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 <boost/algorithm/string.hpp>
  29 #include "sparql.h"
  30
  31 #include <yaz/zgdu.h>
  32
  33 namespace mp = metaproxy_1;
  34 namespace yf = mp::filter;
  35
  36 namespace metaproxy_1 {
  37     namespace filter {
  38         class SPARQL : public Base {
  39             class Session;
  40             class Rep;
  41             class Conf;
  42             class Result;
  43             class FrontendSet;
  44
  45             typedef boost::shared_ptr<Session> SessionPtr;
  46             typedef boost::shared_ptr<Conf> ConfPtr;
  47
  48             typedef boost::shared_ptr<FrontendSet> FrontendSetPtr;
  49             typedef std::map<std::string,FrontendSetPtr> FrontendSets;
  50         public:
  51             SPARQL();
  52             ~SPARQL();
  53             void process(metaproxy_1::Package & package) const;
  54             void configure(const xmlNode * ptr, bool test_only,
  55                            const char *path);
  56             SessionPtr get_session(Package &package, Z_APDU **apdu) const;
  57             void release_session(Package &package) const;
  58             boost::scoped_ptr<Rep> m_p;
  59             std::list<ConfPtr> db_conf;
  60         };
  61         class SPARQL::Conf {
  62         public:
  63             std::string db;
  64             std::string uri;
  65             std::string schema;
  66             yaz_sparql_t s;
  67             ~Conf();
  68         };
  69         class SPARQL::Rep {
  70             friend class SPARQL;
  71             boost::condition m_cond_session_ready;
  72             boost::mutex m_mutex;
  73             std::map<mp::Session,SessionPtr> m_clients;
  74         };
  75         class SPARQL::Result {
  76         public:
  77             Result();
  78             ~Result();
  79         private:
  80             friend class FrontendSet;
  81             friend class Session;
  82             ConfPtr conf;
  83             xmlDoc *doc;
  84         };
  85         class SPARQL::FrontendSet {
  86         private:
  87             friend class Session;
  88             Odr_int hits;
  89             std::string db;
  90             std::list<Result> results;
  91         };
  92         class SPARQL::Session {
  93         public:
  94             Session(const SPARQL *);
  95             ~Session();
  96             void handle_z(Package &package, Z_APDU *apdu);
  97             Z_APDU *search(mp::Package &package,
  98                            Z_APDU *apdu_req,
  99                            mp::odr &odr,
 100                            const char *sparql_query,
 101                            ConfPtr conf, FrontendSetPtr fset);
 102             int invoke_sparql(mp::Package &package,
 103                               const char *sparql_query,
 104                               ConfPtr conf,
 105                               WRBUF w);
 106
 107             Z_Records *fetch(
 108                 Package &package,
 109                 FrontendSetPtr fset,
 110                 ODR odr, Odr_oid *preferredRecordSyntax,
 111                 Z_ElementSetNames *esn,
 112                 int start, int number, int &error_code, std::string &addinfo,
 113                 int *number_returned, int *next_position);
 114             bool m_in_use;
 115         private:
 116             bool m_support_named_result_sets;
 117             FrontendSets m_frontend_sets;
 118             const SPARQL *m_sparql;
 119         };
 120     }
 121 }
 122
 123 yf::SPARQL::Result::~Result()
 124 {
 125     if (doc)
 126         xmlFreeDoc(doc);
 127 }
 128
 129 yf::SPARQL::Result::Result()
 130 {
 131     doc = 0;
 132 }
 133
 134 yf::SPARQL::SPARQL() : m_p(new Rep)
 135 {
 136 }
 137
 138 yf::SPARQL::~SPARQL()
 139 {
 140 }
 141
 142 void yf::SPARQL::configure(const xmlNode *xmlnode, bool test_only,
 143                            const char *path)
 144 {
 145     const xmlNode *ptr = xmlnode->children;
 146     std::string uri;
 147
 148     for (; ptr; ptr = ptr->next)
 149     {
 150         if (ptr->type != XML_ELEMENT_NODE)
 151             continue;
 152         if (!strcmp((const char *) ptr->name, "defaults"))
 153         {
 154             const struct _xmlAttr *attr;
 155             for (attr = ptr->properties; attr; attr = attr->next)
 156             {
 157                 if (!strcmp((const char *) attr->name, "uri"))
 158                     uri = mp::xml::get_text(attr->children);
 159                 else
 160                     throw mp::filter::FilterException(
 161                         "Bad attribute " + std::string((const char *)
 162                                                        attr->name));
 163             }
 164         }
 165         else if (!strcmp((const char *) ptr->name, "db"))
 166         {
 167             yaz_sparql_t s = yaz_sparql_create();
 168             ConfPtr conf(new Conf);
 169             conf->s = s;
 170             conf->uri = uri;
 171
 172             const struct _xmlAttr *attr;
 173             for (attr = ptr->properties; attr; attr = attr->next)
 174             {
