diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/README.http2 | 48 |
1 files changed, 30 insertions, 18 deletions
diff --git a/lib/README.http2 b/lib/README.http2 index f6d9cb9a8..e9084233b 100644 --- a/lib/README.http2 +++ b/lib/README.http2 @@ -1,6 +1,6 @@ HTTP2 with libcurl - Spec: http://tools.ietf.org/html/draft-ietf-httpbis-http2 + Spec: http://www.rfc-editor.org/rfc/rfc7540.txt Document explaining it: http://daniel.haxx.se/http2/ @@ -15,9 +15,7 @@ HTTP2 with libcurl 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 - - We require at least version 0.6.0 + We require at least version 1.0.0. Over an http:// URL @@ -52,16 +50,25 @@ SSL libs GnuTLS: ALPN PolarSSL: ALPN -HTTP Alternative Services +Multiplexing - 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. Spec: - http://tools.ietf.org/html/draft-ietf-httpbis-alt-svc-05 + Starting in 7.43.0, libcurl fully supports HTTP/2 multiplexing, which is the + term for doing multiple independent transfers over the same physical TCP + connection. + + To take advantage of multiplexing, you need to use the multi interface and + set CURLMOPT_PIPELINING to CURLPIPE_MULTIPLEX. With that bit set, libcurl + will attempt to re-use existing HTTP/2 connections and just add a new stream + over that when doing subsequent parallel requests. + + While libcurl sets up a connection to a HTTP server there is a period during + which it doesn't know if it can pipeline or do multiplexing and if you add + new transfers in that period, libcurl will default to start new connections + for those transfers. With the new option CURLOPT_PIPEWAIT (added in 7.43.0), + you can ask that a transfer should rather wait and see in case there's a + connection for the same host in progress that might end up being possible to + multiplex on. It favours keeping the number of connections low to the cost + of slightly longer time to first byte transfered. Applications @@ -72,13 +79,18 @@ curl tool curl offers the --http2 command line option to enable use of http2 -TODO: +HTTP Alternative Services - - Implement multiplexing + 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. Spec: + http://tools.ietf.org/html/draft-ietf-httpbis-alt-svc-05 - - 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? +TODO: - Provide API to set priorities / dependencies of individual streams |