Re: http/2 and Emacs

[Paul Eggert]

Richard Stallman wrote:

> I don't know the name "SPDY".

SPDY is/was an experimental protocol developed by Google, intended as a 
replacement for HTTP that would reduce page load times. It has morphed into 
HTTP/2, which is specified by Internet RFC 7540 (May 2015). HTTP/2 is supported 
by high-volume web sites such as Google and Facebook. Google says about 25% of 
resources in the Chrome browser are now served over HTTP/2, and w3techs says 
about 6.5% of public websites support HTTP/2, up from about 2.5% of websites at 
the end of 2015.

The basic idea of HTTP/2, as the RFC states, is that it:

"allows interleaving of request and response messages on the same connection and 
uses an efficient coding for HTTP header fields. It also allows prioritization 
of requests, letting more important requests complete more quickly, further 
improving performance. The resulting protocol is more friendly to the network 
because fewer TCP connections can be used in comparison to HTTP/1.x.... Finally, 
HTTP/2 also enables more efficient processing of messages through use of binary 
message framing."

HTTP/2 connections are typically encrypted rather than plaintext. This is both 
for security and to speed performance (avoids a roundtrip negotiation). HTTP/2 
also allows server push.

One downside is that HTTP/2 is more of a pain to debug, because of its use of 
multiplexing, compression, encryption, and binary formats. Debugging is doable, 
but the standard debugging tools haven't caught up yet.