UpAndDown/src/session/HttpSession.h

#pragma once

#include <memory>
#include <boost/beast.hpp>
#include <boost/asio.hpp>

namespace uad
{
class HttpSession : public std::enable_shared_from_this<HttpSession>
{
  class Queue
  {
    enum
    {
      limit = 8
    };

    struct work
    {
      virtual void operator()() = 0;
      virtual ~work() = default;
    };

    HttpSession& self_;
    std::vector<std::unique_ptr<work>> items_;

  public:
    explicit Queue(HttpSession& self);

    bool IsFull() const;

    bool OnWrite();

    template <bool isRequest, class Body, class Fields>
    void operator()(boost::beast::http::message<isRequest, Body, Fields>&& msg)
    {
      struct work_impl : work
      {
        HttpSession& self_;
        boost::beast::http::message<isRequest, Body, Fields> msg_;

        work_impl(HttpSession& self, boost::beast::http::message<isRequest, Body, Fields>&& msg) :
            self_(self), msg_(std::move(msg))
        {
        }

        void operator()()
        {
          boost::beast::http::async_write(self_.stream_, msg_,
                            boost::beast::bind_front_handler(&HttpSession::OnWrite,
                                                      self_.shared_from_this(), msg_.need_eof()));
        }
      };

      items_.push_back(boost::make_unique<work_impl>(self_, std::move(msg)));

      if (items_.size() == 1)
        (*items_.front())();
    }
  };

  boost::beast::tcp_stream stream_;
  boost::beast::flat_buffer buffer_;
  std::shared_ptr<std::string const> doc_root_;
  Queue queue_;
  boost::optional<boost::beast::http::request_parser<boost::beast::http::string_body>> parser_;

public:
  HttpSession(boost::asio::ip::tcp::socket&& socket, std::shared_ptr<std::string const> const& doc_root);

  void Run();

private:
  void DoRead();

  void OnRead(boost::beast::error_code ec, std::size_t bytes_transferred);

  void OnWrite(bool close, boost::beast::error_code ec, std::size_t bytes_transferred);

  void DoClose();
};
}