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.serviceId = paramArray.serviceId || null;
  73     this.initStatusOK = false;
  74     this.pingStatusOK = false;
  75     this.searchStatusOK = false;
  76
  77     // for sorting
  78     this.currentSort = "relevance";
  79
  80     // where are we?
  81     this.currentStart = 0;
  82     this.currentNum = 20;
  83
  84     // last full record retrieved
  85     this.currRecID = null;
  86
  87     // current query
  88     this.currQuery = null;
  89
  90     //current raw record offset
  91     this.currRecOffset = null;
  92
  93     //timers
  94     this.statTime = paramArray.stattime || 1000;
  95     this.statTimer = null;
  96     this.termTime = paramArray.termtime || 1000;
  97     this.termTimer = null;
  98     this.showTime = paramArray.showtime || 1000;
  99     this.showTimer = null;
 100     this.showFastCount = 4;
 101     this.bytargetTime = paramArray.bytargettime || 1000;
 102     this.bytargetTimer = null;
 103     this.recordTime = paramArray.recordtime || 500;
 104     this.recordTimer = null;
 105
 106     // counters for each command and applied delay
 107     this.dumpFactor = 500;
 108     this.showCounter = 0;
 109     this.termCounter = 0;
 110     this.statCounter = 0;
 111     this.bytargetCounter = 0;
 112     this.recordCounter = 0;
 113
 114     // active clients, updated by stat and show
 115     // might be an issue since bytarget will poll accordingly
 116     this.activeClients = 1;
 117
 118     // if in proxy mode no need to init
 119     if (paramArray.usesessions != undefined) {
 120          this.useSessions = paramArray.usesessions;
 121         this.initStatusOK = true;
 122     }
 123     // else, auto init session or wait for a user init?
 124     if (this.useSessions && paramArray.autoInit !== false) {
 125         this.init(this.sessionId, this.serviceId);
 126     }
 127 };
 128
 129 pz2.prototype =
 130 {
 131     //error handler for async error throws
 132    throwError: function (errMsg, errCode)
 133    {
 134         var err = new Error(errMsg);
 135         if (errCode) err.code = errCode;
 136
 137         if (this.errorHandler) {
 138             this.errorHandler(err);
 139         }
 140         else {
 141             throw err;
 142         }
 143    },
 144
 145     // stop activity by clearing tiemouts
 146    stop: function ()
 147    {
 148        clearTimeout(this.statTimer);
 149        clearTimeout(this.showTimer);
 150        clearTimeout(this.termTimer);
 151        clearTimeout(this.bytargetTimer);
 152     },
 153
 154     // reset status variables
 155     reset: function ()
 156     {
 157         if ( this.useSessions ) {
 158             this.sessionID = null;
 159             this.initStatusOK = false;
 160             this.pingStatusOK = false;
 161         }
 162         this.searchStatusOK = false;
 163         this.stop();
 164
 165         if ( this.resetCallback )
 166                 this.resetCallback();
 167     },
 168
 169     init: function (sessionId, serviceId)
 170     {
 171         this.reset();
 172
 173         // session id as a param
 174         if (sessionId && this.useSessions ) {
 175             this.initStatusOK = true;
 176             this.sessionID = sessionId;
 177             this.ping();
 178         // old school direct pazpar2 init
 179         } else if (this.useSessions) {
 180             var context = this;
 181             var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 182             var opts = {'command' : 'init'};
 183             if (serviceId) opts.service = serviceId;
 184             request.safeGet(
 185                 opts,
 186                 function(data) {
 187                     if ( data.getElementsByTagName("status")[0]
 188                             .childNodes[0].nodeValue == "OK" ) {
 189                         if ( data.getElementsByTagName("protocol")[0]
 190                                 .childNodes[0].nodeValue
 191                             != context.suppProtoVer )
 192                             throw new Error(
 193                                 "Server's protocol not supported by the client"
 194                             );
 195                         context.initStatusOK = true;
 196                         context.sessionID =
 197                             data.getElementsByTagName("session")[0]
 198                                 .childNodes[0].nodeValue;
 199                         setTimeout(
 200                             function () {
 201                                 context.ping();
 202                             },
 203                             context.keepAlive
 204                         );
 205                         if ( context.initCallback )
 206                             context.initCallback();
 207                     }
 208                     else
 209                         context.throwError('Init failed. Malformed WS resonse.',
 210                                             110);
 211                 }
 212             );
 213         // when through proxy no need to init
 214         } else {
 215             this.initStatusOK = true;
 216         }
 217     },
 218     // no need to ping explicitly
 219     ping: function ()
 220     {
 221         // pinging only makes sense when using pazpar2 directly
 222         if( !this.initStatusOK || !this.useSessions )
 223             throw new Error(
 224             'Pz2.js: Ping not allowed (proxy mode) or session not initialized.'
