js/pz2.js

   1 /*
   2  * Mine
   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     this.showResponseType = paramArray.showResponseType || "xml";
  52
  53     // function callbacks
  54     this.initCallback = paramArray.oninit || null;
  55     this.statCallback = paramArray.onstat || null;
  56     this.showCallback = paramArray.onshow || null;
  57     this.termlistCallback = paramArray.onterm || null;
  58     this.recordCallback = paramArray.onrecord || null;
  59     this.bytargetCallback = paramArray.onbytarget || null;
  60     this.resetCallback = paramArray.onreset || null;
  61
  62     // termlist keys
  63     this.termKeys = paramArray.termlist || "subject";
  64
  65     // some configurational stuff
  66     this.keepAlive = 50000;
  67
  68     if ( paramArray.keepAlive < this.keepAlive )
  69         this.keepAlive = paramArray.keepAlive;
  70
  71     this.sessionID = null;
  72     this.initStatusOK = false;
  73     this.pingStatusOK = false;
  74     this.searchStatusOK = false;
  75
  76     // for sorting
  77     this.currentSort = "relevance";
  78
  79     // where are we?
  80     this.currentStart = 0;
  81     this.currentNum = 20;
  82
  83     // last full record retrieved
  84     this.currRecID = null;
  85
  86     // current query
  87     this.currQuery = null;
  88
  89     //current raw record offset
  90     this.currRecOffset = null;
  91
  92     //timers
  93     this.statTime = paramArray.stattime || 1000;
  94     this.statTimer = null;
  95     this.termTime = paramArray.termtime || 1000;
  96     this.termTimer = null;
  97     this.showTime = paramArray.showtime || 1000;
  98     this.showTimer = null;
  99     this.showFastCount = 4;
 100     this.bytargetTime = paramArray.bytargettime || 1000;
 101     this.bytargetTimer = null;
 102     this.recordTime = paramArray.recordtime || 500;
 103     this.recordTimer = null;
 104
 105     // counters for each command and applied delay
 106     this.dumpFactor = 500;
 107     this.showCounter = 0;
 108     this.termCounter = 0;
 109     this.statCounter = 0;
 110     this.bytargetCounter = 0;
 111     this.recordCounter = 0;
 112
 113     // active clients, updated by stat and show
 114     // might be an issue since bytarget will poll accordingly
 115     this.activeClients = 1;
 116
 117     // if in proxy mode no need to init
 118     if (paramArray.usesessions != undefined) {
 119          this.useSessions = paramArray.usesessions;
 120         this.initStatusOK = true;
 121     }
 122     // else, auto init session or wait for a user init?
 123     if (this.useSessions && paramArray.autoInit !== false) {
 124         this.init();
 125     }
 126 };
 127
 128 pz2.prototype =
 129 {
 130     //error handler for async error throws
 131    throwError: function (errMsg, errCode)
 132    {
 133         var err = new Error(errMsg);
 134         if (errCode) err.code = errCode;
 135
 136         if (this.errorHandler) {
 137             this.errorHandler(err);
 138         }
 139         else {
 140             throw err;
 141         }
 142    },
 143
 144     // stop activity by clearing tiemouts
 145    stop: function ()
 146    {
 147        clearTimeout(this.statTimer);
 148        clearTimeout(this.showTimer);
 149        clearTimeout(this.termTimer);
 150        clearTimeout(this.bytargetTimer);
 151     },
 152
 153     // reset status variables
 154     reset: function ()
 155     {
 156         if ( this.useSessions ) {
 157             this.sessionID = null;
 158             this.initStatusOK = false;
 159             this.pingStatusOK = false;
 160         }
 161         this.searchStatusOK = false;
 162         this.stop();
 163
 164         if ( this.resetCallback )
 165                 this.resetCallback();
 166     },
 167
 168     init: function ( sessionId )
 169     {
 170         this.reset();
 171
 172         // session id as a param
 173         if ( sessionId != undefined && this.useSessions ) {
 174             this.initStatusOK = true;
 175             this.sessionID = sessionId;
 176             this.ping();
 177         // old school direct pazpar2 init
 178         } else if (this.useSessions) {
 179             var context = this;
 180             var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 181             request.safeGet(
 182                 { "command": "init" },
 183                 function(data) {
 184                     if ( data.getElementsByTagName("status")[0]
 185                             .childNodes[0].nodeValue == "OK" ) {
 186                         if ( data.getElementsByTagName("protocol")[0]
 187                                 .childNodes[0].nodeValue
 188                             != context.suppProtoVer )
 189                             throw new Error(
 190                                 "Server's protocol not supported by the client"
 191                             );
 192                         context.initStatusOK = true;
 193                         context.sessionID =
 194                             data.getElementsByTagName("session")[0]
 195                                 .childNodes[0].nodeValue;
