How implement websockets using Boost library in WebAssembly?

Question

I am trying to pass a program that uses websockets in C++ using the Boost library, to WebAssembly for its later use in a web application, or in its defect in a runtime like Wasmtime.

On the one hand I have used Emscripten to compile my C++ application, but I can't get it to work. I have seen that Emscripten has its own section associated to WebSockets, but my intention is to be able to take advantage of my C++ code that uses the Boost library to implement WebSockets.

On the other hand I have been reading about WASI, and maybe this could be a solution to my problem. I have been looking but I do not know if at the moment there is something implemented in reference to websocekts in C++, since what I have seen are proposals based on examples in Rust.

I do not know if someone could help me to solve this problem and to be able to transform my C++ code to WebAssembly and that this is functional in a web environment or in a runtime.

I leave a basic example of the C++ code that I am testing:

#include <iostream>
#include <string>
#include <boost/asio.hpp>
#include <boost/beast.hpp>

int main(int argc, char** argv) {
    try {
        std::string host = "127.0.0.1";
        std::string port = "3333";
        std::string message = "Hello World!";

        boost::asio::io_context ioContext;
        boost::asio::ip::tcp::resolver resolver{ioContext};
        boost::beast::websocket::stream<boost::asio::ip::tcp::socket> webSocket{ioContext};

        auto const results = resolver.resolve(host, port);

        auto endPoint = boost::asio::connect(webSocket.next_layer(), results);

        host += ':' + std::to_string(endPoint.port());

        webSocket.set_option(boost::beast::websocket::stream_base::decorator(
            [](boost::beast::websocket::request_type& req) {
                req.set(boost::beast::http::field::user_agent,
                    std::string(BOOST_BEAST_VERSION_STRING) +
                        " websocket-client-coro");
            }));

        webSocket.handshake(host, "/");

        webSocket.write(boost::asio::buffer(message));

        boost::system::error_code errorCode;
        webSocket.close(boost::beast::websocket::close_code::normal, errorCode);
    }
    catch(std::exception const& e) {
        std::cerr << "There was an error: " << e.what() << std::endl;
        return -1;
    }
    return 0;
}

Thanks

ng-hobby · Answer 1 · 2023-05-24T15:03:35.057

To implement WebSockets using the Boost library in WebAssembly, the following steps are required:

Set up development environment.
Boost Installation.
Include necessary headers.
Initialize the Boost.
Set up the WebSocket connection
Handle messages
Finally, Run the I/O service

Here's a basic example to illustrate these steps:

#include <boost/asio.hpp>
#include <boost/beast.hpp>
#include <iostream>

int main() {
    boost::asio::io_context io_context;
    
    boost::beast::websocket::stream<boost::asio::ip::tcp::socket> ws(io_context);

    // Set up the WebSocket connection
    ws.async_handshake("example.com", "/", [](boost::beast::error_code ec) {
        if (!ec) {
            std::cout << "WebSocket handshake successful!" << std::endl;
            // WebSocket connected, handle messages here
        } else {
            std::cout << "WebSocket handshake error: " << ec.message() << std::endl;
        }
    });

    // Run the I/O service
    io_context.run();

    return 0;
}

In addition, you have to to compile the code using Emscripten to generate WebAssembly output.

emcc your_code.cpp -o your_code.js -s WASM=1 -s USE_BOOST_HEADERS=1 -s USE_BOOST_LIBS=boost_asio,boost_system

First paragraph scores 93.75% on ZeroGPT – Lee May 23 '23 at 06:18 — Lee, May 23 '23 at 06:18

How implement websockets using Boost library in WebAssembly?

1 Answers1