text: //
  // server.cpp
  // ~~~~~~~~~~
  //
  // Copyright (c) 2003-2021 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 "server.hpp"
  #include <signal.h>
  #include <utility>
  
  namespace http {
  namespace server {
  
  server::server(const std::string& address, const std::string& port,
      const std::string& doc_root)
    : io_context_(1),
      signals_(io_context_),
      acceptor_(io_context_),
      connection_manager_(),
      request_handler_(doc_root)
  {
    // Register to handle the signals that indicate when the server should exit.
    // It is safe to register for the same signal multiple times in a program,
    // provided all registration for the specified signal is made through Asio.
    signals_.add(SIGINT);
    signals_.add(SIGTERM);
  #if defined(SIGQUIT)
    signals_.add(SIGQUIT);
  #endif // defined(SIGQUIT)
  
    do_await_stop();
  
    // Open the acceptor with the option to reuse the address (i.e. SO_REUSEADDR).
    asio::ip::tcp::resolver resolver(io_context_);
    asio::ip::tcp::endpoint endpoint =
      *resolver.resolve(address, port).begin();
    acceptor_.open(endpoint.protocol());
    acceptor_.set_option(asio::ip::tcp::acceptor::reuse_address(true));
    acceptor_.bind(endpoint);
    acceptor_.listen();
  
    do_accept();
  }
  
  void server::run()
  {
    // The io_context::run() call will block until all asynchronous operations
    // have finished. While the server is running, there is always at least one
    // asynchronous operation outstanding: the asynchronous accept call waiting
    // for new incoming connections.
    io_context_.run();
  }
  
  void server::do_accept()
  {
    acceptor_.async_accept(
        [this](std::error_code ec, asio::ip::tcp::socket socket)
        {
          // Check whether the server was stopped by a signal before this
          // completion handler had a chance to run.
          if (!acceptor_.is_open())
          {
            return;
          }
  
          if (!ec)
          {
            connection_manager_.start(std::make_shared<connection>(
                std::move(socket), connection_manager_, request_handler_));
          }
  
          do_accept();
        });
  }
  
  void server::do_await_stop()
  {
    signals_.async_wait(
        [this](std::error_code /*ec*/, int /*signo*/)
        {
          // The server is stopped by cancelling all outstanding asynchronous
          // operations. Once all operations have finished the io_context::run()
          // call will exit.
          acceptor_.close();
          connection_manager_.stop_all();
        });
  }
  
  } // namespace server
  } // namespace http
  