 196                         setTimeout(
 197                             function () {
 198                                 context.ping();
 199                             },
 200                             context.keepAlive
 201                         );
 202                         if ( context.initCallback )
 203                             context.initCallback();
 204                     }
 205                     else
 206                         context.throwError('Init failed. Malformed WS resonse.',
 207                                             110);
 208                 }
 209             );
 210         // when through proxy no need to init
 211         } else {
 212             this.initStatusOK = true;
 213         }
 214     },
 215     // no need to ping explicitly
 216     ping: function ()
 217     {
 218         // pinging only makes sense when using pazpar2 directly
 219         if( !this.initStatusOK || !this.useSessions )
 220             throw new Error(
 221             'Pz2.js: Ping not allowed (proxy mode) or session not initialized.'
 222             );
 223         var context = this;
 224         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 225         request.safeGet(
 226             { "command": "ping", "session": this.sessionID },
 227             function(data) {
 228                 if ( data.getElementsByTagName("status")[0]
 229                         .childNodes[0].nodeValue == "OK" ) {
 230                     context.pingStatusOK = true;
 231                     setTimeout(
 232                         function () {
 233                             context.ping();
 234                         },
 235                         context.keepAlive
 236                     );
 237                 }
 238                 else
 239                     context.throwError('Ping failed. Malformed WS resonse.',
 240                                         111);
 241             }
 242         );
 243     },
 244     search: function (query, num, sort, filter, showfrom, addParamsArr)
 245     {
 246         clearTimeout(this.statTimer);
 247         clearTimeout(this.showTimer);
 248         clearTimeout(this.termTimer);
 249         clearTimeout(this.bytargetTimer);
 250
 251         this.showCounter = 0;
 252         this.termCounter = 0;
 253         this.bytargetCounter = 0;
 254         this.statCounter = 0;
 255         this.activeClients = 1;
 256
 257         // no proxy mode
 258         if( !this.initStatusOK )
 259             throw new Error('Pz2.js: session not initialized.');
 260
 261         if( query !== undefined )
 262             this.currQuery = query;
 263         else
 264             throw new Error("Pz2.js: no query supplied to the search command.");
 265
 266         if ( showfrom !== undefined )
 267             var start = showfrom;
 268         else
 269             var start = 0;
 270
 271         var searchParams = {
 272             "command": "search",
 273             "query": this.currQuery,
 274             "session": this.sessionID
 275         };
 276
 277         if (filter !== undefined)
 278             searchParams["filter"] = filter;
 279
 280         // copy additional parmeters, do not overwrite
 281         if (addParamsArr != undefined) {
 282             for (var prop in addParamsArr) {
 283                 if (!searchParams.hasOwnProperty(prop))
 284                     searchParams[prop] = addParamsArr[prop];
 285             }
 286         }
 287
 288         var context = this;
 289         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 290         request.safeGet(
 291             searchParams,
 292             function(data) {
 293                 if ( data.getElementsByTagName("status")[0]
 294                         .childNodes[0].nodeValue == "OK" ) {
 295                     context.searchStatusOK = true;
 296                     //piggyback search
 297                     context.show(start, num, sort);
 298                     if (context.statCallback)
 299                         context.stat();
 300                     if (context.termlistCallback)
 301                         context.termlist();
 302                     if (context.bytargetCallback)
 303                         context.bytarget();
 304                 }
 305                 else
 306                     context.throwError('Search failed. Malformed WS resonse.',
 307                                         112);
 308             }
 309         );
 310     },
 311     stat: function()
 312     {
 313         if( !this.initStatusOK )
 314             throw new Error('Pz2.js: session not initialized.');
 315
 316         // if called explicitly takes precedence
 317         clearTimeout(this.statTimer);
 318
 319         var context = this;
 320         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 321         request.safeGet(
 322             { "command": "stat", "session": this.sessionID },
 323             function(data) {
 324                 if ( data.getElementsByTagName("stat") ) {
 325                     var activeClients =
 326                         Number( data.getElementsByTagName("activeclients")[0]