 175                 if (!strcmp((const char *) attr->name, "path"))
 176                     conf->db = mp::xml::get_text(attr->children);
 177                 else if (!strcmp((const char *) attr->name, "uri"))
 178                     conf->uri = mp::xml::get_text(attr->children);
 179                 else if (!strcmp((const char *) attr->name, "schema"))
 180                     conf->schema = mp::xml::get_text(attr->children);
 181                 else if (!strcmp((const char *) attr->name, "include"))
 182                 {
 183                     std::vector<std::string> dbs;
 184                     std::string db = mp::xml::get_text(attr->children);
 185                     boost::split(dbs, db, boost::is_any_of(" \t"));
 186                     size_t i;
 187                     for (i = 0; i < dbs.size(); i++)
 188                     {
 189                         if (dbs[i].length() == 0)
 190                             continue;
 191                         std::list<ConfPtr>::const_iterator it = db_conf.begin();
 192                         while (1)
 193                             if (it == db_conf.end())
 194                             {
 195                                 throw mp::filter::FilterException(
 196                                     "include db not found: " + dbs[i]);
 197                             }
 198                             else if (dbs[i].compare((*it)->db) == 0)
 199                             {
 200                                 yaz_sparql_include(s, (*it)->s);
 201                                 break;
 202                             }
 203                             else
 204                                 it++;
 205                     }
 206                 }
 207                 else
 208                     throw mp::filter::FilterException(
 209                         "Bad attribute " + std::string((const char *)
 210                                                        attr->name));
 211             }
 212             xmlNode *p = ptr->children;
 213             for (; p; p = p->next)
 214             {
 215                 if (p->type != XML_ELEMENT_NODE)
 216                     continue;
 217                 std::string name = (const char *) p->name;
 218                 const struct _xmlAttr *attr;
 219                 for (attr = p->properties; attr; attr = attr->next)
 220                 {
 221                     if (!strcmp((const char *) attr->name, "type"))
 222                     {
 223                         name.append(".");
 224                         name.append(mp::xml::get_text(attr->children));
 225                     }
 226                     else
 227                         throw mp::filter::FilterException(
 228                             "Bad attribute " + std::string((const char *)
 229                                                            attr->name));
 230                 }
 231                 std::string value = mp::xml::get_text(p);
 232                 if (yaz_sparql_add_pattern(s, name.c_str(), value.c_str()))
 233                 {
 234                     throw mp::filter::FilterException(
 235                         "Bad SPARQL config " + name);
 236                 }
 237             }
 238             if (!conf->uri.length())
 239             {
 240                 throw mp::filter::FilterException("Missing uri");
 241             }
 242             if (!conf->db.length())
 243             {
 244                 throw mp::filter::FilterException("Missing path");
 245             }
 246             db_conf.push_back(conf);
 247         }
 248         else
 249         {
 250             throw mp::filter::FilterException
 251                 ("Bad element "
 252                  + std::string((const char *) ptr->name)
 253                  + " in sparql filter");
 254         }
 255     }
 256 }
 257
 258 yf::SPARQL::Conf::~Conf()
 259 {
 260     yaz_sparql_destroy(s);
 261 }
 262
 263 yf::SPARQL::Session::Session(const SPARQL *sparql) :
 264     m_in_use(true),
 265     m_support_named_result_sets(false),
 266     m_sparql(sparql)
 267 {
 268 }
 269
 270 yf::SPARQL::Session::~Session()
 271 {
 272 }
 273
 274 yf::SPARQL::SessionPtr yf::SPARQL::get_session(Package & package,
 275                                                Z_APDU **apdu) const
 276 {
 277     SessionPtr ptr0;
 278
 279     Z_GDU *gdu = package.request().get();
 280
 281     boost::mutex::scoped_lock lock(m_p->m_mutex);
 282
 283     std::map<mp::Session,SPARQL::SessionPtr>::iterator it;
 284
 285     if (gdu && gdu->which == Z_GDU_Z3950)
 286         *apdu = gdu->u.z3950;
 287     else
 288         *apdu = 0;
 289
 290     while (true)
 291     {
 292         it = m_p->m_clients.find(package.session());
 293         if (it == m_p->m_clients.end())
 294             break;
 295         if (!it->second->m_in_use)
 296         {
 297             it->second->m_in_use = true;
 298             return it->second;
 299         }
 300         m_p->m_cond_session_ready.wait(lock);
 301     }
 302     if (!*apdu)
 303         return ptr0;
 304
 305     // new Z39.50 session ..
