src/filter_virt_db.cpp

   1 /* $Id: filter_virt_db.cpp,v 1.24 2006-01-14 08:38:57 adam Exp $
   2    Copyright (c) 2005, Index Data.
   3
   4 %LICENSE%
   5  */
   6
   7 #include "config.hpp"
   8
   9 #include "filter.hpp"
  10 #include "package.hpp"
  11
  12 #include <boost/thread/mutex.hpp>
  13 #include <boost/thread/condition.hpp>
  14 #include <boost/shared_ptr.hpp>
  15
  16 #include "util.hpp"
  17 #include "filter_virt_db.hpp"
  18
  19 #include <yaz/zgdu.h>
  20 #include <yaz/otherinfo.h>
  21 #include <yaz/diagbib1.h>
  22
  23 #include <map>
  24 #include <iostream>
  25
  26 namespace yf = yp2::filter;
  27
  28 namespace yp2 {
  29     namespace filter {
  30
  31         struct Virt_db::Set {
  32             Set(BackendPtr b, std::string setname);
  33             Set();
  34             ~Set();
  35
  36             BackendPtr m_backend;
  37             std::string m_setname;
  38         };
  39         struct Virt_db::Map {
  40             Map(std::string vhost, std::string route);
  41             Map();
  42             std::string m_vhost;
  43             std::string m_route;
  44         };
  45         struct Virt_db::Backend {
  46             yp2::Session m_backend_session;
  47             std::string m_backend_database;
  48             std::string m_frontend_database;
  49             std::string m_vhost;
  50             std::string m_route;
  51             bool m_named_result_sets;
  52             int m_number_of_sets;
  53         };
  54         struct Virt_db::Frontend {
  55             Frontend(Rep *rep);
  56             ~Frontend();
  57             yp2::Session m_session;
  58             bool m_is_virtual;
  59             bool m_in_use;
  60             std::list<BackendPtr> m_backend_list;
  61             std::map<std::string,Virt_db::Set> m_sets;
  62
  63             void search(Package &package, Z_APDU *apdu);
  64             void present(Package &package, Z_APDU *apdu);
  65             void scan(Package &package, Z_APDU *apdu);
  66
  67             void close(Package &package);
  68             typedef std::map<std::string,Virt_db::Set>::iterator Sets_it;
  69
  70             BackendPtr lookup_backend_from_database(std::string database);
  71             BackendPtr create_backend_from_database(std::string database);
  72
  73             BackendPtr init_backend(std::string database, Package &package,
  74                                     int &error_code, std::string &addinfo);
  75             Rep *m_p;
  76         };
  77         class Virt_db::Rep {
  78             friend class Virt_db;
  79             friend class Frontend;
  80
  81             FrontendPtr get_frontend(Package &package);
  82             void release_frontend(Package &package);
  83         private:
  84             boost::mutex m_sessions_mutex;
  85             std::map<std::string, Virt_db::Map>m_maps;
  86
  87             typedef std::map<std::string,Virt_db::Set>::iterator Sets_it;
  88
  89             boost::mutex m_mutex;
  90             boost::condition m_cond_session_ready;
  91             std::map<yp2::Session, FrontendPtr> m_clients;
  92         };
  93     }
  94 }
  95
  96 using namespace yp2;
  97
  98 yf::Virt_db::BackendPtr yf::Virt_db::Frontend::lookup_backend_from_database(
  99     std::string database)
 100 {
 101     std::list<BackendPtr>::const_iterator map_it;
 102     map_it = m_backend_list.begin();
 103     for (; map_it != m_backend_list.end(); map_it++)
 104         if ((*map_it)->m_frontend_database == database)
 105             return *map_it;
 106     BackendPtr null;
 107     return null;
 108 }
 109
 110 yf::Virt_db::BackendPtr yf::Virt_db::Frontend::create_backend_from_database(
 111     std::string database)
 112 {
 113     std::map<std::string, Virt_db::Map>::iterator map_it;
 114     map_it = m_p->m_maps.find(database);
