js/pz2.js

   1 /*
   2 ** $Id: pz2.js,v 1.70 2008-03-12 11:36:57 jakub Exp $
   3 ** pz2.js - pazpar2's javascript client library.
   4 */
   5
   6 //since explorer is flawed
   7 if (!window['Node']) {
   8     window.Node = new Object();
   9     Node.ELEMENT_NODE = 1;
  10     Node.ATTRIBUTE_NODE = 2;
  11     Node.TEXT_NODE = 3;
  12     Node.CDATA_SECTION_NODE = 4;
  13     Node.ENTITY_REFERENCE_NODE = 5;
  14     Node.ENTITY_NODE = 6;
  15     Node.PROCESSING_INSTRUCTION_NODE = 7;
  16     Node.COMMENT_NODE = 8;
  17     Node.DOCUMENT_NODE = 9;
  18     Node.DOCUMENT_TYPE_NODE = 10;
  19     Node.DOCUMENT_FRAGMENT_NODE = 11;
  20     Node.NOTATION_NODE = 12;
  21 }
  22
  23 // prevent execution of more than once
  24 if(typeof window.pz2 == "undefined") {
  25 window.undefined = window.undefined;
  26
  27 var pz2 = function ( paramArray )
  28 {
  29
  30     // at least one callback required
  31     if ( !paramArray )
  32         throw new Error("Pz2.js: Array with parameters has to be suplied.");
  33
  34     //supported pazpar2's protocol version
  35     this.suppProtoVer = '1';
  36     if (typeof paramArray.pazpar2path != "undefined")
  37         this.pz2String = paramArray.pazpar2path;
  38     else
  39         this.pz2String = "/pazpar2/search.pz2";
  40     this.useSessions = true;
  41
  42     this.stylesheet = paramArray.detailstylesheet || null;
  43     //load stylesheet if required in async mode
  44     if( this.stylesheet ) {
  45         var context = this;
  46         var request = new pzHttpRequest( this.stylesheet );
  47         request.get( {}, function ( doc ) { context.xslDoc = doc; } );
  48     }
  49
  50     this.errorHandler = paramArray.errorhandler || null;
  51
  52     // function callbacks
  53     this.initCallback = paramArray.oninit || null;
  54     this.statCallback = paramArray.onstat || null;
  55     this.showCallback = paramArray.onshow || null;
  56     this.termlistCallback = paramArray.onterm || null;
  57     this.recordCallback = paramArray.onrecord || null;
  58     this.bytargetCallback = paramArray.onbytarget || null;
  59     this.resetCallback = paramArray.onreset || null;
  60
  61     // termlist keys
  62     this.termKeys = paramArray.termlist || "subject";
  63
  64     // some configurational stuff
  65     this.keepAlive = 50000;
  66
  67     if ( paramArray.keepAlive < this.keepAlive )
  68         this.keepAlive = paramArray.keepAlive;
  69
  70     this.sessionID = null;
  71     this.initStatusOK = false;
  72     this.pingStatusOK = false;
  73     this.searchStatusOK = false;
  74
  75     // for sorting
  76     this.currentSort = "relevance";
  77
  78     // where are we?
  79     this.currentStart = 0;
  80     this.currentNum = 20;
  81
  82     // last full record retrieved
  83     this.currRecID = null;
  84
  85     // current query
  86     this.currQuery = null;
  87
  88     //current raw record offset
  89     this.currRecOffset = null;
  90
  91     //timers
  92     this.statTime = paramArray.stattime || 1000;
  93     this.statTimer = null;
  94     this.termTime = paramArray.termtime || 1000;
  95     this.termTimer = null;
  96     this.showTime = paramArray.showtime || 1000;
  97     this.showTimer = null;
  98     this.showFastCount = 4;
  99     this.bytargetTime = paramArray.bytargettime || 1000;
 100     this.bytargetTimer = null;
 101     this.recordTime = paramArray.recordtime || 500;
 102     this.recordTimer = null;
 103
 104     // counters for each command and applied delay
 105     this.dumpFactor = 500;
 106     this.showCounter = 0;
 107     this.termCounter = 0;
 108     this.statCounter = 0;
 109     this.bytargetCounter = 0;
 110     this.recordCounter = 0;
 111
 112     // active clients, updated by stat and show
 113     // might be an issue since bytarget will poll accordingly
 114     this.activeClients = 1;
 115
 116     // if in proxy mode no need to init
 117     if (paramArray.usesessions != undefined) {
 118          this.useSessions = paramArray.usesessions;
 119         this.initStatusOK = true;
 120     }
 121     // else, auto init session or wait for a user init?
