/**
* @author Ed Spencer
* @class Ext.data.AjaxProxy
* @extends Ext.data.ServerProxy
*
* <p>AjaxProxy is one of the most widely-used ways of getting data into your application. It uses AJAX requests to
* load data from the server, usually to be placed into a {@link Ext.data.Store Store}. Let's take a look at a typical
* setup. Here we're going to set up a Store that has an AjaxProxy. To prepare, we'll also set up a
* {@link Ext.data.Model Model}:</p>
*
<pre><code>
Ext.regModel('User', {
fields: ['id', 'name', 'email']
});
//The Store contains the AjaxProxy as an inline configuration
var store = new Ext.data.Store({
model: 'User',
proxy: {
type: 'ajax',
url : 'users.json'
}
});
store.load();
</code></pre>
*
* <p>Our example is going to load user data into a Store, so we start off by defining a {@link Ext.data.Model Model}
* with the fields that we expect the server to return. Next we set up the Store itself, along with a {@link #proxy}
* configuration. This configuration was automatically turned into an Ext.data.AjaxProxy instance, with the url we
* specified being passed into AjaxProxy's constructor. It's as if we'd done this:</p>
*
<pre><code>
new Ext.data.AjaxProxy({
url: 'users.json',
model: 'User',
reader: 'json'
});
</code></pre>
*
* <p>A couple of extra configurations appeared here - {@link #model} and {@link #reader}. These are set by default
* when we create the proxy via the Store - the Store already knows about the Model, and Proxy's default
* {@link Ext.data.Reader Reader} is {@link Ext.data.JsonReader JsonReader}.</p>
*
* <p>Now when we call store.load(), the AjaxProxy springs into action, making a request to the url we configured
* ('users.json' in this case). As we're performing a read, it sends a GET request to that url (see {@link #actionMethods}
* to customize this - by default any kind of read will be sent as a GET request and any kind of write will be sent as a
* POST request).</p>
*
* <p><u>Limitations</u></p>
*
* <p>AjaxProxy cannot be used to retrieve data from other domains. If your application is running on http://domainA.com
* it cannot load data from http://domainB.com because browsers have a built-in security policy that prohibits domains
* talking to each other via AJAX.</p>
*
* <p>If you need to read data from another domain and can't set up a proxy server (some software that runs on your own
* domain's web server and transparently forwards requests to http://domainB.com, making it look like they actually came
* from http://domainA.com), you can use {@link Ext.data.ScriptTagProxy} and a technique known as JSON-P (JSON with
* Padding), which can help you get around the problem so long as the server on http://domainB.com is set up to support
* JSON-P responses. See {@link Ext.data.ScriptTagProxy ScriptTagProxy}'s introduction docs for more details.</p>
*
* <p><u>Readers and Writers</u></p>
*
* <p>AjaxProxy can be configured to use any type of {@link Ext.data.Reader Reader} to decode the server's response. If
* no Reader is supplied, AjaxProxy will default to using a {@link Ext.data.JsonReader JsonReader}. Reader configuration
* can be passed in as a simple object, which the Proxy automatically turns into a {@link Ext.data.Reader Reader}
* instance:</p>
*
<pre><code>
var proxy = new Ext.data.AjaxProxy({
model: 'User',
reader: {
type: 'xml',
root: 'users'
}
});
proxy.getReader(); //returns an {@link Ext.data.XmlReader XmlReader} instance based on the config we supplied
</code></pre>
*
* <p><u>Url generation</u></p>
*
* <p>AjaxProxy automatically inserts any sorting, filtering, paging and grouping options into the url it generates for
* each request. These are controlled with the following configuration options:</p>
*
* <ul style="list-style-type: disc; padding-left: 20px;">
* <li>{@link #pageParam} - controls how the page number is sent to the server
* (see also {@link #startParam} and {@link #limitParam})</li>
* <li>{@link #sortParam} - controls how sort information is sent to the server</li>
* <li>{@link #groupParam} - controls how grouping information is sent to the server</li>
* <li>{@link #filterParam} - controls how filter information is sent to the server</li>
* </ul>
*
* <p>Each request sent by AjaxProxy is described by an {@link Ext.data.Operation Operation}. To see how we can
