X-Git-Url: http://lists.indexdata.com/cgi-bin?a=blobdiff_plain;ds=sidebyside;f=src%2Ffilter_virt_db.cpp;h=20ae5c94b1179f45ef5a024e7354ba86a84bf309;hb=891f355967146e1f2d66e4dc44158a011282c87f;hp=2a86b79fd52fa87473cb5639088ed0813fffbdb6;hpb=6f81e2e8664bbc26dd3626bb02980cdb7fe0abca;p=metaproxy-moved-to-github.git

diff --git a/src/filter_virt_db.cpp b/src/filter_virt_db.cpp
index 2a86b79..20ae5c9 100644
--- a/src/filter_virt_db.cpp
+++ b/src/filter_virt_db.cpp
@@ -1,4 +1,4 @@
-/* $Id: filter_virt_db.cpp,v 1.2 2005-10-24 21:01:53 adam Exp $
+/* $Id: filter_virt_db.cpp,v 1.20 2006-01-11 11:51:50 adam Exp $
    Copyright (c) 2005, Index Data.
 
 %LICENSE%
@@ -7,19 +7,18 @@
 #include "config.hpp"
 
 #include "filter.hpp"
-#include "router.hpp"
 #include "package.hpp"
 
 #include <boost/thread/mutex.hpp>
+#include <boost/thread/condition.hpp>
 
+#include "util.hpp"
 #include "filter_virt_db.hpp"
 
 #include <yaz/zgdu.h>
-#include <yaz/log.h>
 #include <yaz/otherinfo.h>
 #include <yaz/diagbib1.h>
 
-#include <list>
 #include <map>
 #include <iostream>
 
@@ -28,51 +27,162 @@ namespace yf = yp2::filter;
 namespace yp2 {
     namespace filter {
         struct Virt_db_set {
-            Virt_db_set(yp2::Session &id, Z_InternationalString *setname,
-                        std::string vhost);
+            Virt_db_set(yp2::Session &id, std::string setname,
+                        std::string vhost, std::string route,
+                        bool named_result_sets);
+            Virt_db_set();
             ~Virt_db_set();
 
-            yp2::Session m_session;
-            std::string m_setname;
+            yp2::Session m_backend_session;
+            std::string m_backend_setname;
             std::string m_vhost;
+            std::string m_route;
+            bool m_named_result_sets;
         };
         struct Virt_db_session {
             Virt_db_session(yp2::Session &id, bool use_vhost);
+            Virt_db_session();
             yp2::Session m_session;
             bool m_use_vhost;
-            std::list<Virt_db_set> m_sets;
+            std::map<std::string,Virt_db_set> m_sets;
         };
         struct Virt_db_map {
-            Virt_db_map(std::string vhost);
+            Virt_db_map(std::string vhost, std::string route);
             Virt_db_map();
             std::string m_vhost;
+            std::string m_route;
         };
+        struct Frontend {
+            Frontend();
+            ~Frontend();
+            yp2::Session m_session;
+            bool m_use_vhost;
+            bool m_in_use;
+            std::map<std::string,Virt_db_set> m_sets;
+            void search(Package &package, Z_APDU *apdu,
+                        const std::map<std::string, Virt_db_map> &maps);
+            void present(Package &package, Z_APDU *apdu);
+            void close(Package &package);
+            typedef std::map<std::string,Virt_db_set>::iterator Sets_it;
+        };            
         class Virt_db::Rep {
             friend class Virt_db;
             
             void release_session(Package &package);
             void init(Package &package, Z_APDU *apdu, bool &move_later);
             void search(Package &package, Z_APDU *apdu, bool &move_later);
+            void present(Package &package, Z_APDU *apdu, bool &move_later);
+
+            Frontend *get_frontend(Package &package);
+            void release_frontend(Package &package);
         private:
             boost::mutex m_sessions_mutex;
-            std::list<Virt_db_session>m_sessions;
+            std::map<yp2::Session,Virt_db_session>m_sessions;
             std::map<std::string, Virt_db_map>m_maps;
+
+            typedef std::map<yp2::Session,Virt_db_session>::iterator Ses_it;
+            typedef std::map<std::string,Virt_db_set>::iterator Sets_it;
+
+            boost::mutex m_mutex;
+            boost::condition m_cond_session_ready;
+            std::map<yp2::Session,Frontend *> m_clients;
         };
     }
 }
 
-yf::Virt_db_set::Virt_db_set(yp2::Session &id, Z_InternationalString *setname,
-                             std::string vhost)
-    :   m_session(id), m_setname(setname), m_vhost(vhost)
+using namespace yp2;
+
+yf::Frontend::Frontend()
 {
+    m_use_vhost = false;
 }
 