 122     if (this.useSessions && paramArray.autoInit !== false) {
 123         this.init();
 124     }
 125 };
 126
 127 pz2.prototype =
 128 {
 129     //error handler for async error throws
 130    throwError: function (errMsg, errCode)
 131    {
 132         var err = new Error(errMsg);
 133         if (errCode) err.code = errCode;
 134
 135         if (this.errorHandler) {
 136             this.errorHandler(err);
 137         }
 138         else {
 139             throw err;
 140         }
 141    },
 142
 143     // stop activity by clearing tiemouts
 144    stop: function ()
 145    {
 146        clearTimeout(this.statTimer);
 147        clearTimeout(this.showTimer);
 148        clearTimeout(this.termTimer);
 149        clearTimeout(this.bytargetTimer);
 150     },
 151
 152     // reset status variables
 153     reset: function ()
 154     {
 155         if ( this.useSessions ) {
 156             this.sessionID = null;
 157             this.initStatusOK = false;
 158             this.pingStatusOK = false;
 159         }
 160         this.searchStatusOK = false;
 161         this.stop();
 162
 163         if ( this.resetCallback )
 164                 this.resetCallback();
 165     },
 166
 167     init: function ( sessionId )
 168     {
 169         this.reset();
 170
 171         // session id as a param
 172         if ( sessionId != undefined && this.useSessions ) {
 173             this.initStatusOK = true;
 174             this.sessionID = sessionId;
 175             this.ping();
 176         // old school direct pazpar2 init
 177         } else if (this.useSessions) {
 178             var context = this;
 179             var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 180             request.safeGet(
 181                 { "command": "init" },
 182                 function(data) {
 183                     if ( data.getElementsByTagName("status")[0]
 184                             .childNodes[0].nodeValue == "OK" ) {
 185                         if ( data.getElementsByTagName("protocol")[0]
 186                                 .childNodes[0].nodeValue
 187                             != context.suppProtoVer )
 188                             throw new Error(
 189                                 "Server's protocol not supported by the client"
 190                             );
 191                         context.initStatusOK = true;
 192                         context.sessionID =
 193                             data.getElementsByTagName("session")[0]
 194                                 .childNodes[0].nodeValue;
 195                         setTimeout(
 196                             function () {
 197                                 context.ping();
 198                             },
 199                             context.keepAlive
 200                         );
 201                         if ( context.initCallback )
 202                             context.initCallback();
 203                     }
 204                     else
 205                         context.throwError('Init failed. Malformed WS resonse.',
 206                                             110);
 207                 }
 208             );
 209         // when through proxy no need to init
 210         } else {
 211             this.initStatusOK = true;
 212         }
 213     },
 214     // no need to ping explicitly
 215     ping: function ()
 216     {
 217         // pinging only makes sense when using pazpar2 directly
 218         if( !this.initStatusOK || !this.useSessions )
 219             throw new Error(
 220             'Pz2.js: Ping not allowed (proxy mode) or session not initialized.'
