serial_session.h

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#ifndef ROSSERIAL_SERVER_SERIAL_SESSION_H
#define ROSSERIAL_SERVER_SERIAL_SESSION_H
 
#include <iostream>
#include <boost/bind.hpp>
#include <boost/asio.hpp>
 
#include <ros/ros.h>
 
#include "rosserial_server/session.h"
 
namespace rosserial_server
{
 
class SerialSession : public Session<boost::asio::serial_port>
{
public:
  SerialSession(boost::asio::io_service& io_service, std::string port, int baud)
    : Session(io_service), port_(port), baud_(baud), timer_(io_service)
  {
    ROS_INFO_STREAM("rosserial_server session configured for " << port_ << " at " << baud << "bps.");
 
    failed_connection_attempts_ = 0;
    check_connection();
  }
 
private:
  void check_connection()
  {
    if (!is_active())
    {
      attempt_connection();
    }
 
    // Every second, check again if the connection should be reinitialized,
    // if the ROS node is still up.
    if (ros::ok())
    {
      timer_.expires_from_now(boost::posix_time::milliseconds(2000));
      timer_.async_wait(boost::bind(&SerialSession::check_connection, this));
    }
    else
    {
      shutdown();
    }
  }
 
  void attempt_connection()
  {
    ROS_DEBUG("Opening serial port.");
 
    boost::system::error_code ec;
    socket().open(port_, ec);
    if (ec) {
      failed_connection_attempts_++;
      if (failed_connection_attempts_ == 1) {
        ROS_ERROR_STREAM("Unable to open port " << port_ << ": " << ec);
      } else {
        ROS_DEBUG_STREAM("Unable to open port " << port_ << " (" << failed_connection_attempts_ << "): " << ec);
      }
      return;
    }
    ROS_INFO_STREAM("Opened " << port_);
    failed_connection_attempts_ = 0;
 
    typedef boost::asio::serial_port_base serial;
    socket().set_option(serial::baud_rate(baud_));
    socket().set_option(serial::character_size(8));
    socket().set_option(serial::stop_bits(serial::stop_bits::one));
    socket().set_option(serial::parity(serial::parity::none));
    socket().set_option(serial::flow_control(serial::flow_control::none));
 
    // Kick off the session.
    start();
  }
 
  std::string port_;
  int baud_;
  boost::asio::deadline_timer timer_;
  int failed_connection_attempts_;
};
 
}  // namespace
 
#endif  // ROSSERIAL_SERVER_SERIAL_SESSION_H