 306     SessionPtr p(new Session(this));
 307     m_p->m_clients[package.session()] = p;
 308     return p;
 309 }
 310
 311 void yf::SPARQL::release_session(Package &package) const
 312 {
 313     boost::mutex::scoped_lock lock(m_p->m_mutex);
 314     std::map<mp::Session,SessionPtr>::iterator it;
 315
 316     it = m_p->m_clients.find(package.session());
 317     if (it != m_p->m_clients.end())
 318     {
 319         it->second->m_in_use = false;
 320
 321         if (package.session().is_closed())
 322             m_p->m_clients.erase(it);
 323         m_p->m_cond_session_ready.notify_all();
 324     }
 325 }
 326
 327 static bool get_result(xmlDoc *doc, Odr_int *sz, Odr_int pos, xmlDoc **ndoc)
 328 {
 329     xmlNode *ptr = xmlDocGetRootElement(doc);
 330     xmlNode *q0;
 331     Odr_int cur = 0;
 332
 333     if (ndoc)
 334         *ndoc = xmlNewDoc(BAD_CAST "1.0");
 335
 336     if (ptr->type == XML_ELEMENT_NODE &&
 337         !strcmp((const char *) ptr->name, "RDF"))
 338     {
 339         if (ndoc)
 340         {
 341             q0 = xmlCopyNode(ptr, 2);
 342             xmlDocSetRootElement(*ndoc, q0);
 343         }
 344         ptr = ptr->children;
 345
 346         while (ptr && ptr->type != XML_ELEMENT_NODE)
 347             ptr = ptr->next;
 348         if (ptr && ptr->type == XML_ELEMENT_NODE &&
 349             !strcmp((const char *) ptr->name, "Description"))
 350         {
 351             xmlNode *p = ptr->children;
 352
 353             while (p && p->type != XML_ELEMENT_NODE)
 354                 p = p->next;
 355             if (p && p->type == XML_ELEMENT_NODE &&
 356                 !strcmp((const char *) p->name, "type"))
 357             { /* SELECT RESULT */
 358                 for (ptr = ptr->children; ptr; ptr = ptr->next)
 359                     if (ptr->type == XML_ELEMENT_NODE &&
 360                         !strcmp((const char *) ptr->name, "solution"))
 361                     {
 362                         if (cur++ == pos)
 363                         {
 364                             if (ndoc)
 365                             {
 366                                 xmlNode *q1 = xmlCopyNode(ptr, 1);
 367                                 xmlAddChild(q0, q1);
 368                             }
 369                             break;
 370                         }
 371                     }
 372             }
 373             else
 374             {   /* CONSTRUCT result */
 375                 for (; ptr; ptr = ptr->next)
 376                     if (ptr->type == XML_ELEMENT_NODE &&
 377                         !strcmp((const char *) ptr->name, "Description"))
 378                     {
 379                         if (cur++ == pos)
 380                         {
 381                             if (ndoc)
 382                             {
 383                                 xmlNode *q1 = xmlCopyNode(ptr, 1);
 384                                 xmlAddChild(q0, q1);
 385                             }
 386                             return true;
 387                         }
 388                     }
 389             }
 390         }
 391     }
 392     else
 393     {
 394         for (; ptr; ptr = ptr->next)
 395             if (ptr->type == XML_ELEMENT_NODE &&
 396                 !strcmp((const char *) ptr->name, "sparql"))
 397                 break;
 398         if (ptr)
 399         {
 400             if (ndoc)
 401             {
 402                 q0 = xmlCopyNode(ptr, 2);
 403                 xmlDocSetRootElement(*ndoc, q0);
 404             }
 405             for (ptr = ptr->children; ptr; ptr = ptr->next)
 406                 if (ptr->type == XML_ELEMENT_NODE &&
 407                     !strcmp((const char *) ptr->name, "results"))
 408                     break;
 409         }
 410         if (ptr)
 411         {
 412             xmlNode *q1 = 0;
 413             if (ndoc)
 414             {
 415                 q1 = xmlCopyNode(ptr, 0);
 416                 xmlAddChild(q0, q1);
 417             }
 418             for (ptr = ptr->children; ptr; ptr = ptr->next)
