On Tue, Aug 21, 2012 at 2:30 PM, Poul-Henning Kamp <phk@phk.freebsd.dk>wrote: > In message <2A8028EE-0EEC-4E42-89C4-347C33F60B90@checkpoint.com>, Yoav > Nir writ > es: > > >A requirement for downgrade creates too many restrictions, even if we > throw > > SPDY away. The beginning of a 2.0 connection would have to look enough > like > >1.x so as to fool existing servers. > > Yes, and ? > > Sending: > > HEAD / HTTP/1.1 > Upgrade: HTTP/2.0 > > as a preamble on a connection is not very expensive. > > Sending is not a problem... but handling it on the server side could be depending on what work the server needs to do to generate the HEAD response. As per the spec, "The metainformation contained in the HTTP headers in response to a HEAD request SHOULD be identical to the information sent in response to a GET request" .. calculating the Entity Tag, Last-Modified Timestamp, Content-Length and Content-Type headers could be rather more expensive than one may expect depending on what's on the end of that request. - James > -- > Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 > phk@FreeBSD.ORG | TCP/IP since RFC 956 > FreeBSD committer | BSD since 4.3-tahoe > Never attribute to malice what can adequately be explained by incompetence. > >
Received on Tuesday, 21 August 2012 23:25:10 UTC