RE: GET, POST, and side-effects

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] From: Shel Kaphan  <sjk@amazon.com>
] To: Paul Leach
] Cc:  <http-caching@pa.dec.com>;  <mogul@pa.dec.com>
] Subject: RE: GET, POST, and side-effects
] Date: Thursday, January 04, 1996 2:27PM
]
] Paul Leach writes:
]  > It seems pretty straightforward that if a proxy forwards a POST, and
]  > gets back a Location: URI and Expires: or Cache-Control: headers that
]  > say that the returned entity will be fresh for some period of time, it
]  > should be able to serve that entity safely from the cache for that
]  > period of time,
]
] for subsequent GETs, yes.  For subsequent POSTs, not in general 
(because of side
] effects on the origin server).

I agree -- a POST in general has to go back to the origin server. 
Although see my "sine server" for a case where it doesn't.

Paul