 419                 if (ptr->type == XML_ELEMENT_NODE &&
 420                     !strcmp((const char *) ptr->name, "result"))
 421                 {
 422                     if (cur++ == pos)
 423                     {
 424                         if (ndoc)
 425                         {
 426                             xmlNode *q2 = xmlCopyNode(ptr, 1);
 427                             xmlAddChild(q1, q2);
 428                         }
 429                         return true;
 430                     }
 431                 }
 432         }
 433     }
 434     if (sz)
 435         *sz = cur;
 436     return false;
 437 }
 438
 439 Z_Records *yf::SPARQL::Session::fetch(
 440     Package &package,
 441     FrontendSetPtr fset,
 442     ODR odr, Odr_oid *preferredRecordSyntax,
 443     Z_ElementSetNames *esn,
 444     int start, int number, int &error_code, std::string &addinfo,
 445     int *number_returned, int *next_position)
 446 {
 447     Z_Records *rec = (Z_Records *) odr_malloc(odr, sizeof(Z_Records));
 448     std::list<Result>::iterator it = fset->results.begin();
 449     const char *schema = 0;
 450     bool uri_lookup = false;
 451     bool fetch_logged = false;
 452     if (esn && esn->which == Z_ElementSetNames_generic)
 453         schema = esn->u.generic;
 454
 455     for (; it != fset->results.end(); it++)
 456     {
 457         if (yaz_sparql_lookup_schema(it->conf->s, schema))
 458         {
 459             uri_lookup = true;
 460             break;
 461         }
 462         if (!schema || !strcmp(esn->u.generic, it->conf->schema.c_str()))
 463             break;
 464     }
 465     if (it == fset->results.end())
 466     {
 467         rec->which = Z_Records_NSD;
 468         rec->u.nonSurrogateDiagnostic =
 469             zget_DefaultDiagFormat(
 470                 odr,
 471                 YAZ_BIB1_SPECIFIED_ELEMENT_SET_NAME_NOT_VALID_FOR_SPECIFIED_,
 472                 schema);
 473         return rec;
 474     }
 475     rec->which = Z_Records_DBOSD;
 476     rec->u.databaseOrSurDiagnostics = (Z_NamePlusRecordList *)
 477         odr_malloc(odr, sizeof(Z_NamePlusRecordList));
 478     rec->u.databaseOrSurDiagnostics->records = (Z_NamePlusRecord **)
 479         odr_malloc(odr, sizeof(Z_NamePlusRecord *) * number);
 480     int i;
 481     for (i = 0; i < number; i++)
 482     {
 483         rec->u.databaseOrSurDiagnostics->records[i] = (Z_NamePlusRecord *)
 484             odr_malloc(odr, sizeof(Z_NamePlusRecord));
 485         Z_NamePlusRecord *npr = rec->u.databaseOrSurDiagnostics->records[i];
 486         npr->databaseName = odr_strdup(odr, fset->db.c_str());
 487         npr->which = Z_NamePlusRecord_databaseRecord;
 488         xmlDoc *ndoc = 0;
 489
 490         if (!get_result(it->doc, 0, start - 1 + i, &ndoc))
 491         {
 492             if (ndoc)
 493                 xmlFreeDoc(ndoc);
 494             break;
 495         }
 496         xmlNode *ndoc_root = xmlDocGetRootElement(ndoc);
 497         if (!ndoc_root)
 498         {
 499             xmlFreeDoc(ndoc);
 500             break;
 501         }
 502         if (uri_lookup)
 503         {
 504             std::string uri;
 505             xmlNode *n = ndoc_root;
 506             while (n)
 507             {
 508                 if (n->type == XML_ELEMENT_NODE)
 509                 {
 510                     //if (!strcmp((const char *) n->name, "uri"))
 511                     if (!strcmp((const char *) n->name, "uri") ||
 512                         !strcmp((const char *) n->name, "bnode") )
 513                     {
 514                         uri = mp::xml::get_text(n->children);
 515
 516                     }
 517                     n = n->children;
 518                 }
 519                 else
 520                     n = n->next;
 521             }
 522             if (!uri.length())
 523             {
 524                 rec->which = Z_Records_NSD;
 525                 rec->u.nonSurrogateDiagnostic =
 526                     zget_DefaultDiagFormat(
 527                         odr,
 528                         YAZ_BIB1_SYSTEM_ERROR_IN_PRESENTING_RECORDS, 0);
