doc/html/boost_asio/example/cpp11/spawn/echo_server.cpp

   1 //
   2 // echo_server.cpp
   3 // ~~~~~~~~~~~~~~~
   4 //
   5 // Copyright (c) 2003-2014 Christopher M. Kohlhoff (chris at kohlhoff dot com)
   6 //
   7 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   8 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   9 //
  10
  11 #include <boost/asio/io_service.hpp>
  12 #include <boost/asio/ip/tcp.hpp>
  13 #include <boost/asio/spawn.hpp>
  14 #include <boost/asio/steady_timer.hpp>
  15 #include <boost/asio/write.hpp>
  16 #include <iostream>
  17 #include <memory>
  18
  19 using boost::asio::ip::tcp;
  20
  21 class session : public std::enable_shared_from_this<session>
  22 {
  23 public:
  24   explicit session(tcp::socket socket)
  25     : socket_(std::move(socket)),
  26       timer_(socket_.get_io_service()),
  27       strand_(socket_.get_io_service())
  28   {
  29   }
  30
  31   void go()
  32   {
  33     auto self(shared_from_this());
  34     boost::asio::spawn(strand_,
  35         [this, self](boost::asio::yield_context yield)
  36         {
  37           try
  38           {
  39             char data[128];
  40             for (;;)
  41             {
  42               timer_.expires_from_now(std::chrono::seconds(10));
  43               std::size_t n = socket_.async_read_some(boost::asio::buffer(data), yield);
  44               boost::asio::async_write(socket_, boost::asio::buffer(data, n), yield);
  45             }
  46           }
  47           catch (std::exception& e)
  48           {
  49             socket_.close();
  50             timer_.cancel();
  51           }
  52         });
  53
  54     boost::asio::spawn(strand_,
  55         [this, self](boost::asio::yield_context yield)
  56         {
  57           while (socket_.is_open())
  58           {
  59             boost::system::error_code ignored_ec;
  60             timer_.async_wait(yield[ignored_ec]);
  61             if (timer_.expires_from_now() <= std::chrono::seconds(0))
  62               socket_.close();
  63           }
  64         });
  65   }
  66
  67 private:
  68   tcp::socket socket_;
  69   boost::asio::steady_timer timer_;
  70   boost::asio::io_service::strand strand_;
  71 };
  72
  73 int main(int argc, char* argv[])
  74 {
  75   try
  76   {
  77     if (argc != 2)
  78     {
  79       std::cerr << "Usage: echo_server <port>\n";
  80       return 1;
  81     }
  82
  83     boost::asio::io_service io_service;
  84
  85     boost::asio::spawn(io_service,
  86         [&](boost::asio::yield_context yield)
  87         {
  88           tcp::acceptor acceptor(io_service,
  89             tcp::endpoint(tcp::v4(), std::atoi(argv[1])));
  90
  91           for (;;)
  92           {
  93             boost::system::error_code ec;
  94             tcp::socket socket(io_service);
  95             acceptor.async_accept(socket, yield[ec]);
  96             if (!ec) std::make_shared<session>(std::move(socket))->go();
  97           }
  98         });
  99
 100     io_service.run();
 101   }
 102   catch (std::exception& e)
 103   {
 104     std::cerr << "Exception: " << e.what() << "\n";
 105   }
 106
 107   return 0;
 108 }