websocket服务端c++实现代码

WebSocket是一种网络通信协议，它提供了浏览器和服务器之间的全双工通信能力。在C++中实现WebSocket服务端通常需要使用一些第三方库，比如`Boost.Beast`库或者`websocketpp`库。

以下是一个简化的例子，展示了如何使用`Boost.Beast`库来创建一个基本的WebSocket服务端。请注意，你需要先安装Boost库并且确保它配置正确。

#include <boost/beast/core.hpp>
#include <boost/beast/websocket.hpp>
#include <boost/asio/connect.hpp>
#include <boost/asio/ip/tcp.hpp>
#include <iostream>
#include <string>

namespace beast = boost::beast;         // from <boost/beast.hpp>
namespace http = beast::http;           // from <boost/beast/http.hpp>
namespace websocket = beast::websocket; // from <boost/beast/websocket.hpp>
namespace net = boost::asio;            // from <boost/asio.hpp>
using tcp = boost::asio::ip::tcp;       // from <boost/asio/ip/tcp.hpp>

// Echoes back all received WebSocket messages
void do_session(tcp::socket& socket) {
    try {
        // Construct the stream by moving the socket
        websocket::stream<tcp::socket&> ws(socket);

        // Set a decorator to change the Server of the handshake
        ws.set_option(websocket::stream_base::decorator([](websocket::request_type& req) {
            req.set(http::field::server, std::string(BOOST_BEAST_VERSION_STRING) + " websocket-echo");
        }));

        // Perform the websocket handshake
        ws.handshake("localhost", "/");

        // Loop forever receiving and sending messages
        for (;;) {
            // Read a message into our buffer
            beast::flat_buffer buffer;
            ws.read(buffer);

            // Echo the message back
            ws.text(ws.got_text());
            ws.write(buffer.data());
        }
    } catch (std::exception const& e) {
        std::cerr << "Error: " << e.what() << std::endl;
    }
}

int main() {
    try {
        // The io_context is required for all I/O
        net::io_context ioc;

        // Look up the domain name
        tcp::resolver resolver{ioc};
        auto const results = resolver.resolve("example.com", "ws");

        // Make the connection on the IP address we get from a lookup
        tcp::socket socket{ioc};
        net::connect(socket, results);

        // Create the WebSocket and launch the session
        do_session(socket);

    } catch (std::exception const& e) {
        std::cerr << "Error: " << e.what() << std::endl;
    }
    return 0;
}

这段代码展示了如何创建一个简单的WebSocket服务端，它会接收来自客户端的消息并将其原样返回。这是一个基础的实现，真正的服务端实现会更加复杂，包括错误处理、异步操作、多线程等。