 529                 xmlFreeDoc(ndoc);
 530                 return rec;
 531             }
 532             else
 533             {
 534                 mp::wrbuf addinfo, query, w;
 535                 int error = yaz_sparql_from_uri_wrbuf(it->conf->s,
 536                                                       addinfo, query,
 537                                                       uri.c_str(), schema);
 538                 if (!error)
 539                 {
 540                     if (!fetch_logged)
 541                     { // Log the fetch query only once
 542                         package.log("sparql", YLOG_LOG,
 543                             "fetch query: for %s \n%s",
 544                             uri.c_str(), query.c_str() );
 545                         fetch_logged = true;
 546                     }
 547                     else
 548                     {
 549                         package.log("sparql", YLOG_LOG,
 550                             "fetch uri:%s", uri.c_str() );
 551                     }
 552                     //yaz_log(YLOG_LOG, "query=%s", query.c_str());
 553                     error = invoke_sparql(package, query.c_str(),
 554                                           it->conf, w);
 555                 }
 556                 if (error)
 557                 {
 558                     rec->which = Z_Records_NSD;
 559                     rec->u.nonSurrogateDiagnostic =
 560                         zget_DefaultDiagFormat(
 561                             odr,
 562                             error,
 563                             addinfo.len() ? addinfo.c_str() : 0);
 564                     xmlFreeDoc(ndoc);
 565                     return rec;
 566                 }
 567                 npr->u.databaseRecord =
 568                     z_ext_record_xml(odr, w.c_str(), w.len());
 569             }
 570         }
 571         else
 572         {
 573             xmlBufferPtr buf = xmlBufferCreate();
 574             xmlNodeDump(buf, ndoc, ndoc_root, 0, 0);
 575             yaz_log(YLOG_LOG, "record %s %.*s", uri_lookup ? "uri" : "normal",
 576                     (int) buf->use, (const char *) buf->content);
 577             npr->u.databaseRecord =
 578                 z_ext_record_xml(odr, (const char *) buf->content, buf->use);
 579             xmlBufferFree(buf);
 580         }
 581         xmlFreeDoc(ndoc);
 582     }
 583     rec->u.databaseOrSurDiagnostics->num_records = i;
 584     *number_returned = i;
 585     if (start + number > fset->hits)
 586         *next_position = 0;
 587     else
 588         *next_position = start + number;
 589     return rec;
 590 }
 591
 592 int yf::SPARQL::Session::invoke_sparql(mp::Package &package,
 593                                        const char *sparql_query,
 594                                        ConfPtr conf,
 595                                        WRBUF w)
 596 {
 597     Package http_package(package.session(), package.origin());
 598     mp::odr odr;
 599
 600     http_package.copy_filter(package);
 601     Z_GDU *gdu = z_get_HTTP_Request_uri(odr, conf->uri.c_str(), 0, 1);
 602
 603     z_HTTP_header_add(odr, &gdu->u.HTTP_Request->headers,
 604                       "Content-Type", "application/x-www-form-urlencoded");
 605     z_HTTP_header_add(odr, &gdu->u.HTTP_Request->headers,
 606                       "Accept", "application/sparql-results+xml,"
 607                       "application/rdf+xml");
 608     const char *names[2];
 609     names[0] = "query";
 610     names[1] = 0;
 611     const char *values[1];
 612     values[0] = sparql_query;
 613     char *path = 0;
 614     yaz_array_to_uri(&path, odr, (char **) names, (char **) values);
 615
 616     gdu->u.HTTP_Request->content_buf = path;
 617     gdu->u.HTTP_Request->content_len = strlen(path);
 618
 619     yaz_log(YLOG_LOG, "sparql: HTTP request\n%s", sparql_query);
 620
 621     http_package.request() = gdu;
 622     http_package.move();
 623
 624     Z_GDU *gdu_resp = http_package.response().get();
 625
 626     if (!gdu_resp || gdu_resp->which != Z_GDU_HTTP_Response)
 627     {