 115     if (map_it == m_p->m_maps.end())
 116     {
 117         BackendPtr ptr;
 118         return ptr;
 119     }
 120     BackendPtr b(new Backend);
 121
 122     b->m_number_of_sets = 0;
 123     b->m_frontend_database = database;
 124     b->m_named_result_sets = false;
 125     b->m_route = map_it->second.m_route;
 126     b->m_vhost = map_it->second.m_vhost;
 127     const char *sep = strchr(b->m_vhost.c_str(), '/');
 128     std::string backend_database;
 129     if (sep)
 130         b->m_backend_database = std::string(sep+1);
 131     else
 132         b->m_backend_database = database;
 133
 134     return b;
 135 }
 136
 137 yf::Virt_db::BackendPtr yf::Virt_db::Frontend::init_backend(
 138     std::string database, Package &package,
 139     int &error_code, std::string &addinfo)
 140 {
 141     BackendPtr b = create_backend_from_database(database);
 142     if (!b)
 143     {
 144         error_code = YAZ_BIB1_DATABASE_UNAVAILABLE;
 145         addinfo = database;
 146         return b;
 147     }
 148     Package init_package(b->m_backend_session, package.origin());
 149     init_package.copy_filter(package);
 150
 151     yp2::odr odr;
 152
 153     Z_APDU *init_apdu = zget_APDU(odr, Z_APDU_initRequest);
 154
 155     yaz_oi_set_string_oidval(&init_apdu->u.initRequest->otherInfo, odr,
 156                              VAL_PROXY, 1, b->m_vhost.c_str());
 157
 158     Z_InitRequest *req = init_apdu->u.initRequest;
 159
 160     ODR_MASK_SET(req->options, Z_Options_search);
 161     ODR_MASK_SET(req->options, Z_Options_present);
 162     ODR_MASK_SET(req->options, Z_Options_namedResultSets);
 163     ODR_MASK_SET(req->options, Z_Options_scan);
 164
 165     ODR_MASK_SET(req->protocolVersion, Z_ProtocolVersion_1);
 166     ODR_MASK_SET(req->protocolVersion, Z_ProtocolVersion_2);
 167     ODR_MASK_SET(req->protocolVersion, Z_ProtocolVersion_3);
 168
 169     init_package.request() = init_apdu;
 170
 171     init_package.move(b->m_route);  // sending init
 172
 173     if (init_package.session().is_closed())
 174     {
 175         error_code = YAZ_BIB1_DATABASE_UNAVAILABLE;
 176         addinfo = database;
 177         BackendPtr null;
 178         return null;
 179     }
 180     Z_GDU *gdu = init_package.response().get();
 181     // we hope to get an init response
 182     if (gdu && gdu->which == Z_GDU_Z3950 && gdu->u.z3950->which ==
 183         Z_APDU_initResponse)
 184     {
 185         if (ODR_MASK_GET(gdu->u.z3950->u.initResponse->options,
 186                          Z_Options_namedResultSets))
 187         {
 188             b->m_named_result_sets = true;
 189         }
 190     }
 191     else
 192     {
 193         error_code = YAZ_BIB1_DATABASE_UNAVAILABLE;
 194         addinfo = database;
 195         BackendPtr null;
 196         return null;
 197     }
 198     m_backend_list.push_back(b);
 199     return b;
 200 }
 201
 202 void yf::Virt_db::Frontend::search(Package &package, Z_APDU *apdu_req)
 203 {
 204     Z_SearchRequest *req = apdu_req->u.searchRequest;
 205     std::string vhost;
 206     std::string resultSetId = req->resultSetName;
 207     yp2::odr odr;
 208
 209     // only one datatabase for now
 210     if (req->num_databaseNames != 1)
 211     {   // exactly one database must be specified
 212         Z_APDU *apdu =
 213             odr.create_searchResponse(
 214                 apdu_req, YAZ_BIB1_TOO_MANY_DATABASES_SPECIFIED, 0);
 215         package.response() = apdu;
 216
 217         return;
 218     }
 219     std::string database = std::string(req->databaseNames[0]);
 220
 221     BackendPtr b; // null for now
 222     Sets_it sets_it = m_sets.find(req->resultSetName);
 223     if (sets_it != m_sets.end())
 224     {
 225         // result set already exist
 226         // if replace indicator is off: we return diagnostic if
 227         // result set already exist.
