js/pz2.js

   1 /*
   2 ** $Id: pz2.js,v 1.70 2008-03-12 11:36:57 jakub Exp $
   3 ** pz2.js - pazpar2's javascript client library.
   4 */
   5
   6 //since explorer is flawed
   7 if (!window['Node']) {
   8     window.Node = new Object();
   9     Node.ELEMENT_NODE = 1;
  10     Node.ATTRIBUTE_NODE = 2;
  11     Node.TEXT_NODE = 3;
  12     Node.CDATA_SECTION_NODE = 4;
  13     Node.ENTITY_REFERENCE_NODE = 5;
  14     Node.ENTITY_NODE = 6;
  15     Node.PROCESSING_INSTRUCTION_NODE = 7;
  16     Node.COMMENT_NODE = 8;
  17     Node.DOCUMENT_NODE = 9;
  18     Node.DOCUMENT_TYPE_NODE = 10;
  19     Node.DOCUMENT_FRAGMENT_NODE = 11;
  20     Node.NOTATION_NODE = 12;
  21 }
  22
  23 // prevent execution of more than once
  24 if(typeof window.pz2 == "undefined") {
  25 window.undefined = window.undefined;
  26
  27 var pz2 = function ( paramArray )
  28 {
  29
  30     // at least one callback required
  31     if ( !paramArray )
  32         throw new Error("Pz2.js: Array with parameters has to be suplied.");
  33
  34     //supported pazpar2's protocol version
  35     this.suppProtoVer = '1';
  36     if (typeof paramArray.pazpar2path != "undefined")
  37         this.pz2String = paramArray.pazpar2path;
  38     else
  39         this.pz2String = "/pazpar2/search.pz2";
  40     this.useSessions = true;
  41
  42     this.stylesheet = paramArray.detailstylesheet || null;
  43     //load stylesheet if required in async mode
  44     if( this.stylesheet ) {
  45         var context = this;
  46         var request = new pzHttpRequest( this.stylesheet );
  47         request.get( {}, function ( doc ) { context.xslDoc = doc; } );
  48     }
  49
  50     this.errorHandler = paramArray.errorhandler || null;
  51
  52     // function callbacks
  53     this.initCallback = paramArray.oninit || null;
  54     this.statCallback = paramArray.onstat || null;
  55     this.showCallback = paramArray.onshow || null;
  56     this.termlistCallback = paramArray.onterm || null;
  57     this.recordCallback = paramArray.onrecord || null;
  58     this.bytargetCallback = paramArray.onbytarget || null;
  59     this.resetCallback = paramArray.onreset || null;
  60
  61     // termlist keys
  62     this.termKeys = paramArray.termlist || "subject";
  63
  64     // some configurational stuff
  65     this.keepAlive = 50000;
  66
  67     if ( paramArray.keepAlive < this.keepAlive )
  68         this.keepAlive = paramArray.keepAlive;
  69
  70     this.sessionID = null;
  71     this.initStatusOK = false;
  72     this.pingStatusOK = false;
  73     this.searchStatusOK = false;
  74
  75     // for sorting
  76     this.currentSort = "relevance";
  77
  78     // where are we?
  79     this.currentStart = 0;
  80     this.currentNum = 20;
  81
  82     // last full record retrieved
  83     this.currRecID = null;
  84
  85     // current query
  86     this.currQuery = null;
  87
  88     //current raw record offset
  89     this.currRecOffset = null;
  90
  91     //timers
  92     this.statTime = paramArray.stattime || 1000;
  93     this.statTimer = null;
  94     this.termTime = paramArray.termtime || 1000;
  95     this.termTimer = null;
  96     this.showTime = paramArray.showtime || 1000;
  97     this.showTimer = null;
  98     this.showFastCount = 4;
  99     this.bytargetTime = paramArray.bytargettime || 1000;
 100     this.bytargetTimer = null;
 101     this.recordTime = paramArray.recordtime || 500;
 102     this.recordTimer = null;
 103
 104     // counters for each command and applied delay
 105     this.dumpFactor = 500;
 106     this.showCounter = 0;
 107     this.termCounter = 0;
 108     this.statCounter = 0;
 109     this.bytargetCounter = 0;
 110     this.recordCounter = 0;
 111
 112     // active clients, updated by stat and show
 113     // might be an issue since bytarget will poll accordingly
 114     this.activeClients = 1;
 115
 116     // if in proxy mode no need to init
 117     if (paramArray.usesessions != undefined) {
 118          this.useSessions = paramArray.usesessions;
 119         this.initStatusOK = true;
 120     }
 121     // else, auto init session or wait for a user init?
