[Zope-dev] Last-modified and bobobase_modification_time

Dieter Maurer dieter@handshake.de
Tue, 18 Jun 2002 21:29:36 +0200


Wei He writes:
 > ...
 > 2. From the website developers' point of view, there are already many 
 > guidlines on how to create a good webpage. Among them are using the HTTP 
 > Last-modification header to take the advantages of client cache.
I think you overestimate the importance of accurate "Last-Modified"
headers.

  In order for caching to be allowed, there must
  either be a "Last-Modified" or (alternatively) an "Etag" header.

  However, the value of the "Last-Modified" is almost irrelevant
  for caching. I think, it is only used when a HTTP cache
  validates on object, in that is uses this date in an
  "If-Modified-Since" request.

I would use "Expires" and "Cache-Control" for cache control.


Dieter