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1
/*
2
Copyright (c) 2009, Yahoo! Inc. All rights reserved.
3
Code licensed under the BSD License:
4
http://developer.yahoo.net/yui/license.txt
5
version: 2.8.0r4
6
*/
7
/**
8
 * The Connection Manager provides a simplified interface to the XMLHttpRequest
9
 * object.  It handles cross-browser instantiantion of XMLHttpRequest, negotiates the
10
 * interactive states and server response, returning the results to a pre-defined
11
 * callback you create.
12
 *
13
 * @namespace YAHOO.util
14
 * @module connection
15
 * @requires yahoo
16
 * @requires event
17
 */
18

    
19
/**
20
 * The Connection Manager singleton provides methods for creating and managing
21
 * asynchronous transactions.
22
 *
23
 * @class Connect
24
 */
25

    
26
YAHOO.util.Connect =
27
{
28
  /**
29
   * @description Array of MSFT ActiveX ids for XMLHttpRequest.
30
   * @property _msxml_progid
31
   * @private
32
   * @static
33
   * @type array
34
   */
35
	_msxml_progid:[
36
		'Microsoft.XMLHTTP',
37
		'MSXML2.XMLHTTP.3.0',
38
		'MSXML2.XMLHTTP'
39
		],
40

    
41
  /**
42
   * @description Object literal of HTTP header(s)
43
   * @property _http_header
44
   * @private
45
   * @static
46
   * @type object
47
   */
48
	_http_headers:{},
49

    
50
  /**
51
   * @description Determines if HTTP headers are set.
52
   * @property _has_http_headers
53
   * @private
54
   * @static
55
   * @type boolean
56
   */
57
	_has_http_headers:false,
58

    
59
 /**
60
  * @description Determines if a default header of
61
  * Content-Type of 'application/x-www-form-urlencoded'
62
  * will be added to any client HTTP headers sent for POST
63
  * transactions.
64
  * @property _use_default_post_header
65
  * @private
66
  * @static
67
  * @type boolean
68
  */
69
    _use_default_post_header:true,
70

    
71
 /**
72
  * @description The default header used for POST transactions.
73
  * @property _default_post_header
74
  * @private
75
  * @static
76
  * @type boolean
77
  */
78
    _default_post_header:'application/x-www-form-urlencoded; charset=UTF-8',
79

    
80
 /**
81
  * @description The default header used for transactions involving the
82
  * use of HTML forms.
83
  * @property _default_form_header
84
  * @private
85
  * @static
86
  * @type boolean
87
  */
88
    _default_form_header:'application/x-www-form-urlencoded',
89

    
90
 /**
91
  * @description Determines if a default header of
92
  * 'X-Requested-With: XMLHttpRequest'
93
  * will be added to each transaction.
94
  * @property _use_default_xhr_header
95
  * @private
96
  * @static
97
  * @type boolean
98
  */
99
    _use_default_xhr_header:true,
100

    
101
 /**
102
  * @description The default header value for the label
103
  * "X-Requested-With".  This is sent with each
104
  * transaction, by default, to identify the
105
  * request as being made by YUI Connection Manager.
106
  * @property _default_xhr_header
107
  * @private
108
  * @static
109
  * @type boolean
110
  */
111
    _default_xhr_header:'XMLHttpRequest',
112

    
113
 /**
114
  * @description Determines if custom, default headers
115
  * are set for each transaction.
116
  * @property _has_default_header
117
  * @private
118
  * @static
119
  * @type boolean
120
  */
121
    _has_default_headers:true,
122

    
123
 /**
124
  * @description Determines if custom, default headers
125
  * are set for each transaction.
126
  * @property _has_default_header
127
  * @private
128
  * @static
129
  * @type boolean
130
  */
131
    _default_headers:{},
132

    
133
 /**
134
  * @description Collection of polling references to the polling mechanism in handleReadyState.
135
  * @property _poll
136
  * @private
137
  * @static
138
  * @type object
139
  */
140
    _poll:{},
141

    
142
 /**
143
  * @description Queue of timeout values for each transaction callback with a defined timeout value.
144
  * @property _timeOut
145
  * @private
146
  * @static
147
  * @type object
148
  */
149
    _timeOut:{},
150

