Re: expires header merging

["Roy T. Fielding" <fi...@liege.ICS.UCI.EDU>]

Now that HTTP/1.1 is done (at least from my point of view), I decided
to take the weekend off and not read mail.  That explains why I suddenly get
all these protocol questions ...

>> Headers can be divided into 3 types:
>> 
>>  1) those that can be merged (",")  (default for unclassified headers)
>>  2) those that should be duplicated (e.g. set-cookie)
>>  3) those that should be overwritten (expires)
> 
> Yes.  Other possibilities for #3 are Content-type, Location: (?), Date:, 
> Last-Modified, etc.  I'm sure our HTTP cop can provide a more complete 
> list :)

1) Any header defined with #field-value
2) Any header that should be defined with #field-value but broken in Netscape
3) All the rest

> Any unknown header should fall into #1.

Yep, so we should just list (2) and (3):

   (2) Set-Cookie
   (3) Age, Content-Base, Content-Length, Content-Location, Content-MD5,
       Content-Range, Content-Type, Date, ETag, Expires, Last-Modified,
       Location, Retry-After, Server, Vary

The server should override any value for Date, Server, and Location
(if relative), but the rest should not be overwritten if some other
part of the server (e.g., CGI) has already defined them -- that is,
assuming that the most specific generators are run first, the most
specific generator should take precedence over more general defaults.

At least I think so -- mondays are bad for thinking.

.......Roy