PollingProvider.js
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/**
* @class Ext.direct.PollingProvider
*
* <p>Provides for repetitive polling of the server at distinct {@link #interval intervals}.
* The initial request for data originates from the client, and then is responded to by the
* server.</p>
*
* <p>All configurations for the PollingProvider should be generated by the server-side
* API portion of the Ext.Direct stack.</p>
*
* <p>An instance of PollingProvider may be created directly via the new keyword or by simply
* specifying <tt>type = 'polling'</tt>. For example:</p>
* <pre><code>
var pollA = new Ext.direct.PollingProvider({
type:'polling',
url: 'php/pollA.php',
});
Ext.direct.Manager.addProvider(pollA);
pollA.disconnect();
Ext.direct.Manager.addProvider(
{
type:'polling',
url: 'php/pollB.php',
id: 'pollB-provider'
}
);
var pollB = Ext.direct.Manager.getProvider('pollB-provider');
* </code></pre>
*/
Ext.define('Ext.direct.PollingProvider', {
/* Begin Definitions */
extend: 'Ext.direct.JsonProvider',
alias: 'direct.pollingprovider',
uses: ['Ext.direct.ExceptionEvent'],
requires: ['Ext.Ajax', 'Ext.util.DelayedTask'],
/* End Definitions */
/**
* @cfg {Number} interval
* How often to poll the server-side in milliseconds. Defaults to every 3 seconds.
*/
interval: 3000,
/**
* @cfg {Object} baseParams
* An object containing properties which are to be sent as parameters on every polling request
*/
/**
* @cfg {String/Function} url
* The url which the PollingProvider should contact with each request. This can also be
* an imported Ext.Direct method which will accept the baseParams as its only argument.
*/
// private
constructor : function(config){
this.callParent(arguments);
this.addEvents(
/**
* @event beforepoll
* Fired immediately before a poll takes place, an event handler can return false
* in order to cancel the poll.
* @param {Ext.direct.PollingProvider} this
*/
'beforepoll',
/**
* @event poll
* This event has not yet been implemented.
* @param {Ext.direct.PollingProvider} this
*/
'poll'
);
},
// inherited
isConnected: function(){
return !!this.pollTask;
},
/**
* Connect to the server-side and begin the polling process. To handle each
* response subscribe to the data event.
*/
connect: function(){
var me = this, url = me.url;
if (url && !me.pollTask) {
me.pollTask = Ext.TaskManager.start({
run: function(){
if (me.fireEvent('beforepoll', me) !== false) {
if (Ext.isFunction(url)) {
url(me.baseParams);
} else {
Ext.Ajax.request({
url: url,
callback: me.onData,
scope: me,
params: me.baseParams
});
}
}
},
interval: me.interval,
scope: me
});
me.fireEvent('connect', me);
} else if (!url) {
//<debug>
Ext.Error.raise('Error initializing PollingProvider, no url configured.');
//</debug>
}
},
/**
* Disconnect from the server-side and stop the polling process. The disconnect
* event will be fired on a successful disconnect.
*/
disconnect: function(){
var me = this;
if (me.pollTask) {
Ext.TaskManager.stop(me.pollTask);
delete me.pollTask;
me.fireEvent('disconnect', me);
}
},
// private
onData: function(opt, success, response){
var me = this,
i = 0,
len,
events;
if (success) {
events = me.createEvents(response);
for (len = events.length; i < len; ++i) {
me.fireEvent('data', me, events[i]);
}
} else {
me.fireEvent('data', me, new Ext.direct.ExceptionEvent({
data: null,
code: Ext.direct.Manager.exceptions.TRANSPORT,
message: 'Unable to connect to the server.',
xhr: response
}));
}
}
});