 327                                     .childNodes[0].nodeValue );
 328                     context.activeClients = activeClients;
 329
 330                     var stat = Element_parseChildNodes(data.documentElement);
 331
 332                     context.statCounter++;
 333                     var delay = context.statTime
 334                         + context.statCounter * context.dumpFactor;
 335
 336                     if ( activeClients > 0 )
 337                         context.statTimer =
 338                             setTimeout(
 339                                 function () {
 340                                     context.stat();
 341                                 },
 342                                 delay
 343                             );
 344                     context.statCallback(stat);
 345                 }
 346                 else
 347                     context.throwError('Stat failed. Malformed WS resonse.',
 348                                         113);
 349             }
 350         );
 351     },
 352     show: function(start, num, sort)
 353     {
 354         if( !this.searchStatusOK && this.useSessions )
 355             throw new Error(
 356                 'Pz2.js: show command has to be preceded with a search command.'
 357             );
 358
 359         // if called explicitly takes precedence
 360         clearTimeout(this.showTimer);
 361
 362         if( sort !== undefined )
 363             this.currentSort = sort;
 364         if( start !== undefined )
 365             this.currentStart = Number( start );
 366         if( num !== undefined )
 367             this.currentNum = Number( num );
 368
 369         var context = this;
 370         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 371         request.safeGet(
 372           {
 373             "command": "show",
 374             "session": this.sessionID,
 375             "start": this.currentStart,
 376             "num": this.currentNum,
 377             "sort": this.currentSort,
 378             "block": 1,
 379             "type": this.showResponseType
 380           },
 381           function(data, type) {
 382             var show = null;
 383             if (type === "json") {
 384               show = {};
 385               context.activeClients = Number(data.activeclients[0]);
 386               show.activeclients = context.activeClients;
 387               show.merged = Number(data.merged[0]);
 388               show.total = Number(data.total[0]);
 389               show.start = Number(data.start[0]);
 390               show.num = Number(data.num[0]);
 391               show.hits = data.hit;
 392             } else if (data.getElementsByTagName("status")[0]
 393                   .childNodes[0].nodeValue == "OK") {
 394                 // first parse the status data send along with records
 395                 // this is strictly bound to the format
 396                 var activeClients =
 397                   Number(data.getElementsByTagName("activeclients")[0]
 398                       .childNodes[0].nodeValue);
 399                 context.activeClients = activeClients;
 400                 show = {
 401                   "activeclients": activeClients,
 402                   "merged":
 403                     Number( data.getElementsByTagName("merged")[0]
 404                         .childNodes[0].nodeValue ),
 405                   "total":
 406                     Number( data.getElementsByTagName("total")[0]
 407                         .childNodes[0].nodeValue ),
 408                   "start":
 409                     Number( data.getElementsByTagName("start")[0]
 410                         .childNodes[0].nodeValue ),
 411                   "num":
 412                     Number( data.getElementsByTagName("num")[0]
 413                         .childNodes[0].nodeValue ),
 414                   "hits": []
 415                 };
 416                 // parse all the first-level nodes for all <hit> tags
 417                 var hits = data.getElementsByTagName("hit");
 418                 for (i = 0; i < hits.length; i++)
 419                   show.hits[i] = Element_parseChildNodes(hits[i]);
 420             } else {
 421               context.throwError('Show failed. Malformed WS resonse.',
 422                   114);
 423             }
 424             context.showCounter++;
 425             var delay = context.showTime;
 426             if (context.showCounter > context.showFastCount)
 427               delay += context.showCounter * context.dumpFactor;
 428             if ( activeClients > 0 )
 429               context.showTimer = setTimeout(
 430                 function () {
 431                   context.show();
 432                 },
 433                 delay);
 434             context.showCallback(show);
 435           }
 436         );
 437     },
 438     record: function(id, offset, syntax, handler)
 439     {
 440         // we may call record with no previous search if in proxy mode
 441         if(!this.searchStatusOK && this.useSessions)
 442            throw new Error(
 443             'Pz2.js: record command has to be preceded with a search command.'