 628         wrbuf_puts(w, "no HTTP response from backend");
 629         return YAZ_BIB1_TEMPORARY_SYSTEM_ERROR;
 630     }
 631     else if (gdu_resp->u.HTTP_Response->code != 200)
 632     {
 633         wrbuf_printf(w, "sparql: HTTP error %d from backend",
 634                      gdu_resp->u.HTTP_Response->code);
 635         return YAZ_BIB1_TEMPORARY_SYSTEM_ERROR;
 636     }
 637     Z_HTTP_Response *resp = gdu_resp->u.HTTP_Response;
 638     wrbuf_write(w, resp->content_buf, resp->content_len);
 639     return 0;
 640 }
 641
 642 Z_APDU *yf::SPARQL::Session::search(mp::Package &package,
 643                                     Z_APDU *apdu_req,
 644                                     mp::odr &odr,
 645                                     const char *sparql_query,
 646                                     ConfPtr conf, FrontendSetPtr fset)
 647 {
 648     Z_SearchRequest *req = apdu_req->u.searchRequest;
 649     Z_APDU *apdu_res = 0;
 650     mp::wrbuf w;
 651
 652     package.log("sparql", YLOG_LOG,
 653         "search query:\n%s", sparql_query );
 654
 655     int error = invoke_sparql(package, sparql_query, conf, w);
 656     if (error)
 657     {
 658         apdu_res = odr.create_searchResponse(apdu_req, error,
 659                                              w.len() ?
 660                                              w.c_str() : 0);
 661     }
 662     else
 663     {
 664         xmlDocPtr doc = xmlParseMemory(w.c_str(), w.len());
 665         if (!doc)
 666         {
 667             apdu_res = odr.create_searchResponse(
 668                 apdu_req,
 669                 YAZ_BIB1_TEMPORARY_SYSTEM_ERROR,
 670                 "invalid XML from backendbackend");
 671         }
 672         else
 673         {
 674             Result result;
 675             Z_Records *records = 0;
 676             int number_returned = 0;
 677             int next_position = 0;
 678             int error_code = 0;
 679             std::string addinfo;
 680
 681             result.doc = doc;
 682             result.conf = conf;
 683             fset->results.push_back(result);
 684             yaz_log(YLOG_LOG, "saving sparql result xmldoc=%p", doc);
 685
 686             get_result(result.doc, &fset->hits, -1, 0);
 687             m_frontend_sets[req->resultSetName] = fset;
 688
 689             result.doc = 0;
 690
 691             Odr_int number = 0;
 692             const char *element_set_name = 0;
 693             mp::util::piggyback_sr(req, fset->hits, number, &element_set_name);
 694             if (number)
 695             {
 696                 Z_ElementSetNames *esn;
 697
 698                 if (number > *req->smallSetUpperBound)
 699                     esn = req->mediumSetElementSetNames;
 700                 else
 701                     esn = req->smallSetElementSetNames;
 702                 records = fetch(package, fset,
 703                                 odr, req->preferredRecordSyntax, esn,
 704                                 1, number,
 705                                 error_code, addinfo,
 706                                 &number_returned,
 707                                 &next_position);
 708             }
 709             if (error_code)
 710             {
 711                 apdu_res =
 712                     odr.create_searchResponse(
 713                         apdu_req, error_code, addinfo.c_str());
 714             }
 715             else
 716             {
 717                 apdu_res =
 718                     odr.create_searchResponse(apdu_req, 0, 0);
 719                 Z_SearchResponse *resp = apdu_res->u.searchResponse;
 720                 *resp->resultCount = fset->hits;
 721                 *resp->numberOfRecordsReturned = number_returned;
 722                 *resp->nextResultSetPosition = next_position;
 723                 resp->records = records;
 724             }
 725         }
 726     }
 727     return apdu_res;
 728 }
 729
 730 void yf::SPARQL::Session::handle_z(mp::Package &package, Z_APDU *apdu_req)
 731 {
 732     mp::odr odr;
 733     Z_APDU *apdu_res = 0;
 734     if (apdu_req->which == Z_APDU_initRequest)
