Re: Ignore proxy
Josh (josh@netscape.com)
Wed, 2 Apr 1997 03:58:30 -0800 (PST)
>
> Please ignore this message if it is a FAQ.
>
> I wanted to know if there is a way for a proxy to tell a client
> any/all of the following things:
>
> 1. Ignore me and fetch this document yourself. (but if you call me
> again I might change my mind.)
>
Not presently, there is a 305 and maybe 306 redirect which may
allow this functionality to be discussed at memphis.
Current implementations do not allow this.
A workaround is using a Proxy Auto Config file, where
you specify a failover, that way if the proxy is unavailable,
the client will go direct. ( assuming the network allows it )
> 1a. Ignore me for some time.
same as above
>
> 2. I will not fetch this for you. (the "Not Authorized" response?)
>
Yes, the 407 Proxy Authentication Required response is used.
> 2a. I will not cache this for you.
>
> I see this as a way (analagous to "Come Back Later") for a very busy
> proxy to tell clients that they are on their own. Also, a caching
> proxy might want to tell a user agent that it will not cache its
> requests. Of course, there are problems with proxies which are
> gateways -- they should never refuse proxying, but still might refuse
> caching.
For a busy server, it generally makes sense for it to cache
if it has to retreive it anyway. Of course, we're assuming
the object isnt already in the cache-- if it is, then the
proxy can potentially return it from the cache.
The biggest cost for a proxy is the origin retreive (contacting
the web server ), writing a cache file is much cheaper.
In addition, by caching it, if there is a request for the
same object, the proxy can then return it from the cache
next time, which helps the proxy a great deal.
I think in a worst case scenario, it would be O.K. for the
proxy to act such that:
"I am too busy to go to the far away web server for you, but
Ill give you what I have in my cache, even though its out of date".
The client can accept that or attempt to go direct.
>
> Thank you in advance.
>
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Josh Cohen Netscape Communications Corp.
Netscape Fire Department "Mighty Morphin' Proxy
Ranger"
Server Engineering
josh@netscape.com http://home.netscape.com/people/josh/
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