    
151
  /**
152
   * @description The polling frequency, in milliseconds, for HandleReadyState.
153
   * when attempting to determine a transaction's XHR readyState.
154
   * The default is 50 milliseconds.
155
   * @property _polling_interval
156
   * @private
157
   * @static
158
   * @type int
159
   */
160
     _polling_interval:50,
161

    
162
  /**
163
   * @description A transaction counter that increments the transaction id for each transaction.
164
   * @property _transaction_id
165
   * @private
166
   * @static
167
   * @type int
168
   */
169
     _transaction_id:0,
170

    
171
  /**
172
   * @description Custom event that fires at the start of a transaction
173
   * @property startEvent
174
   * @private
175
   * @static
176
   * @type CustomEvent
177
   */
178
	startEvent: new YAHOO.util.CustomEvent('start'),
179

    
180
  /**
181
   * @description Custom event that fires when a transaction response has completed.
182
   * @property completeEvent
183
   * @private
184
   * @static
185
   * @type CustomEvent
186
   */
187
	completeEvent: new YAHOO.util.CustomEvent('complete'),
188

    
189
  /**
190
   * @description Custom event that fires when handleTransactionResponse() determines a
191
   * response in the HTTP 2xx range.
192
   * @property successEvent
193
   * @private
194
   * @static
195
   * @type CustomEvent
196
   */
197
	successEvent: new YAHOO.util.CustomEvent('success'),
198

    
199
  /**
200
   * @description Custom event that fires when handleTransactionResponse() determines a
201
   * response in the HTTP 4xx/5xx range.
202
   * @property failureEvent
203
   * @private
204
   * @static
205
   * @type CustomEvent
206
   */
207
	failureEvent: new YAHOO.util.CustomEvent('failure'),
208

    
209
  /**
210
   * @description Custom event that fires when a transaction is successfully aborted.
211
   * @property abortEvent
212
   * @private
213
   * @static
214
   * @type CustomEvent
215
   */
216
	abortEvent: new YAHOO.util.CustomEvent('abort'),
217

    
218
  /**
219
   * @description A reference table that maps callback custom events members to its specific
220
   * event name.
221
   * @property _customEvents
222
   * @private
223
   * @static
224
   * @type object
225
   */
226
	_customEvents:
227
	{
228
		onStart:['startEvent', 'start'],
229
		onComplete:['completeEvent', 'complete'],
230
		onSuccess:['successEvent', 'success'],
231
		onFailure:['failureEvent', 'failure'],
232
		onUpload:['uploadEvent', 'upload'],
233
		onAbort:['abortEvent', 'abort']
234
	},
235

    
236
  /**
237
   * @description Member to add an ActiveX id to the existing xml_progid array.
238
   * In the event(unlikely) a new ActiveX id is introduced, it can be added
239
   * without internal code modifications.
240
   * @method setProgId
241
   * @public
242
   * @static
243
   * @param {string} id The ActiveX id to be added to initialize the XHR object.
244
   * @return void
245
   */
246
	setProgId:function(id)
247
	{
248
		this._msxml_progid.unshift(id);
249
		YAHOO.log('ActiveX Program Id  ' + id + ' added to _msxml_progid.', 'info', 'Connection');
250
	},
251

    
252
  /**
253
   * @description Member to override the default POST header.
254
   * @method setDefaultPostHeader
255
   * @public
256
   * @static
257
   * @param {boolean} b Set and use default header - true or false .
258
   * @return void
259
   */
260
	setDefaultPostHeader:function(b)
261
	{
262
		if(typeof b == 'string'){
263
			this._default_post_header = b;
264
			YAHOO.log('Default POST header set to  ' + b, 'info', 'Connection');
265
		}
266
		else if(typeof b == 'boolean'){
267
			this._use_default_post_header = b;
268
		}
269
	},
270