+void yf::Frontend::close(Package &package)
+{
+    Sets_it sit = m_sets.begin();
+    for (; sit != m_sets.end(); sit++)
+    {
+        sit->second.m_backend_session.close();
+        Package close_package(sit->second.m_backend_session, package.origin());
+        close_package.copy_filter(package);
+        
+        close_package.move(sit->second.m_route);
+    }
+}
+
+yf::Frontend::~Frontend()
+{
+}
+
+yf::Frontend *yf::Virt_db::Rep::get_frontend(Package &package)
+{
+    boost::mutex::scoped_lock lock(m_mutex);
+
+    std::map<yp2::Session,yf::Frontend *>::iterator it;
+    
+    while(true)
+    {
+        it = m_clients.find(package.session());
+        if (it == m_clients.end())
+            break;
+        
+        if (!it->second->m_in_use)
+        {
+            it->second->m_in_use = true;
+            return it->second;
+        }
+        m_cond_session_ready.wait(lock);
+    }
+    Frontend *f = new Frontend;
+    m_clients[package.session()] = f;
+    f->m_in_use = true;
+    return f;
+}
+
+
+void yf::Virt_db::Rep::release_frontend(Package &package)
+{
+    boost::mutex::scoped_lock lock(m_mutex);
+    std::map<yp2::Session,yf::Frontend *>::iterator it;
+    
+    it = m_clients.find(package.session());
+    if (it != m_clients.end())
+    {
+        if (package.session().is_closed())
+        {
+            std::cout << "Closing IT\n";
+            it->second->close(package);
+            delete it->second;
+            m_clients.erase(it);
+        }
+        else
+        {
+            it->second->m_in_use = false;
+        }
+        m_cond_session_ready.notify_all();
+    }
+}
+
+yf::Virt_db_set::Virt_db_set(yp2::Session &id, std::string setname,
+                             std::string vhost, std::string route,
+                             bool named_result_sets)
+    :   m_backend_session(id), m_backend_setname(setname), m_vhost(vhost),
+        m_route(route), m_named_result_sets(named_result_sets)
+{
+}
+
+
+yf::Virt_db_set::Virt_db_set()
+{
+}
+
+
 yf::Virt_db_set::~Virt_db_set()
 {
 }
 
-yf::Virt_db_map::Virt_db_map(std::string vhost)
-    : m_vhost(vhost) 
+yf::Virt_db_map::Virt_db_map(std::string vhost, std::string route)
+    : m_vhost(vhost), m_route(route) 
 {
 }
 
@@ -80,6 +190,12 @@ yf::Virt_db_map::Virt_db_map()
 {
 }
 
+yf::Virt_db_session::Virt_db_session()
+    : m_use_vhost(false)
+{
+
+}
+
 yf::Virt_db_session::Virt_db_session(yp2::Session &id,
                                      bool use_vhost) :
     m_session(id) , m_use_vhost(use_vhost)
@@ -87,30 +203,167 @@ yf::Virt_db_session::Virt_db_session(yp2::Session &id,
 
 }
 
-yf::Virt_db::Virt_db() {
-    m_p = new Virt_db::Rep;
+yf::Virt_db::Virt_db() : m_p(new Virt_db::Rep)
+{
 }
 
 yf::Virt_db::~Virt_db() {
-    delete m_p;
 }
 
 void yf::Virt_db::Rep::release_session(Package &package)
 {
-    if (package.session().is_closed()) 
+    boost::mutex::scoped_lock lock(m_sessions_mutex);
+    
+    Ses_it it = m_sessions.find(package.session());
+    
+    if (it != m_sessions.end())
+    {
+        Sets_it sit = it->second.m_sets.begin();
+        for (; sit != it->second.m_sets.end(); sit++)
+        {
+            sit->second.m_backend_session.close();
+            Package close_package(sit->second.m_backend_session, package.origin());
+            close_package.copy_filter(package);
+
+            close_package.move(sit->second.m_route);
+        }
+    }
+    m_sessions.erase(package.session());
+}
+
+void yf::Virt_db::Rep::present(Package &package, Z_APDU *apdu, bool &move_later){
+    Session *id = 0;
+    Z_PresentRequest *req = apdu->u.presentRequest;
+    std::string resultSetId = req->resultSetId;
+    yp2::odr odr;
     {
         boost::mutex::scoped_lock lock(m_sessions_mutex);
         
