src/filter_virt_db.cpp

   1 /* $Id: filter_virt_db.cpp,v 1.23 2006-01-13 15:09:35 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             Frontend *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,Frontend *> 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         std::cout << "named_result_sets TRUE\n";
 298         backend_setname = std::string(req->resultSetName);
 299     }
 300     else
 301     {
 302         std::cout << "named_result_sets FALSE\n";
 303         backend_setname = "default";
 304         req->resultSetName = odr_strdup(odr, backend_setname.c_str());
 305     }
 306
 307     const char *backend_database = b->m_backend_database.c_str();
 308     req->databaseNames[0] = odr_strdup(odr, backend_database);
 309
 310     *req->replaceIndicator = 1;
 311
 312     search_package.request() = yazpp_1::GDU(apdu_req);
 313
 314     search_package.move(b->m_route);
 315
 316     if (search_package.session().is_closed())
 317     {
 318         Z_APDU *apdu =
 319             odr.create_searchResponse(
 320                 apdu_req,
 321                 YAZ_BIB1_DATABASE_UNAVAILABLE, database.c_str());
 322         package.response() = apdu;
 323         return;
 324     }
 325     package.response() = search_package.response();
 326
 327     b->m_number_of_sets++;
 328
 329     m_sets[resultSetId] = Virt_db::Set(b, backend_setname);
 330 }
 331
 332 yf::Virt_db::Frontend::Frontend(Rep *rep)
 333 {
 334     m_p = rep;
 335     m_is_virtual = false;
 336 }
 337
 338 void yf::Virt_db::Frontend::close(Package &package)
 339 {
 340     std::list<BackendPtr>::const_iterator b_it;
 341
 342     for (b_it = m_backend_list.begin(); b_it != m_backend_list.end(); b_it++)
 343     {
 344         (*b_it)->m_backend_session.close();
 345         Package close_package((*b_it)->m_backend_session, package.origin());
 346         close_package.copy_filter(package);
 347         close_package.move((*b_it)->m_route);
 348     }
 349     m_backend_list.clear();
 350 }
 351
 352 yf::Virt_db::Frontend::~Frontend()
 353 {
 354 }
 355
 356 yf::Virt_db::Frontend *yf::Virt_db::Rep::get_frontend(Package &package)
 357 {
 358     boost::mutex::scoped_lock lock(m_mutex);
 359
 360     std::map<yp2::Session,yf::Virt_db::Frontend *>::iterator it;
 361
 362     while(true)
 363     {
 364         it = m_clients.find(package.session());
 365         if (it == m_clients.end())
 366             break;
 367
 368         if (!it->second->m_in_use)
 369         {
 370             it->second->m_in_use = true;
 371             return it->second;
 372         }
 373         m_cond_session_ready.wait(lock);
 374     }
 375     Frontend *f = new Frontend(this);
 376     m_clients[package.session()] = f;
 377     f->m_in_use = true;
 378     return f;
 379 }
 380
 381
 382 void yf::Virt_db::Rep::release_frontend(Package &package)
 383 {
 384     boost::mutex::scoped_lock lock(m_mutex);
 385     std::map<yp2::Session,yf::Virt_db::Frontend *>::iterator it;
 386
 387     it = m_clients.find(package.session());
 388     if (it != m_clients.end())
 389     {
 390         if (package.session().is_closed())
 391         {
 392             it->second->close(package);
 393             delete it->second;
 394             m_clients.erase(it);
 395         }
 396         else
 397         {
 398             it->second->m_in_use = false;
 399         }
 400         m_cond_session_ready.notify_all();
 401     }
 402 }
 403
 404 yf::Virt_db::Set::Set(BackendPtr b, std::string setname)
 405     :  m_backend(b), m_setname(setname)
 406 {
 407 }
 408
 409
 410 yf::Virt_db::Set::Set()
 411 {
 412 }
 413
 414
 415 yf::Virt_db::Set::~Set()
 416 {
 417 }
 418
 419 yf::Virt_db::Map::Map(std::string vhost, std::string route)
 420     : m_vhost(vhost), m_route(route)
 421 {
 422 }
 423
 424 yf::Virt_db::Map::Map()
 425 {
 426 }
 427
 428 yf::Virt_db::Virt_db() : m_p(new Virt_db::Rep)
 429 {
 430 }
 431
 432 yf::Virt_db::~Virt_db() {
 433 }
 434
 435 void yf::Virt_db::Frontend::present(Package &package, Z_APDU *apdu_req)
 436 {
 437     Z_PresentRequest *req = apdu_req->u.presentRequest;
 438     std::string resultSetId = req->resultSetId;
 439     yp2::odr odr;
 440
 441     Sets_it sets_it = m_sets.find(resultSetId);
 442     if (sets_it == m_sets.end())
 443     {
 444         Z_APDU *apdu =
 445             odr.create_presentResponse(
 446                 apdu_req,
 447                 YAZ_BIB1_SPECIFIED_RESULT_SET_DOES_NOT_EXIST,
 448                 resultSetId.c_str());
 449         package.response() = apdu;
 450
