js/pz2.js

   1 /*
   2 ** pz2.js - pazpar2's javascript client library.
   3 */
   4
   5 //since explorer is flawed
   6 if (!window['Node']) {
   7     window.Node = new Object();
   8     Node.ELEMENT_NODE = 1;
   9     Node.ATTRIBUTE_NODE = 2;
  10     Node.TEXT_NODE = 3;
  11     Node.CDATA_SECTION_NODE = 4;
  12     Node.ENTITY_REFERENCE_NODE = 5;
  13     Node.ENTITY_NODE = 6;
  14     Node.PROCESSING_INSTRUCTION_NODE = 7;
  15     Node.COMMENT_NODE = 8;
  16     Node.DOCUMENT_NODE = 9;
  17     Node.DOCUMENT_TYPE_NODE = 10;
  18     Node.DOCUMENT_FRAGMENT_NODE = 11;
  19     Node.NOTATION_NODE = 12;
  20 }
  21
  22 // prevent execution of more than once
  23 if(typeof window.pz2 == "undefined") {
  24 window.undefined = window.undefined;
  25
  26 var pz2 = function ( paramArray )
  27 {
  28
  29     // at least one callback required
  30     if ( !paramArray )
  31         throw new Error("Pz2.js: Array with parameters has to be suplied.");
  32
  33     //supported pazpar2's protocol version
  34     this.suppProtoVer = '1';
  35     if (typeof paramArray.pazpar2path != "undefined")
  36         this.pz2String = paramArray.pazpar2path;
  37     else
  38         this.pz2String = "/pazpar2/search.pz2";
  39     this.useSessions = true;
  40
  41     this.stylesheet = paramArray.detailstylesheet || null;
  42     //load stylesheet if required in async mode
  43     if( this.stylesheet ) {
  44         var context = this;
  45         var request = new pzHttpRequest( this.stylesheet );
  46         request.get( {}, function ( doc ) { context.xslDoc = doc; } );
  47     }
  48
  49     this.errorHandler = paramArray.errorhandler || null;
  50
  51     // function callbacks
  52     this.initCallback = paramArray.oninit || null;
  53     this.statCallback = paramArray.onstat || null;
  54     this.showCallback = paramArray.onshow || null;
  55     this.termlistCallback = paramArray.onterm || null;
  56     this.recordCallback = paramArray.onrecord || null;
  57     this.bytargetCallback = paramArray.onbytarget || null;
  58     this.resetCallback = paramArray.onreset || null;
  59
  60     // termlist keys
  61     this.termKeys = paramArray.termlist || "subject";
  62
  63     // some configurational stuff
  64     this.keepAlive = 50000;
  65
  66     if ( paramArray.keepAlive < this.keepAlive )
  67         this.keepAlive = paramArray.keepAlive;
  68
  69     this.sessionID = null;
  70     this.initStatusOK = false;
  71     this.pingStatusOK = false;
  72     this.searchStatusOK = false;
  73
  74     // for sorting
  75     this.currentSort = "relevance";
  76
  77     // where are we?
  78     this.currentStart = 0;
  79     this.currentNum = 20;
  80
  81     // last full record retrieved
  82     this.currRecID = null;
  83
  84     // current query
  85     this.currQuery = null;
  86
  87     //current raw record offset
  88     this.currRecOffset = null;
  89
  90     //timers
  91     this.statTime = paramArray.stattime || 1000;
  92     this.statTimer = null;
  93     this.termTime = paramArray.termtime || 1000;
  94     this.termTimer = null;
  95     this.showTime = paramArray.showtime || 1000;
  96     this.showTimer = null;
  97     this.showFastCount = 4;
  98     this.bytargetTime = paramArray.bytargettime || 1000;
  99     this.bytargetTimer = null;
 100     this.recordTime = paramArray.recordtime || 500;
 101     this.recordTimer = null;
 102
 103     // counters for each command and applied delay
 104     this.dumpFactor = 500;
 105     this.showCounter = 0;
 106     this.termCounter = 0;
 107     this.statCounter = 0;
 108     this.bytargetCounter = 0;
 109     this.recordCounter = 0;
 110
 111     // active clients, updated by stat and show
 112     // might be an issue since bytarget will poll accordingly
 113     this.activeClients = 1;
 114
 115     // if in proxy mode no need to init
 116     if (paramArray.usesessions != undefined) {
 117          this.useSessions = paramArray.usesessions;
 118         this.initStatusOK = true;
 119     }
 120     // else, auto init session or wait for a user init?