 444             );
 445
 446         if( id !== undefined )
 447             this.currRecID = id;
 448
 449         var recordParams = {
 450             "command": "record",
 451             "session": this.sessionID,
 452             "id": this.currRecID
 453         };
 454
 455         this.currRecOffset = null;
 456         if (offset != undefined) {
 457             recordParams["offset"] = offset;
 458             this.currRecOffset = offset;
 459         }
 460
 461         if (syntax != undefined)
 462             recordParams['syntax'] = syntax;
 463
 464         //overwrite default callback id needed
 465         var callback = this.recordCallback;
 466         var args = undefined;
 467         if (handler != undefined) {
 468             callback = handler['callback'];
 469             args = handler['args'];
 470         }
 471
 472         var context = this;
 473         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 474
 475         request.safeGet(
 476             recordParams,
 477             function(data) {
 478                 var recordNode;
 479                 var record;
 480                 //raw record
 481                 if (context.currRecOffset !== null) {
 482                     record = new Array();
 483                     record['xmlDoc'] = data;
 484                     record['offset'] = context.currRecOffset;
 485                     callback(record, args);
 486                 //pz2 record
 487                 } else if ( recordNode =
 488                     data.getElementsByTagName("record")[0] ) {
 489                     // if stylesheet was fetched do not parse the response
 490                     if ( context.xslDoc ) {
 491                         record = new Array();
 492                         record['xmlDoc'] = data;
 493                         record['xslDoc'] = context.xslDoc;
 494                         record['recid'] =
 495                             recordNode.getElementsByTagName("recid")[0]
 496                                 .firstChild.nodeValue;
 497                     //parse record
 498                     } else {
 499                         record = Element_parseChildNodes(recordNode);
 500                     }
 501                     var activeClients =
 502                        Number( data.getElementsByTagName("activeclients")[0]
 503                                 .childNodes[0].nodeValue );
 504                     context.activeClients = activeClients;
 505                     context.recordCounter++;
 506                     var delay = context.recordTime + context.recordCounter * context.dumpFactor;
 507                     if ( activeClients > 0 )
 508                         context.recordTimer =
 509                            setTimeout (
 510                                function() {
 511                                   context.record(id, offset, syntax, handler);
 512                                   },
 513                                   delay
 514                                );
 515                     callback(record, args);
 516                 }
 517                 else
 518                     context.throwError('Record failed. Malformed WS resonse.',
 519                                         115);
 520             }
 521         );
 522     },
 523
 524     termlist: function()
 525     {
 526         if( !this.searchStatusOK && this.useSessions )
 527             throw new Error(
 528             'Pz2.js: termlist command has to be preceded with a search command.'
