src/filter_sparql.cpp

   1 /* This file is part of Metaproxy.
   2    Copyright (C) Index Data
   3
   4 Metaproxy is free software; you can redistribute it and/or modify it under
   5 the terms of the GNU General Public License as published by the Free
   6 Software Foundation; either version 2, or (at your option) any later
   7 version.
   8
   9 Metaproxy is distributed in the hope that it will be useful, but WITHOUT ANY
  10 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12 for more details.
  13
  14 You should have received a copy of the GNU General Public License
  15 along with this program; if not, write to the Free Software
  16 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17 */
  18
  19 #include <metaproxy/package.hpp>
  20 #include <metaproxy/util.hpp>
  21 #include <yaz/log.h>
  22 #include <yaz/srw.h>
  23 #include <yaz/diagbib1.h>
  24 #include <yaz/match_glob.h>
  25 #include <boost/scoped_ptr.hpp>
  26 #include <boost/thread/mutex.hpp>
  27 #include <boost/thread/condition.hpp>
  28 #include "sparql.h"
  29
  30 #include <yaz/zgdu.h>
  31
  32 namespace mp = metaproxy_1;
  33 namespace yf = mp::filter;
  34
  35 namespace metaproxy_1 {
  36     namespace filter {
  37         class SPARQL : public Base {
  38             class Session;
  39             class Rep;
  40             class Conf;
  41             class FrontendSet;
  42
  43             typedef boost::shared_ptr<Session> SessionPtr;
  44             typedef boost::shared_ptr<Conf> ConfPtr;
  45
  46             typedef boost::shared_ptr<FrontendSet> FrontendSetPtr;
  47             typedef std::map<std::string,FrontendSetPtr> FrontendSets;
  48         public:
  49             SPARQL();
  50             ~SPARQL();
  51             void process(metaproxy_1::Package & package) const;
  52             void configure(const xmlNode * ptr, bool test_only,
  53                            const char *path);
  54             SessionPtr get_session(Package &package, Z_APDU **apdu) const;
  55             void release_session(Package &package) const;
  56             boost::scoped_ptr<Rep> m_p;
  57             std::list<ConfPtr> db_conf;
  58         };
  59         class SPARQL::Conf {
  60         public:
  61             std::string db;
  62             std::string uri;
  63             std::string schema;
  64             yaz_sparql_t s;
  65             ~Conf();
  66         };
  67         class SPARQL::Rep {
  68             friend class SPARQL;
  69             boost::condition m_cond_session_ready;
  70             boost::mutex m_mutex;
  71             std::map<mp::Session,SessionPtr> m_clients;
  72         };
  73         class SPARQL::FrontendSet {
  74         public:
  75             FrontendSet();
  76             ~FrontendSet();
  77         private:
  78             friend class Session;
  79             Odr_int hits;
  80             std::string db;
  81             ConfPtr conf;
  82             xmlDoc *doc;
  83         };
  84         class SPARQL::Session {
  85         public:
  86             Session(const SPARQL *);
  87             ~Session();
  88             void handle_z(Package &package, Z_APDU *apdu);
  89             Z_APDU *run_sparql(mp::Package &package,
  90                                Z_APDU *apdu_req,
  91                                mp::odr &odr,
  92                                const char *sparql_query,
  93                                ConfPtr conf);
  94             Z_Records *fetch(
  95                 FrontendSetPtr fset,
  96                 ODR odr, Odr_oid *preferredRecordSyntax,
  97                 Z_ElementSetNames *esn,
  98                 int start, int number, int &error_code, std::string &addinfo,
  99                 int *number_returned, int *next_position);
 100             bool m_in_use;
 101         private:
 102             bool m_support_named_result_sets;
 103             FrontendSets m_frontend_sets;
 104             const SPARQL *m_sparql;
 105         };
 106     }
 107 }
 108
 109 yf::SPARQL::FrontendSet::~FrontendSet()
 110 {
 111     if (doc)
 112         xmlFreeDoc(doc);
 113 }
 114
 115 yf::SPARQL::FrontendSet::FrontendSet()
 116 {
 117     doc = 0;
 118 }
 119
 120 yf::SPARQL::SPARQL() : m_p(new Rep)
 121 {
 122 }
 123
 124 yf::SPARQL::~SPARQL()
 125 {
 126 }
 127
 128 void yf::SPARQL::configure(const xmlNode *xmlnode, bool test_only,
