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         this.activeClients = 1;
 255
 256         // no proxy mode
 257         if( !this.initStatusOK )
 258             throw new Error('Pz2.js: session not initialized.');
 259
 260         if( query !== undefined )
 261             this.currQuery = query;
 262         else
 263             throw new Error("Pz2.js: no query supplied to the search command.");
 264
 265         if ( showfrom !== undefined )
 266             var start = showfrom;
 267         else
 268             var start = 0;
 269
 270         var searchParams = {
 271             "command": "search",
 272             "query": this.currQuery,
 273             "session": this.sessionID
 274         };
 275
 276         if (filter !== undefined)
 277             searchParams["filter"] = filter;
 278
 279         // copy additional parmeters, do not overwrite
 280         if (addParamsArr != undefined) {
 281             for (var prop in addParamsArr) {
 282                 if (!searchParams.hasOwnProperty(prop))
 283                     searchParams[prop] = addParamsArr[prop];
 284             }
 285         }
 286
 287         var context = this;
 288         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 289         request.safeGet(
 290             searchParams,
 291             function(data) {
 292                 if ( data.getElementsByTagName("status")[0]
 293                         .childNodes[0].nodeValue == "OK" ) {
 294                     context.searchStatusOK = true;
 295                     //piggyback search
 296                     context.show(start, num, sort);
 297                     if ( context.statCallback )
 298                         context.stat();
 299                     if ( context.termlistCallback )
 300                         context.termlist();
 301                     if ( context.bytargetCallback )
 302                         context.bytarget();
 303                 }
 304                 else
 305                     context.throwError('Search failed. Malformed WS resonse.',
 306                                         112);
 307             }
 308         );
 309     },
 310     stat: function()
 311     {
 312         if( !this.initStatusOK )
 313             throw new Error('Pz2.js: session not initialized.');
 314
 315         // if called explicitly takes precedence
 316         clearTimeout(this.statTimer);
 317
 318         var context = this;
 319         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 320         request.safeGet(
 321             { "command": "stat", "session": this.sessionID },
 322             function(data) {
 323                 if ( data.getElementsByTagName("stat") ) {
 324                     var activeClients =
 325                         Number( data.getElementsByTagName("activeclients")[0]
 326                                     .childNodes[0].nodeValue );
 327                     context.activeClients = activeClients;
 328
 329                     var stat = Element_parseChildNodes(data.documentElement);
 330
 331                     context.statCounter++;
 332                     var delay = context.statTime
 333                         + context.statCounter * context.dumpFactor;
 334
 335                     if ( activeClients > 0 )
 336                         context.statTimer =
 337                             setTimeout(
 338                                 function () {
 339                                     context.stat();
 340                                 },
 341                                 delay
 342                             );
 343                     context.statCallback(stat);
 344                 }
 345                 else
 346                     context.throwError('Stat failed. Malformed WS resonse.',
 347                                         113);
 348             }
 349         );
 350     },
 351     show: function(start, num, sort)
 352     {
 353         if( !this.searchStatusOK && this.useSessions )
 354             throw new Error(
 355                 'Pz2.js: show command has to be preceded with a search command.'