 221             );
 222         var context = this;
 223         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 224         request.safeGet(
 225             { "command": "ping", "session": this.sessionID },
 226             function(data) {
 227                 if ( data.getElementsByTagName("status")[0]
 228                         .childNodes[0].nodeValue == "OK" ) {
 229                     context.pingStatusOK = true;
 230                     setTimeout(
 231                         function () {
 232                             context.ping();
 233                         },
 234                         context.keepAlive
 235                     );
 236                 }
 237                 else
 238                     context.throwError('Ping failed. Malformed WS resonse.',
 239                                         111);
 240             }
 241         );
 242     },
 243     search: function (query, num, sort, filter, showfrom, addParamsArr)
 244     {
 245         clearTimeout(this.statTimer);
 246         clearTimeout(this.showTimer);
 247         clearTimeout(this.termTimer);
 248         clearTimeout(this.bytargetTimer);
 249
 250         this.showCounter = 0;
 251         this.termCounter = 0;
 252         this.bytargetCounter = 0;
 253         this.statCounter = 0;
 254
 255         // no proxy mode
 256         if( !this.initStatusOK )
 257             throw new Error('Pz2.js: session not initialized.');
 258
 259         if( query !== undefined )
 260             this.currQuery = query;
 261         else
 262             throw new Error("Pz2.js: no query supplied to the search command.");
 263
 264         if ( showfrom !== undefined )
 265             var start = showfrom;
 266         else
 267             var start = 0;
 268
 269         var searchParams = {
 270             "command": "search",
 271             "query": this.currQuery,
 272             "session": this.sessionID
 273         };
 274
 275         if (filter !== undefined)
 276             searchParams["filter"] = filter;
 277
 278         // copy additional parmeters, do not overwrite
 279         if (addParamsArr != undefined) {
 280             for (var prop in addParamsArr) {
 281                 if (!searchParams.hasOwnProperty(prop))
 282                     searchParams[prop] = addParamsArr[prop];
 283             }
 284         }
 285
 286         var context = this;
 287         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 288         request.safeGet(
 289             searchParams,
 290             function(data) {
 291                 if ( data.getElementsByTagName("status")[0]
 292                         .childNodes[0].nodeValue == "OK" ) {
 293                     context.searchStatusOK = true;
 294                     //piggyback search
 295                     context.show(start, num, sort);
 296                     if ( context.statCallback )
 297                         context.stat();
 298                     if ( context.termlistCallback )
 299                         context.termlist();
 300                     if ( context.bytargetCallback )
 301                         context.bytarget();
 302                 }
 303                 else
 304                     context.throwError('Search failed. Malformed WS resonse.',
 305                                         112);
 306             }
 307         );
 308     },
 309     stat: function()
 310     {
 311         if( !this.initStatusOK )
 312             throw new Error('Pz2.js: session not initialized.');
 313
 314         // if called explicitly takes precedence
 315         clearTimeout(this.statTimer);
 316
 317         var context = this;
 318         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 319         request.safeGet(
 320             { "command": "stat", "session": this.sessionID },
 321             function(data) {
 322                 if ( data.getElementsByTagName("stat") ) {
 323                     var activeClients =
 324                         Number( data.getElementsByTagName("activeclients")[0]
 325                                     .childNodes[0].nodeValue );
 326                     context.activeClients = activeClients;
 327                     var stat = {
 328                         "activeclients": activeClients,
 329                         "hits":
 330                             Number( data.getElementsByTagName("hits")[0]
 331                                         .childNodes[0].nodeValue ),
 332                         "records":
 333                             Number( data.getElementsByTagName("records")[0]
 334                                         .childNodes[0].nodeValue ),
 335                         "clients":
 336                             Number( data.getElementsByTagName("clients")[0]
 337                                         .childNodes[0].nodeValue ),
 338                         "initializing":
 339                             Number( data.getElementsByTagName("initializing")[0]
 340                                         .childNodes[0].nodeValue ),
 341                         "searching":
 342                             Number( data.getElementsByTagName("searching")[0]
 343                                         .childNodes[0].nodeValue ),
 344                         "presenting":
 345                             Number( data.getElementsByTagName("presenting")[0]
 346                                         .childNodes[0].nodeValue ),
 347                         "idle":
 348                             Number( data.getElementsByTagName("idle")[0]
 349                                         .childNodes[0].nodeValue ),
 350                         "failed":
 351                             Number( data.getElementsByTagName("failed")[0]
 352                                         .childNodes[0].nodeValue ),
 353                         "error":
 354                             Number( data.getElementsByTagName("error")[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                     var activeClients =
 519                        Number( data.getElementsByTagName("activeclients")[0]
 520                                 .childNodes[0].nodeValue );
 521                     context.activeClients = activeClients;
 522                     context.recordCounter++;
 523                     var delay = context.recordTime + context.recordCounter * context.dumpFactor;
 524                     if ( activeClients > 0 )
 525                         context.recordTimer =
 526                            setTimeout (
 527                                function() {
 528                                   context.record(id, offset, syntax, handler);
 529                                   },
 530                                   delay
 531                                );
 532                     callback(record, args);
 533                 }
 534                 else
 535                     context.throwError('Record failed. Malformed WS resonse.',
 536                                         115);
 537             }
 538         );
 539     },
 540
 541     termlist: function()
 542     {
 543         if( !this.searchStatusOK && this.useSessions )
 544             throw new Error(
 545             'Pz2.js: termlist command has to be preceded with a search command.'
