Am 31.08.2013 12:30, schrieb Jack Applegame:

On Sat, 31 Aug 2013 11:47:35 +0200, Sönke Ludwig wrote:

Is the "If-Modified-Since" header supported maybe? Or "If-None-Match"
with an Etag instead of a last modified date?

Wow! You're right. If-Modified-Since works. It was foolish of me not to check this possibility. Shame.

Another question. Is there a simple way to convert HTTP date/time strings from/to SysTime?

Yes, there are a couple of functions in vibe.inet.message (e.g.
parseRFC822DateTimeString) that work with the format used for HTTP and
other protocols.