 225             );
 226         var context = this;
 227         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 228         request.safeGet(
 229             { "command": "ping", "session": this.sessionID },
 230             function(data) {
 231                 if ( data.getElementsByTagName("status")[0]
 232                         .childNodes[0].nodeValue == "OK" ) {
 233                     context.pingStatusOK = true;
 234                     setTimeout(
 235                         function () {
 236                             context.ping();
 237                         },
 238                         context.keepAlive
 239                     );
 240                 }
 241                 else
 242                     context.throwError('Ping failed. Malformed WS resonse.',
 243                                         111);
 244             }
 245         );
 246     },
 247     search: function (query, num, sort, filter, showfrom, addParamsArr)
 248     {
 249         clearTimeout(this.statTimer);
 250         clearTimeout(this.showTimer);
 251         clearTimeout(this.termTimer);
 252         clearTimeout(this.bytargetTimer);
 253
 254         this.showCounter = 0;
 255         this.termCounter = 0;
 256         this.bytargetCounter = 0;
 257         this.statCounter = 0;
 258         this.activeClients = 1;
 259
 260         // no proxy mode
 261         if( !this.initStatusOK )
 262             throw new Error('Pz2.js: session not initialized.');
 263
 264         if( query !== undefined )
 265             this.currQuery = query;
 266         else
 267             throw new Error("Pz2.js: no query supplied to the search command.");
 268
 269         if ( showfrom !== undefined )
 270             var start = showfrom;
 271         else
 272             var start = 0;
 273
 274         var searchParams = {
 275             "command": "search",
 276             "query": this.currQuery,
 277             "session": this.sessionID
 278         };
 279
 280         if (filter !== undefined)
 281             searchParams["filter"] = filter;
 282
 283         // copy additional parmeters, do not overwrite
 284         if (addParamsArr != undefined) {
 285             for (var prop in addParamsArr) {
 286                 if (!searchParams.hasOwnProperty(prop))
 287                     searchParams[prop] = addParamsArr[prop];
 288             }
 289         }
 290
 291         var context = this;
 292         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 293         request.safeGet(
 294             searchParams,
 295             function(data) {
 296                 if ( data.getElementsByTagName("status")[0]
 297                         .childNodes[0].nodeValue == "OK" ) {
 298                     context.searchStatusOK = true;
 299                     //piggyback search
 300                     context.show(start, num, sort);
 301                     if (context.statCallback)
 302                         context.stat();
 303                     if (context.termlistCallback)
 304                         context.termlist();
 305                     if (context.bytargetCallback)
 306                         context.bytarget();
 307                 }
 308                 else
 309                     context.throwError('Search failed. Malformed WS resonse.',
 310                                         112);
 311             }
 312         );
 313     },
 314     stat: function()
 315     {
 316         if( !this.initStatusOK )
 317             throw new Error('Pz2.js: session not initialized.');
 318
 319         // if called explicitly takes precedence
 320         clearTimeout(this.statTimer);
 321
 322         var context = this;
 323         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 324         request.safeGet(
 325             { "command": "stat", "session": this.sessionID },
 326             function(data) {
 327                 if ( data.getElementsByTagName("stat") ) {
 328                     var activeClients =
 329                         Number( data.getElementsByTagName("activeclients")[0]
 330                                     .childNodes[0].nodeValue );
 331                     context.activeClients = activeClients;
 332
 333                     var stat = Element_parseChildNodes(data.documentElement);
 334
 335                     context.statCounter++;
 336                     var delay = context.statTime
 337                         + context.statCounter * context.dumpFactor;
 338
 339                     if ( activeClients > 0 )
 340                         context.statTimer =
 341                             setTimeout(
 342                                 function () {
 343                                     context.stat();
 344                                 },
 345                                 delay
 346                             );
 347                     context.statCallback(stat);
 348                 }
 349                 else
 350                     context.throwError('Stat failed. Malformed WS resonse.',
 351                                         113);
 352             }
 353         );
 354     },
 355     show: function(start, num, sort)
 356     {
 357         if( !this.searchStatusOK && this.useSessions )
 358             throw new Error(
 359                 'Pz2.js: show command has to be preceded with a search command.'