 228         if (*req->replaceIndicator == 0)
 229         {
 230             Z_APDU *apdu =
 231                 odr.create_searchResponse(
 232                     apdu_req,
 233                     YAZ_BIB1_RESULT_SET_EXISTS_AND_REPLACE_INDICATOR_OFF,
 234                     0);
 235             package.response() = apdu;
 236
 237             return;
 238         }
 239         sets_it->second.m_backend->m_number_of_sets--;
 240
 241         // pick up any existing backend with a database match
 242         std::list<BackendPtr>::const_iterator map_it;
 243         map_it = m_backend_list.begin();
 244         for (; map_it != m_backend_list.end(); map_it++)
 245         {
 246             BackendPtr tmp = *map_it;
 247             if (tmp->m_frontend_database == database)
 248                 break;
 249         }
 250         if (map_it != m_backend_list.end())
 251             b = *map_it;
 252     }
 253     else
 254     {
 255         // new result set.
 256
 257         // pick up any existing database with named result sets ..
 258         // or one which has no result sets.. yet.
 259         std::list<BackendPtr>::const_iterator map_it;
 260         map_it = m_backend_list.begin();
 261         for (; map_it != m_backend_list.end(); map_it++)
 262         {
 263             BackendPtr tmp = *map_it;
 264             if (tmp->m_frontend_database == database &&
 265                 (tmp->m_named_result_sets ||
 266                  tmp->m_number_of_sets == 0))
 267                 break;
 268         }
 269         if (map_it != m_backend_list.end())
 270             b = *map_it;
 271     }
 272     if (!b)  // no backend yet. Must create a new one
 273     {
 274         int error_code;
 275         std::string addinfo;
 276         b = init_backend(database, package, error_code, addinfo);
 277         if (!b)
 278         {
 279             // did not get a backend (unavailable somehow?)
 280
 281             Z_APDU *apdu =
 282                 odr.create_searchResponse(
 283                     apdu_req, error_code, addinfo.c_str());
 284             package.response() = apdu;
 285             return;
 286         }
 287     }
 288     m_sets.erase(req->resultSetName);
 289     // sending search to backend
 290     Package search_package(b->m_backend_session, package.origin());
 291
 292     search_package.copy_filter(package);
 293
 294     std::string backend_setname;
 295     if (b->m_named_result_sets)
 296     {
 297         backend_setname = std::string(req->resultSetName);
 298     }
 299     else
 300     {
 301         backend_setname = "default";
 302         req->resultSetName = odr_strdup(odr, backend_setname.c_str());
 303     }
 304
 305     const char *backend_database = b->m_backend_database.c_str();
 306     req->databaseNames[0] = odr_strdup(odr, backend_database);
 307
 308     *req->replaceIndicator = 1;
 309
 310     search_package.request() = yazpp_1::GDU(apdu_req);
 311
 312     search_package.move(b->m_route);
 313
 314     if (search_package.session().is_closed())
 315     {
 316         Z_APDU *apdu =
 317             odr.create_searchResponse(
 318                 apdu_req,
 319                 YAZ_BIB1_DATABASE_UNAVAILABLE, database.c_str());
 320         package.response() = apdu;
 321         return;
 322     }
 323     package.response() = search_package.response();
 324
 325     b->m_number_of_sets++;
 326
 327     m_sets[resultSetId] = Virt_db::Set(b, backend_setname);
 328 }
 329
 330 yf::Virt_db::Frontend::Frontend(Rep *rep)
 331 {
 332     m_p = rep;
 333     m_is_virtual = false;
 334 }
 335
 336 void yf::Virt_db::Frontend::close(Package &package)
 337 {
 338     std::list<BackendPtr>::const_iterator b_it;
 339
 340     for (b_it = m_backend_list.begin(); b_it != m_backend_list.end(); b_it++)
 341     {
 342         (*b_it)->m_backend_session.close();
