" is used in English. In
such cases it is returning a document about the same thing (the
weather in Oaxaca). In the case of http://news.google.com/ what they
get each time isn't even about the same thing - it is about the same
*sort* of thing (events that have happened recently).

Anyways, perhaps how I interpret what you say will help you debug why
I am not understanding the sense of 200 you are trying to convey, and
I'd appreciate any insight about it. I'd really like to at a minimum
to understand what the idea you have is.

My best interpretation is that what you are saying is true for a
subset of URIs substantially smaller than the 200 responders (without
even having too strict a definition of document).

I don't think one has to nail down exactly what the definition of
document is for the purposes of webarch, but it would be good to get
into the ballpark. Right now I have two points of reference for what a
200 response means, neither of which seem to be close.

1) Something like "the server responded with a representation that
answers the GET according to its intended design" (usually seems to be
true, and a statement about the server, not the resource)
2) Something like "you are getting (mostly) a complete encoding of a
document-like thing - something authored with a purpose, and which is
relatively stable in (interpreted) content but which may change over
time due to the normal process of author revision". (true for an
important class of things on the web, but only a subset of 200
responses)

-Alan

Received on Friday, 24 June 2011 20:46:55 UTC