* customize the generated urls, let's say we're loading the Proxy with the following Operation:</p>
*
<pre><code>
var operation = new Ext.data.Operation({
action: 'read',
page : 2
});
</code></pre>
*
* <p>Now we'll issue the request for this Operation by calling {@link #read}:</p>
*
<pre><code>
var proxy = new Ext.data.AjaxProxy({
url: '/users'
});
proxy.read(operation); //GET /users?page=2
</code></pre>
*
* <p>Easy enough - the Proxy just copied the page property from the Operation. We can customize how this page data is
* sent to the server:</p>
*
<pre><code>
var proxy = new Ext.data.AjaxProxy({
url: '/users',
pagePage: 'pageNumber'
});
proxy.read(operation); //GET /users?pageNumber=2
</code></pre>
*
* <p>Alternatively, our Operation could have been configured to send start and limit parameters instead of page:</p>
*
<pre><code>
var operation = new Ext.data.Operation({
action: 'read',
start : 50,
limit : 25
});
var proxy = new Ext.data.AjaxProxy({
url: '/users'
});
proxy.read(operation); //GET /users?start=50&limit=25
</code></pre>
*
* <p>Again we can customize this url:</p>
*
<pre><code>
var proxy = new Ext.data.AjaxProxy({
url: '/users',
startParam: 'startIndex',
limitParam: 'limitIndex'
});
proxy.read(operation); //GET /users?startIndex=50&limitIndex=25
</code></pre>
*
* <p>AjaxProxy will also send sort and filter information to the server. Let's take a look at how this looks with a
* more expressive Operation object:</p>
*
<pre><code>
var operation = new Ext.data.Operation({
action: 'read',
sorters: [
new Ext.util.Sorter({
property : 'name',
direction: 'ASC'
}),
new Ext.util.Sorter({
property : 'age',
direction: 'DESC'
})
],
filters: [
new Ext.util.Filter({
property: 'eyeColor',
value : 'brown'
})
]
});
</code></pre>
*
* <p>This is the type of object that is generated internally when loading a {@link Ext.data.Store Store} with sorters
* and filters defined. By default the AjaxProxy will JSON encode the sorters and filters, resulting in something like
* this (note that the url is escaped before sending the request, but is left unescaped here for clarity):</p>
*
<pre><code>
var proxy = new Ext.data.AjaxProxy({
url: '/users'
});
proxy.read(operation); //GET /users?sort=[{"property":"name","direction":"ASC"},{"property":"age","direction":"DESC"}]&filter=[{"property":"eyeColor","value":"brown"}]
</code></pre>
*
* <p>We can again customize how this is created by supplying a few configuration options. Let's say our server is set
* up to receive sorting information is a format like "sortBy=name#ASC,age#DESC". We can configure AjaxProxy to provide
* that format like this:</p>
*
<pre><code>
var proxy = new Ext.data.AjaxProxy({
url: '/users',
sortParam: 'sortBy',
filterParam: 'filterBy',
//our custom implementation of sorter encoding - turns our sorters into "name#ASC,age#DESC"
encodeSorters: function(sorters) {
var length = sorters.length,
sortStrs = [],
sorter, i;
for (i = 0; i < length; i++) {
sorter = sorters[i];
sortStrs[i] = sorter.property + '#' + sorter.direction
}
return sortStrs.join(",");
}
});
proxy.read(operation); //GET /users?sortBy=name#ASC,age#DESC&filterBy=[{"property":"eyeColor","value":"brown"}]
</code></pre>
*
* <p>We can also provide a custom {@link #encodeFilters} function to encode our filters.</p>
*
* @constructor
*
* <p>Note that if this HttpProxy is being used by a {@link Ext.data.Store Store}, then the
* Store's call to {@link #load} will override any specified <tt>callback</tt> and <tt>params</tt>
* options. In this case, use the Store's {@link Ext.data.Store#events events} to modify parameters,
* or react to loading events. The Store's {@link Ext.data.Store#baseParams baseParams} may also be
* used to pass parameters known at instantiation time.</p>
*
* <p>If an options parameter is passed, the singleton {@link Ext.Ajax} object will be used to make
* the request.</p>
*/
Ext.data.AjaxProxy = Ext.extend(Ext.data.ServerProxy, {
/**
* @property actionMethods
* Mapping of action name to HTTP request method. In the basic AjaxProxy these are set to 'GET' for 'read' actions and 'POST'
* for 'create', 'update' and 'destroy' actions. The {@link Ext.data.RestProxy} maps these to the correct RESTful methods.