 451         return;
 452     }
 453     Session *id =
 454         new yp2::Session(sets_it->second.m_backend->m_backend_session);
 455
 456     // sending present to backend
 457     Package present_package(*id, package.origin());
 458     present_package.copy_filter(package);
 459
 460     req->resultSetId = odr_strdup(odr, "default");
 461     present_package.request() = yazpp_1::GDU(apdu_req);
 462
 463     present_package.move();
 464
 465     if (present_package.session().is_closed())
 466     {
 467         Z_APDU *apdu =
 468             odr.create_presentResponse(
 469                 apdu_req,
 470                 YAZ_BIB1_RESULT_SET_NO_LONGER_EXISTS_UNILATERALLY_DELETED_BY_,
 471                 resultSetId.c_str());
 472         package.response() = apdu;
 473         m_sets.erase(resultSetId);
 474     }
 475     else
 476     {
 477         package.response() = present_package.response();
 478     }
 479     delete id;
 480 }
 481
 482 void yf::Virt_db::Frontend::scan(Package &package, Z_APDU *apdu_req)
 483 {
 484     Z_ScanRequest *req = apdu_req->u.scanRequest;
 485     std::string vhost;
 486     yp2::odr odr;
 487
 488     // only one datatabase for now
 489     if (req->num_databaseNames != 1)
 490     {   // exactly one database must be specified
 491         Z_APDU *apdu =
 492             odr.create_scanResponse(
 493                 apdu_req,
 494                 YAZ_BIB1_TOO_MANY_DATABASES_SPECIFIED, 0);
 495         package.response() = apdu;
 496         return;
 497     }
 498     std::string database = std::string(req->databaseNames[0]);
 499
 500     BackendPtr b;
 501     // pick up any existing backend with a database match
 502     std::list<BackendPtr>::const_iterator map_it;
 503     map_it = m_backend_list.begin();
 504     for (; map_it != m_backend_list.end(); map_it++)
 505     {
 506         BackendPtr tmp = *map_it;
 507         if (tmp->m_frontend_database == database)
 508             break;
 509     }
 510     if (map_it != m_backend_list.end())
 511         b = *map_it;
 512     if (!b)  // no backend yet. Must create a new one
 513     {
 514         int error_code;
 515         std::string addinfo;
 516         b = init_backend(database, package, error_code, addinfo);
 517         if (!b)
 518         {
 519             // did not get a backend (unavailable somehow?)
 520             Z_APDU *apdu =
 521                 odr.create_scanResponse(
 522                     apdu_req, error_code, addinfo.c_str());
 523             package.response() = apdu;
 524
 525             return;
 526         }
 527     }
 528     // sending scan to backend
 529     Package scan_package(b->m_backend_session, package.origin());
 530
 531     scan_package.copy_filter(package);
 532
 533     const char *backend_database = b->m_backend_database.c_str();
 534     req->databaseNames[0] = odr_strdup(odr, backend_database);
 535
 536     scan_package.request() = yazpp_1::GDU(apdu_req);
 537
 538     scan_package.move(b->m_route);
 539
 540     if (scan_package.session().is_closed())
 541     {
 542         Z_APDU *apdu =
 543             odr.create_scanResponse(
 544                 apdu_req, YAZ_BIB1_DATABASE_UNAVAILABLE, database.c_str());
 545         package.response() = apdu;
 546         return;
 547     }
 548     package.response() = scan_package.response();
 549 }
 550
 551
 552 void yf::Virt_db::add_map_db2vhost(std::string db, std::string vhost,
 553                                    std::string route)
 554 {
 555     m_p->m_maps[db] = Virt_db::Map(vhost, route);
 556 }
 557
 558 void yf::Virt_db::process(Package &package) const
 559 {
 560     yf::Virt_db::Frontend *f = m_p->get_frontend(package);
 561     if (f)
 562     {
 563         Z_GDU *gdu = package.request().get();
 564
 565         if (gdu && gdu->which == Z_GDU_Z3950 && gdu->u.z3950->which ==
 566             Z_APDU_initRequest && !f->m_is_virtual)
 567         {
 568             Z_InitRequest *req = gdu->u.z3950->u.initRequest;
 569
 570             const char *vhost =
 571                 yaz_oi_get_string_oidval(&req->otherInfo, VAL_PROXY, 1, 0);
 572             if (!vhost)
 573             {
 574                 yp2::odr odr;
 575                 Z_APDU *apdu = odr.create_initResponse(gdu->u.z3950, 0, 0);
 576                 Z_InitResponse *resp = apdu->u.initResponse;
 577
 578                 int i;
 579                 static const int masks[] = {
 580                     Z_Options_search,
 581                     Z_Options_present,
 582                     Z_Options_namedResultSets,
