Next Protocol Negotiation is a TLS extension that was created and used
for agreeing to use the SPDY protocol (the precursor to HTTP/2) for
HTTPS. In the early days of HTTP/2, before the spec was finalized and
shipped, the protocol could be enabled using this extension with some
servers.
curl supports the NPN extension with some TLS backends since then, with
a command line option `--npn` and in libcurl with
`CURLOPT_SSL_ENABLE_NPN`.
HTTP/2 proper is made to use the ALPN (Application-Layer Protocol
Negotiation) extension and the NPN extension has no purposes
anymore. The HTTP/2 spec was published in May 2015.
Today, use of NPN in the wild should be extremely rare and most likely
totally extinct. Chrome removed NPN support in Chrome 51, shipped in
June 2016. Removed in Firefox 53, April 2017.
Closes#9307
Mostly based on recent language decisions from "everything curl":
- remove contractions (isn't => is not)
- *an* HTTP (consistency)
- runtime (no hyphen)
- backend (no hyphen)
- URL is uppercase
Closes#8646
The tools.ietf.org domain has been deprecated a while now, with the
links being redirected to datatracker.ietf.org.
Rather than make people eat that redirect time, this change switches the
URL to a more canonical source.
Closes#8317
- Document that HTTP/2 multiplexing is supported by the curl tool when
parallel transfers are used.
Supported since 7.66.0 via --parallel, but the doc wasn't updated.
Closes https://github.com/curl/curl/pull/7259
The productname from Microsoft is "Schannel", but in infof/failf
reporting we use "schannel". This removes different versions.
Closes#3243
Reviewed-by: Daniel Stenberg <daniel@haxx.se>
Supports HTTP/2 over clear TCP
- Optimize switching to HTTP/2 by removing calls to init and setup
before switching. Switching will eventually call setup and setup calls
init.
- Supports new version to “force” the use of HTTP/2 over clean TCP
- Add common line parameter “--http2-prior-knowledge” to the Curl
command line tool.