 129                            const char *path)
 130 {
 131     const xmlNode *ptr = xmlnode->children;
 132
 133     for (; ptr; ptr = ptr->next)
 134     {
 135         if (ptr->type != XML_ELEMENT_NODE)
 136             continue;
 137         if (!strcmp((const char *) ptr->name, "db"))
 138         {
 139             yaz_sparql_t s = yaz_sparql_create();
 140             ConfPtr conf(new Conf);
 141             conf->s = s;
 142
 143             const struct _xmlAttr *attr;
 144             for (attr = ptr->properties; attr; attr = attr->next)
 145             {
 146                 if (!strcmp((const char *) attr->name, "path"))
 147                     conf->db = mp::xml::get_text(attr->children);
 148                 else if (!strcmp((const char *) attr->name, "uri"))
 149                     conf->uri = mp::xml::get_text(attr->children);
 150                 else if (!strcmp((const char *) attr->name, "schema"))
 151                     conf->schema = mp::xml::get_text(attr->children);
 152                 else
 153                     throw mp::filter::FilterException(
 154                         "Bad attribute " + std::string((const char *)
 155                                                        attr->name));
 156             }
 157             xmlNode *p = ptr->children;
 158             for (; p; p = p->next)
 159             {
 160                 if (p->type != XML_ELEMENT_NODE)
 161                     continue;
 162                 std::string name = (const char *) p->name;
 163                 const struct _xmlAttr *attr;
 164                 for (attr = p->properties; attr; attr = attr->next)
 165                 {
 166                     if (!strcmp((const char *) attr->name, "type"))
 167                     {
 168                         name.append(".");
 169                         name.append(mp::xml::get_text(attr->children));
 170                     }
 171                     else
 172                         throw mp::filter::FilterException(
 173                             "Bad attribute " + std::string((const char *)
 174                                                            attr->name));
 175                 }
 176                 std::string value = mp::xml::get_text(p);
 177                 if (yaz_sparql_add_pattern(s, name.c_str(), value.c_str()))
 178                 {
 179                     throw mp::filter::FilterException(
 180                         "Bad SPARQL config " + name);
 181                 }
 182             }
 183             if (!conf->uri.length())
 184             {
 185                 throw mp::filter::FilterException("Missing uri");
 186             }
 187             if (!conf->db.length())
 188             {
 189                 throw mp::filter::FilterException("Missing path");
 190             }
 191             db_conf.push_back(conf);
 192         }
 193         else
 194         {
 195             throw mp::filter::FilterException
 196                 ("Bad element "
 197                  + std::string((const char *) ptr->name)
 198                  + " in sparql filter");
 199         }
 200     }
 201 }
 202
 203 yf::SPARQL::Conf::~Conf()
 204 {
 205     yaz_sparql_destroy(s);
 206 }
 207
 208 yf::SPARQL::Session::Session(const SPARQL *sparql) :
 209     m_in_use(true),
 210     m_support_named_result_sets(false),
 211     m_sparql(sparql)
 212 {
 213 }
 214
 215 yf::SPARQL::Session::~Session()
 216 {
 217 }
 218
 219 yf::SPARQL::SessionPtr yf::SPARQL::get_session(Package & package,
 220                                                Z_APDU **apdu) const
 221 {
 222     SessionPtr ptr0;
 223
 224     Z_GDU *gdu = package.request().get();
 225
 226     boost::mutex::scoped_lock lock(m_p->m_mutex);
 227
 228     std::map<mp::Session,SPARQL::SessionPtr>::iterator it;
 229
 230     if (gdu && gdu->which == Z_GDU_Z3950)
 231         *apdu = gdu->u.z3950;
 232     else
 233         *apdu = 0;
 234
 235     while (true)
 236     {
 237         it = m_p->m_clients.find(package.session());
 238         if (it == m_p->m_clients.end())
 239             break;
 240         if (!it->second->m_in_use)
 241         {
 242             it->second->m_in_use = true;
 243             return it->second;
 244         }
 245         m_p->m_cond_session_ready.wait(lock);
 246     }
 247     if (!*apdu)
 248         return ptr0;
 249
 250     // new Z39.50 session ..
