RE: [ACTION-603] Conversation with Yves, our HTTP expert, about CT and Cache-Control extensions

A non-transparent HTTP proxy is one that is explicitly configured in the
client; HTTP Proxy Transparency is all about layer 4 and says nothing
about layer 7. This Gateway vs Proxy distinction is about layer 7, where
content is transformed, and therefore is a very useful definition for
us. 

Thanks,

Robert


-----Original Message-----
From: public-bpwg-ct-request@w3.org
[mailto:public-bpwg-ct-request@w3.org] On Behalf Of Jo Rabin
Sent: Fri 01 February 2008 17:27
To: fd@w3.org
Cc: public-bpwg-ct
Subject: RE: [ACTION-603] Conversation with Yves, our HTTP expert, about
CT and Cache-Control extensions




> 
> > I wonder whether we do indeed want a Gateway? I'm wondering if this
is
> > merely a choice of words issue or whether there is a deeper
> > significance? My view is that content should be transformed "more in
> > sorrow than in anger", whereas saying it is a Gateway suggests that
> > transformation is a matter of routine.
> 
> Actually, I view it more like saying "beware, CT ain't no routine!":
if
> you do transformation, you are indeed being aggressive, and as such,
> you're not merely a (non-transparent) proxy anymore. Where "not merely
a
> proxy anymore" is "a gateway". That may be too HTTP-centric though and
> we may decide to shrug at it and keep on using the term proxy...

I'm just wonder what the HTTP notion of a non-transparent proxy is, if
it isn't a transforming proxy. Various sections spell out that
transformation is understood to be what a "non transparent" proxy is
expected to be. I obviously don't know enough about the "spirit" to have
this clear in my mind so it would be an advantage if we could get
someone who is knowledgeable to explain this, apparently crucial, point
in detail.

> 
> >
> > I can't say that I infer that the User Agent MUST NOT be changed
from
> > the referenced text. In the preceding section there is an explicit
> > prohibition on changing the Server value. There is no such explicit
> > prohibition noted wrt the User Agent.
> [...]
> 
> It isn't written anywhere for sure. That's where the "spirit" of HTTP
> comes in... We may want to ask other HTTP folks about it to check
> whether they all agree on the matter, but I think Yves' view fairly
> represents theirs. The header is not included in the list of headers
> that MUST NOT change, in part because it MAY change (such as the
> Openwave gateway that added (still does?) a UP.Link/x.y part to the
> User-Agent). But the definition of the User-Agent makes it clear it
must
> contain something that identifies the user agent making the request.
If
> we do define our proxy as a gateway though, the violation of the
> "spirit" disappears, as from the server, the gateway would be viewed
as
> the user agent making the request.
> 
> Again, that may be playing with words, but I guess my point is we
should
> be consistent with the HTTP RFC since it's the base of our guidelines.
> 
Sure, but it seems that we both have to be consistent with the words
that are actually written - i.e. the RFC - and "the spirit" which is
not. I suppose that I could be accused of being a fundamentalist if I
said "If it's not written it doesn't exist", but I am at a loss as to
how one gets the "spirit".

> 
> Maybe we could propose that they actually use a DDR to identify
desktops
> and serve the handheld version by default? (So what, isn't Mobile Web
> supposed to rule over the Web?)

I see you have got the hang of it already! One Web to Rule them All.

> 
> I propose we talk about it in next call.
> 
> 
> >
> > I share Yves's view on rewriting HTTPS URIs however, that
immediately
> > knocks on the head the idea of mobile access to HTTP URIs that are
not
> > mobile friendly - and probably therefore a significant number of
> > useful mobile services.
> 
> I understand it limits the possibilities in terms of useful mobile
> services, and I also understand it's already being done by some
content
> transformation proxies. But the banking example is one that will be
> difficult to put aside when we try to convince external non-mobile
> people that this is amazingly needed.

Better to get the banking people to write mobile interfaces, by far. But
how will they tell the proxies not to transform ...

See you on the call.

Jo

Received on Saturday, 2 February 2008 13:17:03 UTC