 343         Package close_package((*b_it)->m_backend_session, package.origin());
 344         close_package.copy_filter(package);
 345         close_package.move((*b_it)->m_route);
 346     }
 347     m_backend_list.clear();
 348 }
 349
 350 yf::Virt_db::Frontend::~Frontend()
 351 {
 352 }
 353
 354 yf::Virt_db::FrontendPtr yf::Virt_db::Rep::get_frontend(Package &package)
 355 {
 356     boost::mutex::scoped_lock lock(m_mutex);
 357
 358     std::map<yp2::Session,yf::Virt_db::FrontendPtr>::iterator it;
 359
 360     while(true)
 361     {
 362         it = m_clients.find(package.session());
 363         if (it == m_clients.end())
 364             break;
 365
 366         if (!it->second->m_in_use)
 367         {
 368             it->second->m_in_use = true;
 369             return it->second;
 370         }
 371         m_cond_session_ready.wait(lock);
 372     }
 373     FrontendPtr f(new Frontend(this));
 374     m_clients[package.session()] = f;
 375     f->m_in_use = true;
 376     return f;
 377 }
 378
 379 void yf::Virt_db::Rep::release_frontend(Package &package)
 380 {
 381     boost::mutex::scoped_lock lock(m_mutex);
 382     std::map<yp2::Session,yf::Virt_db::FrontendPtr>::iterator it;
 383
 384     it = m_clients.find(package.session());
 385     if (it != m_clients.end())
 386     {
 387         if (package.session().is_closed())
 388         {
 389             it->second->close(package);
 390             m_clients.erase(it);
 391         }
 392         else
 393         {
 394             it->second->m_in_use = false;
 395         }
 396         m_cond_session_ready.notify_all();
 397     }
 398 }
 399
 400 yf::Virt_db::Set::Set(BackendPtr b, std::string setname)
 401     :  m_backend(b), m_setname(setname)
 402 {
 403 }
 404
 405
 406 yf::Virt_db::Set::Set()
 407 {
 408 }
 409
 410
 411 yf::Virt_db::Set::~Set()
 412 {
 413 }
 414
 415 yf::Virt_db::Map::Map(std::string vhost, std::string route)
 416     : m_vhost(vhost), m_route(route)
 417 {
 418 }
 419
 420 yf::Virt_db::Map::Map()
 421 {
 422 }
 423
 424 yf::Virt_db::Virt_db() : m_p(new Virt_db::Rep)
 425 {
 426 }
 427
 428 yf::Virt_db::~Virt_db() {
 429 }
 430
 431 void yf::Virt_db::Frontend::present(Package &package, Z_APDU *apdu_req)
 432 {
 433     Z_PresentRequest *req = apdu_req->u.presentRequest;
 434     std::string resultSetId = req->resultSetId;
 435     yp2::odr odr;
 436
 437     Sets_it sets_it = m_sets.find(resultSetId);
 438     if (sets_it == m_sets.end())
 439     {
 440         Z_APDU *apdu =
 441             odr.create_presentResponse(
 442                 apdu_req,
 443                 YAZ_BIB1_SPECIFIED_RESULT_SET_DOES_NOT_EXIST,
 444                 resultSetId.c_str());
 445         package.response() = apdu;
 446
 447         return;
 448     }
 449     Session *id =
 450         new yp2::Session(sets_it->second.m_backend->m_backend_session);
 451
 452     // sending present to backend
 453     Package present_package(*id, package.origin());
 454     present_package.copy_filter(package);
 455
 456     req->resultSetId = odr_strdup(odr, "default");
 457     present_package.request() = yazpp_1::GDU(apdu_req);
 458
 459     present_package.move();
 460
 461     if (present_package.session().is_closed())
 462     {
 463         Z_APDU *apdu =
 464             odr.create_presentResponse(
 465                 apdu_req,
 466                 YAZ_BIB1_RESULT_SET_NO_LONGER_EXISTS_UNILATERALLY_DELETED_BY_,
 467                 resultSetId.c_str());
 468         package.response() = apdu;
 469         m_sets.erase(resultSetId);
 470     }
 471     else
 472     {
 473         package.response() = present_package.response();
 474     }
 475     delete id;
 476 }
 477
 478 void yf::Virt_db::Frontend::scan(Package &package, Z_APDU *apdu_req)
 479 {
 480     Z_ScanRequest *req = apdu_req->u.scanRequest;