 360             );
 361
 362         // if called explicitly takes precedence
 363         clearTimeout(this.showTimer);
 364
 365         if( sort !== undefined )
 366             this.currentSort = sort;
 367         if( start !== undefined )
 368             this.currentStart = Number( start );
 369         if( num !== undefined )
 370             this.currentNum = Number( num );
 371
 372         var context = this;
 373         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 374         request.safeGet(
 375           {
 376             "command": "show",
 377             "session": this.sessionID,
 378             "start": this.currentStart,
 379             "num": this.currentNum,
 380             "sort": this.currentSort,
 381             "block": 1,
 382             "type": this.showResponseType
 383           },
 384           function(data, type) {
 385             var show = null;
 386             var activeClients = 0;
 387             if (type === "json") {
 388               show = {};
 389               activeClients = Number(data.activeclients[0]);
 390               show.activeclients = activeClients;
 391               show.merged = Number(data.merged[0]);
 392               show.total = Number(data.total[0]);
 393               show.start = Number(data.start[0]);
 394               show.num = Number(data.num[0]);
 395               show.hits = data.hit;
 396             } else if (data.getElementsByTagName("status")[0]
 397                   .childNodes[0].nodeValue == "OK") {
 398                 // first parse the status data send along with records
 399                 // this is strictly bound to the format
 400                 activeClients =
 401                   Number(data.getElementsByTagName("activeclients")[0]
 402                       .childNodes[0].nodeValue);
 403                 show = {
 404                   "activeclients": activeClients,
 405                   "merged":
 406                     Number( data.getElementsByTagName("merged")[0]
 407                         .childNodes[0].nodeValue ),
 408                   "total":
 409                     Number( data.getElementsByTagName("total")[0]
 410                         .childNodes[0].nodeValue ),
 411                   "start":
 412                     Number( data.getElementsByTagName("start")[0]
 413                         .childNodes[0].nodeValue ),
 414                   "num":
 415                     Number( data.getElementsByTagName("num")[0]
 416                         .childNodes[0].nodeValue ),
 417                   "hits": []
 418                 };
 419                 // parse all the first-level nodes for all <hit> tags
 420                 var hits = data.getElementsByTagName("hit");
 421                 for (i = 0; i < hits.length; i++)
 422                   show.hits[i] = Element_parseChildNodes(hits[i]);
 423             } else {
 424               context.throwError('Show failed. Malformed WS resonse.',
 425                   114);
 426             }
 427             context.activeClients = activeClients;
 428             context.showCounter++;
 429             var delay = context.showTime;
 430             if (context.showCounter > context.showFastCount)
 431               delay += context.showCounter * context.dumpFactor;
 432             if ( activeClients > 0 )
 433               context.showTimer = setTimeout(
 434                 function () {
 435                   context.show();
 436                 },
 437                 delay);
 438             context.showCallback(show);
 439           }
 440         );
 441     },
 442     record: function(id, offset, syntax, handler)
 443     {
 444         // we may call record with no previous search if in proxy mode
 445         if(!this.searchStatusOK && this.useSessions)
 446            throw new Error(
 447             'Pz2.js: record command has to be preceded with a search command.'
