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