*/
actionMethods: {
create : 'POST',
read : 'GET',
update : 'POST',
destroy: 'POST'
},
* @cfg {Object} headers Any headers to add to the Ajax request. Defaults to <tt>undefined</tt>.
*/
constructor: function() {
this.addEvents(
/**
* @event exception
* Fires when the server returns an exception
* @param {Ext.data.Proxy} this
* @param {Object} response The response from the AJAX request
* @param {Ext.data.Operation} operation The operation that triggered request
*/
'exception'
);
Ext.data.AjaxProxy.superclass.constructor.apply(this, arguments);
},
/**
* @ignore
*/
doRequest: function(operation, callback, scope) {
var writer = this.getWriter(),
request = this.buildRequest(operation, callback, scope);
if (operation.allowWrite()) {
request = writer.write(request);
}
Ext.apply(request, {
headers : this.headers,
timeout : this.timeout,
scope : this,
callback : this.createRequestCallback(request, operation, callback, scope),
method : this.getMethod(request),
disableCaching: false // explicitly set it to false, ServerProxy handles caching
});
Ext.Ajax.request(request);
return request;
},
/**
* Returns the HTTP method name for a given request. By default this returns based on a lookup on {@link #actionMethods}.
* @param {Ext.data.Request} request The request object
* @return {String} The HTTP method to use (should be one of 'GET', 'POST', 'PUT' or 'DELETE')
*/
getMethod: function(request) {
return this.actionMethods[request.action];
},
/**
* @private
* TODO: This is currently identical to the ScriptTagProxy version except for the return function's signature. There is a lot
* of code duplication inside the returned function so we need to find a way to DRY this up.
* @param {Ext.data.Request} request The Request object
* @param {Ext.data.Operation} operation The Operation being executed
* @param {Function} callback The callback function to be called when the request completes. This is usually the callback
* passed to doRequest
* @param {Object} scope The scope in which to execute the callback function
* @return {Function} The callback function
*/
createRequestCallback: function(request, operation, callback, scope) {
var me = this;
return function(options, success, response) {
if (success === true) {
var reader = me.getReader(),
result = reader.read(response),
records = result.records,
length = records.length,
mc = new Ext.util.MixedCollection(true, function(r) {return r.getId();}),
record, i;
mc.addAll(operation.records);
for (i = 0; i < length; i++) {
record = mc.get(records[i].getId());
if (record) {
record.set(record.data);
}
}
//see comment in buildRequest for why we include the response object here
Ext.apply(operation, {
response : response,
resultSet: result
});
operation.setCompleted();
operation.setSuccessful();
} else {
me.fireEvent('exception', this, response, operation);
//TODO: extract error message from reader
operation.setException();
}
//this callback is the one that was passed to the 'read' or 'write' function above
if (typeof callback == 'function') {
callback.call(scope || me, operation);
}
me.afterRequest(request, true);
};
}
});
Ext.data.ProxyMgr.registerType('ajax', Ext.data.AjaxProxy);
//backwards compatibility, remove in Ext JS 5.0
Ext.data.HttpProxy = Ext.data.AjaxProxy;