 448             );
 449
 450         if( id !== undefined )
 451             this.currRecID = id;
 452
 453         var recordParams = {
 454             "command": "record",
 455             "session": this.sessionID,
 456             "id": this.currRecID
 457         };
 458
 459         this.currRecOffset = null;
 460         if (offset != undefined) {
 461             recordParams["offset"] = offset;
 462             this.currRecOffset = offset;
 463         }
 464
 465         if (syntax != undefined)
 466             recordParams['syntax'] = syntax;
 467
 468         //overwrite default callback id needed
 469         var callback = this.recordCallback;
 470         var args = undefined;
 471         if (handler != undefined) {
 472             callback = handler['callback'];
 473             args = handler['args'];
 474         }
 475
 476         var context = this;
 477         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 478
 479         request.safeGet(
 480             recordParams,
 481             function(data) {
 482                 var recordNode;
 483                 var record;
 484                 //raw record
 485                 if (context.currRecOffset !== null) {
 486                     record = new Array();
 487                     record['xmlDoc'] = data;
 488                     record['offset'] = context.currRecOffset;
 489                     callback(record, args);
 490                 //pz2 record
 491                 } else if ( recordNode =
 492                     data.getElementsByTagName("record")[0] ) {
 493                     // if stylesheet was fetched do not parse the response
 494                     if ( context.xslDoc ) {
 495                         record = new Array();
 496                         record['xmlDoc'] = data;
 497                         record['xslDoc'] = context.xslDoc;
 498                         record['recid'] =
 499                             recordNode.getElementsByTagName("recid")[0]
 500                                 .firstChild.nodeValue;
 501                     //parse record
 502                     } else {
 503                         record = Element_parseChildNodes(recordNode);
 504                     }
 505                     var activeClients =
 506                        Number( data.getElementsByTagName("activeclients")[0]
 507                                 .childNodes[0].nodeValue );
 508                     context.activeClients = activeClients;
 509                     context.recordCounter++;
 510                     var delay = context.recordTime + context.recordCounter * context.dumpFactor;
 511                     if ( activeClients > 0 )
 512                         context.recordTimer =
 513                            setTimeout (
 514                                function() {
 515                                   context.record(id, offset, syntax, handler);
 516                                   },
 517                                   delay
 518                                );
 519                     callback(record, args);
 520                 }
 521                 else
 522                     context.throwError('Record failed. Malformed WS resonse.',
 523                                         115);
 524             }
 525         );
 526     },
 527
 528     termlist: function()
 529     {
 530         if( !this.searchStatusOK && this.useSessions )
 531             throw new Error(
 532             'Pz2.js: termlist command has to be preceded with a search command.'
 533             );
 534
 535         // if called explicitly takes precedence
 536         clearTimeout(this.termTimer);
 537
 538         var context = this;
 539         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 540         request.safeGet(
 541             {
 542                 "command": "termlist",
 543                 "session": this.sessionID,
 544                 "name": this.termKeys
 545             },
 546             function(data) {
 547                 if ( data.getElementsByTagName("termlist") ) {
 548                     var activeClients =
 549                         Number( data.getElementsByTagName("activeclients")[0]
 550                                     .childNodes[0].nodeValue );
 551                     context.activeClients = activeClients;
 552                     var termList = { "activeclients":  activeClients };
 553                     var termLists = data.getElementsByTagName("list");
 554                     //for each termlist
 555                     for (i = 0; i < termLists.length; i++) {
 556                         var listName = termLists[i].getAttribute('name');
 557                         termList[listName] = new Array();
 558                         var terms = termLists[i].getElementsByTagName('term');
 559                         //for each term in the list
 560                         for (j = 0; j < terms.length; j++) {
 561                             var term = {
 562                                 "name":
 563                                     (terms[j].getElementsByTagName("name")[0]
 564                                         .childNodes.length
 565                                     ? terms[j].getElementsByTagName("name")[0]
 566                                         .childNodes[0].nodeValue
 567                                     : 'ERROR'),
 568                                 "freq":
 569                                     terms[j]
 570                                     .getElementsByTagName("frequency")[0]
 571                                     .childNodes[0].nodeValue || 'ERROR'
 572                             };
 573
 574                             var termIdNode =
 575                                 terms[j].getElementsByTagName("id");
 576                             if(terms[j].getElementsByTagName("id").length)
 577                                 term["id"] =
 578                                     termIdNode[0].childNodes[0].nodeValue;
 579                             termList[listName][j] = term;
 580                         }
 581                     }
 582
 583                     context.termCounter++;
 584                     var delay = context.termTime
 585                         + context.termCounter * context.dumpFactor;
 586                     if ( activeClients > 0 )
 587                         context.termTimer =
 588                             setTimeout(
 589                                 function () {
 590                                     context.termlist();
 591                                 },
 592                                 delay
 593                             );
 594
 595                    context.termlistCallback(termList);
 596                 }
 597                 else
 598                     context.throwError('Termlist failed. Malformed WS resonse.',
 599                                         116);
 600             }
 601         );
 602
 603     },
 604     bytarget: function()
 605     {
 606         if( !this.initStatusOK && this.useSessions )
 607             throw new Error(
 608             'Pz2.js: bytarget command has to be preceded with a search command.'