 546             );
 547
 548         // if called explicitly takes precedence
 549         clearTimeout(this.termTimer);
 550
 551         var context = this;
 552         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 553         request.safeGet(
 554             {
 555                 "command": "termlist",
 556                 "session": this.sessionID,
 557                 "name": this.termKeys
 558             },
 559             function(data) {
 560                 if ( data.getElementsByTagName("termlist") ) {
 561                     var activeClients =
 562                         Number( data.getElementsByTagName("activeclients")[0]
 563                                     .childNodes[0].nodeValue );
 564                     context.activeClients = activeClients;
 565                     var termList = { "activeclients":  activeClients };
 566                     var termLists = data.getElementsByTagName("list");
 567                     //for each termlist
 568                     for (i = 0; i < termLists.length; i++) {
 569                         var listName = termLists[i].getAttribute('name');
 570                         termList[listName] = new Array();
 571                         var terms = termLists[i].getElementsByTagName('term');
 572                         //for each term in the list
 573                         for (j = 0; j < terms.length; j++) {
 574                             var term = {
 575                                 "name":
 576                                     (terms[j].getElementsByTagName("name")[0]
 577                                         .childNodes.length
 578                                     ? terms[j].getElementsByTagName("name")[0]
 579                                         .childNodes[0].nodeValue
 580                                     : 'ERROR'),
 581                                 "freq":
 582                                     terms[j]
 583                                     .getElementsByTagName("frequency")[0]
 584                                     .childNodes[0].nodeValue || 'ERROR'
 585                             };
 586
 587                             var termIdNode =
 588                                 terms[j].getElementsByTagName("id");
 589                             if(terms[j].getElementsByTagName("id").length)
 590                                 term["id"] =
 591                                     termIdNode[0].childNodes[0].nodeValue;
 592                             termList[listName][j] = term;
 593                         }
 594                     }
 595
 596                     context.termCounter++;
 597                     var delay = context.termTime
 598                         + context.termCounter * context.dumpFactor;
 599                     if ( activeClients > 0 )
 600                         context.termTimer =
 601                             setTimeout(
 602                                 function () {
 603                                     context.termlist();
 604                                 },
 605                                 delay
 606                             );
 607
 608                    context.termlistCallback(termList);
 609                 }
 610                 else
 611                     context.throwError('Termlist failed. Malformed WS resonse.',
 612                                         116);
 613             }
 614         );
 615
 616     },
 617     bytarget: function()
 618     {
 619         if( !this.initStatusOK && this.useSessions )
 620             throw new Error(
 621             'Pz2.js: bytarget command has to be preceded with a search command.'
