- delete completed TODO from `./CMakeLists.txt`. - convert a C++ comment to C89 in `./CMake/CurlTests.c`. - delete duplicate EOLs from EOF. - add missing EOL at EOF. - delete whitespace at EOL (except from expected test results). - convert tabs to spaces. - convert CRLF EOLs to LF in GHA yaml. - text casing fixes in `./CMakeLists.txt`. - fix a codespell typo in `packages/OS400/initscript.sh`. Closes #11772
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Hyper
Hyper is a separate HTTP library written in Rust. curl can be told to use this library as a backend to deal with HTTP.
Experimental!
Hyper support in curl is considered EXPERIMENTAL until further notice. It needs to be explicitly enabled at build-time.
Further development and tweaking of the Hyper backend support in curl will happen in the master branch using pull-requests, just like ordinary changes.
Hyper version
The C API for Hyper is brand new and is still under development.
build curl with hyper
Using Rust 1.64.0 or later, build hyper and enable its C API like this:
% git clone https://github.com/hyperium/hyper
% cd hyper
% RUSTFLAGS="--cfg hyper_unstable_ffi" cargo rustc --features client,http1,http2,ffi --crate-type cdylib
Also, --release
can be added for a release (optimized) build.
Build curl to use hyper's C API:
% git clone https://github.com/curl/curl
% cd curl
% autoreconf -fi
% ./configure LDFLAGS="-Wl,-rpath,<hyper-dir>/target/debug -Wl,-rpath,<hyper-dir>/target/release" --with-openssl --with-hyper=<hyper-dir>
% make
using Hyper internally
Hyper is a low level HTTP transport library. curl itself provides all HTTP headers and Hyper provides all received headers back to curl.
Therefore, most of the "header logic" in curl as in responding to and acting on specific input and output headers are done the same way in curl code.
The API in Hyper delivers received HTTP headers as (cleaned up) name=value pairs, making it impossible for curl to know the exact byte representation over the wire with Hyper.
Limitations
The hyper backend does not support
CURLOPT_IGNORE_CONTENT_LENGTH
--raw
and disablingCURLOPT_HTTP_TRANSFER_DECODING
- RTSP
- hyper is much stricter about what HTTP header contents it allows
- leading whitespace in first HTTP/1 response header
- HTTP/0.9
- HTTP/2 upgrade using HTTP:// URLs. Aka 'h2c'
Remaining issues
This backend is still not feature complete with the native backend. Areas that still need attention and verification include:
- multiplexed HTTP/2
- h2 Upgrade:
- receiving HTTP/1 trailers
- sending HTTP/1 trailers