 735     {
 736         apdu_res = odr.create_initResponse(apdu_req, 0, 0);
 737         Z_InitRequest *req = apdu_req->u.initRequest;
 738         Z_InitResponse *resp = apdu_res->u.initResponse;
 739
 740         resp->implementationName = odr_strdup(odr, "sparql");
 741         if (ODR_MASK_GET(req->options, Z_Options_namedResultSets))
 742             m_support_named_result_sets = true;
 743         int i;
 744         static const int masks[] = {
 745             Z_Options_search, Z_Options_present,
 746             Z_Options_namedResultSets, -1
 747         };
 748         for (i = 0; masks[i] != -1; i++)
 749             if (ODR_MASK_GET(req->options, masks[i]))
 750                 ODR_MASK_SET(resp->options, masks[i]);
 751         static const int versions[] = {
 752             Z_ProtocolVersion_1,
 753             Z_ProtocolVersion_2,
 754             Z_ProtocolVersion_3,
 755             -1
 756         };
 757         for (i = 0; versions[i] != -1; i++)
 758             if (ODR_MASK_GET(req->protocolVersion, versions[i]))
 759                 ODR_MASK_SET(resp->protocolVersion, versions[i]);
 760             else
 761                 break;
 762         *resp->preferredMessageSize = *req->preferredMessageSize;
 763         *resp->maximumRecordSize = *req->maximumRecordSize;
 764     }
 765     else if (apdu_req->which == Z_APDU_close)
 766     {
 767         apdu_res = odr.create_close(apdu_req,
 768                                     Z_Close_finished, 0);
 769         package.session().close();
 770     }
 771     else if (apdu_req->which == Z_APDU_searchRequest)
 772     {
 773         Z_SearchRequest *req = apdu_req->u.searchRequest;
 774
 775         FrontendSets::iterator fset_it =
 776             m_frontend_sets.find(req->resultSetName);
 777         if (fset_it != m_frontend_sets.end())
 778         {
 779             // result set already exist
 780             // if replace indicator is off: we return diagnostic if
 781             // result set already exist.
 782             if (*req->replaceIndicator == 0)
 783             {
 784                 Z_APDU *apdu =
 785                     odr.create_searchResponse(
 786                         apdu_req,
 787                         YAZ_BIB1_RESULT_SET_EXISTS_AND_REPLACE_INDICATOR_OFF,
 788                         0);
 789                 package.response() = apdu;
 790             }
 791             m_frontend_sets.erase(fset_it);
 792         }
 793         if (req->query->which != Z_Query_type_1)
 794         {
 795             apdu_res = odr.create_searchResponse(
 796                 apdu_req, YAZ_BIB1_QUERY_TYPE_UNSUPP, 0);
 797         }
 798         else if (req->num_databaseNames != 1)
 799         {
 800             apdu_res = odr.create_searchResponse(
 801                 apdu_req,
 802                 YAZ_BIB1_ACCESS_TO_SPECIFIED_DATABASE_DENIED, 0);
 803         }
 804         else
 805         {
 806             std::string db = req->databaseNames[0];
 807             std::list<ConfPtr>::const_iterator it;
 808             FrontendSetPtr fset(new FrontendSet);
 809
 810             m_frontend_sets.erase(req->resultSetName);
 811             fset->db = db;
 812             it = m_sparql->db_conf.begin();
 813             for (; it != m_sparql->db_conf.end(); it++)
 814                 if ((*it)->schema.length() > 0
 815                     && yaz_match_glob((*it)->db.c_str(), db.c_str()))
 816                 {
 817                     mp::wrbuf addinfo_wr;
 818                     mp::wrbuf sparql_wr;
 819                     int error =
 820                         yaz_sparql_from_rpn_wrbuf((*it)->s,
 821                                                   addinfo_wr, sparql_wr,
 822                                                   req->query->u.type_1);
 823                     if (error)
 824                     {
 825                         apdu_res = odr.create_searchResponse(
 826                             apdu_req, error,
 827                             addinfo_wr.len() ? addinfo_wr.c_str() : 0);
 828                     }