 529             );
 530
 531         // if called explicitly takes precedence
 532         clearTimeout(this.termTimer);
 533
 534         var context = this;
 535         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 536         request.safeGet(
 537             {
 538                 "command": "termlist",
 539                 "session": this.sessionID,
 540                 "name": this.termKeys
 541             },
 542             function(data) {
 543                 if ( data.getElementsByTagName("termlist") ) {
 544                     var activeClients =
 545                         Number( data.getElementsByTagName("activeclients")[0]
 546                                     .childNodes[0].nodeValue );
 547                     context.activeClients = activeClients;
 548                     var termList = { "activeclients":  activeClients };
 549                     var termLists = data.getElementsByTagName("list");
 550                     //for each termlist
 551                     for (i = 0; i < termLists.length; i++) {
 552                         var listName = termLists[i].getAttribute('name');
 553                         termList[listName] = new Array();
 554                         var terms = termLists[i].getElementsByTagName('term');
 555                         //for each term in the list
 556                         for (j = 0; j < terms.length; j++) {
 557                             var term = {
 558                                 "name":
 559                                     (terms[j].getElementsByTagName("name")[0]
 560                                         .childNodes.length
 561                                     ? terms[j].getElementsByTagName("name")[0]
 562                                         .childNodes[0].nodeValue
 563                                     : 'ERROR'),
 564                                 "freq":
 565                                     terms[j]
 566                                     .getElementsByTagName("frequency")[0]
 567                                     .childNodes[0].nodeValue || 'ERROR'
 568                             };
 569
 570                             var termIdNode =
 571                                 terms[j].getElementsByTagName("id");
 572                             if(terms[j].getElementsByTagName("id").length)
 573                                 term["id"] =
 574                                     termIdNode[0].childNodes[0].nodeValue;
 575                             termList[listName][j] = term;
 576                         }
 577                     }
 578
 579                     context.termCounter++;
 580                     var delay = context.termTime
 581                         + context.termCounter * context.dumpFactor;
 582                     if ( activeClients > 0 )
 583                         context.termTimer =
 584                             setTimeout(
 585                                 function () {
 586                                     context.termlist();
 587                                 },
 588                                 delay
 589                             );
 590
 591                    context.termlistCallback(termList);
 592                 }
 593                 else
 594                     context.throwError('Termlist failed. Malformed WS resonse.',
 595                                         116);
 596             }
 597         );
 598
 599     },
 600     bytarget: function()
 601     {
 602         if( !this.initStatusOK && this.useSessions )
 603             throw new Error(
 604             'Pz2.js: bytarget command has to be preceded with a search command.'
 605             );
 606
 607         // no need to continue
 608         if( !this.searchStatusOK )
 609             return;
 610
 611         // if called explicitly takes precedence
 612         clearTimeout(this.bytargetTimer);
 613
 614         var context = this;
 615         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 616         request.safeGet(
 617             { "command": "bytarget", "session": this.sessionID },
 618             function(data) {
 619                 if ( data.getElementsByTagName("status")[0]
 620                         .childNodes[0].nodeValue == "OK" ) {
 621                     var targetNodes = data.getElementsByTagName("target");
 622                     var bytarget = new Array();
 623                     for ( i = 0; i < targetNodes.length; i++) {
 624                         bytarget[i] = new Array();