 609             );
 610
 611         // no need to continue
 612         if( !this.searchStatusOK )
 613             return;
 614
 615         // if called explicitly takes precedence
 616         clearTimeout(this.bytargetTimer);
 617
 618         var context = this;
 619         var request = new pzHttpRequest(this.pz2String, this.errorHandler);
 620         request.safeGet(
 621             { "command": "bytarget", "session": this.sessionID },
 622             function(data) {
 623                 if ( data.getElementsByTagName("status")[0]
 624                         .childNodes[0].nodeValue == "OK" ) {
 625                     var targetNodes = data.getElementsByTagName("target");
 626                     var bytarget = new Array();
 627                     for ( i = 0; i < targetNodes.length; i++) {
 628                         bytarget[i] = new Array();
 629                         for( j = 0; j < targetNodes[i].childNodes.length; j++ ) {
 630                             if ( targetNodes[i].childNodes[j].nodeType
 631                                 == Node.ELEMENT_NODE ) {
 632                                 var nodeName =
 633                                     targetNodes[i].childNodes[j].nodeName;
 634                                 var nodeText =
 635                                     targetNodes[i].childNodes[j]
 636                                         .firstChild.nodeValue;
 637                                 bytarget[i][nodeName] = nodeText;
 638                             }
 639                         }
 640                         if (bytarget[i]["state"]=="Client_Disconnected") {
 641                           bytarget[i]["hits"] = "Error";
 642                         } else if (bytarget[i]["state"]=="Client_Error") {
 643                           bytarget[i]["hits"] = "Error";
 644                         } else if (bytarget[i]["state"]=="Client_Working") {
 645                           bytarget[i]["hits"] = "...";
 646                         }
 647                         if (bytarget[i].diagnostic == "1") {
 648                           bytarget[i].diagnostic = "Permanent system error";
 649                         } else if (bytarget[i].diagnostic == "2") {
 650                           bytarget[i].diagnostic = "Temporary system error";
 651                         }
 652                     }
 653
 654                     context.bytargetCounter++;
 655                     var delay = context.bytargetTime
 656                         + context.bytargetCounter * context.dumpFactor;
 657                     if ( context.activeClients > 0 )
 658                         context.bytargetTimer =
 659                             setTimeout(
 660                                 function () {
 661                                     context.bytarget();
 662                                 },
 663                                 delay
 664                             );
 665
 666                     context.bytargetCallback(bytarget);
 667                 }
 668                 else
 669                     context.throwError('Bytarget failed. Malformed WS resonse.',
 670                                         117);
 671             }
 672         );
 673     },
 674
 675     // just for testing, probably shouldn't be here
 676     showNext: function(page)
 677     {
 678         var step = page || 1;
 679         this.show( ( step * this.currentNum ) + this.currentStart );
 680     },
 681
 682     showPrev: function(page)
 683     {
 684         if (this.currentStart == 0 )
 685             return false;
 686         var step = page || 1;
 687         var newStart = this.currentStart - (step * this.currentNum );
 688         this.show( newStart > 0 ? newStart : 0 );
 689     },
 690
 691     showPage: function(pageNum)
 692     {
 693         //var page = pageNum || 1;
 694         this.show(pageNum * this.currentNum);
 695     }
 696 };
 697
 698 /*
 699 ********************************************************************************
 700 ** AJAX HELPER CLASS ***********************************************************
 701 ********************************************************************************
 702 */
 703 var pzHttpRequest = function ( url, errorHandler ) {
 704         this.maxUrlLength = 2048;
 705         this.request = null;
 706         this.url = url;