    
271
  /**
272
   * @description Member to override the default transaction header..
273
   * @method setDefaultXhrHeader
274
   * @public
275
   * @static
276
   * @param {boolean} b Set and use default header - true or false .
277
   * @return void
278
   */
279
	setDefaultXhrHeader:function(b)
280
	{
281
		if(typeof b == 'string'){
282
			this._default_xhr_header = b;
283
			YAHOO.log('Default XHR header set to  ' + b, 'info', 'Connection');
284
		}
285
		else{
286
			this._use_default_xhr_header = b;
287
		}
288
	},
289

    
290
  /**
291
   * @description Member to modify the default polling interval.
292
   * @method setPollingInterval
293
   * @public
294
   * @static
295
   * @param {int} i The polling interval in milliseconds.
296
   * @return void
297
   */
298
	setPollingInterval:function(i)
299
	{
300
		if(typeof i == 'number' && isFinite(i)){
301
			this._polling_interval = i;
302
			YAHOO.log('Default polling interval set to ' + i +'ms', 'info', 'Connection');
303
		}
304
	},
305

    
306
  /**
307
   * @description Instantiates a XMLHttpRequest object and returns an object with two properties:
308
   * the XMLHttpRequest instance and the transaction id.
309
   * @method createXhrObject
310
   * @private
311
   * @static
312
   * @param {int} transactionId Property containing the transaction id for this transaction.
313
   * @return object
314
   */
315
	createXhrObject:function(transactionId)
316
	{
317
		var obj,http,i;
318
		try
319
		{
320
			// Instantiates XMLHttpRequest in non-IE browsers and assigns to http.
321
			http = new XMLHttpRequest();
322
			//  Object literal with http and tId properties
323
			obj = { conn:http, tId:transactionId, xhr: true };
324
			YAHOO.log('XHR object created for transaction ' + transactionId, 'info', 'Connection');
325
		}
326
		catch(e)
327
		{
328
			for(i=0; i<this._msxml_progid.length; ++i){
329
				try
330
				{
331
					// Instantiates XMLHttpRequest for IE and assign to http
332
					http = new ActiveXObject(this._msxml_progid[i]);
333
					//  Object literal with conn and tId properties
334
					obj = { conn:http, tId:transactionId, xhr: true };
335
					YAHOO.log('ActiveX XHR object created for transaction ' + transactionId, 'info', 'Connection');
336
					break;
337
				}
338
				catch(e1){}
339
			}
340
		}
341
		finally
342
		{
343
			return obj;
344
		}
345
	},
346

    
347
  /**
348
   * @description This method is called by asyncRequest to create a
349
   * valid connection object for the transaction.  It also passes a
350
   * transaction id and increments the transaction id counter.
351
   * @method getConnectionObject
352
   * @private
353
   * @static
354
   * @return {object}
355
   */
356
	getConnectionObject:function(t)
357
	{
358
		var o, tId = this._transaction_id;
359

    
360
		try
361
		{
362
			if(!t){
363
				o = this.createXhrObject(tId);
364
			}
365
			else{
366
				o = {tId:tId};
367
				if(t==='xdr'){
368
					o.conn = this._transport;
369
					o.xdr = true;
370
				}
371
				else if(t==='upload'){
372
					o.upload = true;
373
				}
374
			}
375

    
376
			if(o){
377
				this._transaction_id++;
378
			}
379
		}
380
		catch(e){}
381
		return o;
382
	},
383

    
384
  /**
385
   * @description Method for initiating an asynchronous request via the XHR object.
386
   * @method asyncRequest
387
   * @public
388
   * @static
389
   * @param {string} method HTTP transaction method
390
   * @param {string} uri Fully qualified path of resource
391
   * @param {callback} callback User-defined callback function or object
392
   * @param {string} postData POST body
393
   * @return {object} Returns the connection object
394
   */
395
	asyncRequest:function(method, uri, callback, postData)
396
	{
397
		var o,t,args = (callback && callback.argument)?callback.argument:null;
398

    
399
		if(this._isFileUpload){
400
			t = 'upload';
401
		}
402
		else if(callback.xdr){
403
			t = 'xdr';
404
		}
405

    
406
		o = this.getConnectionObject(t);
407
		if(!o){
408
			YAHOO.log('Unable to create connection object.', 'error', 'Connection');
409
			return null;
410
		}
411
		else{
412

