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authorDaniel Stenberg <daniel@haxx.se>2015-03-25 12:13:16 +0100
committerDaniel Stenberg <daniel@haxx.se>2015-03-25 12:13:16 +0100
commiteb2a6180fbb73410c89647784f1c249ce2000b6e (patch)
treef57c805f95aeab2845655b3a1d9c0f79aa2bec83
parent7b223a3a21d95b17d6c1a90af091b132c1a755fa (diff)
README.http2: refreshed and added TODO items
-rw-r--r--lib/README.http238
1 files changed, 24 insertions, 14 deletions
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.
+