 122     if (this.useSessions && paramArray.autoInit !== false) {
 123         this.init();
 124     }
 125 };
 126
 127 pz2.prototype =
 128 {
 129     //error handler for async error throws
 130    throwError: function (errMsg, errCode)
 131    {
 132         var err = new Error(errMsg);
 133         if (errCode) err.code = errCode;
 134
 135         if (this.errorHandler) {
 136             this.errorHandler(err);
 137         }
 138         else {
 139             throw err;
 140         }
 141    },
 142
 143     // stop activity by clearing tiemouts
 144    stop: function ()
 145    {
 146        clearTimeout(this.statTimer);
 147        clearTimeout(this.showTimer);
 148        clearTimeout(this.termTimer);
 149        clearTimeout(this.bytargetTimer);
 150     },
 151
 152     // reset status variables
 153     reset: function ()
 154     {
 155         if ( this.useSessions ) {
 156             this.sessionID = null;
 157             this.initStatusOK = false;
 158             this.pingStatusOK = false;
 159         }
 160         this.searchStatusOK = false;
 161         this.stop();
 162
 163         if ( this.resetCallback )
 164                 this.resetCallback();
 165     },
 166
 167     init: function ( sessionId )
 168     {
 169         this.reset();
 170
 171         // session id as a param
 172         if ( sessionId != undefined && this.useSessions ) {
 173             this.initStatusOK = true;
 174             this.sessionID = sessionId;
 175             this.ping();
 176         // old school direct pazpar2 init
 177         } else if (this.useSessions) {
 178             var context = this;
 179             var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 180             request.safeGet(
 181                 { "command": "init" },
 182                 function(data) {
 183                     if ( data.getElementsByTagName("status")[0]
 184                             .childNodes[0].nodeValue == "OK" ) {
 185                         if ( data.getElementsByTagName("protocol")[0]
 186                                 .childNodes[0].nodeValue
 187                             != context.suppProtoVer )
 188                             throw new Error(
 189                                 "Server's protocol not supported by the client"
 190                             );
 191                         context.initStatusOK = true;
 192                         context.sessionID =
 193                             data.getElementsByTagName("session")[0]
 194                                 .childNodes[0].nodeValue;
 195                         setTimeout(
 196                             function () {
 197                                 context.ping();
 198                             },
 199                             context.keepAlive
 200                         );
 201                         if ( context.initCallback )
 202                             context.initCallback();
 203                     }
 204                     else
 205                         context.throwError('Init failed. Malformed WS resonse.',
 206                                             110);
 207                 }
 208             );
 209         // when through proxy no need to init
 210         } else {
 211             this.initStatusOK = true;
 212         }
 213     },
 214     // no need to ping explicitly
 215     ping: function ()
 216     {
 217         // pinging only makes sense when using pazpar2 directly
 218         if( !this.initStatusOK || !this.useSessions )
 219             throw new Error(
 220             'Pz2.js: Ping not allowed (proxy mode) or session not initialized.'
 221             );
 222         var context = this;
 223         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 224         request.safeGet(
 225             { "command": "ping", "session": this.sessionID },
 226             function(data) {
 227                 if ( data.getElementsByTagName("status")[0]
 228                         .childNodes[0].nodeValue == "OK" ) {
 229                     context.pingStatusOK = true;
 230                     setTimeout(
 231                         function () {
 232                             context.ping();
 233                         },
 234                         context.keepAlive
 235                     );
 236                 }
 237                 else
 238                     context.throwError('Ping failed. Malformed WS resonse.',
 239                                         111);
 240             }
 241         );
 242     },
 243     search: function (query, num, sort, filter, showfrom, addParamsArr)
 244     {
 245         clearTimeout(this.statTimer);
 246         clearTimeout(this.showTimer);
 247         clearTimeout(this.termTimer);
 248         clearTimeout(this.bytargetTimer);
 249
 250         this.showCounter = 0;
 251         this.termCounter = 0;
 252         this.bytargetCounter = 0;
 253         this.statCounter = 0;
 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();
 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 ()
 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.callback(this.request.responseXML);
 791             } else {
 792                 var err = new Error("HTTP response not OK: "
 793                             + this.request.status + " - "
 794                             + this.request.statusText );
 795                 err.code = '00' + this.request.status;
 796
 797                 if (this.errorHandler) {
 798                     this.errorHandler(err);