 121     if (this.useSessions && paramArray.autoInit !== false) {
 122         this.init();
 123     }
 124 };
 125
 126 pz2.prototype =
 127 {
 128     //error handler for async error throws
 129    throwError: function (errMsg, errCode)
 130    {
 131         var err = new Error(errMsg);
 132         if (errCode) err.code = errCode;
 133
 134         if (this.errorHandler) {
 135             this.errorHandler(err);
 136         }
 137         else {
 138             throw err;
 139         }
 140    },
 141
 142     // stop activity by clearing tiemouts
 143    stop: function ()
 144    {
 145        clearTimeout(this.statTimer);
 146        clearTimeout(this.showTimer);
 147        clearTimeout(this.termTimer);
 148        clearTimeout(this.bytargetTimer);
 149     },
 150
 151     // reset status variables
 152     reset: function ()
 153     {
 154         if ( this.useSessions ) {
 155             this.sessionID = null;
 156             this.initStatusOK = false;
 157             this.pingStatusOK = false;
 158         }
 159         this.searchStatusOK = false;
 160         this.stop();
 161
 162         if ( this.resetCallback )
 163                 this.resetCallback();
 164     },
 165
 166     init: function ( sessionId )
 167     {
 168         this.reset();
 169
 170         // session id as a param
 171         if ( sessionId != undefined && this.useSessions ) {
 172             this.initStatusOK = true;
 173             this.sessionID = sessionId;
 174             this.ping();
 175         // old school direct pazpar2 init
 176         } else if (this.useSessions) {
 177             var context = this;
 178             var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 179             request.safeGet(
 180                 { "command": "init" },
 181                 function(data) {
 182                     if ( data.getElementsByTagName("status")[0]
 183                             .childNodes[0].nodeValue == "OK" ) {
 184                         if ( data.getElementsByTagName("protocol")[0]
 185                                 .childNodes[0].nodeValue
 186                             != context.suppProtoVer )
 187                             throw new Error(
 188                                 "Server's protocol not supported by the client"
 189                             );
 190                         context.initStatusOK = true;
 191                         context.sessionID =
 192                             data.getElementsByTagName("session")[0]
 193                                 .childNodes[0].nodeValue;
 194                         setTimeout(
 195                             function () {
 196                                 context.ping();
 197                             },
 198                             context.keepAlive
 199                         );
 200                         if ( context.initCallback )
 201                             context.initCallback();
 202                     }
 203                     else
 204                         context.throwError('Init failed. Malformed WS resonse.',
 205                                             110);
 206                 }
 207             );
 208         // when through proxy no need to init
 209         } else {
 210             this.initStatusOK = true;
 211         }
 212     },
 213     // no need to ping explicitly
 214     ping: function ()
 215     {
 216         // pinging only makes sense when using pazpar2 directly
 217         if( !this.initStatusOK || !this.useSessions )
 218             throw new Error(
 219             'Pz2.js: Ping not allowed (proxy mode) or session not initialized.'