-        std::list<Virt_db_session>::iterator it;
-        for (it = m_sessions.begin(); it != m_sessions.end(); it++)
+        Ses_it it = m_sessions.find(package.session());
+        if (it == m_sessions.end())
         {
-            if (package.session() == (*it).m_session)
-                break;
+            package.response() = odr.create_close(
+                Z_Close_protocolError,
+                "no session for present request");
+            package.session().close();
+            return;
         }
-        if (it == m_sessions.end())
+        if (it->second.m_use_vhost)
+        {
+            move_later = true;
             return;
-        m_sessions.erase(it);
+        }
+        Sets_it sets_it = it->second.m_sets.find(resultSetId);
+        if (sets_it == it->second.m_sets.end())
+        {
+            Z_APDU *apdu = zget_APDU(odr, Z_APDU_presentResponse);
+            
+            Z_Records *rec = (Z_Records *) odr_malloc(odr, sizeof(Z_Records));
+            apdu->u.presentResponse->records = rec;
+            rec->which = Z_Records_NSD;
+            rec->u.nonSurrogateDiagnostic =
+                zget_DefaultDiagFormat(
+                    odr,
+                    YAZ_BIB1_SPECIFIED_RESULT_SET_DOES_NOT_EXIST,
+                    resultSetId.c_str());
+            package.response() = apdu;
+
+            return;
+        }
+        id = new yp2::Session(sets_it->second.m_backend_session);
+    }
+    
+    // sending present to backend
+    Package present_package(*id, package.origin());
+    present_package.copy_filter(package);
+    
+    req->resultSetId = odr_strdup(odr, "default");
+    present_package.request() = yazpp_1::GDU(apdu);
+
+    present_package.move();
+
+    if (present_package.session().is_closed())
+    {
+        Z_APDU *apdu = zget_APDU(odr, Z_APDU_presentResponse);
+        
+        Z_Records *rec = (Z_Records *) odr_malloc(odr, sizeof(Z_Records));
+        apdu->u.presentResponse->records = rec;
+        rec->which = Z_Records_NSD;
+        rec->u.nonSurrogateDiagnostic =
+            zget_DefaultDiagFormat(
+                odr,
+                YAZ_BIB1_RESULT_SET_NO_LONGER_EXISTS_UNILATERALLY_DELETED_BY_,
+                resultSetId.c_str());
+        package.response() = apdu;
+        
+        boost::mutex::scoped_lock lock(m_sessions_mutex);
+        Ses_it it = m_sessions.find(package.session());
+        if (it != m_sessions.end())
+            it->second.m_sets.erase(resultSetId);
+    }
+    else
+    {
+        package.response() = present_package.response();
+    }
+    delete id;
+}
+
+void yf::Frontend::present(Package &package, Z_APDU *apdu)
+{
+    Session *id = 0;
+    Z_PresentRequest *req = apdu->u.presentRequest;
+    std::string resultSetId = req->resultSetId;
+    yp2::odr odr;
+
+    Sets_it sets_it = m_sets.find(resultSetId);
+    if (sets_it == m_sets.end())
+    {
+        Z_APDU *apdu = zget_APDU(odr, Z_APDU_presentResponse);
+        
+        Z_Records *rec = (Z_Records *) odr_malloc(odr, sizeof(Z_Records));
+        apdu->u.presentResponse->records = rec;
+        rec->which = Z_Records_NSD;
+        rec->u.nonSurrogateDiagnostic =
+            zget_DefaultDiagFormat(
+                odr,
+                YAZ_BIB1_SPECIFIED_RESULT_SET_DOES_NOT_EXIST,
+                resultSetId.c_str());
+        package.response() = apdu;
+        
+        return;
+    }
+    id = new yp2::Session(sets_it->second.m_backend_session);
+    
+    // sending present to backend
+    Package present_package(*id, package.origin());
+    present_package.copy_filter(package);
+    
+    req->resultSetId = odr_strdup(odr, "default");
+    present_package.request() = yazpp_1::GDU(apdu);
+
+    present_package.move();
+
+    if (present_package.session().is_closed())
+    {
+        Z_APDU *apdu = zget_APDU(odr, Z_APDU_presentResponse);
+        
+        Z_Records *rec = (Z_Records *) odr_malloc(odr, sizeof(Z_Records));
+        apdu->u.presentResponse->records = rec;
+        rec->which = Z_Records_NSD;
+        rec->u.nonSurrogateDiagnostic =
+            zget_DefaultDiagFormat(
+                odr,
+                YAZ_BIB1_RESULT_SET_NO_LONGER_EXISTS_UNILATERALLY_DELETED_BY_,
+                resultSetId.c_str());
+        package.response() = apdu;
+        
+        m_sets.erase(resultSetId);
     }
+    else
+    {
+        package.response() = present_package.response();
+    }
+    delete id;
 }
 
