curl-curl/docs/cmdline-opts/http2-prior-knowledge.md
Daniel Stenberg aa18891dda
docs/cmdline-opts: unify HTTP version style in --help output
$ curl -h all | grep -- --http

Now:

     --http0.9                      Allow HTTP/0.9 responses
 -0, --http1.0                      Use HTTP/1.0
     --http1.1                      Use HTTP/1.1
     --http2                        Use HTTP/2
     --http2-prior-knowledge        Use HTTP/2 without HTTP/1.1 Upgrade
     --http3                        Use HTTP/3
     --http3-only                   Use HTTP/3 only

Before:

     --http0.9                      Allow HTTP 0.9 responses
 -0, --http1.0                      Use HTTP 1.0
     --http1.1                      Use HTTP 1.1
     --http2                        Use HTTP/2
     --http2-prior-knowledge        Use HTTP 2 without HTTP/1.1 Upgrade
     --http3                        Use HTTP v3
     --http3-only                   Use HTTP v3 only

Closes #16542
2025-03-03 23:09:19 +01:00

853 B

c SPDX-License-Identifier Long Tags Protocols Added Mutexed Requires Help Category Multi See-also Example
Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. curl http2-prior-knowledge Versions HTTP 7.49.0 http1.1 http1.0 http2 http3 HTTP/2 Use HTTP/2 without HTTP/1.1 Upgrade http boolean
http2
http3
--http2-prior-knowledge $URL

--http2-prior-knowledge

Issue a non-TLS HTTP requests using HTTP/2 directly without HTTP/1.1 Upgrade. It requires prior knowledge that the server supports HTTP/2 straight away. HTTPS requests still do HTTP/2 the standard way with negotiated protocol version in the TLS handshake.

Since 8.10.0 if this option is set for an HTTPS request then the application layer protocol version (ALPN) offered to the server is only HTTP/2. Prior to that both HTTP/1.1 and HTTP/2 were offered.