 220             );
 221         var context = this;
 222         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 223         request.safeGet(
 224             { "command": "ping", "session": this.sessionID },
 225             function(data) {
 226                 if ( data.getElementsByTagName("status")[0]
 227                         .childNodes[0].nodeValue == "OK" ) {
 228                     context.pingStatusOK = true;
 229                     setTimeout(
 230                         function () {
 231                             context.ping();
 232                         },
 233                         context.keepAlive
 234                     );
 235                 }
 236                 else
 237                     context.throwError('Ping failed. Malformed WS resonse.',
 238                                         111);
 239             }
 240         );
 241     },
 242     search: function (query, num, sort, filter, showfrom, addParamsArr)
 243     {
 244         clearTimeout(this.statTimer);
 245         clearTimeout(this.showTimer);
 246         clearTimeout(this.termTimer);
 247         clearTimeout(this.bytargetTimer);
 248
 249         this.showCounter = 0;
 250         this.termCounter = 0;
 251         this.bytargetCounter = 0;
 252         this.statCounter = 0;
 253         this.activeClients = 1;
 254
 255         // no proxy mode
 256         if( !this.initStatusOK )
 257             throw new Error('Pz2.js: session not initialized.');
 258
 259         if( query !== undefined )
 260             this.currQuery = query;
 261         else
 262             throw new Error("Pz2.js: no query supplied to the search command.");
 263
 264         if ( showfrom !== undefined )
 265             var start = showfrom;
 266         else
 267             var start = 0;
 268
 269         var searchParams = {
 270             "command": "search",
 271             "query": this.currQuery,
 272             "session": this.sessionID
 273         };
 274
 275         if (filter !== undefined)
 276             searchParams["filter"] = filter;
 277
 278         // copy additional parmeters, do not overwrite
 279         if (addParamsArr != undefined) {
 280             for (var prop in addParamsArr) {
 281                 if (!searchParams.hasOwnProperty(prop))
 282                     searchParams[prop] = addParamsArr[prop];
 283             }
 284         }
 285
 286         var context = this;
 287         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 288         request.safeGet(
 289             searchParams,
 290             function(data) {
 291                 if ( data.getElementsByTagName("status")[0]
 292                         .childNodes[0].nodeValue == "OK" ) {
 293                     context.searchStatusOK = true;
 294                     //piggyback search
 295                     context.show(start, num, sort);
 296                     if ( context.statCallback )
 297                         context.stat();
 298                     if ( context.termlistCallback )
 299                         context.termlist();
 300                     if ( context.bytargetCallback )
 301                         context.bytarget();
 302                 }
 303                 else
 304                     context.throwError('Search failed. Malformed WS resonse.',
 305                                         112);
 306             }
 307         );
 308     },
 309     stat: function()
 310     {
 311         if( !this.initStatusOK )
 312             throw new Error('Pz2.js: session not initialized.');
 313
 314         // if called explicitly takes precedence
 315         clearTimeout(this.statTimer);
 316
 317         var context = this;
 318         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 319         request.safeGet(
 320             { "command": "stat", "session": this.sessionID },
 321             function(data) {
 322                 if ( data.getElementsByTagName("stat") ) {
 323                     var activeClients =
 324                         Number( data.getElementsByTagName("activeclients")[0]
 325                                     .childNodes[0].nodeValue );
 326                     context.activeClients = activeClients;
 327
 328                     var stat = Element_parseChildNodes(data.documentElement);
 329
 330                     context.statCounter++;
 331                     var delay = context.statTime
 332                         + context.statCounter * context.dumpFactor;
 333
 334                     if ( activeClients > 0 )
 335                         context.statTimer =
 336                             setTimeout(
 337                                 function () {
 338                                     context.stat();
 339                                 },
 340                                 delay
 341                             );
 342                     context.statCallback(stat);
 343                 }
 344                 else
 345                     context.throwError('Stat failed. Malformed WS resonse.',
 346                                         113);
 347             }
 348         );
 349     },
 350     show: function(start, num, sort)
 351     {
 352         if( !this.searchStatusOK && this.useSessions )
 353             throw new Error(
 354                 'Pz2.js: show command has to be preceded with a search command.'