 void yf::Virt_db::Rep::search(Package &package, Z_APDU *apdu, bool &move_later)
@@ -118,30 +371,30 @@ void yf::Virt_db::Rep::search(Package &package, Z_APDU *apdu, bool &move_later)
     Z_SearchRequest *req = apdu->u.searchRequest;
     std::string vhost;
     std::string database;
-    Session *id = 0;
+    std::string resultSetId = req->resultSetName;
+    std::string route;
+    bool support_named_result_sets = false;  // whether backend supports it
+    yp2::odr odr;
     {
         boost::mutex::scoped_lock lock(m_sessions_mutex);
-        
-        std::list<Virt_db_session>::iterator it;
-        for (it = m_sessions.begin(); it != m_sessions.end(); it++)
-        {
-            if (package.session() == (*it).m_session)
-                break;
-        }
+
+        Ses_it it = m_sessions.find(package.session());
         if (it == m_sessions.end())
         {
-            // error should be returned
-            move_later = true;
+            package.response() = odr.create_close(
+                Z_Close_protocolError,
+                "no session for search request");
+            package.session().close();
+
             return;
         }
-        if ((*it).m_use_vhost)
+        if (it->second.m_use_vhost)
         {
             move_later = true;
             return;
         }
         if (req->num_databaseNames != 1)
         {   // exactly one database must be specified
-            ODR odr = odr_createmem(ODR_ENCODE);
             Z_APDU *apdu = zget_APDU(odr, Z_APDU_searchResponse);
             
             Z_Records *rec = (Z_Records *) odr_malloc(odr, sizeof(Z_Records));
@@ -152,7 +405,6 @@ void yf::Virt_db::Rep::search(Package &package, Z_APDU *apdu, bool &move_later)
                     odr, YAZ_BIB1_TOO_MANY_DATABASES_SPECIFIED, 0);
             package.response() = apdu;
             
-            odr_destroy(odr);
             return;
         }
         database = req->databaseNames[0];
@@ -160,7 +412,6 @@ void yf::Virt_db::Rep::search(Package &package, Z_APDU *apdu, bool &move_later)
         map_it = m_maps.find(database);
         if (map_it == m_maps.end()) 
         {   // no map for database: return diagnostic
-            ODR odr = odr_createmem(ODR_ENCODE);
             Z_APDU *apdu = zget_APDU(odr, Z_APDU_searchResponse);
             
             Z_Records *rec = (Z_Records *) odr_malloc(odr, sizeof(Z_Records));
@@ -168,36 +419,75 @@ void yf::Virt_db::Rep::search(Package &package, Z_APDU *apdu, bool &move_later)
             rec->which = Z_Records_NSD;
             rec->u.nonSurrogateDiagnostic =
                 zget_DefaultDiagFormat(
-                    odr, YAZ_BIB1_DATABASE_UNAVAILABLE, database.c_str());
+                    odr, YAZ_BIB1_DATABASE_DOES_NOT_EXIST, database.c_str());
             package.response() = apdu;
             
-            odr_destroy(odr);
             return;
         }
+        if (*req->replaceIndicator == 0)
+        {
+            Sets_it sets_it = it->second.m_sets.find(req->resultSetName);
+            if (sets_it != it->second.m_sets.end())
+            {
+                Z_APDU *apdu = zget_APDU(odr, Z_APDU_searchResponse);
+                
+                Z_Records *rec = (Z_Records *) odr_malloc(odr, sizeof(Z_Records));
+                apdu->u.searchResponse->records = rec;
+                rec->which = Z_Records_NSD;
+                rec->u.nonSurrogateDiagnostic =
+                    zget_DefaultDiagFormat(
+                        odr,
+                        YAZ_BIB1_RESULT_SET_EXISTS_AND_REPLACE_INDICATOR_OFF,
+                        0);
+                package.response() = apdu;
+                
+                return;
+            }
+        }
+        it->second.m_sets.erase(req->resultSetName);
         vhost = map_it->second.m_vhost;
-        id = new Session;
-        (*it).m_sets.push_back(Virt_db_set(*id, req->resultSetName, vhost));
+        route = map_it->second.m_route;
     }
+    // we might look for an existing session with same vhost
+    Session id;
     const char *vhost_cstr = vhost.c_str();
     if (true)
     {  // sending init to backend
-        Package init_package(*id, package.origin());
+        Package init_package(id, package.origin());
         init_package.copy_filter(package);
         