 622             );
 623
 624         // no need to continue
 625         if( !this.searchStatusOK )
 626             return;
 627
 628         // if called explicitly takes precedence
 629         clearTimeout(this.bytargetTimer);
 630
 631         var context = this;
 632         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 633         request.safeGet(
 634             { "command": "bytarget", "session": this.sessionID },
 635             function(data) {
 636                 if ( data.getElementsByTagName("status")[0]
 637                         .childNodes[0].nodeValue == "OK" ) {
 638                     var targetNodes = data.getElementsByTagName("target");
 639                     var bytarget = new Array();
 640                     for ( i = 0; i < targetNodes.length; i++) {
 641                         bytarget[i] = new Array();
 642                         for( j = 0; j < targetNodes[i].childNodes.length; j++ ) {
 643                             if ( targetNodes[i].childNodes[j].nodeType
 644                                 == Node.ELEMENT_NODE ) {
 645                                 var nodeName =
 646                                     targetNodes[i].childNodes[j].nodeName;
 647                                 var nodeText =
 648                                     targetNodes[i].childNodes[j]
 649                                         .firstChild.nodeValue;
 650                                 bytarget[i][nodeName] = nodeText;
 651                             }
 652                         }
 653                     }
 654
 655                     context.bytargetCounter++;
 656                     var delay = context.bytargetTime
 657                         + context.bytargetCounter * context.dumpFactor;
 658                     if ( context.activeClients > 0 )
 659                         context.bytargetTimer =
 660                             setTimeout(
 661                                 function () {
 662                                     context.bytarget();
 663                                 },
 664                                 delay
 665                             );
 666
 667                     context.bytargetCallback(bytarget);
 668                 }
 669                 else
 670                     context.throwError('Bytarget failed. Malformed WS resonse.',
 671                                         117);
 672             }
 673         );
 674     },
 675
 676     // just for testing, probably shouldn't be here
 677     showNext: function(page)
 678     {
 679         var step = page || 1;
 680         this.show( ( step * this.currentNum ) + this.currentStart );
 681     },
 682
 683     showPrev: function(page)
 684     {
 685         if (this.currentStart == 0 )
 686             return false;
 687         var step = page || 1;
 688         var newStart = this.currentStart - (step * this.currentNum );
 689         this.show( newStart > 0 ? newStart : 0 );
 690     },
 691
 692     showPage: function(pageNum)
 693     {
 694         //var page = pageNum || 1;
 695         this.show(pageNum * this.currentNum);
 696     }
 697 };
 698
 699 /*
 700 ********************************************************************************
 701 ** AJAX HELPER CLASS ***********************************************************
 702 ********************************************************************************
 703 */
 704 var pzHttpRequest = function ( url, errorHandler ) {
 705         this.maxUrlLength = 2048;
 706         this.request = null;
 707         this.url = url;
 708         this.errorHandler = errorHandler || null;
 709         this.async = true;
 710         this.requestHeaders = {};
 711
 712         if ( window.XMLHttpRequest ) {
 713             this.request = new XMLHttpRequest();
 714         } else if ( window.ActiveXObject ) {
 715             try {
 716                 this.request = new ActiveXObject( 'Msxml2.XMLHTTP' );
 717             } catch (err) {
 718                 this.request = new ActiveXObject( 'Microsoft.XMLHTTP' );
 719             }
 720         }
 721 };
 722
 723 pzHttpRequest.prototype =
 724 {
 725     safeGet: function ( params, callback )
 726     {
 727         var encodedParams =  this.encodeParams(params);
 728         var url = this._urlAppendParams(encodedParams);
 729         if (url.length >= this.maxUrlLength) {
 730             this.requestHeaders["Content-Type"]
 731                 = "application/x-www-form-urlencoded";