 355             );
 356
 357         // if called explicitly takes precedence
 358         clearTimeout(this.showTimer);
 359
 360         if( sort !== undefined )
 361             this.currentSort = sort;
 362         if( start !== undefined )
 363             this.currentStart = Number( start );
 364         if( num !== undefined )
 365             this.currentNum = Number( num );
 366
 367         var context = this;
 368         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 369         request.safeGet(
 370             {
 371                 "command": "show",
 372                 "session": this.sessionID,
 373                 "start": this.currentStart,
 374                 "num": this.currentNum,
 375                 "sort": this.currentSort,
 376                 "block": 1
 377             },
 378             function(data) {
 379                 if ( data.getElementsByTagName("status")[0]
 380                         .childNodes[0].nodeValue == "OK" ) {
 381                     // first parse the status data send along with records
 382                     // this is strictly bound to the format
 383                     var activeClients =
 384                         Number( data.getElementsByTagName("activeclients")[0]
 385                                     .childNodes[0].nodeValue );
 386                     context.activeClients = activeClients;
 387                     var show = {
 388                         "activeclients": activeClients,
 389                         "merged":
 390                             Number( data.getElementsByTagName("merged")[0]
 391                                         .childNodes[0].nodeValue ),
 392                         "total":
 393                             Number( data.getElementsByTagName("total")[0]
 394                                         .childNodes[0].nodeValue ),
 395                         "start":
 396                             Number( data.getElementsByTagName("start")[0]
 397                                         .childNodes[0].nodeValue ),
 398                         "num":
 399                             Number( data.getElementsByTagName("num")[0]
 400                                         .childNodes[0].nodeValue ),
 401                         "hits": []
 402                     };
 403                     // parse all the first-level nodes for all <hit> tags
 404                     var hits = data.getElementsByTagName("hit");
 405                     for (i = 0; i < hits.length; i++)
 406                         show.hits[i] = Element_parseChildNodes(hits[i]);
 407
 408                     context.showCounter++;
 409                     var delay = context.showTime;
 410                     if (context.showCounter > context.showFastCount)
 411                             delay += context.showCounter * context.dumpFactor;
 412                     if ( activeClients > 0 )
 413                         context.showTimer = setTimeout(
 414                             function () {
 415                                 context.show();
 416                             },
 417                             delay);
 418                     global_show = show;
 419                     context.showCallback(show);
 420                 }
 421                 else
 422                     context.throwError('Show failed. Malformed WS resonse.',
 423                                         114);
 424             }
 425         );
 426     },
 427     record: function(id, offset, syntax, handler)
 428     {
 429         // we may call record with no previous search if in proxy mode
 430         if(!this.searchStatusOK && this.useSessions)
 431            throw new Error(
 432             'Pz2.js: record command has to be preceded with a search command.'
 433             );
 434
 435         if( id !== undefined )
 436             this.currRecID = id;
 437
 438         var recordParams = {
 439             "command": "record",
 440             "session": this.sessionID,
 441             "id": this.currRecID
 442         };
 443
 444         this.currRecOffset = null;
 445         if (offset != undefined) {
 446             recordParams["offset"] = offset;
 447             this.currRecOffset = offset;
 448         }
 449
 450         if (syntax != undefined)
 451             recordParams['syntax'] = syntax;
 452
 453         //overwrite default callback id needed
 454         var callback = this.recordCallback;
 455         var args = undefined;
 456         if (handler != undefined) {
 457             callback = handler['callback'];
 458             args = handler['args'];
 459         }
 460
 461         var context = this;
 462         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 463
 464         request.safeGet(
 465             recordParams,
 466             function(data) {
 467                 var recordNode;
 468                 var record;
 469                 //raw record
 470                 if (context.currRecOffset !== null) {
 471                     record = new Array();
 472                     record['xmlDoc'] = data;
 473                     record['offset'] = context.currRecOffset;
 474                     callback(record, args);
 475                 //pz2 record
 476                 } else if ( recordNode =
 477                     data.getElementsByTagName("record")[0] ) {
 478                     // if stylesheet was fetched do not parse the response
 479                     if ( context.xslDoc ) {
 480                         record = new Array();
 481                         record['xmlDoc'] = data;
 482                         record['xslDoc'] = context.xslDoc;
 483                         record['recid'] =
 484                             recordNode.getElementsByTagName("recid")[0]
 485                                 .firstChild.nodeValue;
 486                     //parse record
 487                     } else {
 488                         record = Element_parseChildNodes(recordNode);
 489                     }
 490                     var activeClients =
 491                        Number( data.getElementsByTagName("activeclients")[0]
 492                                 .childNodes[0].nodeValue );
 493                     context.activeClients = activeClients;
 494                     context.recordCounter++;
 495                     var delay = context.recordTime + context.recordCounter * context.dumpFactor;
 496                     if ( activeClients > 0 )
 497                         context.recordTimer =
 498                            setTimeout (
 499                                function() {
 500                                   context.record(id, offset, syntax, handler);
 501                                   },
 502                                   delay
 503                                );
 504                     callback(record, args);
 505                 }
 506                 else
 507                     context.throwError('Record failed. Malformed WS resonse.',
 508                                         115);
 509             }
 510         );
 511     },
 512
 513     termlist: function()
 514     {
 515         if( !this.searchStatusOK && this.useSessions )
 516             throw new Error(
 517             'Pz2.js: termlist command has to be preceded with a search command.'