 481     std::string vhost;
 482     yp2::odr odr;
 483
 484     // only one datatabase for now
 485     if (req->num_databaseNames != 1)
 486     {   // exactly one database must be specified
 487         Z_APDU *apdu =
 488             odr.create_scanResponse(
 489                 apdu_req,
 490                 YAZ_BIB1_TOO_MANY_DATABASES_SPECIFIED, 0);
 491         package.response() = apdu;
 492         return;
 493     }
 494     std::string database = std::string(req->databaseNames[0]);
 495
 496     BackendPtr b;
 497     // pick up any existing backend with a database match
 498     std::list<BackendPtr>::const_iterator map_it;
 499     map_it = m_backend_list.begin();
 500     for (; map_it != m_backend_list.end(); map_it++)
 501     {
 502         BackendPtr tmp = *map_it;
 503         if (tmp->m_frontend_database == database)
 504             break;
 505     }
 506     if (map_it != m_backend_list.end())
 507         b = *map_it;
 508     if (!b)  // no backend yet. Must create a new one
 509     {
 510         int error_code;
 511         std::string addinfo;
 512         b = init_backend(database, package, error_code, addinfo);
 513         if (!b)
 514         {
 515             // did not get a backend (unavailable somehow?)
 516             Z_APDU *apdu =
 517                 odr.create_scanResponse(
 518                     apdu_req, error_code, addinfo.c_str());
 519             package.response() = apdu;
 520
 521             return;
 522         }
 523     }
 524     // sending scan to backend
 525     Package scan_package(b->m_backend_session, package.origin());
 526
 527     scan_package.copy_filter(package);
 528
 529     const char *backend_database = b->m_backend_database.c_str();
 530     req->databaseNames[0] = odr_strdup(odr, backend_database);
 531
 532     scan_package.request() = yazpp_1::GDU(apdu_req);
 533
 534     scan_package.move(b->m_route);
 535
 536     if (scan_package.session().is_closed())
 537     {
 538         Z_APDU *apdu =
 539             odr.create_scanResponse(
 540                 apdu_req, YAZ_BIB1_DATABASE_UNAVAILABLE, database.c_str());
 541         package.response() = apdu;
 542         return;
 543     }
 544     package.response() = scan_package.response();
 545 }
 546
 547
 548 void yf::Virt_db::add_map_db2vhost(std::string db, std::string vhost,
 549                                    std::string route)
 550 {
 551     m_p->m_maps[db] = Virt_db::Map(vhost, route);
 552 }
 553
 554 void yf::Virt_db::process(Package &package) const
 555 {
 556     FrontendPtr f = m_p->get_frontend(package);
 557
 558     Z_GDU *gdu = package.request().get();
 559
 560     if (gdu && gdu->which == Z_GDU_Z3950 && gdu->u.z3950->which ==
 561         Z_APDU_initRequest && !f->m_is_virtual)
 562     {
 563         Z_InitRequest *req = gdu->u.z3950->u.initRequest;
 564
 565         const char *vhost =
 566             yaz_oi_get_string_oidval(&req->otherInfo, VAL_PROXY, 1, 0);
 567         if (!vhost)
 568         {
 569             yp2::odr odr;
 570             Z_APDU *apdu = odr.create_initResponse(gdu->u.z3950, 0, 0);
 571             Z_InitResponse *resp = apdu->u.initResponse;
 572
 573             int i;
 574             static const int masks[] = {
 575                 Z_Options_search,
 576                 Z_Options_present,
 577                 Z_Options_namedResultSets,
 578                 Z_Options_scan,
 579                 -1
 580             };
 581             for (i = 0; masks[i] != -1; i++)
 582                 if (ODR_MASK_GET(req->options, masks[i]))
 583                     ODR_MASK_SET(resp->options, masks[i]);
 584
 585             static const int versions[] = {
 586                 Z_ProtocolVersion_1,
 587                 Z_ProtocolVersion_2,
 588                 Z_ProtocolVersion_3,
 589                 -1
 590             };
