[Web-SIG] WSGI for HTTP/2.0 ?

Robert Collins robertc at robertcollins.net
Sat Sep 13 20:40:47 CEST 2014

So HTTP/2.0 (http://http2.github.io/http2-spec/index.html) is far
advanced, and my puny google-fu cannot find any upstream work on
making a) updating and or replacing WSGI to support HTTP/2's new
capabilities or b) an HTTP/2 capable SimplerServer or similar
reference server in the standard library . Huge apologies if I'm wrong
and pointers accepted!

I did find things like
https://evonove.it/blog/2012/django-jetty-spdy-blazing-fast/ which
uses Jython and the Jetty web server to do SPDY (the Google experiment
that has formed much of the basis of HTTP/2) or
which doesn't expose any of the new HTTP/2 features.

So, I'd like to kick of such work, I think the spec is sufficiently
stable now that we can design APIs in Python for it with confidence,
even though we may need to tweak things it won't be disruptive.

Specific things that I think we need to cater for:
 - the streaming and multiplexing facilities
(http://http2.github.io/http2-spec/index.html#rfc.section.5 and
http://http2.github.io/http2-spec/index.html#FrameTypes) - this is a
fairly fundamental departure from HTTP/1.x's strict 'request-response'
model and exposing it should offer very nice capabilities to site
authors. HTTP1.x requests look like a half-closed stream on an HTTP/2
connection, but its entirely possible via the extension mechanism to
run bidirectional data on a stream initiated by either end (whiile the
client has a single open stream the server can push a new associated
stream at any point)
 - flow control
(http://http2.github.io/http2-spec/index.html#fc-principles) - for
file uploads for instance, we can now rate limit single clients
directly within the protocol
 - the resource tree
(http://http2.github.io/http2-spec/index.html#pri-depend) - if we have
concurrent requests being handled for one client it is now possible to
explicitly model which ones should be processed and put on the wire
first, and this should flow up into the application to a degree
 - GOAWAY (http://http2.github.io/http2-spec/index.html#ConnectionErrorHandler)
 - backwards compat - making sure that straight PEP-3333 apps still
work well when the server connection is HTTP/2

Is anyone interested in collaborating on an update to WSGI to support
HTTP/2's new features?


Robert Collins <rbtcollins at hp.com>
Distinguished Technologist
HP Converged Cloud

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