topic_service_client.h

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#ifndef SWRI_ROSCPP_TOPIC_SERVICE_CLIENT_H_
#define SWRI_ROSCPP_TOPIC_SERVICE_CLIENT_H_

#include <ros/node_handle.h>

#include <boost/thread/mutex.hpp>

#include <map>

namespace swri
{

template<class MReq, class MRes>
class TopicServiceClientRaw
{
private:
  typedef
  boost::mutex request_lock_;
  ros::Subscriber response_sub_;
  ros::Publisher request_pub_;
  boost::shared_ptr<MRes> response_;

  ros::Duration timeout_;
  std::string name_;
  std::string service_name_;

  int sequence_;

public:
  TopicServiceClientRaw() : sequence_(0), timeout_(ros::Duration(4.0))
  {

  }

  void initialize(ros::NodeHandle &nh,
                const std::string &service,
                const std::string &client_name = "")
  {
    name_ = client_name.length() ? client_name : ros::this_node::getName();
    std::string rservice = nh.resolveName(service);
    service_name_ = rservice;

    request_pub_ = nh.advertise<MReq>(rservice + "/request", 10);
    response_sub_ = nh.subscribe(rservice + "/response", 10, &TopicServiceClientRaw<MReq, MRes>::response_callback, this);
  }

  bool call(MReq& request, MRes& response)
  {
    boost::mutex::scoped_lock scoped_lock(request_lock_);

    // block for response
    request.srv_header.stamp = ros::Time::now();
    request.srv_header.sequence = sequence_;
    request.srv_header.sender = name_;

    // Wait until we get a subscriber and publisher
    while (request_pub_.getNumSubscribers() == 0 || response_sub_.getNumPublishers() == 0)
    {
      ros::Duration(0.002).sleep();
      ros::spinOnce();

      if (ros::Time::now() - request.srv_header.stamp > timeout_)
      {
        return false;
      }
    }
    request_pub_.publish(request);

    // Wait until we get a response
    while (!response_ && ros::Time::now() - request.srv_header.stamp < timeout_)
    {
      ros::Duration(0.002).sleep();
      ros::spinOnce();
    }

    sequence_++;
    if (response_)
    {
      response = *response_;
      response_.reset();
      return response.srv_header.result;
    }
    return false;
  }

  std::string getService()
  {
    return service_name_;
  }

  bool exists()
  {
    return request_pub_.getNumSubscribers() > 0 && response_sub_.getNumPublishers() > 0;
  }

  // The service server can output a console log message when the
  // service is called if desired.
  void setLogCalls(bool enable);
  bool logCalls() const;
private:

  void response_callback(const boost::shared_ptr<MRes>& message)
  {
    ROS_DEBUG("Got response for %s with sequence %i",
             message->srv_header.sender.c_str(), message->srv_header.sequence);

    if (message->srv_header.sender != name_)
    {
      ROS_DEBUG("Got response from another client, ignoring..");
      return;
    }

    if (message->srv_header.sequence != sequence_)
    {
      ROS_WARN("Got wrong sequence number, ignoring..");
      return;
    }

    response_ = message;
  }
};  // class TopicServiceClientRaw

template<class MReq>
class TopicServiceClient: public TopicServiceClientRaw<typename MReq:: Request, typename MReq:: Response>
{
public:
  bool call(MReq& req)
  {
    return TopicServiceClientRaw<typename MReq:: Request, typename MReq:: Response>::call(req.request, req.response);
  }

};  // class TopicServiceClient


}  // namespace swri
#endif  // SWRI_ROSCPP_TOPIC_SERVICE_SERVER_H_