 356             );
 357
 358         // if called explicitly takes precedence
 359         clearTimeout(this.showTimer);
 360
 361         if( sort !== undefined )
 362             this.currentSort = sort;
 363         if( start !== undefined )
 364             this.currentStart = Number( start );
 365         if( num !== undefined )
 366             this.currentNum = Number( num );
 367
 368         var context = this;
 369         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 370         request.safeGet(
 371             {
 372                 "command": "show",
 373                 "session": this.sessionID,
 374                 "start": this.currentStart,
 375                 "num": this.currentNum,
 376                 "sort": this.currentSort,
 377                 "block": 1
 378             },
 379             function(data) {
 380                 if ( data.getElementsByTagName("status")[0]
 381                         .childNodes[0].nodeValue == "OK" ) {
 382                     // first parse the status data send along with records
 383                     // this is strictly bound to the format
 384                     var activeClients =
 385                         Number( data.getElementsByTagName("activeclients")[0]
 386                                     .childNodes[0].nodeValue );
 387                     context.activeClients = activeClients;
 388                     var show = {
 389                         "activeclients": activeClients,
 390                         "merged":
 391                             Number( data.getElementsByTagName("merged")[0]
 392                                         .childNodes[0].nodeValue ),
 393                         "total":
 394                             Number( data.getElementsByTagName("total")[0]
 395                                         .childNodes[0].nodeValue ),
 396                         "start":
 397                             Number( data.getElementsByTagName("start")[0]
 398                                         .childNodes[0].nodeValue ),
 399                         "num":
 400                             Number( data.getElementsByTagName("num")[0]
 401                                         .childNodes[0].nodeValue ),
 402                         "hits": []
 403                     };
 404                     // parse all the first-level nodes for all <hit> tags
 405                     var hits = data.getElementsByTagName("hit");
 406                     for (i = 0; i < hits.length; i++)
 407                         show.hits[i] = Element_parseChildNodes(hits[i]);
 408
 409                     context.showCounter++;
 410                     var delay = context.showTime;
 411                     if (context.showCounter > context.showFastCount)
 412                             delay += context.showCounter * context.dumpFactor;
 413                     if ( activeClients > 0 )
 414                         context.showTimer = setTimeout(
 415                             function () {
 416                                 context.show();
 417                             },
 418                             delay);
 419                     global_show = show;
 420                     context.showCallback(show);
 421                 }
 422                 else
 423                     context.throwError('Show failed. Malformed WS resonse.',
 424                                         114);
 425             }
 426         );
 427     },
 428     record: function(id, offset, syntax, handler)
 429     {
 430         // we may call record with no previous search if in proxy mode
 431         if(!this.searchStatusOK && this.useSessions)
 432            throw new Error(
 433             'Pz2.js: record command has to be preceded with a search command.'
 434             );
 435
 436         if( id !== undefined )
 437             this.currRecID = id;
 438
 439         var recordParams = {
 440             "command": "record",
 441             "session": this.sessionID,
 442             "id": this.currRecID
 443         };
 444
 445         this.currRecOffset = null;
 446         if (offset != undefined) {
 447             recordParams["offset"] = offset;
 448             this.currRecOffset = offset;
 449         }
 450
 451         if (syntax != undefined)
 452             recordParams['syntax'] = syntax;
 453
 454         //overwrite default callback id needed
 455         var callback = this.recordCallback;
 456         var args = undefined;
 457         if (handler != undefined) {
 458             callback = handler['callback'];
 459             args = handler['args'];
 460         }
 461
 462         var context = this;
 463         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 464
 465         request.safeGet(
 466             recordParams,
 467             function(data) {
 468                 var recordNode;
 469                 var record;
 470                 //raw record
 471                 if (context.currRecOffset !== null) {
 472                     record = new Array();
 473                     record['xmlDoc'] = data;
 474                     record['offset'] = context.currRecOffset;
 475                     callback(record, args);
 476                 //pz2 record
 477                 } else if ( recordNode =
 478                     data.getElementsByTagName("record")[0] ) {
 479                     // if stylesheet was fetched do not parse the response
 480                     if ( context.xslDoc ) {
 481                         record = new Array();
 482                         record['xmlDoc'] = data;
 483                         record['xslDoc'] = context.xslDoc;
 484                         record['recid'] =
 485                             recordNode.getElementsByTagName("recid")[0]
 486                                 .firstChild.nodeValue;
 487                     //parse record
 488                     } else {
 489                         record = Element_parseChildNodes(recordNode);
 490                     }
 491                     var activeClients =
 492                        Number( data.getElementsByTagName("activeclients")[0]
 493                                 .childNodes[0].nodeValue );
 494                     context.activeClients = activeClients;
 495                     context.recordCounter++;
 496                     var delay = context.recordTime + context.recordCounter * context.dumpFactor;
 497                     if ( activeClients > 0 )
 498                         context.recordTimer =
 499                            setTimeout (
 500                                function() {
 501                                   context.record(id, offset, syntax, handler);
 502                                   },
 503                                   delay
 504                                );
 505                     callback(record, args);
 506                 }
 507                 else
 508                     context.throwError('Record failed. Malformed WS resonse.',
 509                                         115);
 510             }
 511         );
 512     },
 513
 514     termlist: function()
 515     {
 516         if( !this.searchStatusOK && this.useSessions )
 517             throw new Error(
 518             'Pz2.js: termlist command has to be preceded with a search command.'