-        ODR odr = odr_createmem(ODR_ENCODE);
         Z_APDU *init_apdu = zget_APDU(odr, Z_APDU_initRequest);
         
         yaz_oi_set_string_oidval(&init_apdu->u.initRequest->otherInfo, odr,
                                  VAL_PROXY, 1, vhost_cstr);
         
         init_package.request() = init_apdu;
-        odr_destroy(odr);
 
-        init_package.move();  // send init 
+        init_package.move(route);  // sending init 
 
         if (init_package.session().is_closed())
         {
-            ODR odr = odr_createmem(ODR_ENCODE);
+            Z_APDU *apdu = zget_APDU(odr, Z_APDU_searchResponse);
+            
+            Z_Records *rec = (Z_Records *) odr_malloc(odr, sizeof(Z_Records));
+            apdu->u.searchResponse->records = rec;
+            rec->which = Z_Records_NSD;
+            rec->u.nonSurrogateDiagnostic =
+                zget_DefaultDiagFormat(
+                    odr, YAZ_BIB1_DATABASE_UNAVAILABLE, database.c_str());
+            package.response() = apdu;
+        }
+        Z_GDU *gdu = init_package.response().get();
+        // we hope to get an init response
+        if (gdu && gdu->which == Z_GDU_Z3950 && gdu->u.z3950->which ==
+            Z_APDU_initResponse)
+        {
+            if (ODR_MASK_GET(gdu->u.z3950->u.initResponse->options,
+                             Z_Options_namedResultSets))
+                support_named_result_sets = true;
+        }
+        else
+        {
             Z_APDU *apdu = zget_APDU(odr, Z_APDU_searchResponse);
             
             Z_Records *rec = (Z_Records *) odr_malloc(odr, sizeof(Z_Records));
@@ -208,39 +498,207 @@ void yf::Virt_db::Rep::search(Package &package, Z_APDU *apdu, bool &move_later)
                     odr, YAZ_BIB1_DATABASE_UNAVAILABLE, database.c_str());
             package.response() = apdu;
             
-            odr_destroy(odr);
             return;
         }
     }
     // sending search to backend
-    Package search_package(*id, package.origin());
+    Package search_package(id, package.origin());
+
     search_package.copy_filter(package);
     const char *sep = strchr(vhost_cstr, '/');
-    ODR odr = odr_createmem(ODR_ENCODE);
     if (sep)
         req->databaseNames[0] = odr_strdup(odr, sep+1);
-    
+
+    *req->replaceIndicator = 1;
+
+    std::string backend_resultSetId = "default";
+    req->resultSetName = odr_strdup(odr, backend_resultSetId.c_str());
     search_package.request() = yazpp_1::GDU(apdu);
     
-    odr_destroy(odr);
-    
-    search_package.move();
+    search_package.move(route);
 
+    if (search_package.session().is_closed())
+    {
+        Z_APDU *apdu = zget_APDU(odr, Z_APDU_searchResponse);
+        
+        Z_Records *rec = (Z_Records *) odr_malloc(odr, sizeof(Z_Records));
+        apdu->u.searchResponse->records = rec;
+        rec->which = Z_Records_NSD;
+        rec->u.nonSurrogateDiagnostic =
+            zget_DefaultDiagFormat(
+                odr, YAZ_BIB1_DATABASE_UNAVAILABLE, database.c_str());
+        package.response() = apdu;
+        
+        return;
+    }
     package.response() = search_package.response();
+    
+    boost::mutex::scoped_lock lock(m_sessions_mutex);
+    Ses_it it = m_sessions.find(package.session());
+    if (it != m_sessions.end())
+        it->second.m_sets[resultSetId] =
+            Virt_db_set(id, backend_resultSetId, vhost, route,
+                        support_named_result_sets);
 }
 