 251     SessionPtr p(new Session(this));
 252     m_p->m_clients[package.session()] = p;
 253     return p;
 254 }
 255
 256 void yf::SPARQL::release_session(Package &package) const
 257 {
 258     boost::mutex::scoped_lock lock(m_p->m_mutex);
 259     std::map<mp::Session,SessionPtr>::iterator it;
 260
 261     it = m_p->m_clients.find(package.session());
 262     if (it != m_p->m_clients.end())
 263     {
 264         it->second->m_in_use = false;
 265
 266         if (package.session().is_closed())
 267             m_p->m_clients.erase(it);
 268         m_p->m_cond_session_ready.notify_all();
 269     }
 270 }
 271
 272 static xmlNode *get_result(xmlDoc *doc, Odr_int *sz, Odr_int pos)
 273 {
 274     xmlNode *ptr = xmlDocGetRootElement(doc);
 275     Odr_int cur = 0;
 276
 277     if (ptr->type == XML_ELEMENT_NODE &&
 278         !strcmp((const char *) ptr->name, "RDF"))
 279     {
 280         ptr = ptr->children;
 281
 282         while (ptr && ptr->type != XML_ELEMENT_NODE)
 283             ptr = ptr->next;
 284         if (ptr && ptr->type == XML_ELEMENT_NODE &&
 285             !strcmp((const char *) ptr->name, "Description"))
 286         {
 287             xmlNode *p = ptr->children;
 288
 289             while (p && p->type != XML_ELEMENT_NODE)
 290                 p = p->next;
 291             if (p && p->type == XML_ELEMENT_NODE &&
 292                 !strcmp((const char *) p->name, "type"))
 293             { /* SELECT RESULT */
 294                 for (ptr = ptr->children; ptr; ptr = ptr->next)
 295                     if (ptr->type == XML_ELEMENT_NODE &&
 296                         !strcmp((const char *) ptr->name, "solution"))
 297                     {
 298                         if (cur++ == pos)
 299                             break;
 300                     }
 301             }
 302             else
 303             {   /* CONSTRUCT result */
 304                 for (; ptr; ptr = ptr->next)
 305                     if (ptr->type == XML_ELEMENT_NODE &&
 306                         !strcmp((const char *) ptr->name, "Description"))
 307                     {
 308                         if (cur++ == pos)
 309                             break;
 310                     }
 311             }
 312         }
 313     }
 314     else
 315     {
 316         for (; ptr; ptr = ptr->next)
 317             if (ptr->type == XML_ELEMENT_NODE &&
 318                 !strcmp((const char *) ptr->name, "sparql"))
 319                 break;
 320         if (ptr)
 321         {
 322             for (ptr = ptr->children; ptr; ptr = ptr->next)
 323                 if (ptr->type == XML_ELEMENT_NODE &&
 324                     !strcmp((const char *) ptr->name, "results"))
 325                     break;
 326         }
 327         if (ptr)
 328         {
 329             for (ptr = ptr->children; ptr; ptr = ptr->next)
 330                 if (ptr->type == XML_ELEMENT_NODE &&
 331                     !strcmp((const char *) ptr->name, "result"))
 332                 {
 333                     if (cur++ == pos)
 334                         break;
 335                 }
 336         }
 337     }
 338     if (sz)
 339         *sz = cur;
 340     return ptr;
 341 }
 342
 343 Z_Records *yf::SPARQL::Session::fetch(
 344     FrontendSetPtr fset,
 345     ODR odr, Odr_oid *preferredRecordSyntax,
 346     Z_ElementSetNames *esn,
 347     int start, int number, int &error_code, std::string &addinfo,
 348     int *number_returned, int *next_position)
 349 {
 350     Z_Records *rec = (Z_Records *) odr_malloc(odr, sizeof(Z_Records));
 351     if (esn && esn->which == Z_ElementSetNames_generic &&
 352         fset->conf->schema.length())