 519             );
 520
 521         // if called explicitly takes precedence
 522         clearTimeout(this.termTimer);
 523
 524         var context = this;
 525         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 526         request.safeGet(
 527             {
 528                 "command": "termlist",
 529                 "session": this.sessionID,
 530                 "name": this.termKeys
 531             },
 532             function(data) {
 533                 if ( data.getElementsByTagName("termlist") ) {
 534                     var activeClients =
 535                         Number( data.getElementsByTagName("activeclients")[0]
 536                                     .childNodes[0].nodeValue );
 537                     context.activeClients = activeClients;
 538                     var termList = { "activeclients":  activeClients };
 539                     var termLists = data.getElementsByTagName("list");
 540                     //for each termlist
 541                     for (i = 0; i < termLists.length; i++) {
 542                         var listName = termLists[i].getAttribute('name');
 543                         termList[listName] = new Array();
 544                         var terms = termLists[i].getElementsByTagName('term');
 545                         //for each term in the list
 546                         for (j = 0; j < terms.length; j++) {
 547                             var term = {
 548                                 "name":
 549                                     (terms[j].getElementsByTagName("name")[0]
 550                                         .childNodes.length
 551                                     ? terms[j].getElementsByTagName("name")[0]
 552                                         .childNodes[0].nodeValue
 553                                     : 'ERROR'),
 554                                 "freq":
 555                                     terms[j]
 556                                     .getElementsByTagName("frequency")[0]
 557                                     .childNodes[0].nodeValue || 'ERROR'
 558                             };
 559
 560                             var termIdNode =
 561                                 terms[j].getElementsByTagName("id");
 562                             if(terms[j].getElementsByTagName("id").length)
 563                                 term["id"] =
 564                                     termIdNode[0].childNodes[0].nodeValue;
 565                             termList[listName][j] = term;
 566                         }
 567                     }
 568
 569                     context.termCounter++;
 570                     var delay = context.termTime
 571                         + context.termCounter * context.dumpFactor;
 572                     if ( activeClients > 0 )
 573                         context.termTimer =
 574                             setTimeout(
 575                                 function () {
 576                                     context.termlist();
 577                                 },
 578                                 delay
 579                             );
 580
 581                    context.termlistCallback(termList);
 582                 }
 583                 else
 584                     context.throwError('Termlist failed. Malformed WS resonse.',
 585                                         116);
 586             }
 587         );
 588
 589     },
 590     bytarget: function()
 591     {
 592         if( !this.initStatusOK && this.useSessions )
 593             throw new Error(
 594             'Pz2.js: bytarget command has to be preceded with a search command.'