    
413
			// Intialize any transaction-specific custom events, if provided.
414
			if(callback && callback.customevents){
415
				this.initCustomEvents(o, callback);
416
			}
417

    
418
			if(this._isFormSubmit){
419
				if(this._isFileUpload){
420
					this.uploadFile(o, callback, uri, postData);
421
					return o;
422
				}
423

    
424
				// If the specified HTTP method is GET, setForm() will return an
425
				// encoded string that is concatenated to the uri to
426
				// create a querystring.
427
				if(method.toUpperCase() == 'GET'){
428
					if(this._sFormData.length !== 0){
429
						// If the URI already contains a querystring, append an ampersand
430
						// and then concatenate _sFormData to the URI.
431
						uri += ((uri.indexOf('?') == -1)?'?':'&') + this._sFormData;
432
					}
433
				}
434
				else if(method.toUpperCase() == 'POST'){
435
					// If POST data exist in addition to the HTML form data,
436
					// it will be concatenated to the form data.
437
					postData = postData?this._sFormData + "&" + postData:this._sFormData;
438
				}
439
			}
440

    
441
			if(method.toUpperCase() == 'GET' && (callback && callback.cache === false)){
442
				// If callback.cache is defined and set to false, a
443
				// timestamp value will be added to the querystring.
444
				uri += ((uri.indexOf('?') == -1)?'?':'&') + "rnd=" + new Date().valueOf().toString();
445
			}
446

    
447
			// Each transaction will automatically include a custom header of
448
			// "X-Requested-With: XMLHttpRequest" to identify the request as
449
			// having originated from Connection Manager.
450
			if(this._use_default_xhr_header){
451
				if(!this._default_headers['X-Requested-With']){
452
					this.initHeader('X-Requested-With', this._default_xhr_header, true);
453
					YAHOO.log('Initialize transaction header X-Request-Header to XMLHttpRequest.', 'info', 'Connection');
454
				}
455
			}
456

    
457
			//If the transaction method is POST and the POST header value is set to true
458
			//or a custom value, initalize the Content-Type header to this value.
459
			if((method.toUpperCase() === 'POST' && this._use_default_post_header) && this._isFormSubmit === false){
460
				this.initHeader('Content-Type', this._default_post_header);
461
				YAHOO.log('Initialize header Content-Type to application/x-www-form-urlencoded; UTF-8 for POST transaction.', 'info', 'Connection');
462
			}
463

    
464
			if(o.xdr){
465
				this.xdr(o, method, uri, callback, postData);
466
				return o;
467
			}
468

    
469
			o.conn.open(method, uri, true);
470
			//Initialize all default and custom HTTP headers,
471
			if(this._has_default_headers || this._has_http_headers){
472
				this.setHeader(o);
473
			}
474

    
475
			this.handleReadyState(o, callback);
476
			o.conn.send(postData || '');
477
			YAHOO.log('Transaction ' + o.tId + ' sent.', 'info', 'Connection');
478

    
479
			// Reset the HTML form data and state properties as
480
			// soon as the data are submitted.
481
			if(this._isFormSubmit === true){
482
				this.resetFormState();
483
			}
484

    
485
			// Fire global custom event -- startEvent
486
			this.startEvent.fire(o, args);
487

    
488
			if(o.startEvent){
489
				// Fire transaction custom event -- startEvent
490
				o.startEvent.fire(o, args);
491
			}
492

    
493
			return o;
494
		}
495
	},
496

    
497
  /**
498
   * @description This method creates and subscribes custom events,
499
   * specific to each transaction
500
   * @method initCustomEvents
501
   * @private
502
   * @static
503
   * @param {object} o The connection object
504
   * @param {callback} callback The user-defined callback object
505
   * @return {void}
506
   */
507
	initCustomEvents:function(o, callback)
508
	{
509
		var prop;
510
		// Enumerate through callback.customevents members and bind/subscribe
511
		// events that match in the _customEvents table.
512
		for(prop in callback.customevents){
513
			if(this._customEvents[prop][0]){
514
				// Create the custom event
515
				o[this._customEvents[prop][0]] = new YAHOO.util.CustomEvent(this._customEvents[prop][1], (callback.scope)?callback.scope:null);
516
				YAHOO.log('Transaction-specific Custom Event ' + o[this._customEvents[prop][1]] + ' created.', 'info', 'Connection');
517

