service_client.h

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//=================================================================================================
// Copyright (c) 2013, Johannes Meyer, TU Darmstadt
// All rights reserved.

// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above copyright
//       notice, this list of conditions and the following disclaimer in the
//       documentation and/or other materials provided with the distribution.
//     * Neither the name of the Flight Systems and Automatic Control group,
//       TU Darmstadt, nor the names of its contributors may be used to
//       endorse or promote products derived from this software without
//       specific prior written permission.

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
// ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY
// DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
// ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
// SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//=================================================================================================

#ifndef TOPIC_PROXY_SERVICE_CLIENT_H
#define TOPIC_PROXY_SERVICE_CLIENT_H

#include <ros/forwards.h>
#include <ros/common.h>
#include <ros/service_traits.h>
#include <ros/serialization.h>

namespace topic_proxy
{

class ServiceClient {
public:
  ServiceClient();
  ServiceClient(const ServiceClient& rhs);
  ~ServiceClient();

  template <typename Service>
  ServiceClient(const std::string& service_name, const std::string& host = std::string(), uint32_t port = 0, const ros::M_string& header_values = ros::M_string())
  {
    init<Service>(service_name, host, port, header_values);
  }

  template <typename Service>
  bool init(const std::string& service_name, std::string host = std::string(), uint32_t port = 0, const ros::M_string& header_values = ros::M_string())
  {
    return init(service_name, std::string(ros::service_traits::md5sum<Service>()), host, port, header_values);
  }

  bool init(const std::string& service_name, const std::string& service_md5sum, std::string host = std::string(), uint32_t port = 0, const ros::M_string& header_values = ros::M_string());

  template<class MReq, class MRes>
  bool call(MReq& req, MRes& res)
  {
    namespace st = ros::service_traits;

    if (!isValid())
    {
      return false;
    }

    if (strcmp(st::md5sum(req), st::md5sum(res)))
    {
      ROS_ERROR("The request and response parameters to the service "
                 "call must be autogenerated from the same "
                 "server definition file (.srv). your service call "
                 "for %s appeared to use request/response types "
                 "from different .srv files. (%s vs. %s)", impl_->name_.c_str(), st::md5sum(req), st::md5sum(res));
      return false;
    }

    return call(req, res, st::md5sum(req));
  }

  template<class Service>
  bool call(Service& service)
  {
    namespace st = ros::service_traits;

    if (!isValid())
    {
      return false;
    }

    return call(service.request, service.response, st::md5sum(service));
  }

  template<typename MReq, typename MRes>
  bool call(const MReq& req, MRes& resp, const std::string& service_md5sum)
  {
    namespace ser = ros::serialization;
    ros::SerializedMessage ser_req = ser::serializeMessage(req);
    ros::SerializedMessage ser_resp;
    bool ok = call(ser_req, ser_resp, service_md5sum);
    if (!ok)
    {
      return false;
    }

    try
    {
      ser::deserializeMessage(ser_resp, resp);
    }
    catch (std::exception& e)
    {
      deserializeFailed(e);
      return false;
    }

    return true;
  }

  bool call(const ros::SerializedMessage& req, ros::SerializedMessage& resp, const std::string& service_md5sum);

  bool isValid() const;

  void shutdown();

  std::string getService();

private:
  // This works around a problem with the OSX linker that causes the static variable declared by
  // ROS_ERROR to error with missing symbols when it's used directly in the templated call() method above
  // This for some reason only showed up in the rxtools package
  void deserializeFailed(const std::exception& e)
  {
    ROS_ERROR("Exception thrown while while deserializing service call: %s", e.what());
  }

  struct Impl
  {
    Impl();
    ~Impl();

    void shutdown();
    bool isValid() const;

    ros::ServiceServerLinkPtr server_link_;
    std::string name_;
    ros::M_string header_values_;
    bool is_shutdown_;
  };
  typedef boost::shared_ptr<Impl> ImplPtr;
  typedef boost::weak_ptr<Impl> ImplWPtr;

  ImplPtr impl_;
};

} // namespace topic_proxy

#endif // TOPIC_PROXY_SERVICE_CLIENT_H