// // 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 #include #include #include #include #include #include #include #include using asio::ip::tcp; class session : public boost::enable_shared_from_this { public: explicit session(asio::io_context& io_context) : strand_(asio::make_strand(io_context)), socket_(io_context), timer_(io_context) { } tcp::socket& socket() { return socket_; } void go() { asio::spawn(strand_, boost::bind(&session::echo, shared_from_this(), _1)); asio::spawn(strand_, boost::bind(&session::timeout, shared_from_this(), _1)); } private: void echo(asio::yield_context yield) { try { char data[128]; for (;;) { timer_.expires_after(asio::chrono::seconds(10)); std::size_t n = socket_.async_read_some(asio::buffer(data), yield); asio::async_write(socket_, asio::buffer(data, n), yield); } } catch (std::exception& e) { socket_.close(); timer_.cancel(); } } void timeout(asio::yield_context yield) { while (socket_.is_open()) { asio::error_code ignored_ec; timer_.async_wait(yield[ignored_ec]); if (timer_.expiry() <= asio::steady_timer::clock_type::now()) socket_.close(); } } asio::strand strand_; tcp::socket socket_; asio::steady_timer timer_; }; void do_accept(asio::io_context& io_context, unsigned short port, asio::yield_context yield) { tcp::acceptor acceptor(io_context, tcp::endpoint(tcp::v4(), port)); for (;;) { asio::error_code ec; boost::shared_ptr new_session(new session(io_context)); acceptor.async_accept(new_session->socket(), yield[ec]); if (!ec) new_session->go(); } } int main(int argc, char* argv[]) { try { if (argc != 2) { std::cerr << "Usage: echo_server \n"; return 1; } asio::io_context io_context; asio::spawn(io_context, boost::bind(do_accept, boost::ref(io_context), atoi(argv[1]), _1)); io_context.run(); } catch (std::exception& e) { std::cerr << "Exception: " << e.what() << "\n"; } return 0; }