forked from boostorg/beast
awaitable examples are simplified
No need for `rebind_executor` as `asio::deferred` is now the default completion token.
This commit is contained in:
Mohammad Nejati
committed by
Mohammad Nejati
Mohammad Nejati
parent
aabd5b51d3
commit
ff5672ec07
@@ -13,162 +13,141 @@
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//
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//------------------------------------------------------------------------------
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#include <boost/beast/core.hpp>
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#include <boost/beast/websocket.hpp>
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#include <boost/asio/as_tuple.hpp>
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#include <boost/asio/awaitable.hpp>
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#include <boost/asio/co_spawn.hpp>
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#include <boost/asio/detached.hpp>
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#include <boost/asio/use_awaitable.hpp>
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#include <boost/asio/io_context.hpp>
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#include <boost/beast/core.hpp>
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#include <boost/beast/websocket.hpp>
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#include <algorithm>
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#include <cstdlib>
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#include <functional>
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#include <iostream>
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#include <memory>
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#include <string>
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#include <thread>
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#include <vector>
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#if defined(BOOST_ASIO_HAS_CO_AWAIT)
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namespace beast = boost::beast; // from <boost/beast.hpp>
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namespace http = beast::http; // from <boost/beast/http.hpp>
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namespace websocket = beast::websocket; // from <boost/beast/websocket.hpp>
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namespace net = boost::asio; // from <boost/asio.hpp>
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using tcp = boost::asio::ip::tcp; // from <boost/asio/ip/tcp.hpp>
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using stream = websocket::stream<
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typename beast::tcp_stream::rebind_executor<
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typename net::use_awaitable_t<>::executor_with_default<net::any_io_executor>>::other>;
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//------------------------------------------------------------------------------
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namespace beast = boost::beast;
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namespace http = beast::http;
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namespace websocket = beast::websocket;
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namespace net = boost::asio;
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// Echoes back all received WebSocket messages
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net::awaitable<void>
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do_session(stream ws)
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do_session(websocket::stream<beast::tcp_stream> stream)
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{
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// Set suggested timeout settings for the websocket
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ws.set_option(
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websocket::stream_base::timeout::suggested(
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beast::role_type::server));
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stream.set_option(
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websocket::stream_base::timeout::suggested(beast::role_type::server));
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// Set a decorator to change the Server of the handshake
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ws.set_option(websocket::stream_base::decorator(
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stream.set_option(websocket::stream_base::decorator(
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[](websocket::response_type& res)
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{
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res.set(http::field::server,
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res.set(
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http::field::server,
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std::string(BOOST_BEAST_VERSION_STRING) +
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" websocket-server-coro");
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}));
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// Accept the websocket handshake
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co_await ws.async_accept();
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co_await stream.async_accept();
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try
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for(;;)
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{
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for(;;)
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{
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// This buffer will hold the incoming message
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beast::flat_buffer buffer;
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// This buffer will hold the incoming message
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beast::flat_buffer buffer;
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// Read a message
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co_await ws.async_read(buffer);
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// Read a message
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auto [ec, _] = co_await stream.async_read(buffer, net::as_tuple);
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// Echo the message back
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ws.text(ws.got_text());
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co_await ws.async_write(buffer.data());
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}
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}
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catch(const boost::system::system_error & se)
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{
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if (se.code() != websocket::error::closed)
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throw;
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if(ec == websocket::error::closed)
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co_return;
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if(ec)
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throw boost::system::system_error{ ec };
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// Echo the message back
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stream.text(stream.got_text());
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co_await stream.async_write(buffer.data());
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}
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}
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//------------------------------------------------------------------------------
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// Accepts incoming connections and launches the sessions
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net::awaitable<void>
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do_listen(
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tcp::endpoint endpoint)
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do_listen(net::ip::tcp::endpoint endpoint)
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{
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// Open the acceptor
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auto acceptor = net::use_awaitable.as_default_on(tcp::acceptor(co_await net::this_coro::executor));
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acceptor.open(endpoint.protocol());
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// Allow address reuse
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acceptor.set_option(net::socket_base::reuse_address(true));
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// Bind to the server address
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acceptor.bind(endpoint);
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// Start listening for connections
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acceptor.listen(net::socket_base::max_listen_connections);
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auto executor = co_await net::this_coro::executor;
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auto acceptor = net::ip::tcp::acceptor{ executor, endpoint };
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for(;;)
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boost::asio::co_spawn(
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acceptor.get_executor(),
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do_session(stream(co_await acceptor.async_accept())),
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[](std::exception_ptr e)
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{
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net::co_spawn(
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executor,
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do_session(websocket::stream<beast::tcp_stream>{
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co_await acceptor.async_accept() }),
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[](std::exception_ptr e)
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{
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if(e)
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{
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if (e)
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try
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{
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try
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{
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std::rethrow_exception(e);
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}
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catch (std::exception &e) {
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std::cerr << "Error in session: " << e.what() << "\n";
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}
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std::rethrow_exception(e);
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}
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});
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catch(std::exception& e)
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{
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std::cerr << "Error in session: " << e.what() << "\n";
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}
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}
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});
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}
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}
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int main(int argc, char* argv[])
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int
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main(int argc, char* argv[])
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{
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// Check command line arguments.
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if (argc != 4)
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if(argc != 4)
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{
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std::cerr <<
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"Usage: websocket-server-awaitable <address> <port> <threads>\n" <<
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"Example:\n" <<
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" websocket-server-awaitable 0.0.0.0 8080 1\n";
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std::cerr
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<< "Usage: websocket-server-awaitable <address> <port> <threads>\n"
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<< "Example:\n"
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<< " websocket-server-awaitable 0.0.0.0 8080 1\n";
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return EXIT_FAILURE;
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}
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auto const address = net::ip::make_address(argv[1]);
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auto const port = static_cast<unsigned short>(std::atoi(argv[2]));
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auto const port = static_cast<unsigned short>(std::atoi(argv[2]));
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auto const threads = std::max<int>(1, std::atoi(argv[3]));
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// The io_context is required for all I/O
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net::io_context ioc(threads);
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// Spawn a listening port
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boost::asio::co_spawn(
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ioc,
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do_listen(tcp::endpoint{address, port}),
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[](std::exception_ptr e)
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{
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if (e)
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try
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{
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std::rethrow_exception(e);
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}
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catch(std::exception & e)
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{
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std::cerr << "Error: " << e.what() << "\n";
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}
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});
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net::co_spawn(
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ioc,
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do_listen(net::ip::tcp::endpoint{ address, port }),
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[](std::exception_ptr e)
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{
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if(e)
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{
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try
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{
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std::rethrow_exception(e);
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}
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catch(std::exception const& e)
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{
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std::cerr << "Error: " << e.what() << std::endl;
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}
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}
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});
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// Run the I/O service on the requested number of threads
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std::vector<std::thread> v;
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v.reserve(threads - 1);
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for(auto i = threads - 1; i > 0; --i)
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v.emplace_back(
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[&ioc]
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{
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ioc.run();
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});
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v.emplace_back([&ioc] { ioc.run(); });
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ioc.run();
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return EXIT_SUCCESS;
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@@ -176,10 +155,11 @@ int main(int argc, char* argv[])
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#else
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int main(int, char * [])
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int
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main(int, char*[])
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{
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std::printf("awaitables require C++20\n");
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return 1;
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return EXIT_FAILURE;
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}
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#endif
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#endif
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