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- //
- // chat_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 <cstdlib>
- #include <deque>
- #include <iostream>
- #include <list>
- #include <memory>
- #include <set>
- #include <utility>
- #include <boost/asio.hpp>
- #include "chat_message.hpp"
- using boost::asio::ip::tcp;
- //----------------------------------------------------------------------
- typedef std::deque<chat_message> chat_message_queue;
- //----------------------------------------------------------------------
- class chat_participant
- {
- public:
- virtual ~chat_participant() {}
- virtual void deliver(const chat_message& msg) = 0;
- };
- typedef std::shared_ptr<chat_participant> chat_participant_ptr;
- //----------------------------------------------------------------------
- class chat_room
- {
- public:
- void join(chat_participant_ptr participant)
- {
- participants_.insert(participant);
- for (auto msg: recent_msgs_)
- participant->deliver(msg);
- }
- void leave(chat_participant_ptr participant)
- {
- participants_.erase(participant);
- }
- void deliver(const chat_message& msg)
- {
- recent_msgs_.push_back(msg);
- while (recent_msgs_.size() > max_recent_msgs)
- recent_msgs_.pop_front();
- for (auto participant: participants_)
- participant->deliver(msg);
- }
- private:
- std::set<chat_participant_ptr> participants_;
- enum { max_recent_msgs = 100 };
- chat_message_queue recent_msgs_;
- };
- //----------------------------------------------------------------------
- class chat_session
- : public chat_participant,
- public std::enable_shared_from_this<chat_session>
- {
- public:
- chat_session(tcp::socket socket, chat_room& room)
- : socket_(std::move(socket)),
- room_(room)
- {
- }
- void start()
- {
- room_.join(shared_from_this());
- do_read_header();
- }
- void deliver(const chat_message& msg)
- {
- bool write_in_progress = !write_msgs_.empty();
- write_msgs_.push_back(msg);
- if (!write_in_progress)
- {
- do_write();
- }
- }
- private:
- void do_read_header()
- {
- auto self(shared_from_this());
- boost::asio::async_read(socket_,
- boost::asio::buffer(read_msg_.data(), chat_message::header_length),
- [this, self](boost::system::error_code ec, std::size_t /*length*/)
- {
- if (!ec && read_msg_.decode_header())
- {
- do_read_body();
- }
- else
- {
- room_.leave(shared_from_this());
- }
- });
- }
- void do_read_body()
- {
- auto self(shared_from_this());
- boost::asio::async_read(socket_,
- boost::asio::buffer(read_msg_.body(), read_msg_.body_length()),
- [this, self](boost::system::error_code ec, std::size_t /*length*/)
- {
- if (!ec)
- {
- room_.deliver(read_msg_);
- do_read_header();
- }
- else
- {
- room_.leave(shared_from_this());
- }
- });
- }
- void do_write()
- {
- auto self(shared_from_this());
- boost::asio::async_write(socket_,
- boost::asio::buffer(write_msgs_.front().data(),
- write_msgs_.front().length()),
- [this, self](boost::system::error_code ec, std::size_t /*length*/)
- {
- if (!ec)
- {
- write_msgs_.pop_front();
- if (!write_msgs_.empty())
- {
- do_write();
- }
- }
- else
- {
- room_.leave(shared_from_this());
- }
- });
- }
- tcp::socket socket_;
- chat_room& room_;
- chat_message read_msg_;
- chat_message_queue write_msgs_;
- };
- //----------------------------------------------------------------------
- class chat_server
- {
- public:
- chat_server(boost::asio::io_context& io_context,
- const tcp::endpoint& endpoint)
- : acceptor_(io_context, endpoint)
- {
- do_accept();
- }
- private:
- void do_accept()
- {
- acceptor_.async_accept(
- [this](boost::system::error_code ec, tcp::socket socket)
- {
- if (!ec)
- {
- std::make_shared<chat_session>(std::move(socket), room_)->start();
- }
- do_accept();
- });
- }
- tcp::acceptor acceptor_;
- chat_room room_;
- };
- //----------------------------------------------------------------------
- int main(int argc, char* argv[])
- {
- try
- {
- if (argc < 2)
- {
- std::cerr << "Usage: chat_server <port> [<port> ...]\n";
- return 1;
- }
- boost::asio::io_context io_context;
- std::list<chat_server> servers;
- for (int i = 1; i < argc; ++i)
- {
- tcp::endpoint endpoint(tcp::v4(), std::atoi(argv[i]));
- servers.emplace_back(io_context, endpoint);
- }
- io_context.run();
- }
- catch (std::exception& e)
- {
- std::cerr << "Exception: " << e.what() << "\n";
- }
- return 0;
- }
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