From eb2a6180fbb73410c89647784f1c249ce2000b6e Mon Sep 17 00:00:00 2001 From: Daniel Stenberg Date: Wed, 25 Mar 2015 12:13:16 +0100 Subject: README.http2: refreshed and added TODO items --- lib/README.http2 | 38 ++++++++++++++++++++++++-------------- 1 file changed, 24 insertions(+), 14 deletions(-) (limited to 'lib') diff --git a/lib/README.http2 b/lib/README.http2 index 936e3bb31..f6d9cb9a8 100644 --- a/lib/README.http2 +++ b/lib/README.http2 @@ -1,8 +1,9 @@ - HTTP2 with libcurl Spec: http://tools.ietf.org/html/draft-ietf-httpbis-http2 + Document explaining it: http://daniel.haxx.se/http2/ + Build prerequisites - nghttp2 - OpenSSL, NSS, GnutTLS or PolarSSL with a new enough version @@ -10,8 +11,8 @@ HTTP2 with libcurl nghttp2 (https://github.com/tatsuhiro-t/nghttp2) libcurl uses this 3rd party library for the low level protocol handling - parts. The reason for this is that HTTP2 is much more complex at that layer - than HTTP1.1 (which we implement on our own) and that nghttp2 is an already + parts. The reason for this is that HTTP/2 is much more complex at that layer + than HTTP/1.1 (which we implement on our own) and that nghttp2 is an already existing and well functional library. Right now, nghttp2 implements http2 draft-14 @@ -20,9 +21,9 @@ HTTP2 with libcurl Over an http:// URL - If CURLOPT_HTTP_VERSION is set to CURL_HTTP_VERSION_2, libcurl will include - an upgrade header in the initial request to the host to allow upgrading to - http2. + If CURLOPT_HTTP_VERSION is set to CURL_HTTP_VERSION_2_0, libcurl will + include an upgrade header in the initial request to the host to allow + upgrading to http2. Possibly we can later introduce an option that will cause libcurl to fail if not possible to upgrade. Possibly we introduce an option that makes libcurl @@ -30,10 +31,10 @@ HTTP2 with libcurl Over an https:// URL - If CURLOPT_HTTP_VERSION is set to CURL_HTTP_VERSION_2, libcurl will use ALPN - (or NPN) to negotiate which protocol to continue with. Possibly introduce an - option that will cause libcurl to fail if not possible to use http2. - Consider options to explicitly disable ALPN and/or NPN. + If CURLOPT_HTTP_VERSION is set to CURL_HTTP_VERSION_2_0, libcurl will use + ALPN (or NPN) to negotiate which protocol to continue with. Possibly + introduce an option that will cause libcurl to fail if not possible to use + http2. Consider options to explicitly disable ALPN and/or NPN. ALPN is the TLS extension that http2 is expected to use. The NPN extension is for a similar purpose, was made prior to ALPN and is used for SPDY so @@ -51,15 +52,16 @@ SSL libs GnuTLS: ALPN PolarSSL: ALPN -Alt-Svc +HTTP Alternative Services - Alt-Svc is a suggested new header with a corresponding frame (ALTSVC) in + Alt-Svc is a suggested extension with a corresponding frame (ALTSVC) in http2 that tells the client about an alternative "route" to the same content for the same origin server that you get the response from. A browser or long-living client can use that hint to create a new connection asynchronously. For libcurl, we may introduce a way to bring such clues to the applicaton and/or let a subsequent request use the alternate route - automatically. + automatically. Spec: + http://tools.ietf.org/html/draft-ietf-httpbis-alt-svc-05 Applications @@ -70,8 +72,16 @@ curl tool curl offers the --http2 command line option to enable use of http2 -To consider: +TODO: + + - Implement multiplexing - How to tell libcurl when using the multi interface that all or some of the handles are allowed to re-use the same physical connection. Can we just re-use existing pipelining logic? + + - Provide API to set priorities / dependencies of individual streams + + - Implement "prior-knowledge" HTTP/2 connecitons over clear text so that + curl can connect with HTTP/2 at once without 1.1+Upgrade. + -- cgit v1.2.3