 625                         for( j = 0; j < targetNodes[i].childNodes.length; j++ ) {
 626                             if ( targetNodes[i].childNodes[j].nodeType
 627                                 == Node.ELEMENT_NODE ) {
 628                                 var nodeName =
 629                                     targetNodes[i].childNodes[j].nodeName;
 630                                 var nodeText =
 631                                     targetNodes[i].childNodes[j]
 632                                         .firstChild.nodeValue;
 633                                 bytarget[i][nodeName] = nodeText;
 634                             }
 635                         }
 636                     }
 637
 638                     context.bytargetCounter++;
 639                     var delay = context.bytargetTime
 640                         + context.bytargetCounter * context.dumpFactor;
 641                     if ( context.activeClients > 0 )
 642                         context.bytargetTimer =
 643                             setTimeout(
 644                                 function () {
 645                                     context.bytarget();
 646                                 },
 647                                 delay
 648                             );
 649
 650                     context.bytargetCallback(bytarget);
 651                 }
 652                 else
 653                     context.throwError('Bytarget failed. Malformed WS resonse.',
 654                                         117);
 655             }
 656         );
 657     },
 658
 659     // just for testing, probably shouldn't be here
 660     showNext: function(page)
 661     {
 662         var step = page || 1;
 663         this.show( ( step * this.currentNum ) + this.currentStart );
 664     },
 665
 666     showPrev: function(page)
 667     {
 668         if (this.currentStart == 0 )
 669             return false;
 670         var step = page || 1;
 671         var newStart = this.currentStart - (step * this.currentNum );
 672         this.show( newStart > 0 ? newStart : 0 );
 673     },
 674
 675     showPage: function(pageNum)
 676     {
 677         //var page = pageNum || 1;
 678         this.show(pageNum * this.currentNum);
 679     }
 680 };
 681
 682 /*
 683 ********************************************************************************
 684 ** AJAX HELPER CLASS ***********************************************************
 685 ********************************************************************************
 686 */
 687 var pzHttpRequest = function ( url, errorHandler ) {
 688         this.maxUrlLength = 2048;
 689         this.request = null;
 690         this.url = url;
 691         this.errorHandler = errorHandler || null;
 692         this.async = true;
 693         this.requestHeaders = {};
 694
 695         if ( window.XMLHttpRequest ) {
 696             this.request = new XMLHttpRequest();
 697         } else if ( window.ActiveXObject ) {
 698             try {
 699                 this.request = new ActiveXObject( 'Msxml2.XMLHTTP' );
 700             } catch (err) {
 701                 this.request = new ActiveXObject( 'Microsoft.XMLHTTP' );
 702             }
 703         }
 704 };
 705
 706 pzHttpRequest.prototype =
 707 {
 708     safeGet: function ( params, callback )
 709     {
 710         var encodedParams =  this.encodeParams(params);
 711         var url = this._urlAppendParams(encodedParams);
 712         if (url.length >= this.maxUrlLength) {
 713             this.requestHeaders["Content-Type"]
 714                 = "application/x-www-form-urlencoded";
 715             this._send( 'POST', this.url, encodedParams, callback );
 716         } else {
 717             this._send( 'GET', url, '', callback );
 718         }
 719     },
 720
 721     get: function ( params, callback )
 722     {
 723         this._send( 'GET', this._urlAppendParams(this.encodeParams(params)),
 724             '', callback );
 725     },
 726
 727     post: function ( params, data, callback )
 728     {
 729         this._send( 'POST', this._urlAppendParams(this.encodeParams(params)),
 730             data, callback );
 731     },
 732
 733     load: function ()
 734     {
 735         this.async = false;
 736         this.request.open( 'GET', this.url, this.async );
 737         this.request.send('');
 738         if ( this.request.status == 200 )
 739             return this.request.responseXML;
 740     },
 741