 732             this._send( 'POST', this.url, encodedParams, callback );
 733         } else {
 734             this._send( 'GET', url, '', callback );
 735         }
 736     },
 737
 738     get: function ( params, callback )
 739     {
 740         this._send( 'GET', this._urlAppendParams(this.encodeParams(params)),
 741             '', callback );
 742     },
 743
 744     post: function ( params, data, callback )
 745     {
 746         this._send( 'POST', this._urlAppendParams(this.encodeParams(params)),
 747             data, callback );
 748     },
 749
 750     load: function ()
 751     {
 752         this.async = false;
 753         this.request.open( 'GET', this.url, this.async );
 754         this.request.send('');
 755         if ( this.request.status == 200 )
 756             return this.request.responseXML;
 757     },
 758
 759     encodeParams: function (params)
 760     {
 761         var sep = "";
 762         var encoded = "";
 763         for (var key in params) {
 764             if (params[key] != null) {
 765                 encoded += sep + key + '=' + encodeURIComponent(params[key]);
 766                 sep = '&';
 767             }
 768         }
 769         return encoded;
 770     },
 771
 772     _send: function ( type, url, data, callback)
 773     {
 774         var context = this;
 775         this.callback = callback;
 776         this.async = true;
 777         this.request.open( type, url, this.async );
 778         for (var key in this.requestHeaders)
 779             this.request.setRequestHeader(key, this.requestHeaders[key]);
 780         this.request.onreadystatechange = function () {
 781             context._handleResponse();
 782         }
 783         this.request.send(data);
 784     },
 785
 786     _urlAppendParams: function (encodedParams)
 787     {
 788         if (encodedParams)
 789             return this.url + "?" + encodedParams;
 790         else
 791             return this.url;
 792     },
 793
 794     _handleResponse: function ()
 795     {
 796         if ( this.request.readyState == 4 ) {
 797             // pick up appplication errors first
 798             var errNode = null;
 799             if (this.request.responseXML &&
 800                 (errNode = this.request.responseXML.documentElement)
 801                 && errNode.nodeName == 'error') {
 802                 var errMsg = errNode.getAttribute("msg");
 803                 var errCode = errNode.getAttribute("code");
 804                 var errAddInfo = '';
 805                 if (errNode.childNodes.length)
 806                     errAddInfo = ': ' + errNode.childNodes[0].nodeValue;
 807
 808                 var err = new Error(errMsg + errAddInfo);
 809                 err.code = errCode;
 810
 811                 if (this.errorHandler) {
 812                     this.errorHandler(err);
 813                 }
 814                 else {
 815                     throw err;
 816                 }
 817             } else if (this.request.status == 200) {
 818                 this.callback(this.request.responseXML);
 819             } else {
 820                 var err = new Error("HTTP response not OK: "
 821                             + this.request.status + " - "
 822                             + this.request.statusText );
 823                 err.code = '00' + this.request.status;
 824
 825                 if (this.errorHandler) {
 826                     this.errorHandler(err);
 827                 }
 828                 else {
 829                     throw err;
 830                 }
 831             }
 832         }
 833     }
 834 };
 835
 836 /*
 837 ********************************************************************************
 838 ** XML HELPER FUNCTIONS ********************************************************
 839 ********************************************************************************
 840 */
 841
 842 // DOMDocument
 843
 844 if ( window.ActiveXObject) {
 845     var DOMDoc = document;
 846 } else {
 847     var DOMDoc = Document.prototype;
 848 }
 849
 850 DOMDoc.newXmlDoc = function ( root )
 851 {
 852     var doc;
 853
 854     if (document.implementation && document.implementation.createDocument) {
 855         doc = document.implementation.createDocument('', root, null);
 856     } else if ( window.ActiveXObject ) {
 857         doc = new ActiveXObject("MSXML2.DOMDocument");
 858         doc.loadXML('<' + root + '/>');
 859     } else {
 860         throw new Error ('No XML support in this browser');