 518             );
 519
 520         // if called explicitly takes precedence
 521         clearTimeout(this.termTimer);
 522
 523         var context = this;
 524         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 525         request.safeGet(
 526             {
 527                 "command": "termlist",
 528                 "session": this.sessionID,
 529                 "name": this.termKeys
 530             },
 531             function(data) {
 532                 if ( data.getElementsByTagName("termlist") ) {
 533                     var activeClients =
 534                         Number( data.getElementsByTagName("activeclients")[0]
 535                                     .childNodes[0].nodeValue );
 536                     context.activeClients = activeClients;
 537                     var termList = { "activeclients":  activeClients };
 538                     var termLists = data.getElementsByTagName("list");
 539                     //for each termlist
 540                     for (i = 0; i < termLists.length; i++) {
 541                         var listName = termLists[i].getAttribute('name');
 542                         termList[listName] = new Array();
 543                         var terms = termLists[i].getElementsByTagName('term');
 544                         //for each term in the list
 545                         for (j = 0; j < terms.length; j++) {
 546                             var term = {
 547                                 "name":
 548                                     (terms[j].getElementsByTagName("name")[0]
 549                                         .childNodes.length
 550                                     ? terms[j].getElementsByTagName("name")[0]
 551                                         .childNodes[0].nodeValue
 552                                     : 'ERROR'),
 553                                 "freq":
 554                                     terms[j]
 555                                     .getElementsByTagName("frequency")[0]
 556                                     .childNodes[0].nodeValue || 'ERROR'
 557                             };
 558
 559                             var termIdNode =
 560                                 terms[j].getElementsByTagName("id");
 561                             if(terms[j].getElementsByTagName("id").length)
 562                                 term["id"] =
 563                                     termIdNode[0].childNodes[0].nodeValue;
 564                             termList[listName][j] = term;
 565                         }
 566                     }
 567
 568                     context.termCounter++;
 569                     var delay = context.termTime
 570                         + context.termCounter * context.dumpFactor;
 571                     if ( activeClients > 0 )
 572                         context.termTimer =
 573                             setTimeout(
 574                                 function () {
 575                                     context.termlist();
 576                                 },
 577                                 delay
 578                             );
 579
 580                    context.termlistCallback(termList);
 581                 }
 582                 else
 583                     context.throwError('Termlist failed. Malformed WS resonse.',
 584                                         116);
 585             }
 586         );
 587
 588     },
 589     bytarget: function()
 590     {
 591         if( !this.initStatusOK && this.useSessions )
 592             throw new Error(
 593             'Pz2.js: bytarget command has to be preceded with a search command.'
