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Code Issues Releases Wiki Activity

README.http2: refreshed and added TODO items

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Daniel Stenberg 2015-03-25 12:13:16 +01:00
parent 7b223a3a21
commit eb2a6180fb
1 changed files with 24 additions and 14 deletions
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lib/README.http2
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@ -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.