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Proxy Class

Proxies are used by Stores to handle the loading and saving of Model data. Usually developers will not need to create or interact with proxies directly.

Types of Proxy

There are two main types of Proxy - Client and Server. The Client proxies save their data locally and include the following subclasses:

  • LocalStorageProxy - saves its data to localStorage if the browser supports it
  • SessionStorageProxy - saves its data to sessionStorage if the browsers supports it
  • MemoryProxy - holds data in memory only, any data is lost when the page is refreshed

The Server proxies save their data by sending requests to some remote server. These proxies include:

  • Ajax - sends requests to a server on the same domain
  • JsonP - uses JSON-P to send requests to a server on a different domain
  • Rest - uses RESTful HTTP methods (GET/PUT/POST/DELETE) to communicate with server
  • Direct - uses Ext.direct.Manager to send requests

Proxies operate on the principle that all operations performed are either Create, Read, Update or Delete. These four operations are mapped to the methods create, read, update and destroy respectively. Each Proxy subclass implements these functions.

The CRUD methods each expect an Operation object as the sole argument. The Operation encapsulates information about the action the Store wishes to perform, the model instances that are to be modified, etc. See the Operation documentation for more details. Each CRUD method also accepts a callback function to be called asynchronously on completion.

Proxies also support batching of Operations via a batch object, invoked by the batch method.

Namespace: Ext.data.proxy

Base Types

Base Interfaces

Constructors

Name Description
Proxy(object) Creates the Proxy
Proxy(ProxyConfig)
Proxy(Object[])

Methods

Name Description
addEvents(object) Adds the specified events to the list of events which this Observable may fire.
addListener(object, Delegate, object, object) Appends an event handler to this object. For example:
myGridPanel.on("mouseover", this.onMouseOver, this);
            
The method also allows for a single argument to be passed which is a config object containing properties which specify multiple events. For example:
myGridPanel.on({
            cellClick: this.onCellClick,
            mouseover: this.onMouseOver,
            mouseout: this.onMouseOut,
            scope: this // Important. Ensure "this" is correct during handler execution
            });
            
One can also specify options for each event handler separately:
myGridPanel.on({
            cellClick: {fn: this.onCellClick, scope: this, single: true},
            mouseover: {fn: panel.onMouseOver, scope: panel}
            });
            
Names of methods in a specified scope may also be used. Note that scope MUST be specified to use this option:
myGridPanel.on({
            cellClick: {fn: 'onCellClick', scope: this, single: true},
            mouseover: {fn: 'onMouseOver', scope: panel}
            });
            
addManagedListener(object, object, Delegate, object, object) Adds listeners to any Observable object (or Ext.Element) which are automatically removed when this Component is destroyed.
batch(object) Performs a batch of Operations, in the order specified by batchOrder. Used internally by Ext.data.Store's sync method. Example usage:
myProxy.batch({
            create : [myModel1, myModel2],
            update : [myModel3],
            destroy: [myModel4, myModel5]
            });
            
Where the myModel* above are Model instances - in this case 1 and 2 are new instances and have not been saved before, 3 has been saved previously but needs to be updated, and 4 and 5 have already been saved but should now be destroyed. Note that the previous version of this method took 2 arguments (operations and listeners). While this is still supported for now, the current signature is now a single options argument that can contain both operations and listeners, in addition to other options. The multi-argument signature will likely be deprecated in a future release.
clearListeners() Removes all listeners for this object including the managed listeners
clearManagedListeners() Removes all managed listeners for this object.
continueFireEvent(JsString, object, object) Continue to fire event.
create(Operation, Delegate, object) Performs the given create operation.
createRelayer(object, object) Creates an event handling function which refires the event from this object as the passed event name.
destroy(Operation, Delegate, object) Performs the given destroy operation.
enableBubble(object) Enables events fired by this Observable to bubble up an owner hierarchy by calling this.getBubbleTarget() if present. There is no implementation in the Observable base class. This is commonly used by Ext.Components to bubble events to owner Containers. See Ext.Component.getBubbleTarget. The default implementation in Ext.Component returns the Component's immediate owner. But if a known target is required, this can be overridden to access the required target more quickly. Example:
  Ext.override(Ext.form.field.Base, {
            //  Add functionality to Field's initComponent to enable the change event to bubble
            initComponent : Ext.Function.createSequence(Ext.form.field.Base.prototype.initComponent, function() {
            this.enableBubble('change');
            }),
            //  We know that we want Field's events to bubble directly to the FormPanel.
            getBubbleTarget : function() {
            if (!this.formPanel) {
            this.formPanel = this.findParentByType('form');
            }
            return this.formPanel;
            }
            });
            var myForm = new Ext.formPanel({
            title: 'User Details',
            items: [{
            ...
            }],
            listeners: {
            change: function() {
            // Title goes red if form has been modified.
            myForm.header.setStyle('color', 'red');
            }
            }
            });
            
fireEvent(JsString, Object[]) Fires the specified event with the passed parameters (minus the event name, plus the options object passed to addListener). An event may be set to bubble up an Observable parent hierarchy (See Ext.Component.getBubbleTarget) by calling enableBubble.
getBubbleParent() Gets the bubbling parent for an Observable
getModel() Returns the model attached to this Proxy
getReader() Returns the reader currently attached to this proxy instance
getWriter() Returns the writer currently attached to this proxy instance
hasListener(JsString) Checks to see if this object has any listeners for a specified event, or whether the event bubbles. The answer indicates whether the event needs firing or not.
mon(object, object, Delegate, object, object) Shorthand for addManagedListener. Adds listeners to any Observable object (or Ext.Element) which are automatically removed when this Component is destroyed.
mun(object, object, Delegate, object) Shorthand for removeManagedListener. Removes listeners that were added by the mon method.
on(object, Delegate, object, object) Shorthand for addListener. Appends an event handler to this object. For example:
myGridPanel.on("mouseover", this.onMouseOver, this);
            
