1 //
2 // async_tcp_echo_server.cpp
3 // ~~~~~~~~~~~~~~~~~~~~~~~~~
4 //
5 // Copyright (c) 2003-2020 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 <cstdlib>
12 #include <iostream>
13 #include <memory>
14 #include <utility>
15 #include <boost/asio.hpp>
16
17 using boost::asio::ip::tcp;
18
19 class session
20 : public std::enable_shared_from_this<session>
21 {
22 public:
session(tcp::socket socket)23 session(tcp::socket socket)
24 : socket_(std::move(socket))
25 {
26 }
27
start()28 void start()
29 {
30 do_read();
31 }
32
33 private:
do_read()34 void do_read()
35 {
36 auto self(shared_from_this());
37 socket_.async_read_some(boost::asio::buffer(data_, max_length),
38 [this, self](boost::system::error_code ec, std::size_t length)
39 {
40 if (!ec)
41 {
42 do_write(length);
43 }
44 });
45 }
46
do_write(std::size_t length)47 void do_write(std::size_t length)
48 {
49 auto self(shared_from_this());
50 boost::asio::async_write(socket_, boost::asio::buffer(data_, length),
51 [this, self](boost::system::error_code ec, std::size_t /*length*/)
52 {
53 if (!ec)
54 {
55 do_read();
56 }
57 });
58 }
59
60 tcp::socket socket_;
61 enum { max_length = 1024 };
62 char data_[max_length];
63 };
64
65 class server
66 {
67 public:
server(boost::asio::io_context & io_context,short port)68 server(boost::asio::io_context& io_context, short port)
69 : acceptor_(io_context, tcp::endpoint(tcp::v4(), port))
70 {
71 do_accept();
72 }
73
74 private:
do_accept()75 void do_accept()
76 {
77 acceptor_.async_accept(
78 [this](boost::system::error_code ec, tcp::socket socket)
79 {
80 if (!ec)
81 {
82 std::make_shared<session>(std::move(socket))->start();
83 }
84
85 do_accept();
86 });
87 }
88
89 tcp::acceptor acceptor_;
90 };
91
main(int argc,char * argv[])92 int main(int argc, char* argv[])
93 {
94 try
95 {
96 if (argc != 2)
97 {
98 std::cerr << "Usage: async_tcp_echo_server <port>\n";
99 return 1;
100 }
101
102 boost::asio::io_context io_context;
103
104 server s(io_context, std::atoi(argv[1]));
105
106 io_context.run();
107 }
108 catch (std::exception& e)
109 {
110 std::cerr << "Exception: " << e.what() << "\n";
111 }
112
113 return 0;
114 }
115