23 Nov
2001
23 Nov
'01
5:33 p.m.
alex writes:
you have to set 2 headers: Expires: -1 Cache-Control: No-Cache
in zope you set them with RESPONSE.setHeader('Expires','-1') RESPONSE.setHeader('Cache-Control','No-Cache') The HTTP spec requires "Expires" to have a datetime value in a specific restricted format (RFC822 with timezone fixed to GMT). "-1" does not meet this specification.
Thus, setting "Expires" to "-1" may or may not work... Moreover, "Cache-Control" is defined in "HTTP 1.1" but not in "HTTP 1.0". Therefore, HTTP 1.1 compliant agents will understand it, while older agents (implemennting a superset of HTTP 1.0) may or may not understand it. "Expires" is already defined by HTTP 1.0. Dieter