The method also allows for a single argument to be passed which is a config object containing properties which specify multiple events. For example:
myGridPanel.on({
            cellClick: this.onCellClick,
            mouseover: this.onMouseOver,
            mouseout: this.onMouseOut,
            scope: this // Important. Ensure "this" is correct during handler execution
            });
            
One can also specify options for each event handler separately:
myGridPanel.on({
            cellClick: {fn: this.onCellClick, scope: this, single: true},
            mouseover: {fn: panel.onMouseOver, scope: panel}
            });
            
Names of methods in a specified scope may also be used. Note that scope MUST be specified to use this option:
myGridPanel.on({
            cellClick: {fn: 'onCellClick', scope: this, single: true},
            mouseover: {fn: 'onMouseOver', scope: panel}
            });
            
prepareClass(Delegate) Prepares a given class for observable instances. This method is called when a class derives from this class or uses this class as a mixin.
read(Operation, Delegate, object) Performs the given read operation.
relayEvents(object, JsArray<T>, object) Relays selected events from the specified Observable as if the events were fired by this. For example if you are extending Grid, you might decide to forward some events from store. So you can do this inside your initComponent:
this.relayEvents(this.getStore(), ['load']);
            
The grid instance will then have an observable 'load' event which will be passed the parameters of the store's load event and any function fired with the grid's load event would have access to the grid using the this keyword.
removeListener(JsString, Delegate, object) Removes an event handler.
removeManagedListener(object, object, Delegate, object) Removes listeners that were added by the mon method.
removeManagedListenerItem(bool, object) Remove a single managed listener item
resumeEvents() Resumes firing events (see suspendEvents). If events were suspended using the queueSuspended parameter, then all events fired during event suspension will be sent to any listeners now.
setModel(object, bool) Sets the model associated with this proxy. This will only usually be called by a Store
setReader(object) Sets the Proxy's Reader by string, config object or Reader instance
setWriter(object) Sets the Proxy's Writer by string, config object or Writer instance
suspendEvents(bool) Suspends the firing of all events. (see resumeEvents)
un(JsString, Delegate, object) Shorthand for removeListener. Removes an event handler.
update(Operation, Delegate, object) Performs the given update operation.

Fields

Name Description
batchActions True to batch actions of a particular type when synchronizing the store. Defaults to true. Defaults to: true
batchOrder Comma-separated ordering 'create', 'update' and 'destroy' actions when batching. Override this to set a different order for the batched CRUD actions to be executed in. Defaults to 'create,update,destroy'. Defaults to: "create,update,destroy"
defaultReaderType The default registered reader type. Defaults to 'json'. Defaults to: "json"
defaultWriterType The default registered writer type. Defaults to 'json'. Defaults to: "json"
listeners A config object containing one or more event handlers to be added to this object during initialization. This should be a valid listeners config object as specified in the addListener example for attaching multiple handlers at once. DOM events from Ext JS Components While some Ext JS Component classes export selected DOM events (e.g. "click", "mouseover" etc), this is usually only done when extra value can be added. For example the DataView's itemclick event passing the node clicked on. To access DOM events directly from a child element of a Component, we need to specify the element option to identify the Component property to add a DOM listener to:
new Ext.panel.Panel({
            width: 400,
            height: 200,
            dockedItems: [{
            xtype: 'toolbar'
            }],
            listeners: {
            click: {
            element: 'el', //bind to the underlying el property on the panel
            fn: function(){ console.log('click el'); }
            },
            dblclick: {
            element: 'body', //bind to the underlying body property on the panel
            fn: function(){ console.log('dblclick body'); }
            }
            }
            });
            
model The name of the Model to tie to this Proxy. Can be either the string name of the Model, or a reference to the Model constructor. Required.
reader The Ext.data.reader.Reader to use to decode the server's response or data read from client. This can either be a Reader instance, a config object or just a valid Reader type name (e.g. 'json', 'xml').
writer The Ext.data.writer.Writer to use to encode any request sent to the server or saved to client. This can either be a Writer instance, a config object or just a valid Writer type name (e.g. 'json', 'xml').

Properties

Name Description
eventsSuspended Initial suspended call count. Incremented when suspendEvents is called, decremented when resumeEvents is called. Defaults to: 0
hasListeners This object holds a key for any event that has a listener. The listener may be set directly on the instance, or on its class or a super class (via observe) or on the MVC EventBus. The values of this object are truthy (a non-zero number) and falsy (0 or undefined). They do not represent an exact count of listeners. The value for an event is truthy if the event must be fired and is falsy if there is no need to fire the event. The intended use of this property is to avoid the expense of fireEvent calls when there are no listeners. This can be particularly helpful when one would otherwise have to call fireEvent hundreds or thousands of times. It is used like this:
if (this.hasListeners.foo) {
           this.fireEvent('foo', this, arg1);
           }
            
isObservable true in this class to identify an object as an instantiated Observable, or subclass thereof. Defaults to: true
isProxy true in this class to identify an object as an instantiated Proxy, or subclass thereof. Defaults to: true
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