 861     }
 862
 863     return doc;
 864 }
 865
 866
 867 DOMDoc.parseXmlFromString = function ( xmlString )
 868 {
 869     var doc;
 870
 871     if ( window.DOMParser ) {
 872         var parser = new DOMParser();
 873         doc = parser.parseFromString( xmlString, "text/xml");
 874     } else if ( window.ActiveXObject ) {
 875         doc = new ActiveXObject("MSXML2.DOMDocument");
 876         doc.loadXML( xmlString );
 877     } else {
 878         throw new Error ("No XML parsing support in this browser.");
 879     }
 880
 881     return doc;
 882 }
 883
 884 DOMDoc.transformToDoc = function (xmlDoc, xslDoc)
 885 {
 886     if ( window.XSLTProcessor ) {
 887         var proc = new XSLTProcessor();
 888         proc.importStylesheet( xslDoc );
 889         return proc.transformToDocument(xmlDoc);
 890     } else if ( window.ActiveXObject ) {
 891         return document.parseXmlFromString(xmlDoc.transformNode(xslDoc));
 892     } else {
 893         alert( 'Unable to perform XSLT transformation in this browser' );
 894     }
 895 }
 896
 897 // DOMElement
 898
 899 Element_removeFromDoc = function (DOM_Element)
 900 {
 901     DOM_Element.parentNode.removeChild(DOM_Element);
 902 }
 903
 904 Element_emptyChildren = function (DOM_Element)
 905 {
 906     while( DOM_Element.firstChild ) {
 907         DOM_Element.removeChild( DOM_Element.firstChild )
 908     }
 909 }
 910
 911 Element_appendTransformResult = function ( DOM_Element, xmlDoc, xslDoc )
 912 {
 913     if ( window.XSLTProcessor ) {
 914         var proc = new XSLTProcessor();
 915         proc.importStylesheet( xslDoc );
 916         var docFrag = false;
 917         docFrag = proc.transformToFragment( xmlDoc, DOM_Element.ownerDocument );
 918         DOM_Element.appendChild(docFrag);
 919     } else if ( window.ActiveXObject ) {
 920         DOM_Element.innerHTML = xmlDoc.transformNode( xslDoc );
 921     } else {
 922         alert( 'Unable to perform XSLT transformation in this browser' );
 923     }
 924 }
 925
 926 Element_appendTextNode = function (DOM_Element, tagName, textContent )
 927 {
 928     var node = DOM_Element.ownerDocument.createElement(tagName);
 929     var text = DOM_Element.ownerDocument.createTextNode(textContent);
 930
 931     DOM_Element.appendChild(node);
 932     node.appendChild(text);
 933
 934     return node;
 935 }
 936
 937 Element_setTextContent = function ( DOM_Element, textContent )
 938 {
 939     if (typeof DOM_Element.textContent !== "undefined") {
 940         DOM_Element.textContent = textContent;
 941     } else if (typeof DOM_Element.innerText !== "undefined" ) {
 942         DOM_Element.innerText = textContent;
 943     } else {
 944         throw new Error("Cannot set text content of the node, no such method.");
 945     }
 946 }
 947
 948 Element_getTextContent = function (DOM_Element)
 949 {
 950     if ( typeof DOM_Element.textContent != 'undefined' ) {
 951         return DOM_Element.textContent;
 952     } else if (typeof DOM_Element.text != 'undefined') {
 953         return DOM_Element.text;
 954     } else {
 955         throw new Error("Cannot get text content of the node, no such method.");
 956     }
 957 }
 958
 959 Element_parseChildNodes = function (node)
 960 {
 961     var parsed = {};
 962     var hasChildElems = false;
 963
 964     if (node.hasChildNodes()) {
 965         var children = node.childNodes;
 966         for (var i = 0; i < children.length; i++) {
 967             var child = children[i];
 968             if (child.nodeType == Node.ELEMENT_NODE) {
 969                 hasChildElems = true;
 970                 var nodeName = child.nodeName;
 971                 if (!(nodeName in parsed))
 972                     parsed[nodeName] = [];
 973                 parsed[nodeName].push(Element_parseChildNodes(child));
 974             }
 975         }
 976     }
 977
 978     var attrs = node.attributes;
 979     for (var i = 0; i < attrs.length; i++) {
 980         var attrName = '@' + attrs[i].nodeName;
 981         var attrValue = attrs[i].nodeValue;
 982         parsed[attrName] = attrValue;
 983     }
 984
 985     // if no nested elements, get text content
 986     if (node.hasChildNodes() && !hasChildElems) {
 987         if (node.attributes.length)
 988             parsed['textContent'] = node.firstChild.nodeValue;
 989         else
 990             parsed = node.firstChild.nodeValue;
 991     }
 992
 993     return parsed;
 994 }
 995
 996 /* do not remove trailing bracket */
 997 }