 829                     else
 830                     {
 831                         Z_APDU *apdu_1 = search(package, apdu_req, odr,
 832                                                 sparql_wr.c_str(), *it,
 833                                                 fset);
 834                         if (!apdu_res)
 835                             apdu_res = apdu_1;
 836                     }
 837                 }
 838             if (apdu_res == 0)
 839             {
 840                 apdu_res = odr.create_searchResponse(
 841                     apdu_req, YAZ_BIB1_DATABASE_DOES_NOT_EXIST, db.c_str());
 842             }
 843         }
 844     }
 845     else if (apdu_req->which == Z_APDU_presentRequest)
 846     {
 847         Z_PresentRequest *req = apdu_req->u.presentRequest;
 848         FrontendSets::iterator fset_it =
 849             m_frontend_sets.find(req->resultSetId);
 850         if (fset_it == m_frontend_sets.end())
 851         {
 852             apdu_res =
 853                 odr.create_presentResponse(
 854                     apdu_req, YAZ_BIB1_SPECIFIED_RESULT_SET_DOES_NOT_EXIST,
 855                     req->resultSetId);
 856             package.response() = apdu_res;
 857             return;
 858         }
 859         int number_returned = 0;
 860         int next_position = 0;
 861         int error_code = 0;
 862         std::string addinfo;
 863         Z_ElementSetNames *esn = 0;
 864         if (req->recordComposition)
 865         {
 866             if (req->recordComposition->which == Z_RecordComp_simple)
 867                 esn = req->recordComposition->u.simple;
 868             else
 869             {
 870                 apdu_res =
 871                     odr.create_presentResponse(
 872                         apdu_req,
 873                         YAZ_BIB1_ONLY_A_SINGLE_ELEMENT_SET_NAME_SUPPORTED,
 874                         0);
 875                 package.response() = apdu_res;
 876                 return;
 877             }
 878         }
 879         Z_Records *records = fetch(
 880             package,
 881             fset_it->second,
 882             odr, req->preferredRecordSyntax, esn,
 883             *req->resultSetStartPoint, *req->numberOfRecordsRequested,
 884             error_code, addinfo,
 885             &number_returned,
 886             &next_position);
 887         if (error_code)
 888         {
 889             apdu_res =
 890                 odr.create_presentResponse(apdu_req, error_code,
 891                                            addinfo.c_str());
 892         }
 893         else
 894         {
 895             apdu_res =
 896                 odr.create_presentResponse(apdu_req, 0, 0);
 897             Z_PresentResponse *resp = apdu_res->u.presentResponse;
 898             resp->records = records;
 899             *resp->numberOfRecordsReturned = number_returned;
 900             *resp->nextResultSetPosition = next_position;
 901         }
 902     }
 903     else
 904     {
 905         apdu_res = odr.create_close(apdu_req,
 906                                     Z_Close_protocolError,
 907                                     "sparql: unhandled APDU");
 908         package.session().close();
 909     }
 910
 911     assert(apdu_res);
 912     package.response() = apdu_res;
 913 }
 914
 915 void yf::SPARQL::process(mp::Package &package) const
 916 {
 917     Z_APDU *apdu;
 918     SessionPtr p = get_session(package, &apdu);
 919     if (p && apdu)
 920     {
 921         p->handle_z(package, apdu);
 922     }
 923     else
 924         package.move();
 925     release_session(package);
 926 }
 927
 928 static mp::filter::Base* filter_creator()
 929 {
 930     return new mp::filter::SPARQL;
 931 }
 932
 933 extern "C" {
 934     struct metaproxy_1_filter_struct metaproxy_1_filter_sparql = {
 935         0,
 936         "sparql",
 937         filter_creator
 938     };
 939 }
 940
 941
 942 /*
 943  * Local variables:
 944  * c-basic-offset: 4
 945  * c-file-style: "Stroustrup"
 946  * indent-tabs-mode: nil
 947  * End:
 948  * vim: shiftwidth=4 tabstop=8 expandtab
 949  */
 950