 595             );
 596
 597         // no need to continue
 598         if( !this.searchStatusOK )
 599             return;
 600
 601         // if called explicitly takes precedence
 602         clearTimeout(this.bytargetTimer);
 603
 604         var context = this;
 605         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 606         request.safeGet(
 607             { "command": "bytarget", "session": this.sessionID },
 608             function(data) {
 609                 if ( data.getElementsByTagName("status")[0]
 610                         .childNodes[0].nodeValue == "OK" ) {
 611                     var targetNodes = data.getElementsByTagName("target");
 612                     var bytarget = new Array();
 613                     for ( i = 0; i < targetNodes.length; i++) {
 614                         bytarget[i] = new Array();
 615                         for( j = 0; j < targetNodes[i].childNodes.length; j++ ) {
 616                             if ( targetNodes[i].childNodes[j].nodeType
 617                                 == Node.ELEMENT_NODE ) {
 618                                 var nodeName =
 619                                     targetNodes[i].childNodes[j].nodeName;
 620                                 var nodeText =
 621                                     targetNodes[i].childNodes[j]
 622                                         .firstChild.nodeValue;
 623                                 bytarget[i][nodeName] = nodeText;
 624                             }
 625                         }
 626                     }
 627
 628                     context.bytargetCounter++;
 629                     var delay = context.bytargetTime
 630                         + context.bytargetCounter * context.dumpFactor;
 631                     if ( context.activeClients > 0 )
 632                         context.bytargetTimer =
 633                             setTimeout(
 634                                 function () {
 635                                     context.bytarget();
 636                                 },
 637                                 delay
 638                             );
 639
 640                     context.bytargetCallback(bytarget);
 641                 }
 642                 else
 643                     context.throwError('Bytarget failed. Malformed WS resonse.',
 644                                         117);
 645             }
 646         );
 647     },
 648
 649     // just for testing, probably shouldn't be here
 650     showNext: function(page)
 651     {
 652         var step = page || 1;
 653         this.show( ( step * this.currentNum ) + this.currentStart );
 654     },
 655
 656     showPrev: function(page)
 657     {
 658         if (this.currentStart == 0 )
 659             return false;
 660         var step = page || 1;
 661         var newStart = this.currentStart - (step * this.currentNum );
 662         this.show( newStart > 0 ? newStart : 0 );
 663     },
 664
 665     showPage: function(pageNum)
 666     {
 667         //var page = pageNum || 1;
 668         this.show(pageNum * this.currentNum);
 669     }
 670 };
 671
 672 /*
 673 ********************************************************************************
 674 ** AJAX HELPER CLASS ***********************************************************
 675 ********************************************************************************
 676 */
 677 var pzHttpRequest = function ( url, errorHandler ) {
 678         this.maxUrlLength = 2048;
 679         this.request = null;
 680         this.url = url;
 681         this.errorHandler = errorHandler || null;
 682         this.async = true;
 683         this.requestHeaders = {};
 684
 685         if ( window.XMLHttpRequest ) {
 686             this.request = new XMLHttpRequest();
 687         } else if ( window.ActiveXObject ) {
 688             try {
 689                 this.request = new ActiveXObject( 'Msxml2.XMLHTTP' );
 690             } catch (err) {
 691                 this.request = new ActiveXObject( 'Microsoft.XMLHTTP' );
 692             }
 693         }
 694 };
 695
 696 pzHttpRequest.prototype =
 697 {
 698     safeGet: function ( params, callback )
 699     {
 700         var encodedParams =  this.encodeParams(params);
 701         var url = this._urlAppendParams(encodedParams);
 702         if (url.length >= this.maxUrlLength) {
 703             this.requestHeaders["Content-Type"]
 704                 = "application/x-www-form-urlencoded";