-void yf::Virt_db::Rep::init(Package &package, Z_APDU *apdu, bool &move_later)
+void yf::Frontend::search(Package &package, Z_APDU *apdu,
+                          const std::map<std::string, Virt_db_map> &maps)
 {
-    boost::mutex::scoped_lock lock(m_sessions_mutex);
-    std::list<Virt_db_session>::iterator it;
+    Z_SearchRequest *req = apdu->u.searchRequest;
+    std::string vhost;
+    std::string database;
+    std::string resultSetId = req->resultSetName;
+    bool support_named_result_sets = false;  // whether backend supports it
+    yp2::odr odr;
+    
+    if (req->num_databaseNames != 1)
+    {   // exactly one database must be specified
+        Z_APDU *apdu = zget_APDU(odr, Z_APDU_searchResponse);
+        
+        Z_Records *rec = (Z_Records *) odr_malloc(odr, sizeof(Z_Records));
+        apdu->u.searchResponse->records = rec;
+        rec->which = Z_Records_NSD;
+        rec->u.nonSurrogateDiagnostic =
+            zget_DefaultDiagFormat(
+                odr, YAZ_BIB1_TOO_MANY_DATABASES_SPECIFIED, 0);
+        package.response() = apdu;
+        
+        return;
+    }
+    database = req->databaseNames[0];
+    std::map<std::string, Virt_db_map>::const_iterator map_it;
+    map_it = maps.find(database);
+    if (map_it == maps.end()) 
+    {   // no map for database: return diagnostic
+        Z_APDU *apdu = zget_APDU(odr, Z_APDU_searchResponse);
+        
+        Z_Records *rec = (Z_Records *) odr_malloc(odr, sizeof(Z_Records));
+        apdu->u.searchResponse->records = rec;
+        rec->which = Z_Records_NSD;
+        rec->u.nonSurrogateDiagnostic =
+            zget_DefaultDiagFormat(
+                odr, YAZ_BIB1_DATABASE_DOES_NOT_EXIST, database.c_str());
+        package.response() = apdu;
+        
+        return;
+    }
+    if (*req->replaceIndicator == 0)
+    {
+        Sets_it sets_it = m_sets.find(req->resultSetName);
+        if (sets_it != m_sets.end())
+        {
+            Z_APDU *apdu = zget_APDU(odr, Z_APDU_searchResponse);
+            
+            Z_Records *rec = (Z_Records *) odr_malloc(odr, sizeof(Z_Records));
+            apdu->u.searchResponse->records = rec;
+            rec->which = Z_Records_NSD;
+            rec->u.nonSurrogateDiagnostic =
+                zget_DefaultDiagFormat(
+                    odr,
+                    YAZ_BIB1_RESULT_SET_EXISTS_AND_REPLACE_INDICATOR_OFF,
+                    0);
+            package.response() = apdu;
+            
+            return;
+        }
+    }
+    m_sets.erase(req->resultSetName);
+    vhost = map_it->second.m_vhost;
+    std::string route = map_it->second.m_route;
+    // we might look for an existing session with same vhost
+    Session id;
+    const char *vhost_cstr = vhost.c_str();
+    if (true)
+    {  // sending init to backend
+        Package init_package(id, package.origin());
+        init_package.copy_filter(package);
+        
+        Z_APDU *init_apdu = zget_APDU(odr, Z_APDU_initRequest);
+        
+        yaz_oi_set_string_oidval(&init_apdu->u.initRequest->otherInfo, odr,
+                                 VAL_PROXY, 1, vhost_cstr);
+        
+        init_package.request() = init_apdu;
+
+        init_package.move(route);  // sending init 
+
+        if (init_package.session().is_closed())
+        {
+            Z_APDU *apdu = zget_APDU(odr, Z_APDU_searchResponse);
+            
+            Z_Records *rec = (Z_Records *) odr_malloc(odr, sizeof(Z_Records));
+            apdu->u.searchResponse->records = rec;
+            rec->which = Z_Records_NSD;
+            rec->u.nonSurrogateDiagnostic =
+                zget_DefaultDiagFormat(
+                    odr, YAZ_BIB1_DATABASE_UNAVAILABLE, database.c_str());
+            package.response() = apdu;
+        }
+        Z_GDU *gdu = init_package.response().get();
+        // we hope to get an init response
+        if (gdu && gdu->which == Z_GDU_Z3950 && gdu->u.z3950->which ==
+            Z_APDU_initResponse)
+        {
+            if (ODR_MASK_GET(gdu->u.z3950->u.initResponse->options,
+                             Z_Options_namedResultSets))
+                support_named_result_sets = true;
+        }
+        else
+        {
+            Z_APDU *apdu = zget_APDU(odr, Z_APDU_searchResponse);
+            
+            Z_Records *rec = (Z_Records *) odr_malloc(odr, sizeof(Z_Records));
+            apdu->u.searchResponse->records = rec;
+            rec->which = Z_Records_NSD;
+            rec->u.nonSurrogateDiagnostic =
+                zget_DefaultDiagFormat(
+                    odr, YAZ_BIB1_DATABASE_UNAVAILABLE, database.c_str());
+            package.response() = apdu;
+            
+            return;
+        }
+    }
+    // sending search to backend
+    Package search_package(id, package.origin());
+
+    search_package.copy_filter(package);
+    const char *sep = strchr(vhost_cstr, '/');
+    if (sep)
+        req->databaseNames[0] = odr_strdup(odr, sep+1);
+
+    *req->replaceIndicator = 1;
+
+    std::string backend_resultSetId = "default";
+    req->resultSetName = odr_strdup(odr, backend_resultSetId.c_str());
+    search_package.request() = yazpp_1::GDU(apdu);
+    
+    search_package.move(route);
 