    
518
				// Subscribe the custom event
519
				o[this._customEvents[prop][0]].subscribe(callback.customevents[prop]);
520
				YAHOO.log('Transaction-specific Custom Event ' + o[this._customEvents[prop][1]] + ' subscribed.', 'info', 'Connection');
521
			}
522
		}
523
	},
524

    
525
  /**
526
   * @description This method serves as a timer that polls the XHR object's readyState
527
   * property during a transaction, instead of binding a callback to the
528
   * onreadystatechange event.  Upon readyState 4, handleTransactionResponse
529
   * will process the response, and the timer will be cleared.
530
   * @method handleReadyState
531
   * @private
532
   * @static
533
   * @param {object} o The connection object
534
   * @param {callback} callback The user-defined callback object
535
   * @return {void}
536
   */
537

    
538
    handleReadyState:function(o, callback)
539

    
540
    {
541
		var oConn = this,
542
			args = (callback && callback.argument)?callback.argument:null;
543

    
544
		if(callback && callback.timeout){
545
			this._timeOut[o.tId] = window.setTimeout(function(){ oConn.abort(o, callback, true); }, callback.timeout);
546
		}
547

    
548
		this._poll[o.tId] = window.setInterval(
549
			function(){
550
				if(o.conn && o.conn.readyState === 4){
551

    
552
					// Clear the polling interval for the transaction
553
					// and remove the reference from _poll.
554
					window.clearInterval(oConn._poll[o.tId]);
555
					delete oConn._poll[o.tId];
556

    
557
					if(callback && callback.timeout){
558
						window.clearTimeout(oConn._timeOut[o.tId]);
559
						delete oConn._timeOut[o.tId];
560
					}
561

    
562
					// Fire global custom event -- completeEvent
563
					oConn.completeEvent.fire(o, args);
564

    
565
					if(o.completeEvent){
566
						// Fire transaction custom event -- completeEvent
567
						o.completeEvent.fire(o, args);
568
					}
569

    
570
					oConn.handleTransactionResponse(o, callback);
571
				}
572
			}
573
		,this._polling_interval);
574
    },
575

    
576
  /**
577
   * @description This method attempts to interpret the server response and
578
   * determine whether the transaction was successful, or if an error or
579
   * exception was encountered.
580
   * @method handleTransactionResponse
581
   * @private
582
   * @static
583
   * @param {object} o The connection object
584
   * @param {object} callback The user-defined callback object
585
   * @param {boolean} isAbort Determines if the transaction was terminated via abort().
586
   * @return {void}
587
   */
588
    handleTransactionResponse:function(o, callback, isAbort)
589
    {
590
		var httpStatus, responseObject,
591
			args = (callback && callback.argument)?callback.argument:null,
592
			xdrS = (o.r && o.r.statusText === 'xdr:success')?true:false,
593
			xdrF = (o.r && o.r.statusText === 'xdr:failure')?true:false,
594
			xdrA = isAbort;
595

    
596
		try
597
		{
598
			if((o.conn.status !== undefined && o.conn.status !== 0) || xdrS){
599
				// XDR requests will not have HTTP status defined. The
600
				// statusText property will define the response status
601
				// set by the Flash transport.
602
				httpStatus = o.conn.status;
603
			}
604
			else if(xdrF && !xdrA){
605
				// Set XDR transaction failure to a status of 0, which
606
				// resolves as an HTTP failure, instead of an exception.
607
				httpStatus = 0;
608
			}
609
			else{
610
				httpStatus = 13030;
611
			}
612
		}
613
		catch(e){
614

    
615
			 // 13030 is a custom code to indicate the condition -- in Mozilla/FF --
616
			 // when the XHR object's status and statusText properties are
617
			 // unavailable, and a query attempt throws an exception.
618
			httpStatus = 13030;
619
		}
620