 707         this.errorHandler = errorHandler || null;
 708         this.async = true;
 709         this.requestHeaders = {};
 710
 711         if ( window.XMLHttpRequest ) {
 712             this.request = new XMLHttpRequest();
 713         } else if ( window.ActiveXObject ) {
 714             try {
 715                 this.request = new ActiveXObject( 'Msxml2.XMLHTTP' );
 716             } catch (err) {
 717                 this.request = new ActiveXObject( 'Microsoft.XMLHTTP' );
 718             }
 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(url); /// url used ONLY for error reporting
 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 (savedUrlForErrorReporting)
 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.request.responseXML == null) {
 819               if (this.request.responseText != null) {
 820                 //assume JSON
 821
 822                 var json = null;
 823                 var text = this.request.responseText;
 824                 if (typeof window.JSON == "undefined")
 825                     json = eval("(" + text + ")");
 826                 else {
 827                     try {
 828                         json = JSON.parse(text);
 829                     }
 830                     catch (e) {
 831                         // Safari: eval will fail as well. Considering trying JSON2 (non-native implementation) instead
 832                         /* DEBUG only works in mk2-mobile
 833                         if (document.getElementById("log"))
 834                             document.getElementById("log").innerHTML = "" + e + " " + length + ": " + text;
 835                         */
 836                         try {
 837                             json = eval("(" + text + ")");
 838                         }
 839                         catch (e) {
 840                             /* DEBUG only works in mk2-mobile
 841                             if (document.getElementById("log"))
 842                                 document.getElementById("log").innerHTML = "" + e + " " + length + ": " + text;
 843                             */
 844                         }
 845                     }
 846                 }
 847                 this.callback(json, "json");
 848               } else {
 849                 var err = new Error("XML response is empty but no error " +
 850                                     "for " + savedUrlForErrorReporting);
 851                 err.code = -1;
 852                 if (this.errorHandler) {
 853                     this.errorHandler(err);
 854                 } else {
 855                     throw err;
 856                 }
 857               }
 858             } else if (this.request.status == 200) {
 859                 this.callback(this.request.responseXML);
 860             } else {
 861                 var err = new Error("HTTP response not OK: "
 862                             + this.request.status + " - "
 863                             + this.request.statusText );
 864                 err.code = '00' + this.request.status;
 865                 if (this.errorHandler) {
 866                     this.errorHandler(err);
 867                 }
 868                 else {
 869                     throw err;
 870                 }
 871             }
 872         }
 873     }
 874 };
 875
 876 /*
 877 ********************************************************************************
 878 ** XML HELPER FUNCTIONS ********************************************************
 879 ********************************************************************************
 880 */
 881
 882 // DOMDocument
 883
 884 if ( window.ActiveXObject) {
 885     var DOMDoc = document;
 886 } else {
 887     var DOMDoc = Document.prototype;
 888 }
 889
 890 DOMDoc.newXmlDoc = function ( root )
 891 {
 892     var doc;
 893
 894     if (document.implementation && document.implementation.createDocument) {
 895         doc = document.implementation.createDocument('', root, null);
 896     } else if ( window.ActiveXObject ) {
 897         doc = new ActiveXObject("MSXML2.DOMDocument");
 898         doc.loadXML('<' + root + '/>');
 899     } else {
 900         throw new Error ('No XML support in this browser');
 901     }
 902
 903     return doc;
 904 }
 905
 906
 907 DOMDoc.parseXmlFromString = function ( xmlString )
 908 {
 909     var doc;