 591             for (i = 0; versions[i] != -1; i++)
 592                 if (ODR_MASK_GET(req->protocolVersion, versions[i]))
 593                     ODR_MASK_SET(resp->protocolVersion, versions[i]);
 594                 else
 595                     break;
 596
 597             package.response() = apdu;
 598             f->m_is_virtual = true;
 599         }
 600         else
 601             package.move();
 602     }
 603     else if (!f->m_is_virtual)
 604         package.move();
 605     else if (gdu && gdu->which == Z_GDU_Z3950)
 606     {
 607         Z_APDU *apdu = gdu->u.z3950;
 608         if (apdu->which == Z_APDU_initRequest)
 609         {
 610             yp2::odr odr;
 611
 612             package.response() = odr.create_close(
 613                 apdu,
 614                 Z_Close_protocolError,
 615                 "double init");
 616
 617             package.session().close();
 618         }
 619         else if (apdu->which == Z_APDU_searchRequest)
 620         {
 621             f->search(package, apdu);
 622         }
 623         else if (apdu->which == Z_APDU_presentRequest)
 624         {
 625             f->present(package, apdu);
 626         }
 627         else if (apdu->which == Z_APDU_scanRequest)
 628         {
 629             f->scan(package, apdu);
 630         }
 631         else
 632         {
 633             yp2::odr odr;
 634
 635             package.response() = odr.create_close(
 636                 apdu, Z_Close_protocolError,
 637                 "unsupported APDU in filter_virt_db");
 638
 639             package.session().close();
 640         }
 641     }
 642     m_p->release_frontend(package);
 643 }
 644
 645
 646 void yp2::filter::Virt_db::configure(const xmlNode * ptr)
 647 {
 648     for (ptr = ptr->children; ptr; ptr = ptr->next)
 649     {
 650         if (ptr->type != XML_ELEMENT_NODE)
 651             continue;
 652         if (!strcmp((const char *) ptr->name, "virtual"))
 653         {
 654             std::string database;
 655             std::string target;
 656             xmlNode *v_node = ptr->children;
 657             for (; v_node; v_node = v_node->next)
 658             {
 659                 if (v_node->type != XML_ELEMENT_NODE)
 660                     continue;
 661
 662                 if (yp2::xml::is_element_yp2(v_node, "database"))
 663                     database = yp2::xml::get_text(v_node);
 664                 else if (yp2::xml::is_element_yp2(v_node, "target"))
 665                     target = yp2::xml::get_text(v_node);
 666                 else
 667                     throw yp2::filter::FilterException
 668                         ("Bad element "
 669                          + std::string((const char *) v_node->name)
 670                          + " in virtual section"
 671                             );
 672             }
 673             std::string route = yp2::xml::get_route(ptr);
 674             add_map_db2vhost(database, target, route);
 675             std::cout << "Add " << database << "->" << target
 676                       << "," << route << "\n";
 677         }
 678         else
 679         {
 680             throw yp2::filter::FilterException
 681                 ("Bad element "
 682                  + std::string((const char *) ptr->name)
 683                  + " in virt_db filter");
 684         }
 685     }
 686 }
 687
 688 static yp2::filter::Base* filter_creator()
 689 {
 690     return new yp2::filter::Virt_db;
 691 }
 692
 693 extern "C" {
 694     struct yp2_filter_struct yp2_filter_virt_db = {
 695         0,
 696         "virt_db",
 697         filter_creator
 698     };
 699 }
 700
 701
 702 /*
 703  * Local variables:
 704  * c-basic-offset: 4
 705  * indent-tabs-mode: nil
 706  * c-file-style: "stroustrup"
 707  * End:
 708  * vim: shiftwidth=4 tabstop=8 expandtab
 709  */