 705             this._send( 'POST', this.url, encodedParams, callback );
 706         } else {
 707             this._send( 'GET', url, '', callback );
 708         }
 709     },
 710
 711     get: function ( params, callback )
 712     {
 713         this._send( 'GET', this._urlAppendParams(this.encodeParams(params)),
 714             '', callback );
 715     },
 716
 717     post: function ( params, data, callback )
 718     {
 719         this._send( 'POST', this._urlAppendParams(this.encodeParams(params)),
 720             data, callback );
 721     },
 722
 723     load: function ()
 724     {
 725         this.async = false;
 726         this.request.open( 'GET', this.url, this.async );
 727         this.request.send('');
 728         if ( this.request.status == 200 )
 729             return this.request.responseXML;
 730     },
 731
 732     encodeParams: function (params)
 733     {
 734         var sep = "";
 735         var encoded = "";
 736         for (var key in params) {
 737             if (params[key] != null) {
 738                 encoded += sep + key + '=' + encodeURIComponent(params[key]);
 739                 sep = '&';
 740             }
 741         }
 742         return encoded;
 743     },
 744
 745     _send: function ( type, url, data, callback)
 746     {
 747         var context = this;
 748         this.callback = callback;
 749         this.async = true;
 750         this.request.open( type, url, this.async );
 751         for (var key in this.requestHeaders)
 752             this.request.setRequestHeader(key, this.requestHeaders[key]);
 753         this.request.onreadystatechange = function () {
 754             context._handleResponse();
 755         }
 756         this.request.send(data);
 757     },
 758
 759     _urlAppendParams: function (encodedParams)
 760     {
 761         if (encodedParams)
 762             return this.url + "?" + encodedParams;
 763         else
 764             return this.url;
 765     },
 766
 767     _handleResponse: function ()
 768     {
 769         if ( this.request.readyState == 4 ) {
 770             // pick up appplication errors first
 771             var errNode = null;
 772             if (this.request.responseXML &&
 773                 (errNode = this.request.responseXML.documentElement)
 774                 && errNode.nodeName == 'error') {
 775                 var errMsg = errNode.getAttribute("msg");
 776                 var errCode = errNode.getAttribute("code");
 777                 var errAddInfo = '';
 778                 if (errNode.childNodes.length)
 779                     errAddInfo = ': ' + errNode.childNodes[0].nodeValue;
 780
 781                 var err = new Error(errMsg + errAddInfo);
 782                 err.code = errCode;
 783
 784                 if (this.errorHandler) {
 785                     this.errorHandler(err);
 786                 }
 787                 else {
 788                     throw err;
 789                 }
 790             } else if (this.request.status == 200) {
 791                 this.callback(this.request.responseXML);
 792             } else {
 793                 var err = new Error("HTTP response not OK: "
 794                             + this.request.status + " - "
 795                             + this.request.statusText );
 796                 err.code = '00' + this.request.status;
 797
 798                 if (this.errorHandler) {
 799                     this.errorHandler(err);
 800                 }
 801                 else {
 802                     throw err;
 803                 }
 804             }
 805         }
 806     }
 807 };
 808
 809 /*
 810 ********************************************************************************
 811 ** XML HELPER FUNCTIONS ********************************************************
 812 ********************************************************************************
 813 */
 814
 815 // DOMDocument
 816
 817 if ( window.ActiveXObject) {
 818     var DOMDoc = document;
 819 } else {
 820     var DOMDoc = Document.prototype;
 821 }
 822
 823 DOMDoc.newXmlDoc = function ( root )
 824 {
 825     var doc;
 826
 827     if (document.implementation && document.implementation.createDocument) {
 828         doc = document.implementation.createDocument('', root, null);
 829     } else if ( window.ActiveXObject ) {
 830         doc = new ActiveXObject("MSXML2.DOMDocument");
 831         doc.loadXML('<' + root + '/>');
 832     } else {
 833         throw new Error ('No XML support in this browser');
