WebSocket in C++: Libraries and Practical Application

C++ WebSocket Library: Complete Overview and Usage Examples

WebSocket is a full-duplex communication protocol over TCP that provides a persistent connection between a client and a server. Unlike HTTP, WebSocket allows sending messages in both directions without constant repeated requests, making it ideal for chats, online games, stock quotes, and other real-time applications.

In C++, there are several mature libraries for working with WebSocket. In this article, we will look at three of the most popular options: Boost.Beast, uWebSockets, and libwebsockets. We will analyze their features, installation, and provide working code examples.

1. Boost.Beast — Powerful and Standardized

Boost.Beast is a library based on Boost.Asio that implements HTTP and WebSocket protocols. It is part of Boost (starting from version 1.66) and is the de facto standard for serious C++ projects.

Installation

# Installing Boost (Ubuntu/Debian)sudo apt install libboost-all-dev

# Or build from source with the --with-beast option

WebSocket Server Example (Echo Server)

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

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

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

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

            websocket::stream<tcp::socket> ws{std::move(socket)};            ws.accept();

            for (;;) {                beast::flat_buffer buffer;                ws.read(buffer);                std::string msg = beast::buffers_to_string(buffer.data());                std::cout << "Received: " << msg << std::endl;

                ws.text(ws.got_text());                ws.write(buffer.data());            }        }    } catch (const std::exception& e) {        std::cerr << "Error: " << e.what() << std::endl;    }    return 0;}

WebSocket Client Example

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

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

int main() {    try {        net::io_context ioc;        tcp::resolver resolver{ioc};        websocket::stream<tcp::socket> ws{ioc};

        auto const results = resolver.resolve("localhost", "8080");        net::connect(ws.next_layer(), results.begin(), results.end());        ws.handshake("localhost", "/");

        ws.write(net::buffer(std::string("Hello, server!")));        beast::flat_buffer buffer;        ws.read(buffer);        std::cout << "Response: " << beast::buffers_to_string(buffer.data()) << std::endl;

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

2. uWebSockets — Fast and Lightweight

uWebSockets (µWebSockets) is a high-performance library written in C++11. It uses its own event loop and supports both HTTP and WebSocket. It is distinguished by minimal memory consumption and high speed.

Installation

git clone https://github.com/uNetworking/uWebSockets.gitcd uWebSocketsmakesudo make install

Echo Server Example

#include <uwebsoc