-    for (it = m_sessions.begin(); it != m_sessions.end(); it++)
+    if (search_package.session().is_closed())
     {
-        if (package.session() == (*it).m_session)
-            break;
+        Z_APDU *apdu = zget_APDU(odr, Z_APDU_searchResponse);
+        
+        Z_Records *rec = (Z_Records *) odr_malloc(odr, sizeof(Z_Records));
+        apdu->u.searchResponse->records = rec;
+        rec->which = Z_Records_NSD;
+        rec->u.nonSurrogateDiagnostic =
+            zget_DefaultDiagFormat(
+                odr, YAZ_BIB1_DATABASE_UNAVAILABLE, database.c_str());
+        package.response() = apdu;
+        
+        return;
     }
-    if (it != m_sessions.end())
-        m_sessions.erase(it);
+    package.response() = search_package.response();
+    
+    m_sets[resultSetId] =
+        Virt_db_set(id, backend_resultSetId, vhost, route,
+                    support_named_result_sets);
+}
+
+void yf::Virt_db::Rep::init(Package &package, Z_APDU *apdu, bool &move_later)
+{
+    release_session(package);
+    boost::mutex::scoped_lock lock(m_sessions_mutex);
 
     Z_InitRequest *req = apdu->u.initRequest;
     
@@ -248,42 +706,130 @@ void yf::Virt_db::Rep::init(Package &package, Z_APDU *apdu, bool &move_later)
         yaz_oi_get_string_oidval(&req->otherInfo, VAL_PROXY, 1, 0);
     if (!vhost)
     {
-        ODR odr = odr_createmem(ODR_ENCODE);
-        
+        yp2::odr odr;
         Z_APDU *apdu = zget_APDU(odr, Z_APDU_initResponse);
         Z_InitResponse *resp = apdu->u.initResponse;
         
         int i;
         static const int masks[] = {
-            Z_Options_search, Z_Options_present, 0 
+            Z_Options_search, Z_Options_present, Z_Options_namedResultSets, -1 
         };
-        for (i = 0; masks[i]; i++)
+        for (i = 0; masks[i] != -1; i++)
             if (ODR_MASK_GET(req->options, masks[i]))
                 ODR_MASK_SET(resp->options, masks[i]);
         
+        static const int versions[] = {
+            Z_ProtocolVersion_1,
+            Z_ProtocolVersion_2,
+            Z_ProtocolVersion_3,
+            -1
+        };
+        for (i = 0; versions[i] != -1; i++)
+            if (ODR_MASK_GET(req->protocolVersion, versions[i]))
+                ODR_MASK_SET(resp->protocolVersion, versions[i]);
+            else
+                break;
+
         package.response() = apdu;
         
-        odr_destroy(odr);
-
-        m_sessions.push_back(Virt_db_session(package.session(), false));
+        m_sessions[package.session()] = Virt_db_session(package.session(), false);
     }
     else
     {
-        m_sessions.push_back(Virt_db_session(package.session(), true));
-        move_later = true;
+        m_sessions[package.session()] = Virt_db_session(package.session(), true);
+        package.move();
     }
 }
 
-void yf::Virt_db::add_map_db2vhost(std::string db, std::string vhost)
+void yf::Virt_db::add_map_db2vhost(std::string db, std::string vhost,
+                                   std::string route)
 {
-    m_p->m_maps[db] = Virt_db_map(vhost);
+    m_p->m_maps[db] = Virt_db_map(vhost, route);
 }
 
