Re: Meaning of header fields Date and Age:

Recipients of date values are encouraged to be robust in
accepting date values that may have been sent by non-HTTP
applications, as is sometimes the case when retrieving or posting
messages via proxies/gateways to SMTP or NNTP.

The presence of an Age header field in a response implies that a
 response is not first-hand. However, the converse is not true, since
 the lack of an Age header field in a response does not imply that the

  ----- Original Message ----- 
  From: Greg Robson-Garth 
  To: www-talk@w3.org 
  Sent: Tuesday, July 06, 2004 11:50 AM
  Subject: Meaning of header fields Date and Age:


  What do these fields mean.

   

  According to "the spec", RFC2616 the Date the date/time the message was generated at the origin server.

   

  1. Date

  In a cache server, assuming the message is now resident in the cache and has been requested by a HTTP client. Should the cache server send with message with:

   

  a)       the Date header as it received it from the origin server

  b)       generate a new Date header being the date/time the message is sent from the cache and calculate the age as the residence time

   

  2. Age

  Does the Age header represent the seconds relative to the date/time in the date header. So if the Age is say Age: 60 and the time is 03:00:00, then its birth time (for a want of a better word) is 02:59:00. If this is the case, then surely the correct calculation of corrected_received_age in 13.2.3 should be

   

              now - date_value + age_value

   

  Can anyone comment ?

   

  --Greg

  Author, FreeProxy