    
621
		if((httpStatus >= 200 && httpStatus < 300) || httpStatus === 1223 || xdrS){
622
			responseObject = o.xdr ? o.r : this.createResponseObject(o, args);
623
			if(callback && callback.success){
624
				if(!callback.scope){
625
					callback.success(responseObject);
626
					YAHOO.log('Success callback. HTTP code is ' + httpStatus, 'info', 'Connection');
627
				}
628
				else{
629
					// If a scope property is defined, the callback will be fired from
630
					// the context of the object.
631
					callback.success.apply(callback.scope, [responseObject]);
632
					YAHOO.log('Success callback with scope. HTTP code is ' + httpStatus, 'info', 'Connection');
633
				}
634
			}
635

    
636
			// Fire global custom event -- successEvent
637
			this.successEvent.fire(responseObject);
638

    
639
			if(o.successEvent){
640
				// Fire transaction custom event -- successEvent
641
				o.successEvent.fire(responseObject);
642
			}
643
		}
644
		else{
645
			switch(httpStatus){
646
				// The following cases are wininet.dll error codes that may be encountered.
647
				case 12002: // Server timeout
648
				case 12029: // 12029 to 12031 correspond to dropped connections.
649
				case 12030:
650
				case 12031:
651
				case 12152: // Connection closed by server.
652
				case 13030: // See above comments for variable status.
653
					// XDR transactions will not resolve to this case, since the
654
					// response object is already built in the xdr response.
655
					responseObject = this.createExceptionObject(o.tId, args, (isAbort?isAbort:false));
656
					if(callback && callback.failure){
657
						if(!callback.scope){
658
							callback.failure(responseObject);
659
							YAHOO.log('Failure callback. Exception detected. Status code is ' + httpStatus, 'warn', 'Connection');
660
						}
661
						else{
662
							callback.failure.apply(callback.scope, [responseObject]);
663
							YAHOO.log('Failure callback with scope. Exception detected. Status code is ' + httpStatus, 'warn', 'Connection');
664
						}
665
					}
666

    
667
					break;
668
				default:
669
					responseObject = (o.xdr) ? o.response : this.createResponseObject(o, args);
670
					if(callback && callback.failure){
671
						if(!callback.scope){
672
							callback.failure(responseObject);
673
							YAHOO.log('Failure callback. HTTP status code is ' + httpStatus, 'warn', 'Connection');
674
						}
675
						else{
676
							callback.failure.apply(callback.scope, [responseObject]);
677
							YAHOO.log('Failure callback with scope. HTTP status code is ' + httpStatus, 'warn', 'Connection');
678
						}
679
					}
680
			}
681

    
682
			// Fire global custom event -- failureEvent
683
			this.failureEvent.fire(responseObject);
684

    
685
			if(o.failureEvent){
686
				// Fire transaction custom event -- failureEvent
687
				o.failureEvent.fire(responseObject);
688
			}
689

    
690
		}
691

    
692
		this.releaseObject(o);
693
		responseObject = null;
694
    },
695

    
696
  /**
697
   * @description This method evaluates the server response, creates and returns the results via
698
   * its properties.  Success and failure cases will differ in the response
699
   * object's property values.
700
   * @method createResponseObject
701
   * @private
702
   * @static
703
   * @param {object} o The connection object
704
   * @param {callbackArg} callbackArg The user-defined argument or arguments to be passed to the callback
705
   * @return {object}
706
   */
707
    createResponseObject:function(o, callbackArg)
708
    {
709
		var obj = {}, headerObj = {},
710
			i, headerStr, header, delimitPos;
711

    
712
		try
713
		{
714
			headerStr = o.conn.getAllResponseHeaders();
715
			header = headerStr.split('\n');
716
			for(i=0; i<header.length; i++){
717
				delimitPos = header[i].indexOf(':');
718
				if(delimitPos != -1){
719
					headerObj[header[i].substring(0,delimitPos)] = YAHOO.lang.trim(header[i].substring(delimitPos+2));
720
				}
721
			}
722
		}
723
		catch(e){}
724

    
725
		obj.tId = o.tId;
726
		// Normalize IE's response to HTTP 204 when Win error 1223.
727
		obj.status = (o.conn.status == 1223)?204:o.conn.status;
728
		// Normalize IE's statusText to "No Content" instead of "Unknown".
729
		obj.statusText = (o.conn.status == 1223)?"No Content":o.conn.statusText;
730
		obj.getResponseHeader = headerObj;
731
		obj.getAllResponseHeaders = headerStr;
732
		obj.responseText = o.conn.responseText;
733
		obj.responseXML = o.conn.responseXML;
734