 910
 911     if ( window.DOMParser ) {
 912         var parser = new DOMParser();
 913         doc = parser.parseFromString( xmlString, "text/xml");
 914     } else if ( window.ActiveXObject ) {
 915         doc = new ActiveXObject("MSXML2.DOMDocument");
 916         doc.loadXML( xmlString );
 917     } else {
 918         throw new Error ("No XML parsing support in this browser.");
 919     }
 920
 921     return doc;
 922 }
 923
 924 DOMDoc.transformToDoc = function (xmlDoc, xslDoc)
 925 {
 926     if ( window.XSLTProcessor ) {
 927         var proc = new XSLTProcessor();
 928         proc.importStylesheet( xslDoc );
 929         return proc.transformToDocument(xmlDoc);
 930     } else if ( window.ActiveXObject ) {
 931         return document.parseXmlFromString(xmlDoc.transformNode(xslDoc));
 932     } else {
 933         alert( 'Unable to perform XSLT transformation in this browser' );
 934     }
 935 }
 936
 937 // DOMElement
 938
 939 Element_removeFromDoc = function (DOM_Element)
 940 {
 941     DOM_Element.parentNode.removeChild(DOM_Element);
 942 }
 943
 944 Element_emptyChildren = function (DOM_Element)
 945 {
 946     while( DOM_Element.firstChild ) {
 947         DOM_Element.removeChild( DOM_Element.firstChild )
 948     }
 949 }
 950
 951 Element_appendTransformResult = function ( DOM_Element, xmlDoc, xslDoc )
 952 {
 953     if ( window.XSLTProcessor ) {
 954         var proc = new XSLTProcessor();
 955         proc.importStylesheet( xslDoc );
 956         var docFrag = false;
 957         docFrag = proc.transformToFragment( xmlDoc, DOM_Element.ownerDocument );
 958         DOM_Element.appendChild(docFrag);
 959     } else if ( window.ActiveXObject ) {
 960         DOM_Element.innerHTML = xmlDoc.transformNode( xslDoc );
 961     } else {
 962         alert( 'Unable to perform XSLT transformation in this browser' );
 963     }
 964 }
 965
 966 Element_appendTextNode = function (DOM_Element, tagName, textContent )
 967 {
 968     var node = DOM_Element.ownerDocument.createElement(tagName);
 969     var text = DOM_Element.ownerDocument.createTextNode(textContent);
 970
 971     DOM_Element.appendChild(node);
 972     node.appendChild(text);
 973
 974     return node;
 975 }
 976
 977 Element_setTextContent = function ( DOM_Element, textContent )
 978 {
 979     if (typeof DOM_Element.textContent !== "undefined") {
 980         DOM_Element.textContent = textContent;
 981     } else if (typeof DOM_Element.innerText !== "undefined" ) {
 982         DOM_Element.innerText = textContent;
 983     } else {
 984         throw new Error("Cannot set text content of the node, no such method.");
 985     }
 986 }
 987
 988 Element_getTextContent = function (DOM_Element)
 989 {
 990     if ( typeof DOM_Element.textContent != 'undefined' ) {
 991         return DOM_Element.textContent;
 992     } else if (typeof DOM_Element.text != 'undefined') {
 993         return DOM_Element.text;
 994     } else {
 995         throw new Error("Cannot get text content of the node, no such method.");
 996     }
 997 }
 998
 999 Element_parseChildNodes = function (node)
1000 {
1001     var parsed = {};
1002     var hasChildElems = false;
1003
1004     if (node.hasChildNodes()) {
1005         var children = node.childNodes;
1006         for (var i = 0; i < children.length; i++) {
1007             var child = children[i];
1008             if (child.nodeType == Node.ELEMENT_NODE) {
1009                 hasChildElems = true;
1010                 var nodeName = child.nodeName;
1011                 if (!(nodeName in parsed))
1012                     parsed[nodeName] = [];
1013                 parsed[nodeName].push(Element_parseChildNodes(child));
1014             }
1015         }
1016     }
1017
1018     var attrs = node.attributes;
1019     for (var i = 0; i < attrs.length; i++) {
1020         var attrName = '@' + attrs[i].nodeName;
1021         var attrValue = attrs[i].nodeValue;
1022         parsed[attrName] = attrValue;
1023     }
1024
1025     // if no nested elements, get text content
1026     if (node.hasChildNodes() && !hasChildElems) {
1027         if (node.attributes.length)
1028             parsed['#text'] = node.firstChild.nodeValue;
1029         else
1030             parsed = node.firstChild.nodeValue;
1031     }
1032
1033     return parsed;
1034 }
1035
1036 /* do not remove trailing bracket */
1037 }