 799                 }
 800                 else {
 801                     throw err;
 802                 }
 803             }
 804         }
 805     }
 806 };
 807
 808 /*
 809 ********************************************************************************
 810 ** XML HELPER FUNCTIONS ********************************************************
 811 ********************************************************************************
 812 */
 813
 814 // DOMDocument
 815
 816 if ( window.ActiveXObject) {
 817     var DOMDoc = document;
 818 } else {
 819     var DOMDoc = Document.prototype;
 820 }
 821
 822 DOMDoc.newXmlDoc = function ( root )
 823 {
 824     var doc;
 825
 826     if (document.implementation && document.implementation.createDocument) {
 827         doc = document.implementation.createDocument('', root, null);
 828     } else if ( window.ActiveXObject ) {
 829         doc = new ActiveXObject("MSXML2.DOMDocument");
 830         doc.loadXML('<' + root + '/>');
 831     } else {
 832         throw new Error ('No XML support in this browser');
 833     }
 834
 835     return doc;
 836 }
 837
 838
 839 DOMDoc.parseXmlFromString = function ( xmlString )
 840 {
 841     var doc;
 842
 843     if ( window.DOMParser ) {
 844         var parser = new DOMParser();
 845         doc = parser.parseFromString( xmlString, "text/xml");
 846     } else if ( window.ActiveXObject ) {
 847         doc = new ActiveXObject("MSXML2.DOMDocument");
 848         doc.loadXML( xmlString );
 849     } else {
 850         throw new Error ("No XML parsing support in this browser.");
 851     }
 852
 853     return doc;
 854 }
 855
 856 DOMDoc.transformToDoc = function (xmlDoc, xslDoc)
 857 {
 858     if ( window.XSLTProcessor ) {
 859         var proc = new XSLTProcessor();
 860         proc.importStylesheet( xslDoc );
 861         return proc.transformToDocument(xmlDoc);
 862     } else if ( window.ActiveXObject ) {
 863         return document.parseXmlFromString(xmlDoc.transformNode(xslDoc));
 864     } else {
 865         alert( 'Unable to perform XSLT transformation in this browser' );
 866     }
 867 }
 868
 869 // DOMElement
 870
 871 Element_removeFromDoc = function (DOM_Element)
 872 {
 873     DOM_Element.parentNode.removeChild(DOM_Element);
 874 }
 875
 876 Element_emptyChildren = function (DOM_Element)
 877 {
 878     while( DOM_Element.firstChild ) {
 879         DOM_Element.removeChild( DOM_Element.firstChild )
 880     }
 881 }
 882
 883 Element_appendTransformResult = function ( DOM_Element, xmlDoc, xslDoc )
 884 {
 885     if ( window.XSLTProcessor ) {
 886         var proc = new XSLTProcessor();
 887         proc.importStylesheet( xslDoc );
 888         var docFrag = false;
 889         docFrag = proc.transformToFragment( xmlDoc, DOM_Element.ownerDocument );
 890         DOM_Element.appendChild(docFrag);
 891     } else if ( window.ActiveXObject ) {
 892         DOM_Element.innerHTML = xmlDoc.transformNode( xslDoc );
 893     } else {
 894         alert( 'Unable to perform XSLT transformation in this browser' );
 895     }
 896 }
 897
 898 Element_appendTextNode = function (DOM_Element, tagName, textContent )
 899 {
 900     var node = DOM_Element.ownerDocument.createElement(tagName);
 901     var text = DOM_Element.ownerDocument.createTextNode(textContent);
 902
 903     DOM_Element.appendChild(node);
 904     node.appendChild(text);
 905
 906     return node;
 907 }
 908
 909 Element_setTextContent = function ( DOM_Element, textContent )
 910 {
 911     if (typeof DOM_Element.textContent !== "undefined") {
 912         DOM_Element.textContent = textContent;
 913     } else if (typeof DOM_Element.innerText !== "undefined" ) {
 914         DOM_Element.innerText = textContent;
 915     } else {
 916         throw new Error("Cannot set text content of the node, no such method.");
 917     }
 918 }
 919
 920 Element_getTextContent = function (DOM_Element)
 921 {
 922     if ( typeof DOM_Element.textContent != 'undefined' ) {
 923         return DOM_Element.textContent;
 924     } else if (typeof DOM_Element.text != 'undefined') {
 925         return DOM_Element.text;
 926     } else {
 927         throw new Error("Cannot get text content of the node, no such method.");
 928     }
 929 }
 930
 931 Element_parseChildNodes = function (node)
 932 {
 933     var parsed = {};
 934     var hasChildElems = false;
 935
 936     if (node.hasChildNodes()) {
 937         var children = node.childNodes;
 938         for (var i = 0; i < children.length; i++) {
 939             var child = children[i];
 940             if (child.nodeType == Node.ELEMENT_NODE) {
 941                 hasChildElems = true;
 942                 var nodeName = child.nodeName;
 943                 if (!(nodeName in parsed))
 944                     parsed[nodeName] = [];
 945                 parsed[nodeName].push(Element_parseChildNodes(child));
 946             }
 947         }
 948     }
 949
 950     var attrs = node.attributes;
 951     for (var i = 0; i < attrs.length; i++) {
 952         var attrName = '@' + attrs[i].nodeName;
 953         var attrValue = attrs[i].nodeValue;
 954         parsed[attrName] = attrValue;
 955     }
 956
 957     // if no nested elements, get text content
 958     if (node.hasChildNodes() && !hasChildElems) {
 959         if (node.attributes.length)
 960             parsed['textContent'] = node.firstChild.nodeValue;
 961         else
 962             parsed = node.firstChild.nodeValue;
 963     }
 964
 965     return parsed;
 966 }
 967
 968 /* do not remove trailing bracket */
 969 }