    
735
		if(callbackArg){
736
			obj.argument = callbackArg;
737
		}
738

    
739
		return obj;
740
    },
741

    
742
  /**
743
   * @description If a transaction cannot be completed due to dropped or closed connections,
744
   * there may be not be enough information to build a full response object.
745
   * The failure callback will be fired and this specific condition can be identified
746
   * by a status property value of 0.
747
   *
748
   * If an abort was successful, the status property will report a value of -1.
749
   *
750
   * @method createExceptionObject
751
   * @private
752
   * @static
753
   * @param {int} tId The Transaction Id
754
   * @param {callbackArg} callbackArg The user-defined argument or arguments to be passed to the callback
755
   * @param {boolean} isAbort Determines if the exception case is caused by a transaction abort
756
   * @return {object}
757
   */
758
    createExceptionObject:function(tId, callbackArg, isAbort)
759
    {
760
		var COMM_CODE = 0,
761
			COMM_ERROR = 'communication failure',
762
			ABORT_CODE = -1,
763
			ABORT_ERROR = 'transaction aborted',
764
			obj = {};
765

    
766
		obj.tId = tId;
767
		if(isAbort){
768
			obj.status = ABORT_CODE;
769
			obj.statusText = ABORT_ERROR;
770
		}
771
		else{
772
			obj.status = COMM_CODE;
773
			obj.statusText = COMM_ERROR;
774
		}
775

    
776
		if(callbackArg){
777
			obj.argument = callbackArg;
778
		}
779

    
780
		return obj;
781
    },
782

    
783
  /**
784
   * @description Method that initializes the custom HTTP headers for the each transaction.
785
   * @method initHeader
786
   * @public
787
   * @static
788
   * @param {string} label The HTTP header label
789
   * @param {string} value The HTTP header value
790
   * @param {string} isDefault Determines if the specific header is a default header
791
   * automatically sent with each transaction.
792
   * @return {void}
793
   */
794
	initHeader:function(label, value, isDefault)
795
	{
796
		var headerObj = (isDefault)?this._default_headers:this._http_headers;
797

    
798
		headerObj[label] = value;
799
		if(isDefault){
800
			this._has_default_headers = true;
801
		}
802
		else{
803
			this._has_http_headers = true;
804
		}
805
	},
806

    
807

    
808
  /**
809
   * @description Accessor that sets the HTTP headers for each transaction.
810
   * @method setHeader
811
   * @private
812
   * @static
813
   * @param {object} o The connection object for the transaction.
814
   * @return {void}
815
   */
816
	setHeader:function(o)
817
	{
818
		var prop;
819
		if(this._has_default_headers){
820
			for(prop in this._default_headers){
821
				if(YAHOO.lang.hasOwnProperty(this._default_headers, prop)){
822
					o.conn.setRequestHeader(prop, this._default_headers[prop]);
823
					YAHOO.log('Default HTTP header ' + prop + ' set with value of ' + this._default_headers[prop], 'info', 'Connection');
824
				}
825
			}
826
		}
827

    
828
		if(this._has_http_headers){
829
			for(prop in this._http_headers){
830
				if(YAHOO.lang.hasOwnProperty(this._http_headers, prop)){
831
					o.conn.setRequestHeader(prop, this._http_headers[prop]);
832
					YAHOO.log('HTTP header ' + prop + ' set with value of ' + this._http_headers[prop], 'info', 'Connection');
833
				}
834
			}
835

    
836
			this._http_headers = {};
837
			this._has_http_headers = false;
838
		}
839
	},
840

    
841
  /**
842
   * @description Resets the default HTTP headers object
843
   * @method resetDefaultHeaders
844
   * @public
845
   * @static
846
   * @return {void}
847
   */
848
	resetDefaultHeaders:function(){
849
		this._default_headers = {};
850
		this._has_default_headers = false;
851
	},
852