 353     {
 354         if (strcmp(esn->u.generic, fset->conf->schema.c_str()))
 355         {
 356             rec->which = Z_Records_NSD;
 357             rec->u.nonSurrogateDiagnostic =
 358                 zget_DefaultDiagFormat(
 359                     odr,
 360                     YAZ_BIB1_SPECIFIED_ELEMENT_SET_NAME_NOT_VALID_FOR_SPECIFIED_,
 361                     esn->u.generic);
 362             return rec;
 363         }
 364     }
 365     rec->which = Z_Records_DBOSD;
 366     rec->u.databaseOrSurDiagnostics = (Z_NamePlusRecordList *)
 367         odr_malloc(odr, sizeof(Z_NamePlusRecordList));
 368     rec->u.databaseOrSurDiagnostics->records = (Z_NamePlusRecord **)
 369         odr_malloc(odr, sizeof(Z_NamePlusRecord *) * number);
 370     int i;
 371     for (i = 0; i < number; i++)
 372     {
 373         rec->u.databaseOrSurDiagnostics->records[i] = (Z_NamePlusRecord *)
 374             odr_malloc(odr, sizeof(Z_NamePlusRecord));
 375         Z_NamePlusRecord *npr = rec->u.databaseOrSurDiagnostics->records[i];
 376         npr->databaseName = odr_strdup(odr, fset->db.c_str());
 377         npr->which = Z_NamePlusRecord_databaseRecord;
 378
 379         xmlNode *node = get_result(fset->doc, 0, start - 1 + i);
 380         if (!node)
 381             break;
 382         assert(node->type == XML_ELEMENT_NODE);
 383         xmlNode *tmp = xmlCopyNode(node, 1);
 384         xmlBufferPtr buf = xmlBufferCreate();
 385         xmlNodeDump(buf, tmp->doc, tmp, 0, 0);
 386         npr->u.databaseRecord =
 387             z_ext_record_xml(odr, (const char *) buf->content, buf->use);
 388         xmlFreeNode(tmp);
 389         xmlBufferFree(buf);
 390     }
 391     rec->u.databaseOrSurDiagnostics->num_records = i;
 392     *number_returned = i;
 393     if (start + number > fset->hits)
 394         *next_position = 0;
 395     else
 396         *next_position = start + number;
 397     return rec;
 398 }
 399
 400 Z_APDU *yf::SPARQL::Session::run_sparql(mp::Package &package,
 401                                         Z_APDU *apdu_req,
 402                                         mp::odr &odr,
 403                                         const char *sparql_query,
 404                                         ConfPtr conf)
 405 {
 406     Z_SearchRequest *req = apdu_req->u.searchRequest;
 407     Package http_package(package.session(), package.origin());
 408
 409     http_package.copy_filter(package);
 410     Z_GDU *gdu = z_get_HTTP_Request_uri(odr, conf->uri.c_str(), 0, 1);
 411
 412     z_HTTP_header_add(odr, &gdu->u.HTTP_Request->headers,
 413                       "Content-Type", "application/x-www-form-urlencoded");
 414     z_HTTP_header_add(odr, &gdu->u.HTTP_Request->headers,
 415                       "Accept", "application/sparql-results+xml,"
 416                       "application/rdf+xml");
 417     const char *names[2];
 418     names[0] = "query";
 419     names[1] = 0;
 420     const char *values[1];
 421     values[0] = sparql_query;
 422     char *path = 0;
 423     yaz_array_to_uri(&path, odr, (char **) names, (char **) values);
 424
 425     gdu->u.HTTP_Request->content_buf = path;
 426     gdu->u.HTTP_Request->content_len = strlen(path);
 427
 428     yaz_log(YLOG_LOG, "sparql: HTTP request\n%s", sparql_query);
 429
 430     http_package.request() = gdu;
 431     http_package.move();
 432
 433     Z_GDU *gdu_resp = http_package.response().get();
 434     Z_APDU *apdu_res = 0;
 435     if (!gdu_resp || gdu_resp->which != Z_GDU_HTTP_Response)
 436     {
 437         yaz_log(YLOG_LOG, "sparql: no HTTP response");
 438         apdu_res = odr.create_searchResponse(apdu_req,
 439                                              YAZ_BIB1_TEMPORARY_SYSTEM_ERROR,