 594             );
 595
 596         // no need to continue
 597         if( !this.searchStatusOK )
 598             return;
 599
 600         // if called explicitly takes precedence
 601         clearTimeout(this.bytargetTimer);
 602
 603         var context = this;
 604         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 605         request.safeGet(
 606             { "command": "bytarget", "session": this.sessionID },
 607             function(data) {
 608                 if ( data.getElementsByTagName("status")[0]
 609                         .childNodes[0].nodeValue == "OK" ) {
 610                     var targetNodes = data.getElementsByTagName("target");
 611                     var bytarget = new Array();
 612                     for ( i = 0; i < targetNodes.length; i++) {
 613                         bytarget[i] = new Array();
 614                         for( j = 0; j < targetNodes[i].childNodes.length; j++ ) {
 615                             if ( targetNodes[i].childNodes[j].nodeType
 616                                 == Node.ELEMENT_NODE ) {
 617                                 var nodeName =
 618                                     targetNodes[i].childNodes[j].nodeName;
 619                                 var nodeText =
 620                                     targetNodes[i].childNodes[j]
 621                                         .firstChild.nodeValue;
 622                                 bytarget[i][nodeName] = nodeText;
 623                             }
 624                         }
 625                     }
 626
 627                     context.bytargetCounter++;
 628                     var delay = context.bytargetTime
 629                         + context.bytargetCounter * context.dumpFactor;
 630                     if ( context.activeClients > 0 )
 631                         context.bytargetTimer =
 632                             setTimeout(
 633                                 function () {
 634                                     context.bytarget();
 635                                 },
 636                                 delay
 637                             );
 638
 639                     context.bytargetCallback(bytarget);
 640                 }
 641                 else
 642                     context.throwError('Bytarget failed. Malformed WS resonse.',
 643                                         117);
 644             }
 645         );
 646     },
 647
 648     // just for testing, probably shouldn't be here
 649     showNext: function(page)
 650     {
 651         var step = page || 1;
 652         this.show( ( step * this.currentNum ) + this.currentStart );
 653     },
 654
 655     showPrev: function(page)
 656     {
 657         if (this.currentStart == 0 )
 658             return false;
 659         var step = page || 1;
 660         var newStart = this.currentStart - (step * this.currentNum );
 661         this.show( newStart > 0 ? newStart : 0 );
 662     },
 663
 664     showPage: function(pageNum)
 665     {
 666         //var page = pageNum || 1;
 667         this.show(pageNum * this.currentNum);
 668     }
 669 };
 670
 671 /*
 672 ********************************************************************************
 673 ** AJAX HELPER CLASS ***********************************************************
 674 ********************************************************************************
 675 */
 676 var pzHttpRequest = function ( url, errorHandler ) {
 677         this.maxUrlLength = 2048;
 678         this.request = null;
 679         this.url = url;
 680         this.errorHandler = errorHandler || null;
 681         this.async = true;
 682         this.requestHeaders = {};
 683
 684         if ( window.XMLHttpRequest ) {
 685             this.request = new XMLHttpRequest();
 686         } else if ( window.ActiveXObject ) {
 687             try {
 688                 this.request = new ActiveXObject( 'Msxml2.XMLHTTP' );
 689             } catch (err) {
 690                 this.request = new ActiveXObject( 'Microsoft.XMLHTTP' );
 691             }
 692         }
 693 };
 694
 695 pzHttpRequest.prototype =
 696 {
 697     safeGet: function ( params, callback )
 698     {
 699         var encodedParams =  this.encodeParams(params);
 700         var url = this._urlAppendParams(encodedParams);
 701         if (url.length >= this.maxUrlLength) {
 702             this.requestHeaders["Content-Type"]
 703                 = "application/x-www-form-urlencoded";
 704             this._send( 'POST', this.url, encodedParams, callback );
 705         } else {
 706             this._send( 'GET', url, '', callback );
 707         }
 708     },
 709
 710     get: function ( params, callback )