    
853
  /**
854
   * @description Method to terminate a transaction, if it has not reached readyState 4.
855
   * @method abort
856
   * @public
857
   * @static
858
   * @param {object} o The connection object returned by asyncRequest.
859
   * @param {object} callback  User-defined callback object.
860
   * @param {string} isTimeout boolean to indicate if abort resulted from a callback timeout.
861
   * @return {boolean}
862
   */
863
	abort:function(o, callback, isTimeout)
864
	{
865
		var abortStatus,
866
			args = (callback && callback.argument)?callback.argument:null;
867
			o = o || {};
868

    
869
		if(o.conn){
870
			if(o.xhr){
871
				if(this.isCallInProgress(o)){
872
					// Issue abort request
873
					o.conn.abort();
874

    
875
					window.clearInterval(this._poll[o.tId]);
876
					delete this._poll[o.tId];
877

    
878
					if(isTimeout){
879
						window.clearTimeout(this._timeOut[o.tId]);
880
						delete this._timeOut[o.tId];
881
					}
882

    
883
					abortStatus = true;
884
				}
885
			}
886
			else if(o.xdr){
887
				o.conn.abort(o.tId);
888
				abortStatus = true;
889
			}
890
		}
891
		else if(o.upload){
892
			var frameId = 'yuiIO' + o.tId;
893
			var io = document.getElementById(frameId);
894

    
895
			if(io){
896
				// Remove all listeners on the iframe prior to
897
				// its destruction.
898
				YAHOO.util.Event.removeListener(io, "load");
899
				// Destroy the iframe facilitating the transaction.
900
				document.body.removeChild(io);
901
				YAHOO.log('File upload iframe destroyed. Id is:' + frameId, 'info', 'Connection');
902

    
903
				if(isTimeout){
904
					window.clearTimeout(this._timeOut[o.tId]);
905
					delete this._timeOut[o.tId];
906
				}
907

    
908
				abortStatus = true;
909
			}
910
		}
911
		else{
912
			abortStatus = false;
913
		}
914

    
915
		if(abortStatus === true){
916
			// Fire global custom event -- abortEvent
917
			this.abortEvent.fire(o, args);
918

    
919
			if(o.abortEvent){
920
				// Fire transaction custom event -- abortEvent
921
				o.abortEvent.fire(o, args);
922
			}
923

    
924
			this.handleTransactionResponse(o, callback, true);
925
			YAHOO.log('Transaction ' + o.tId + ' aborted.', 'info', 'Connection');
926
		}
927

    
928
		return abortStatus;
929
	},
930

    
931
  /**
932
   * @description Determines if the transaction is still being processed.
933
   * @method isCallInProgress
934
   * @public
935
   * @static
936
   * @param {object} o The connection object returned by asyncRequest
937
   * @return {boolean}
938
   */
939
	isCallInProgress:function(o)
940
	{
941
		o = o || {};
942
		// if the XHR object assigned to the transaction has not been dereferenced,
943
		// then check its readyState status.  Otherwise, return false.
944
		if(o.xhr && o.conn){
945
			return o.conn.readyState !== 4 && o.conn.readyState !== 0;
946
		}
947
		else if(o.xdr && o.conn){
948
			return o.conn.isCallInProgress(o.tId);
949
		}
950
		else if(o.upload === true){
951
			return document.getElementById('yuiIO' + o.tId)?true:false;
952
		}
953
		else{
954
			return false;
955
		}
956
	},
957

    
958
  /**
959
   * @description Dereference the XHR instance and the connection object after the transaction is completed.
960
   * @method releaseObject
961
   * @private
962
   * @static
963
   * @param {object} o The connection object
964
   * @return {void}
965
   */
966
	releaseObject:function(o)
967
	{
968
		if(o && o.conn){
969
			//dereference the XHR instance.
970
			o.conn = null;
971

    
972
			YAHOO.log('Connection object for transaction ' + o.tId + ' destroyed.', 'info', 'Connection');
973

    
974
			//dereference the connection object.
975
			o = null;
976
		}
977
	}
978
};
979

    
980
YAHOO.register("connection_core", YAHOO.util.Connect, {version: "2.8.0r4", build: "2449"});
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