session_adv.cpp

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/*
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// author: Rosen Diankov
#include <ros/node.h>
#include <ros/session.h>
#include <boost/thread/mutex.hpp>

#include "roscpp_sessions/simple_session.h"
#include "roscpp_sessions/set_variable.h"
#include "roscpp_sessions/get_variable.h"
#include "roscpp_sessions/add_variables.h"

#include <map>

using namespace std;
using namespace ros;

// keeps track of created variables
class SimpleSessionInstance
{
public:
    void set_variable(const string& name, int val) { variables[name] = val; }
    int get_variable(const string& name) {
        ROS_ASSERT(variables.find(name)!=variables.end());
        return variables[name];
    }
    void add_variables(const string& result, const string& name1, const string& name2) {
        ROS_ASSERT(variables.find(name1)!=variables.end());
        ROS_ASSERT(variables.find(name2)!=variables.end());
        variables[result] = variables[name1] + variables[name2];
    }

private:
    map<string,int> variables;
};

class SimpleSession : public ros::Node
{
    string _sessionname;
public:
    SimpleSession() : ros::Node("simple_session")
    {
        advertiseService("session_adv",&SimpleSession::startsession,this,1);
        _sessionname = mapName("session_adv");

        // advertise persistent services, the protocol for these differs!
        advertiseService("set_variable",&SimpleSession::set_variable,this,-1);
        advertiseService("get_variable",&SimpleSession::get_variable,this,-1);
        advertiseService("add_variables",&SimpleSession::add_variables,this,-1);
    }

    template <class MReq>
    SimpleSessionInstance* getstate(const MReq& req)
    {
        if( !req.__connection_header )
            return NULL;

        ros::M_string::const_iterator it = req.__connection_header->find(_sessionname);
        if( it == req.__connection_header->end() ) {
            ROS_WARN("failed to find header key %s\n",_sessionname.c_str());
            return NULL;
        }

        boost::mutex::scoped_lock lock(map_mutex);

        int sessionid = atoi(it->second.c_str());
        if( mapsessions.find(sessionid) == mapsessions.end() ) {
            ROS_WARN("failed to find session id %d\n", sessionid);
            return NULL;
        }
        return mapsessions[sessionid].get();
    }

    bool startsession(roscpp_sessions::simple_session::Request& req, roscpp_sessions::simple_session::Response& res) {
        if( req.sessionid ) {
            // destroy
            int success = mapsessions.erase(req.sessionid)>0;
            cout << "terminate session: " << req.sessionid << ", success: " << success << endl;
        }
        else {
            // start a new session with id
            int id = rand();
            ROS_ASSERT( mapsessions.find(id) == mapsessions.end() );
            mapsessions[id].reset(new SimpleSessionInstance());
            cout << "simple session " << id << " started with options " << req.options << endl;
            res.sessionid = id;
        }
        return true;
    }

    bool set_variable(roscpp_sessions::set_variable::Request& req,
                      roscpp_sessions::set_variable::Response& res)
    {
        SimpleSessionInstance* pinst = getstate(req);
        if( pinst == NULL )
            return false;
        pinst->set_variable(req.variable,req.value);
        return true;
    }

    bool get_variable(roscpp_sessions::get_variable::Request& req,
                      roscpp_sessions::get_variable::Response& res)
    {
        SimpleSessionInstance* pinst = getstate(req);
        if( pinst == NULL )
            return false;
        res.result = pinst->get_variable(req.variable);
        return true;
    }

    bool add_variables(roscpp_sessions::add_variables::Request& req,
                      roscpp_sessions::add_variables::Response& res)
    {
        SimpleSessionInstance* pinst = getstate(req);
        if( pinst == NULL )
            return false;
        pinst->add_variables(req.result, req.variable1,req.variable2);
        return true;
    }

private:
    map<int,boost::shared_ptr<SimpleSessionInstance> > mapsessions;
    boost::mutex map_mutex;
};

int main(int argc, char **argv)
{
  ros::init(argc, argv);
  SimpleSession session;
  session.spin();
  
  return 0;
}