 711     {
 712         this._send( 'GET', this._urlAppendParams(this.encodeParams(params)),
 713             '', callback );
 714     },
 715
 716     post: function ( params, data, callback )
 717     {
 718         this._send( 'POST', this._urlAppendParams(this.encodeParams(params)),
 719             data, callback );
 720     },
 721
 722     load: function ()
 723     {
 724         this.async = false;
 725         this.request.open( 'GET', this.url, this.async );
 726         this.request.send('');
 727         if ( this.request.status == 200 )
 728             return this.request.responseXML;
 729     },
 730
 731     encodeParams: function (params)
 732     {
 733         var sep = "";
 734         var encoded = "";
 735         for (var key in params) {
 736             if (params[key] != null) {
 737                 encoded += sep + key + '=' + encodeURIComponent(params[key]);
 738                 sep = '&';
 739             }
 740         }
 741         return encoded;
 742     },
 743
 744     _send: function ( type, url, data, callback)
 745     {
 746         var context = this;
 747         this.callback = callback;
 748         this.async = true;
 749         this.request.open( type, url, this.async );
 750         for (var key in this.requestHeaders)
 751             this.request.setRequestHeader(key, this.requestHeaders[key]);
 752         this.request.onreadystatechange = function () {
 753             context._handleResponse(url); /// url used ONLY for error reporting
 754         }
 755         this.request.send(data);
 756     },
 757
 758     _urlAppendParams: function (encodedParams)
 759     {
 760         if (encodedParams)
 761             return this.url + "?" + encodedParams;
 762         else
 763             return this.url;
 764     },
 765
 766     _handleResponse: function (savedUrlForErrorReporting)
 767     {
 768         if ( this.request.readyState == 4 ) {
 769             // pick up appplication errors first
 770             var errNode = null;
 771             if (this.request.responseXML &&
 772                 (errNode = this.request.responseXML.documentElement)
 773                 && errNode.nodeName == 'error') {
 774                 var errMsg = errNode.getAttribute("msg");
 775                 var errCode = errNode.getAttribute("code");
 776                 var errAddInfo = '';
 777                 if (errNode.childNodes.length)
 778                     errAddInfo = ': ' + errNode.childNodes[0].nodeValue;
 779
 780                 var err = new Error(errMsg + errAddInfo);
 781                 err.code = errCode;
 782
 783                 if (this.errorHandler) {
 784                     this.errorHandler(err);
 785                 }
 786                 else {
 787                     throw err;
 788                 }
 789             } else if (this.request.status == 200 &&
 790                        this.request.responseXML == null) {
 791                 var err = new Error("XML response is empty but no error " +
 792                                     "for " + savedUrlForErrorReporting);
 793                 err.code = -1;
 794                 if (this.errorHandler) {
 795                     this.errorHandler(err);
 796                 } else {
 797                     throw err;
 798                 }
 799             } else if (this.request.status == 200) {
 800                 this.callback(this.request.responseXML);
 801             } else {
 802                 var err = new Error("HTTP response not OK: "
 803                             + this.request.status + " - "
 804                             + this.request.statusText );
 805                 err.code = '00' + this.request.status;
 806
 807                 if (this.errorHandler) {
 808                     this.errorHandler(err);
 809                 }
 810                 else {
 811                     throw err;
 812                 }
 813             }
 814         }
 815     }
 816 };
 817
 818 /*
 819 ********************************************************************************
 820 ** XML HELPER FUNCTIONS ********************************************************
 821 ********************************************************************************
 822 */
 823
 824 // DOMDocument
 825
 826 if ( window.ActiveXObject) {
 827     var DOMDoc = document;
 828 } else {
 829     var DOMDoc = Document.prototype;
 830 }
 831
 832 DOMDoc.newXmlDoc = function ( root )
 833 {
 834     var doc;
 835
 836     if (document.implementation && document.implementation.createDocument) {
 837         doc = document.implementation.createDocument('', root, null);
 838     } else if ( window.ActiveXObject ) {