 440                                              "no HTTP response from backend");
 441     }
 442     else if (gdu_resp->u.HTTP_Response->code != 200)
 443     {
 444         mp::wrbuf w;
 445
 446         wrbuf_printf(w, "sparql: HTTP error %d from backend",
 447                      gdu_resp->u.HTTP_Response->code);
 448         apdu_res = odr.create_searchResponse(apdu_req,
 449                                              YAZ_BIB1_TEMPORARY_SYSTEM_ERROR,
 450                                              w.c_str());
 451     }
 452     else
 453     {
 454         Z_HTTP_Response *resp = gdu_resp->u.HTTP_Response;
 455         FrontendSetPtr fset(new FrontendSet);
 456
 457         fset->doc = xmlParseMemory(resp->content_buf, resp->content_len);
 458         fset->db = req->databaseNames[0];
 459         fset->conf = conf;
 460         if (!fset->doc)
 461             apdu_res = odr.create_searchResponse(apdu_req,
 462                                              YAZ_BIB1_TEMPORARY_SYSTEM_ERROR,
 463                                              "invalid XML from backendbackend");
 464         else
 465         {
 466             Z_Records *records = 0;
 467             int number_returned = 0;
 468             int next_position = 0;
 469             int error_code = 0;
 470             std::string addinfo;
 471
 472             get_result(fset->doc, &fset->hits, -1);
 473             m_frontend_sets[req->resultSetName] = fset;
 474
 475             Odr_int number = 0;
 476             const char *element_set_name = 0;
 477             mp::util::piggyback_sr(req, fset->hits, number, &element_set_name);
 478             if (number)
 479             {
 480                 Z_ElementSetNames *esn;
 481
 482                 if (number > *req->smallSetUpperBound)
 483                     esn = req->mediumSetElementSetNames;
 484                 else
 485                     esn = req->smallSetElementSetNames;
 486                 records = fetch(fset,
 487                                 odr, req->preferredRecordSyntax, esn,
 488                                 1, number,
 489                                 error_code, addinfo,
 490                                 &number_returned,
 491                                 &next_position);
 492             }
 493             if (error_code)
 494             {
 495                 apdu_res =
 496                     odr.create_searchResponse(
 497                         apdu_req, error_code, addinfo.c_str());
 498             }
 499             else
 500             {
 501                 apdu_res =
 502                     odr.create_searchResponse(apdu_req, 0, 0);
 503                 Z_SearchResponse *resp = apdu_res->u.searchResponse;
 504                 *resp->resultCount = fset->hits;
 505                 *resp->numberOfRecordsReturned = number_returned;
 506                 *resp->nextResultSetPosition = next_position;
 507                 resp->records = records;
 508             }
 509         }
 510     }
 511     return apdu_res;
 512 }
 513
 514 void yf::SPARQL::Session::handle_z(mp::Package &package, Z_APDU *apdu_req)
 515 {
 516     mp::odr odr;
 517     Z_APDU *apdu_res = 0;
 518     if (apdu_req->which == Z_APDU_initRequest)
 519     {
 520         apdu_res = odr.create_initResponse(apdu_req, 0, 0);
 521         Z_InitRequest *req = apdu_req->u.initRequest;
 522         Z_InitResponse *resp = apdu_res->u.initResponse;
 523
 524         resp->implementationName = odr_strdup(odr, "sparql");
 525         if (ODR_MASK_GET(req->options, Z_Options_namedResultSets))
 526             m_support_named_result_sets = true;
 527         int i;