+#if 0
 void yf::Virt_db::process(Package &package) const
 {
-    Z_GDU *gdu = package.request().get();
+    yf::Frontend *f = m_p->get_frontend(package);
+    if (f)
+    {
+        Z_GDU *gdu = package.request().get();
+        if (!gdu || gdu->which != Z_GDU_Z3950 || f->m_use_vhost)
+            package.move();
+        else
+        {
+            Z_APDU *apdu = gdu->u.z3950;
+            if (apdu->which == Z_APDU_initRequest)
+            {
+                Z_InitRequest *req = apdu->u.initRequest;
+                
+                const char *vhost =
+                    yaz_oi_get_string_oidval(&req->otherInfo, VAL_PROXY, 1, 0);
+                if (!vhost)
+                {
+                    yp2::odr odr;
+                    Z_APDU *apdu = zget_APDU(odr, Z_APDU_initResponse);
+                    Z_InitResponse *resp = apdu->u.initResponse;
+                    
+                    int i;
+                    static const int masks[] = {
+                        Z_Options_search, Z_Options_present, Z_Options_namedResultSets, -1 
+                    };
+                    for (i = 0; masks[i] != -1; i++)
+                        if (ODR_MASK_GET(req->options, masks[i]))
+                            ODR_MASK_SET(resp->options, masks[i]);
+                    
+                    static const int versions[] = {
+                        Z_ProtocolVersion_1,
+                        Z_ProtocolVersion_2,
+                        Z_ProtocolVersion_3,
+                        -1
+                    };
+                    for (i = 0; versions[i] != -1; i++)
+                        if (ODR_MASK_GET(req->protocolVersion, versions[i]))
+                            ODR_MASK_SET(resp->protocolVersion, versions[i]);
+                        else
+                            break;
+                    
+                    package.response() = apdu;
+                }
+                else
+                {
+                    f->m_use_vhost = true;
+                    package.move();
+                }
+            }
+            else if (apdu->which == Z_APDU_searchRequest)
+            {
+                f->search(package, apdu, m_p->m_maps);
+            }
+            else if (apdu->which == Z_APDU_presentRequest)
+            {
+                f->present(package, apdu);
+            }
+            else
+            {
+                yp2::odr odr;
+                
+                package.response() = odr.create_close(
+                    Z_Close_protocolError,
+                    "unsupported APDU in filter_virt_db");
+                
+                package.session().close();
+            }
+        }
+    }
+    m_p->release_frontend(package);
+}
 
-    if (!gdu || gdu->which != Z_GDU_Z3950)
+#else
+void yf::Virt_db::process(Package &package) const
+{
+    Z_GDU *gdu = package.request().get();
+    
+    if (package.session().is_closed())
+        m_p->release_session(package);
+    else if (!gdu || gdu->which != Z_GDU_Z3950)
         package.move();
     else
     {
@@ -297,22 +843,85 @@ void yf::Virt_db::process(Package &package) const
         {
             m_p->search(package, apdu, move_later);
         }
+        else if (apdu->which == Z_APDU_presentRequest)
+        {
+            m_p->present(package, apdu, move_later);
+        }
+        else if (apdu->which == Z_APDU_close)
+        {
+            package.session().close();
+            m_p->release_session(package);
+        }
         else
         {
-            ODR odr = odr_createmem(ODR_ENCODE);
+            yp2::odr odr;
             
-            Z_APDU *apdu = zget_APDU(odr, Z_APDU_close);
-            
-            *apdu->u.close->closeReason = Z_Close_protocolError;
-            
-            package.response() = apdu;
+            package.response() = odr.create_close(
+                Z_Close_protocolError,
+                "unsupported APDU in filter_virt_db");
+                                                 
             package.session().close();
-            odr_destroy(odr);
+            m_p->release_session(package);
         }
         if (move_later)
             package.move();
     }
-    m_p->release_session(package);
+}
+#endif
+
+void yp2::filter::Virt_db::configure(const xmlNode * ptr)
+{
+    for (ptr = ptr->children; ptr; ptr = ptr->next)
+    {
+        if (ptr->type != XML_ELEMENT_NODE)
+            continue;
+        if (!strcmp((const char *) ptr->name, "virtual"))
+        {
+            std::string database;
+            std::string target;
+            xmlNode *v_node = ptr->children;
+            for (; v_node; v_node = v_node->next)
+            {
+                if (v_node->type != XML_ELEMENT_NODE)
+                    continue;
+                
+                if (yp2::xml::is_element_yp2(v_node, "database"))
+                    database = yp2::xml::get_text(v_node);
+                else if (yp2::xml::is_element_yp2(v_node, "target"))
+                    target = yp2::xml::get_text(v_node);
+                else
+                    throw yp2::filter::FilterException
+                        ("Bad element " 
+                         + std::string((const char *) v_node->name)
+                         + " in virtual section"
+                            );
+            }
+            std::string route = yp2::xml::get_route(ptr);
+            add_map_db2vhost(database, target, route);
+            std::cout << "Add " << database << "->" << target
+                      << "," << route << "\n";
+        }
+        else
+        {
+            throw yp2::filter::FilterException
+                ("Bad element " 
+                 + std::string((const char *) ptr->name)
+                 + " in virt_db filter");
+        }
+    }
+}
+
+static yp2::filter::Base* filter_creator()
+{
+    return new yp2::filter::Virt_db;
+}
+
+extern "C" {
+    struct yp2_filter_struct yp2_filter_virt_db = {
+        0,
+        "virt_db",
+        filter_creator
+    };
 }