 742     encodeParams: function (params)
 743     {
 744         var sep = "";
 745         var encoded = "";
 746         for (var key in params) {
 747             if (params[key] != null) {
 748                 encoded += sep + key + '=' + encodeURIComponent(params[key]);
 749                 sep = '&';
 750             }
 751         }
 752         return encoded;
 753     },
 754
 755     _send: function ( type, url, data, callback)
 756     {
 757         var context = this;
 758         this.callback = callback;
 759         this.async = true;
 760         this.request.open( type, url, this.async );
 761         for (var key in this.requestHeaders)
 762             this.request.setRequestHeader(key, this.requestHeaders[key]);
 763         this.request.onreadystatechange = function () {
 764             context._handleResponse(url); /// url used ONLY for error reporting
 765         }
 766         this.request.send(data);
 767     },
 768
 769     _urlAppendParams: function (encodedParams)
 770     {
 771         if (encodedParams)
 772             return this.url + "?" + encodedParams;
 773         else
 774             return this.url;
 775     },
 776
 777     _handleResponse: function (savedUrlForErrorReporting)
 778     {
 779         if ( this.request.readyState == 4 ) {
 780             // pick up appplication errors first
 781             var errNode = null;
 782             if (this.request.responseXML &&
 783                 (errNode = this.request.responseXML.documentElement)
 784                 && errNode.nodeName == 'error') {
 785                 var errMsg = errNode.getAttribute("msg");
 786                 var errCode = errNode.getAttribute("code");
 787                 var errAddInfo = '';
 788                 if (errNode.childNodes.length)
 789                     errAddInfo = ': ' + errNode.childNodes[0].nodeValue;
 790
 791                 var err = new Error(errMsg + errAddInfo);
 792                 err.code = errCode;
 793
 794                 if (this.errorHandler) {
 795                     this.errorHandler(err);
 796                 }
 797                 else {
 798                     throw err;
 799                 }
 800             } else if (this.request.status == 200 &&
 801                        this.request.responseXML == null) {
 802               if (this.request.responseText != null) {
 803                 //assume JSON
 804                 var json = eval("(" + this.request.responseText + ")");
 805                 this.callback(json, "json");
 806               } else {
 807                 var err = new Error("XML response is empty but no error " +
 808                                     "for " + savedUrlForErrorReporting);
 809                 err.code = -1;
 810                 if (this.errorHandler) {
 811                     this.errorHandler(err);
 812                 } else {
 813                     throw err;
 814                 }
 815               }
 816             } else if (this.request.status == 200) {
 817                 this.callback(this.request.responseXML);
 818             } else {
 819                 var err = new Error("HTTP response not OK: "
 820                             + this.request.status + " - "
 821                             + this.request.statusText );
 822                 err.code = '00' + this.request.status;
 823                 if (this.errorHandler) {
 824                     this.errorHandler(err);
 825                 }
 826                 else {
 827                     throw err;
 828                 }
 829             }
 830         }
 831     }
 832 };
 833
 834 /*
 835 ********************************************************************************
 836 ** XML HELPER FUNCTIONS ********************************************************
 837 ********************************************************************************
 838 */
 839
 840 // DOMDocument
 841
 842 if ( window.ActiveXObject) {
 843     var DOMDoc = document;
 844 } else {
 845     var DOMDoc = Document.prototype;
 846 }
 847
 848 DOMDoc.newXmlDoc = function ( root )
 849 {
 850     var doc;
 851
 852     if (document.implementation && document.implementation.createDocument) {
 853         doc = document.implementation.createDocument('', root, null);
 854     } else if ( window.ActiveXObject ) {
 855         doc = new ActiveXObject("MSXML2.DOMDocument");
 856         doc.loadXML('<' + root + '/>');
 857     } else {
 858         throw new Error ('No XML support in this browser');
