doc/html/boost_asio/example/cpp17/coroutines_ts/refactored_echo_server.cpp
//
// refactored_echo_server.cpp
// ~~~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2019 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#include <boost/asio/co_spawn.hpp>
#include <boost/asio/detached.hpp>
#include <boost/asio/io_context.hpp>
#include <boost/asio/ip/tcp.hpp>
#include <boost/asio/signal_set.hpp>
#include <boost/asio/write.hpp>
#include <cstdio>
using boost::asio::ip::tcp;
using boost::asio::awaitable;
using boost::asio::co_spawn;
using boost::asio::detached;
using boost::asio::use_awaitable;
namespace this_coro = boost::asio::this_coro;
awaitable<void> echo_once(tcp::socket& socket)
{
char data[128];
std::size_t n = co_await socket.async_read_some(boost::asio::buffer(data), use_awaitable);
co_await async_write(socket, boost::asio::buffer(data, n), use_awaitable);
}
awaitable<void> echo(tcp::socket socket)
{
try
{
for (;;)
{
// The asynchronous operations to echo a single chunk of data have been
// refactored into a separate function. When this function is called, the
// operations are still performed in the context of the current
// coroutine, and the behaviour is functionally equivalent.
co_await echo_once(socket);
}
}
catch (std::exception& e)
{
std::printf("echo Exception: %s\n", e.what());
}
}
awaitable<void> listener()
{
auto executor = co_await this_coro::executor;
tcp::acceptor acceptor(executor, {tcp::v4(), 55555});
for (;;)
{
tcp::socket socket = co_await acceptor.async_accept(use_awaitable);
co_spawn(executor,
[socket = std::move(socket)]() mutable
{
return echo(std::move(socket));
},
detached);
}
}
int main()
{
try
{
boost::asio::io_context io_context(1);
boost::asio::signal_set signals(io_context, SIGINT, SIGTERM);
signals.async_wait([&](auto, auto){ io_context.stop(); });
co_spawn(io_context, listener, detached);
io_context.run();
}
catch (std::exception& e)
{
std::printf("Exception: %s\n", e.what());
}
}