 528         static const int masks[] = {
 529             Z_Options_search, Z_Options_present,
 530             Z_Options_namedResultSets, -1
 531         };
 532         for (i = 0; masks[i] != -1; i++)
 533             if (ODR_MASK_GET(req->options, masks[i]))
 534                 ODR_MASK_SET(resp->options, masks[i]);
 535         static const int versions[] = {
 536             Z_ProtocolVersion_1,
 537             Z_ProtocolVersion_2,
 538             Z_ProtocolVersion_3,
 539             -1
 540         };
 541         for (i = 0; versions[i] != -1; i++)
 542             if (ODR_MASK_GET(req->protocolVersion, versions[i]))
 543                 ODR_MASK_SET(resp->protocolVersion, versions[i]);
 544             else
 545                 break;
 546         *resp->preferredMessageSize = *req->preferredMessageSize;
 547         *resp->maximumRecordSize = *req->maximumRecordSize;
 548     }
 549     else if (apdu_req->which == Z_APDU_close)
 550     {
 551         apdu_res = odr.create_close(apdu_req,
 552                                     Z_Close_finished, 0);
 553         package.session().close();
 554     }
 555     else if (apdu_req->which == Z_APDU_searchRequest)
 556     {
 557         Z_SearchRequest *req = apdu_req->u.searchRequest;
 558
 559         FrontendSets::iterator fset_it =
 560             m_frontend_sets.find(req->resultSetName);
 561         if (fset_it != m_frontend_sets.end())
 562         {
 563             // result set already exist
 564             // if replace indicator is off: we return diagnostic if
 565             // result set already exist.
 566             if (*req->replaceIndicator == 0)
 567             {
 568                 Z_APDU *apdu =
 569                     odr.create_searchResponse(
 570                         apdu_req,
 571                         YAZ_BIB1_RESULT_SET_EXISTS_AND_REPLACE_INDICATOR_OFF,
 572                         0);
 573                 package.response() = apdu_res;
 574             }
 575             m_frontend_sets.erase(fset_it);
 576         }
 577         if (req->query->which != Z_Query_type_1)
 578         {
 579             apdu_res = odr.create_searchResponse(
 580                 apdu_req, YAZ_BIB1_QUERY_TYPE_UNSUPP, 0);
 581         }
 582         else if (req->num_databaseNames != 1)
 583         {
 584             apdu_res = odr.create_searchResponse(
 585                 apdu_req,
 586                 YAZ_BIB1_ACCESS_TO_SPECIFIED_DATABASE_DENIED, 0);
 587         }
 588         else
 589         {
 590             std::string db = req->databaseNames[0];
 591             std::list<ConfPtr>::const_iterator it;
 592
 593             it = m_sparql->db_conf.begin();
 594             for (; it != m_sparql->db_conf.end(); it++)
 595                 if (yaz_match_glob((*it)->db.c_str(), db.c_str()))
 596                     break;
 597             if (it == m_sparql->db_conf.end())
 598             {
 599                 apdu_res = odr.create_searchResponse(
 600                     apdu_req, YAZ_BIB1_DATABASE_DOES_NOT_EXIST, db.c_str());
 601             }
 602             else
 603             {
 604                 WRBUF addinfo_wr = wrbuf_alloc();
 605                 WRBUF sparql_wr = wrbuf_alloc();
 606                 int error =
 607                     yaz_sparql_from_rpn_wrbuf((*it)->s,
 608                                               addinfo_wr, sparql_wr,
 609                                               req->query->u.type_1);
 610                 if (error)
 611                 {
 612                     apdu_res = odr.create_searchResponse(
 613                         apdu_req, error,
 614                         wrbuf_len(addinfo_wr) ?
