C++怎么使用Boost.Beast实现HTTP/WebSocket服务器_C++网络编程与Boost.Beast应用

sudo apt-get install libboost-all-dev

g++ -std=c++17 server.cpp -lboost_system -lpthread

#include <boost/beast/core.hpp>
#include <boost/beast/http.hpp>
#include <boost/beast/version.hpp>
#include <boost/asio/ip/tcp.hpp>
#include <memory>
#include <string>

namespace beast = boost::beast;
namespace http = beast::http;
namespace net = boost::asio;
using tcp = net::ip::tcp;

// 发送HTTP响应
void send_response(http::response<http::string_body>& response, 
                   tcp::socket& socket) {
    auto msg = std::make_shared<http::response<http::string_body>>(std::move(response));
    http::async_write(socket, *msg,
        [&socket, msg](beast::error_code ec, std::size_t) {
            socket.shutdown(tcp::socket::shutdown_send, ec);
            socket.close();
        });
}

// 处理HTTP请求
void handle_request(tcp::socket socket, http::request<http::string_body> req) {
    http::response<http::string_body> res{http::status::ok, req.version()};
    res.set(http::field::server, "Boost.Beast");
    res.body() = "Hello from HTTP server!";
    res.prepare_payload();
    send_response(std::move(res), std::move(socket));
}

// 接收请求
void do_session(tcp::socket socket) {
    beast::flat_buffer buffer;
    http::request<http::string_body> req;
    
    http::async_read(socket, buffer, req,
        [&socket, buffer = std::move(buffer)]
        (beast::error_code ec, std::size_t) mutable {
            if(!ec) handle_request(std::move(socket), std::move(req));
        });
}

#include <boost/beast/websocket.hpp>

namespace websocket = beast::websocket;

class websocket_session : public std::enable_shared_from_this<websocket_session> {
    websocket::stream<tcp::socket> ws_;

public:
    explicit websocket_session(tcp::socket socket)
        : ws_(std::move(socket)) {}

    void run() {
        ws_.async_accept(
            [self = shared_from_this()](beast::error_code ec) {
                if(ec) return;
                self->do_read();
            });
    }

    void do_read() {
        ws_.async_read(
            buffer_,
            [self = shared_from_this()](beast::error_code ec, std::size_t) {
                if(ec) return;
                self->do_write();
            });
    }

    void do_write() {
        ws_.text(ws_.got_text());
        ws_.async_write(
            buffer_.data(),
            [self = shared_from_this()](beast::error_code ec, std::size_t) {
                if(ec) return;
                self->do_read();
            });
    }

private:
    beast::flat_buffer buffer_;
};

// 检查是否为WebSocket升级请求
bool is_websocket_upgrade(const http::request<http::string_body>& req) {
    return req.method() == http::verb::get
        && req.target() == "/ws"
        && req[http::field::upgrade] == "websocket";
}

if(is_websocket_upgrade(req)) {
    std::make_shared<websocket_session>(std::move(socket))->run();
} else {
    handle_request(std::move(socket), std::move(req));
}

int main() {
    net::io_context ioc;
    tcp::acceptor acceptor(ioc, {tcp::v4(), 8080});

    while(true) {
        tcp::socket socket(ioc);
        acceptor.accept(socket);
        do_session(std::move(socket));
    }
}