 834     }
 835
 836     return doc;
 837 }
 838
 839
 840 DOMDoc.parseXmlFromString = function ( xmlString )
 841 {
 842     var doc;
 843
 844     if ( window.DOMParser ) {
 845         var parser = new DOMParser();
 846         doc = parser.parseFromString( xmlString, "text/xml");
 847     } else if ( window.ActiveXObject ) {
 848         doc = new ActiveXObject("MSXML2.DOMDocument");
 849         doc.loadXML( xmlString );
 850     } else {
 851         throw new Error ("No XML parsing support in this browser.");
 852     }
 853
 854     return doc;
 855 }
 856
 857 DOMDoc.transformToDoc = function (xmlDoc, xslDoc)
 858 {
 859     if ( window.XSLTProcessor ) {
 860         var proc = new XSLTProcessor();
 861         proc.importStylesheet( xslDoc );
 862         return proc.transformToDocument(xmlDoc);
 863     } else if ( window.ActiveXObject ) {
 864         return document.parseXmlFromString(xmlDoc.transformNode(xslDoc));
 865     } else {
 866         alert( 'Unable to perform XSLT transformation in this browser' );
 867     }
 868 }
 869
 870 // DOMElement
 871
 872 Element_removeFromDoc = function (DOM_Element)
 873 {
 874     DOM_Element.parentNode.removeChild(DOM_Element);
 875 }
 876
 877 Element_emptyChildren = function (DOM_Element)
 878 {
 879     while( DOM_Element.firstChild ) {
 880         DOM_Element.removeChild( DOM_Element.firstChild )
 881     }
 882 }
 883
 884 Element_appendTransformResult = function ( DOM_Element, xmlDoc, xslDoc )
 885 {
 886     if ( window.XSLTProcessor ) {
 887         var proc = new XSLTProcessor();
 888         proc.importStylesheet( xslDoc );
 889         var docFrag = false;
 890         docFrag = proc.transformToFragment( xmlDoc, DOM_Element.ownerDocument );
 891         DOM_Element.appendChild(docFrag);
 892     } else if ( window.ActiveXObject ) {
 893         DOM_Element.innerHTML = xmlDoc.transformNode( xslDoc );
 894     } else {
 895         alert( 'Unable to perform XSLT transformation in this browser' );
 896     }
 897 }
 898
 899 Element_appendTextNode = function (DOM_Element, tagName, textContent )
 900 {
 901     var node = DOM_Element.ownerDocument.createElement(tagName);
 902     var text = DOM_Element.ownerDocument.createTextNode(textContent);
 903
 904     DOM_Element.appendChild(node);
 905     node.appendChild(text);
 906
 907     return node;
 908 }
 909
 910 Element_setTextContent = function ( DOM_Element, textContent )
 911 {
 912     if (typeof DOM_Element.textContent !== "undefined") {
 913         DOM_Element.textContent = textContent;
 914     } else if (typeof DOM_Element.innerText !== "undefined" ) {
 915         DOM_Element.innerText = textContent;
 916     } else {
 917         throw new Error("Cannot set text content of the node, no such method.");
 918     }
 919 }
 920
 921 Element_getTextContent = function (DOM_Element)
 922 {
 923     if ( typeof DOM_Element.textContent != 'undefined' ) {
 924         return DOM_Element.textContent;
 925     } else if (typeof DOM_Element.text != 'undefined') {
 926         return DOM_Element.text;
 927     } else {
 928         throw new Error("Cannot get text content of the node, no such method.");
 929     }
 930 }
 931
 932 Element_parseChildNodes = function (node)
 933 {
 934     var parsed = {};
 935     var hasChildElems = false;
 936
 937     if (node.hasChildNodes()) {
 938         var children = node.childNodes;
 939         for (var i = 0; i < children.length; i++) {
 940             var child = children[i];
 941             if (child.nodeType == Node.ELEMENT_NODE) {
 942                 hasChildElems = true;
 943                 var nodeName = child.nodeName;
 944                 if (!(nodeName in parsed))
 945                     parsed[nodeName] = [];
 946                 parsed[nodeName].push(Element_parseChildNodes(child));
 947             }
 948         }
 949     }
 950
 951     var attrs = node.attributes;
 952     for (var i = 0; i < attrs.length; i++) {
 953         var attrName = '@' + attrs[i].nodeName;
 954         var attrValue = attrs[i].nodeValue;
 955         parsed[attrName] = attrValue;
 956     }
 957
 958     // if no nested elements, get text content
 959     if (node.hasChildNodes() && !hasChildElems) {
 960         if (node.attributes.length)
 961             parsed['textContent'] = node.firstChild.nodeValue;
 962         else
 963             parsed = node.firstChild.nodeValue;
 964     }
 965
 966     return parsed;
 967 }
 968
 969 /* do not remove trailing bracket */
 970 }