 615                         wrbuf_cstr(addinfo_wr) : 0);
 616                 }
 617                 else
 618                 {
 619                     apdu_res = run_sparql(package, apdu_req, odr,
 620                                           wrbuf_cstr(sparql_wr), *it);
 621                 }
 622                 wrbuf_destroy(addinfo_wr);
 623                 wrbuf_destroy(sparql_wr);
 624             }
 625         }
 626     }
 627     else if (apdu_req->which == Z_APDU_presentRequest)
 628     {
 629         Z_PresentRequest *req = apdu_req->u.presentRequest;
 630         FrontendSets::iterator fset_it =
 631             m_frontend_sets.find(req->resultSetId);
 632         if (fset_it == m_frontend_sets.end())
 633         {
 634             apdu_res =
 635                 odr.create_presentResponse(
 636                     apdu_req, YAZ_BIB1_SPECIFIED_RESULT_SET_DOES_NOT_EXIST,
 637                     req->resultSetId);
 638             package.response() = apdu_res;
 639             return;
 640         }
 641         int number_returned = 0;
 642         int next_position = 0;
 643         int error_code = 0;
 644         std::string addinfo;
 645         Z_ElementSetNames *esn = 0;
 646         if (req->recordComposition)
 647         {
 648             if (req->recordComposition->which == Z_RecordComp_simple)
 649                 esn = req->recordComposition->u.simple;
 650             else
 651             {
 652                 apdu_res =
 653                     odr.create_presentResponse(
 654                         apdu_req,
 655                         YAZ_BIB1_ONLY_A_SINGLE_ELEMENT_SET_NAME_SUPPORTED,
 656                         0);
 657                 package.response() = apdu_res;
 658                 return;
 659             }
 660         }
 661         Z_Records *records = fetch(
 662             fset_it->second,
 663             odr, req->preferredRecordSyntax, esn,
 664             *req->resultSetStartPoint, *req->numberOfRecordsRequested,
 665             error_code, addinfo,
 666             &number_returned,
 667             &next_position);
 668         if (error_code)
 669         {
 670             apdu_res =
 671                 odr.create_presentResponse(apdu_req, error_code,
 672                                            addinfo.c_str());
 673         }
 674         else
 675         {
 676             apdu_res =
 677                 odr.create_presentResponse(apdu_req, 0, 0);
 678             Z_PresentResponse *resp = apdu_res->u.presentResponse;
 679             resp->records = records;
 680             *resp->numberOfRecordsReturned = number_returned;
 681             *resp->nextResultSetPosition = next_position;
 682         }
 683     }
 684     else
 685     {
 686         apdu_res = odr.create_close(apdu_req,
 687                                     Z_Close_protocolError,
 688                                     "sparql: unhandled APDU");
 689         package.session().close();
 690     }
 691
 692     assert(apdu_res);
 693     package.response() = apdu_res;
 694 }
 695
 696 void yf::SPARQL::process(mp::Package &package) const
 697 {
 698     Z_APDU *apdu;
 699     SessionPtr p = get_session(package, &apdu);
 700     if (p && apdu)
 701     {
 702         p->handle_z(package, apdu);
 703     }
 704     else
 705         package.move();
 706     release_session(package);
 707 }
 708
 709 static mp::filter::Base* filter_creator()
 710 {
 711     return new mp::filter::SPARQL;
 712 }
 713
 714 extern "C" {
 715     struct metaproxy_1_filter_struct metaproxy_1_filter_sparql = {
 716         0,
 717         "sparql",
 718         filter_creator
 719     };
 720 }
 721
 722
 723 /*
 724  * Local variables:
 725  * c-basic-offset: 4
 726  * c-file-style: "Stroustrup"
 727  * indent-tabs-mode: nil
 728  * End:
 729  * vim: shiftwidth=4 tabstop=8 expandtab
 730  */
 731