 583                     Z_Options_scan,
 584                     -1
 585                 };
 586                 for (i = 0; masks[i] != -1; i++)
 587                     if (ODR_MASK_GET(req->options, masks[i]))
 588                         ODR_MASK_SET(resp->options, masks[i]);
 589
 590                 static const int versions[] = {
 591                     Z_ProtocolVersion_1,
 592                     Z_ProtocolVersion_2,
 593                     Z_ProtocolVersion_3,
 594                     -1
 595                 };
 596                 for (i = 0; versions[i] != -1; i++)
 597                     if (ODR_MASK_GET(req->protocolVersion, versions[i]))
 598                         ODR_MASK_SET(resp->protocolVersion, versions[i]);
 599                     else
 600                         break;
 601
 602                 package.response() = apdu;
 603                 f->m_is_virtual = true;
 604             }
 605             else
 606                 package.move();
 607         }
 608         else if (!f->m_is_virtual)
 609             package.move();
 610         else if (gdu && gdu->which == Z_GDU_Z3950)
 611         {
 612             Z_APDU *apdu = gdu->u.z3950;
 613             if (apdu->which == Z_APDU_initRequest)
 614             {
 615                 yp2::odr odr;
 616
 617                 package.response() = odr.create_close(
 618                     apdu,
 619                     Z_Close_protocolError,
 620                     "double init");
 621
 622                 package.session().close();
 623             }
 624             else if (apdu->which == Z_APDU_searchRequest)
 625             {
 626                 f->search(package, apdu);
 627             }
 628             else if (apdu->which == Z_APDU_presentRequest)
 629             {
 630                 f->present(package, apdu);
 631             }
 632             else if (apdu->which == Z_APDU_scanRequest)
 633             {
 634                 f->scan(package, apdu);
 635             }
 636             else
 637             {
 638                 yp2::odr odr;
 639
 640                 package.response() = odr.create_close(
 641                     apdu, Z_Close_protocolError,
 642                     "unsupported APDU in filter_virt_db");
 643
 644                 package.session().close();
 645             }
 646         }
 647     }
 648     m_p->release_frontend(package);
 649 }
 650
 651
 652 void yp2::filter::Virt_db::configure(const xmlNode * ptr)
 653 {
 654     for (ptr = ptr->children; ptr; ptr = ptr->next)
 655     {
 656         if (ptr->type != XML_ELEMENT_NODE)
 657             continue;
 658         if (!strcmp((const char *) ptr->name, "virtual"))
 659         {
 660             std::string database;
 661             std::string target;
 662             xmlNode *v_node = ptr->children;
 663             for (; v_node; v_node = v_node->next)
 664             {
 665                 if (v_node->type != XML_ELEMENT_NODE)
 666                     continue;
 667
 668                 if (yp2::xml::is_element_yp2(v_node, "database"))
 669                     database = yp2::xml::get_text(v_node);
 670                 else if (yp2::xml::is_element_yp2(v_node, "target"))
 671                     target = yp2::xml::get_text(v_node);
 672                 else
 673                     throw yp2::filter::FilterException
 674                         ("Bad element "
 675                          + std::string((const char *) v_node->name)
 676                          + " in virtual section"
 677                             );
 678             }
 679             std::string route = yp2::xml::get_route(ptr);
 680             add_map_db2vhost(database, target, route);
 681             std::cout << "Add " << database << "->" << target
 682                       << "," << route << "\n";
 683         }
 684         else
 685         {
 686             throw yp2::filter::FilterException
 687                 ("Bad element "
 688                  + std::string((const char *) ptr->name)
 689                  + " in virt_db filter");
 690         }
 691     }
 692 }
 693
 694 static yp2::filter::Base* filter_creator()
 695 {
 696     return new yp2::filter::Virt_db;
 697 }
 698
 699 extern "C" {
 700     struct yp2_filter_struct yp2_filter_virt_db = {
 701         0,
 702         "virt_db",
 703         filter_creator
 704     };
 705 }
 706
 707
 708 /*
 709  * Local variables:
 710  * c-basic-offset: 4
 711  * indent-tabs-mode: nil
 712  * c-file-style: "stroustrup"
 713  * End:
 714  * vim: shiftwidth=4 tabstop=8 expandtab
 715  */