 859     }
 860
 861     return doc;
 862 }
 863
 864
 865 DOMDoc.parseXmlFromString = function ( xmlString )
 866 {
 867     var doc;
 868
 869     if ( window.DOMParser ) {
 870         var parser = new DOMParser();
 871         doc = parser.parseFromString( xmlString, "text/xml");
 872     } else if ( window.ActiveXObject ) {
 873         doc = new ActiveXObject("MSXML2.DOMDocument");
 874         doc.loadXML( xmlString );
 875     } else {
 876         throw new Error ("No XML parsing support in this browser.");
 877     }
 878
 879     return doc;
 880 }
 881
 882 DOMDoc.transformToDoc = function (xmlDoc, xslDoc)
 883 {
 884     if ( window.XSLTProcessor ) {
 885         var proc = new XSLTProcessor();
 886         proc.importStylesheet( xslDoc );
 887         return proc.transformToDocument(xmlDoc);
 888     } else if ( window.ActiveXObject ) {
 889         return document.parseXmlFromString(xmlDoc.transformNode(xslDoc));
 890     } else {
 891         alert( 'Unable to perform XSLT transformation in this browser' );
 892     }
 893 }
 894
 895 // DOMElement
 896
 897 Element_removeFromDoc = function (DOM_Element)
 898 {
 899     DOM_Element.parentNode.removeChild(DOM_Element);
 900 }
 901
 902 Element_emptyChildren = function (DOM_Element)
 903 {
 904     while( DOM_Element.firstChild ) {
 905         DOM_Element.removeChild( DOM_Element.firstChild )
 906     }
 907 }
 908
 909 Element_appendTransformResult = function ( DOM_Element, xmlDoc, xslDoc )
 910 {
 911     if ( window.XSLTProcessor ) {
 912         var proc = new XSLTProcessor();
 913         proc.importStylesheet( xslDoc );
 914         var docFrag = false;
 915         docFrag = proc.transformToFragment( xmlDoc, DOM_Element.ownerDocument );
 916         DOM_Element.appendChild(docFrag);
 917     } else if ( window.ActiveXObject ) {
 918         DOM_Element.innerHTML = xmlDoc.transformNode( xslDoc );
 919     } else {
 920         alert( 'Unable to perform XSLT transformation in this browser' );
 921     }
 922 }
 923
 924 Element_appendTextNode = function (DOM_Element, tagName, textContent )
 925 {
 926     var node = DOM_Element.ownerDocument.createElement(tagName);
 927     var text = DOM_Element.ownerDocument.createTextNode(textContent);
 928
 929     DOM_Element.appendChild(node);
 930     node.appendChild(text);
 931
 932     return node;
 933 }
 934
 935 Element_setTextContent = function ( DOM_Element, textContent )
 936 {
 937     if (typeof DOM_Element.textContent !== "undefined") {
 938         DOM_Element.textContent = textContent;
 939     } else if (typeof DOM_Element.innerText !== "undefined" ) {
 940         DOM_Element.innerText = textContent;
 941     } else {
 942         throw new Error("Cannot set text content of the node, no such method.");
 943     }
 944 }
 945
 946 Element_getTextContent = function (DOM_Element)
 947 {
 948     if ( typeof DOM_Element.textContent != 'undefined' ) {
 949         return DOM_Element.textContent;
 950     } else if (typeof DOM_Element.text != 'undefined') {
 951         return DOM_Element.text;
 952     } else {
 953         throw new Error("Cannot get text content of the node, no such method.");
 954     }
 955 }
 956
 957 Element_parseChildNodes = function (node)
 958 {
 959     var parsed = {};
 960     var hasChildElems = false;
 961
 962     if (node.hasChildNodes()) {
 963         var children = node.childNodes;
 964         for (var i = 0; i < children.length; i++) {
 965             var child = children[i];
 966             if (child.nodeType == Node.ELEMENT_NODE) {
 967                 hasChildElems = true;
 968                 var nodeName = child.nodeName;
 969                 if (!(nodeName in parsed))
 970                     parsed[nodeName] = [];
 971                 parsed[nodeName].push(Element_parseChildNodes(child));
 972             }
 973         }
 974     }
 975
 976     var attrs = node.attributes;
 977     for (var i = 0; i < attrs.length; i++) {
 978         var attrName = '@' + attrs[i].nodeName;
 979         var attrValue = attrs[i].nodeValue;
 980         parsed[attrName] = attrValue;
 981     }
 982
 983     // if no nested elements, get text content
 984     if (node.hasChildNodes() && !hasChildElems) {
 985         if (node.attributes.length)
 986             parsed['#text'] = node.firstChild.nodeValue;
 987         else
 988             parsed = node.firstChild.nodeValue;
 989     }
 990
 991     return parsed;
 992 }
 993
 994 /* do not remove trailing bracket */
 995 }