docs/source/PollingProvider.html

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   9     <pre class="prettyprint lang-js">/*!
  10  * Ext JS Library 3.2.2
  11  * Copyright(c) 2006-2010 Ext JS, Inc.
  12  * licensing@extjs.com
  13  * http://www.extjs.com/license
  14  */
  15 <div id="cls-Ext.direct.PollingProvider"></div>/**
  16  * @class Ext.direct.PollingProvider
  17  * @extends Ext.direct.JsonProvider
  18  *
  19  * <p>Provides for repetitive polling of the server at distinct {@link #interval intervals}.
  20  * The initial request for data originates from the client, and then is responded to by the
  21  * server.</p>
  22  *
  23  * <p>All configurations for the PollingProvider should be generated by the server-side
  24  * API portion of the Ext.Direct stack.</p>
  25  *
  26  * <p>An instance of PollingProvider may be created directly via the new keyword or by simply
  27  * specifying <tt>type = 'polling'</tt>.  For example:</p>
  28  * <pre><code>
  29 var pollA = new Ext.direct.PollingProvider({
  30     type:'polling',
  31     url: 'php/pollA.php',
  32 });
  33 Ext.Direct.addProvider(pollA);
  34 pollA.disconnect();
  35
  36 Ext.Direct.addProvider(
  37     {
  38         type:'polling',
  39         url: 'php/pollB.php',
  40         id: 'pollB-provider'
  41     }
  42 );
  43 var pollB = Ext.Direct.getProvider('pollB-provider');
  44  * </code></pre>
  45  */
  46 Ext.direct.PollingProvider = Ext.extend(Ext.direct.JsonProvider, {
  47     <div id="cfg-Ext.direct.PollingProvider-priority"></div>/**
  48      * @cfg {Number} priority
  49      * Priority of the request (defaults to <tt>3</tt>). See {@link Ext.direct.Provider#priority}.
  50      */
  51     // override default priority
  52     priority: 3,
  53
  54     <div id="cfg-Ext.direct.PollingProvider-interval"></div>/**
  55      * @cfg {Number} interval
  56      * How often to poll the server-side in milliseconds (defaults to <tt>3000</tt> - every
  57      * 3 seconds).
  58      */
  59     interval: 3000,
  60
  61     <div id="cfg-Ext.direct.PollingProvider-baseParams"></div>/**
  62      * @cfg {Object} baseParams An object containing properties which are to be sent as parameters
  63      * on every polling request
  64      */
  65
  66     <div id="cfg-Ext.direct.PollingProvider-url"></div>/**
  67      * @cfg {String/Function} url
  68      * The url which the PollingProvider should contact with each request. This can also be
  69      * an imported Ext.Direct method which will accept the baseParams as its only argument.
  70      */
  71
  72     // private
  73     constructor : function(config){
  74         Ext.direct.PollingProvider.superclass.constructor.call(this, config);
  75         this.addEvents(
  76             <div id="event-Ext.direct.PollingProvider-beforepoll"></div>/**
  77              * @event beforepoll
  78              * Fired immediately before a poll takes place, an event handler can return false
  79              * in order to cancel the poll.
  80              * @param {Ext.direct.PollingProvider}
  81              */
  82             'beforepoll',
  83             <div id="event-Ext.direct.PollingProvider-poll"></div>/**
  84              * @event poll
  85              * This event has not yet been implemented.
  86              * @param {Ext.direct.PollingProvider}
  87              */
  88             'poll'
  89         );
  90     },
  91
  92     // inherited
  93     isConnected: function(){
  94         return !!this.pollTask;
  95     },
  96
  97     <div id="method-Ext.direct.PollingProvider-connect"></div>/**
  98      * Connect to the server-side and begin the polling process. To handle each
  99      * response subscribe to the data event.
 100      */
 101     connect: function(){
 102         if(this.url && !this.pollTask){
 103             this.pollTask = Ext.TaskMgr.start({
 104                 run: function(){
 105                     if(this.fireEvent('beforepoll', this) !== false){
 106                         if(typeof this.url == 'function'){
 107                             this.url(this.baseParams);
 108                         }else{
 109                             Ext.Ajax.request({
 110                                 url: this.url,
 111                                 callback: this.onData,
 112                                 scope: this,
 113                                 params: this.baseParams
 114                             });
 115                         }
 116                     }
 117                 },
 118                 interval: this.interval,
 119                 scope: this
 120             });
 121             this.fireEvent('connect', this);
 122         }else if(!this.url){
 123             throw 'Error initializing PollingProvider, no url configured.';
 124         }
 125     },
 126
 127     <div id="method-Ext.direct.PollingProvider-disconnect"></div>/**
 128      * Disconnect from the server-side and stop the polling process. The disconnect
 129      * event will be fired on a successful disconnect.
 130      */
 131     disconnect: function(){
 132         if(this.pollTask){
 133             Ext.TaskMgr.stop(this.pollTask);
 134             delete this.pollTask;
 135             this.fireEvent('disconnect', this);
 136         }
 137     },
 138
 139     // private
 140     onData: function(opt, success, xhr){
 141         if(success){
 142             var events = this.getEvents(xhr);
 143             for(var i = 0, len = events.length; i < len; i++){
 144                 var e = events[i];
 145                 this.fireEvent('data', this, e);
 146             }
 147         }else{
 148             var e = new Ext.Direct.ExceptionEvent({
 149                 data: e,
 150                 code: Ext.Direct.exceptions.TRANSPORT,
 151                 message: 'Unable to connect to the server.',
 152                 xhr: xhr
 153             });
 154             this.fireEvent('data', this, e);
 155         }
 156     }
 157 });
 158
 159 Ext.Direct.PROVIDERS['polling'] = Ext.direct.PollingProvider;</pre>
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