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» Conditional GET Support for perpubplat #

As part of being a good netizen, I added conditional GET support (per 9.3 in the HTTP 1.1 spec) to perpubplat in the form of ETag (MD5 of feed URI and last modified date) and Last-Modified headers on generated Atom feeds and corresponding If-None-Match and If-Modified-Since headers on requests for Atom feeds with proper precedence. (For precedence, the spec dictates that a successful If-None-Match assertion means that any If-Modified-Since assertion is ignored.) A quick curl experiment shows that things appear to work:

$ curl -i -s -o - http://mult.ifario.us/f/t/haskell/atom.xml | \
> egrep \^ETag\|\^Last-Modified\|\^HTTP\/
HTTP/1.1 200 OK
Last-Modified: Sat, 23 Feb 2008 23:55:23 GMT
ETag: 78790a6a7d6bddd10f6f9c412f2aba97
$ curl -H 'If-None-Match: 78790a6a7d6bddd10f6f9c412f2aba97' \
> -i -s -o - http://mult.ifario.us/f/t/haskell/atom.xml | \
> egrep \^HTTP\/
HTTP/1.1 304 Not Modified
$ curl -H 'If-Modified-Since: Sat, 23 Feb 2008 23:55:23 GMT' \
> -i -s -o - http://mult.ifario.us/f/t/haskell/atom.xml | \
> egrep \^HTTP\/
HTTP/1.1 304 Not Modified
$ curl -H 'If-None-Match: foo' -H 'If-Modified-Since: Sat, 23 Feb 2008 23:55:23 GMT'
> -i -s -o - http://mult.ifario.us/f/t/haskell/atom.xml | \
> egrep \^HTTP\/
HTTP/1.1 200 OK