Boost.Beast HTTP/2-3 Support for C++: A Guide for Tech Enthusiasts
Boost.Beast is a C++ header-only library serving as a foundation for writing interoperable networking libraries by providing low-level HTTP/1, WebSocket, and networking protocol vocabulary types and algorithms.
HTTP/2 and HTTP/3 Support
HTTP/2 and HTTP/3 are the latest versions of the HTTP protocol, offering improved performance, security, and efficiency compared to HTTP/1. Boost.Beast now provides experimental support for both HTTP/2 and HTTP/3, enabling developers to build modern, high-performance client and server applications in C++.
Key Concepts
To leverage HTTP/2 and HTTP/3 support in Boost.Beast, you need to understand several key concepts:
- Asynchronous operations
- Streams and multiplexing
- Header compression and decompression
- Server name indication (SNI) and ALPN
Applications
Boost.Beast's HTTP/2 and HTTP/3 support can be applied in various scenarios, such as building high-performance web servers, implementing modern client applications, and developing microservices architectures.
Significance
Adding HTTP/2 and HTTP/3 support to your C++ projects is crucial for achieving optimal performance, security, and interoperability with modern web services and applications.
Getting Started
To start using Boost.Beast's HTTP/2 and HTTP/3 support, you need to:
- Include the required headers
- Initialize the IO_context and related objects
- Create a Boost.Asio SSL context (for HTTP/2 over TLS)
- Set up the HTTP/2 or HTTP/3 session
- Perform asynchronous read and write operations
Example: HTTP/2 Client
#include <boost/beast/core.hpp>
#include <boost/beast/http.hpp>
#include <boost/beast/version.hpp>
#include <boost/asio/connect.hpp>
#include <boost/asio/ip/tcp.hpp>
namespace beast = boost::beast;
namespace http = beast::http;
namespace net = boost::asio;
using tcp = net::ip::tcp;
int main(int argc, char* argv[]) {
try {
net::io_context ioc;
tcp::resolver resolver{ioc};
auto const results = resolver.resolve("www.example.com", "http");
auto const host = results.front().host_name();
auto const port = results.front().port();
// The io_context is required for all I/O
net::ssl::context ctx{net::ssl::context::sslv23_client};
// This buffer will hold the incoming response
beast::flat_buffer buffer;
// Set up an HTTP/2 client
http::request req{http::verb::get, "/", 11};
req.set(http::field::host, host);
req.set(http::field::user_agent, BOOST_BEAST_VERSION_STRING);
// The SSL stream encapsulates the TCP stream and provides the
// SSL/TLS context.
net::ssl::stream ssl_stream{ioc, ctx};
// Perform the SSL handshake
ssl_stream.handshake(host, port);
// Set up an HTTP/2 session
http::async_client<http::string_body> client{ioc};
client.set_verify_mode(net::ssl::verify_peer);
client.set_verify_callback(
[](bool preverified, boost::asio::ssl::verify_context& ctx) {
return preverified;
}
);
client.handshake(ssl_stream.next_layer(), host, port);
// Make the request
client.request(req);
// Read the response
beast::journal j;
http::response res;
http::read(client, buffer, res);
// If we get here then the connection is closed gracefully
// The make_printable() function helps print a ConstBufferSequence
std::cout << beast::make_printable(res.body()) << std::endl;
return EXIT_SUCCESS;
}
catch (std::exception const& e) {
std::cerr << "Error: " << e.what() << std::endl;
return EXIT_FAILURE;
}
}
References
-
Books:
- Boost C++ Libraries, Incubator Series: Boost.Asio by Christopher M. Kohlhoff
- Network Programming with Boost.Asio: A Tutorial and Guide to the Asio C++ Libraries by Gordon Griesel
-
Articles:
-
Online Resources: