On Sun, 2003-09-14 at 22:59, Bjorn Stabell wrote: > Dieter wrote: > > Please read the HTTP 1.1 spec... > > > > Caching requires either an "ETag" or "Last-Modified" header. > > For good reasons... > > That would explain why it never got "fixed", but that's not how I > understand the RFC: http://www.w3.org/Protocols/rfc2616/rfc2616.html > > http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.21 > http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13.2 > Indicates that "Expires" is enough to make content cacheable, and that > it should be considered "fresh" until its expire time unless clients or > servers use cache-control headers to force a revalidation. > > Last-Modified and Etag are used to validate the content after it expires > using If-Modified-Since and If-None-Match respectively. > > Is there a thread discussing this already somewhere? > > [ Btw, Zope does return an empty Etag header; does that cause any > confusion? ]
I have a report that it does, at least for one hardware-based cache; I added a feature to z2.py for a client to turn this off. The empty E-tag exists to support *very* broken clients (MSOffice over WebFolders); it should be removed, perhaps with a knob which allows re-enabling it for the sites that actually have people editing content using those clients. A proposal to allow setting the header in a more useful way would be welcome. Tres. -- =============================================================== Tres Seaver [EMAIL PROTECTED] Zope Corporation "Zope Dealers" http://www.zope.com _______________________________________________ Zope-Dev maillist - [EMAIL PROTECTED] http://mail.zope.org/mailman/listinfo/zope-dev ** No cross posts or HTML encoding! ** (Related lists - http://mail.zope.org/mailman/listinfo/zope-announce http://mail.zope.org/mailman/listinfo/zope )
