Subject: RE: handling Proxy-Connection

From: "Matt Lynch" <[email-masked]>
Date: Mon, 31 Dec 2001 10:33:34 +1100

Here's my two cents worth... (from rfc2616)

Section 19.3 (Tolerant Applications) says:
"We therefore recommend that operational applications be tolerant of
deviations whenever those deviations can be interpreted unambiguously."

The Proxy-Connection header can be interpreted unambiguously.

Section 19.6 (Compatibility with Previous Versions) says:

"It is beyond the scope of a protocol specification to mandate
compliance with previous versions. HTTP/1.1 was deliberately
designed, however, to make supporting previous versions easy."

So don't implement the header on a HTTP/1.1 connection, but implement it
full for any client which sends it on HTTP/1.0 connection.  So, to truly
be compatible with previous versions, applications must support this
header.

Matt

-----Original Message-----
From: Marc Slemko [mailto:[email-masked]]
Sent: Thursday, 27 December 2001 6:50 PM
To: Joris Dobbelsteen
Cc: Matt Lynch; WWW WG (E-mail)
Subject: RE: handling Proxy-Connection

On Fri, 21 Dec 2001, Joris Dobbelsteen wrote:

> This header is obsolete in HTTP/1.1 and SHOULD NOT be used in future
> implementations. The connection header will handle this in HTTP/1.1
> 
> Proxy-Connection was designed for persistent connections in HTTP/1.0.
It's
> in a completely different RFC (if documented), so look through the
RFC-index
> file. You should rely on this header only and only if you are using
HTTP/1.0
> (and use a proxy).

Be that as it may, it is still necessary to explicitly deal with
this header if you are implementing a proxy.  Then you must strip
the Proxy-Connection header before forwarding the request, ie.  it
is a hop by hop header.

This is the case even if you don't want to explicitly support it
in your proxy to allow for persistent connections with 1.0 clients.
If you don't strip it, you will run into ugly issues when chaining
proxys if any proxy in the chain understands it.

I don't know if this requirement is documented in any spec, or if
it is just another of the "gotta know it" ones.

---

From: "Roy T. Fielding" <[email-masked]>
Date: Wed, 2 Jan 2002 12:20:32 -0800

> The Proxy-Connection header can be interpreted unambiguously.

No, it can't.  That is why it should never be implemented.  Since there
exist some buggy clents that send it, the proper thing to do in a proxy
is strip the header, just like many of the other undocumented bugs in
client implementations.

That field was created by some folks at Netscape and has never been part
of any draft of any version of HTTP.

....Roy