 839         doc = new ActiveXObject("MSXML2.DOMDocument");
 840         doc.loadXML('<' + root + '/>');
 841     } else {
 842         throw new Error ('No XML support in this browser');
 843     }
 844
 845     return doc;
 846 }
 847
 848
 849 DOMDoc.parseXmlFromString = function ( xmlString )
 850 {
 851     var doc;
 852
 853     if ( window.DOMParser ) {
 854         var parser = new DOMParser();
 855         doc = parser.parseFromString( xmlString, "text/xml");
 856     } else if ( window.ActiveXObject ) {
 857         doc = new ActiveXObject("MSXML2.DOMDocument");
 858         doc.loadXML( xmlString );
 859     } else {
 860         throw new Error ("No XML parsing support in this browser.");
 861     }
 862
 863     return doc;
 864 }
 865
 866 DOMDoc.transformToDoc = function (xmlDoc, xslDoc)
 867 {
 868     if ( window.XSLTProcessor ) {
 869         var proc = new XSLTProcessor();
 870         proc.importStylesheet( xslDoc );
 871         return proc.transformToDocument(xmlDoc);
 872     } else if ( window.ActiveXObject ) {
 873         return document.parseXmlFromString(xmlDoc.transformNode(xslDoc));
 874     } else {
 875         alert( 'Unable to perform XSLT transformation in this browser' );
 876     }
 877 }
 878
 879 // DOMElement
 880
 881 Element_removeFromDoc = function (DOM_Element)
 882 {
 883     DOM_Element.parentNode.removeChild(DOM_Element);
 884 }
 885
 886 Element_emptyChildren = function (DOM_Element)
 887 {
 888     while( DOM_Element.firstChild ) {
 889         DOM_Element.removeChild( DOM_Element.firstChild )
 890     }
 891 }
 892
 893 Element_appendTransformResult = function ( DOM_Element, xmlDoc, xslDoc )
 894 {
 895     if ( window.XSLTProcessor ) {
 896         var proc = new XSLTProcessor();
 897         proc.importStylesheet( xslDoc );
 898         var docFrag = false;
 899         docFrag = proc.transformToFragment( xmlDoc, DOM_Element.ownerDocument );
 900         DOM_Element.appendChild(docFrag);
 901     } else if ( window.ActiveXObject ) {
 902         DOM_Element.innerHTML = xmlDoc.transformNode( xslDoc );
 903     } else {
 904         alert( 'Unable to perform XSLT transformation in this browser' );
 905     }
 906 }
 907
 908 Element_appendTextNode = function (DOM_Element, tagName, textContent )
 909 {
 910     var node = DOM_Element.ownerDocument.createElement(tagName);
 911     var text = DOM_Element.ownerDocument.createTextNode(textContent);
 912
 913     DOM_Element.appendChild(node);
 914     node.appendChild(text);
 915
 916     return node;
 917 }
 918
 919 Element_setTextContent = function ( DOM_Element, textContent )
 920 {
 921     if (typeof DOM_Element.textContent !== "undefined") {
 922         DOM_Element.textContent = textContent;
 923     } else if (typeof DOM_Element.innerText !== "undefined" ) {
 924         DOM_Element.innerText = textContent;
 925     } else {
 926         throw new Error("Cannot set text content of the node, no such method.");
 927     }
 928 }
 929
 930 Element_getTextContent = function (DOM_Element)
 931 {
 932     if ( typeof DOM_Element.textContent != 'undefined' ) {
 933         return DOM_Element.textContent;
 934     } else if (typeof DOM_Element.text != 'undefined') {
 935         return DOM_Element.text;
 936     } else {
 937         throw new Error("Cannot get text content of the node, no such method.");
 938     }
 939 }
 940
 941 Element_parseChildNodes = function (node)
 942 {
 943     var parsed = {};
 944     var hasChildElems = false;
 945
 946     if (node.hasChildNodes()) {
 947         var children = node.childNodes;
 948         for (var i = 0; i < children.length; i++) {
 949             var child = children[i];
 950             if (child.nodeType == Node.ELEMENT_NODE) {
 951                 hasChildElems = true;
 952                 var nodeName = child.nodeName;
 953                 if (!(nodeName in parsed))
 954                     parsed[nodeName] = [];
 955                 parsed[nodeName].push(Element_parseChildNodes(child));
 956             }
 957         }
 958     }
 959
 960     var attrs = node.attributes;
 961     for (var i = 0; i < attrs.length; i++) {
 962         var attrName = '@' + attrs[i].nodeName;
 963         var attrValue = attrs[i].nodeValue;
 964         parsed[attrName] = attrValue;
 965     }
 966
 967     // if no nested elements, get text content
 968     if (node.hasChildNodes() && !hasChildElems) {
 969         if (node.attributes.length)
 970             parsed['textContent'] = node.firstChild.nodeValue;
 971         else
 972             parsed = node.firstChild.nodeValue;
 973     }
 974
 975     return parsed;
 976 }
 977
 978 /* do not remove trailing bracket */
 979 }