231 lines
8.9 KiB
JavaScript
231 lines
8.9 KiB
JavaScript
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/*
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* Ext JS Library 2.3.0
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* Copyright(c) 2006-2009, Ext JS, LLC.
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* licensing@extjs.com
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*
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* http://extjs.com/license
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*/
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/**
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* @class Ext.data.JsonReader
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* @extends Ext.data.DataReader
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* Data reader class to create an Array of {@link Ext.data.Record} objects from a JSON response
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* based on mappings in a provided {@link Ext.data.Record} constructor.<br>
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* <p>
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* Example code:
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* <pre><code>
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var Employee = Ext.data.Record.create([
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{name: 'firstname'}, // Map the Record's "firstname" field to the row object's key of the same name
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{name: 'job', mapping: 'occupation'} // Map the "job" field to the row object's "occupation" key
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]);
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var myReader = new Ext.data.JsonReader({
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totalProperty: "results", // The property which contains the total dataset size (optional)
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root: "rows", // The property which contains an Array of row objects
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id: "id" // The property within each row object that provides an ID for the record (optional)
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}, Employee);
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</code></pre>
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* <p>
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* This would consume a JSON object of the form:
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* <pre><code>
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{
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results: 2,
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rows: [
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{ id: 1, firstname: 'Bill', occupation: 'Gardener' }, // a row object
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{ id: 2, firstname: 'Ben' , occupation: 'Horticulturalist' } // another row object
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]
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}
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</code></pre>
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* <p>It is possible to change a JsonReader's metadata at any time by including a
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* <b><tt>metaData</tt></b> property in the data object. If this is detected in the
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* object, a {@link Ext.data.Store Store} object using this Reader will reconfigure
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* itself to use the newly provided field definition and fire its
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* {@link Ext.data.Store#metachange metachange} event. In
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* undergoing this change, the Store sets its {@link Ext.data.Store#sortInfo sortInfo} property
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* from the <tt>sortInfo</tt> property in the new metadata. Note that reconfiguring a Store
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* potentially invalidates objects which may refer to Fields or Records which no longer exist.</p>
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*
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* <p>The <b><tt>metaData</tt></b> property may contain any of the configuration
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* options for this class. Additionally, it may contain a <b><tt>fields</tt></b>
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* property which the JsonReader will use as an argument to {@link Ext.data.Record#create}
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* to configure the layout of the Records which it will produce.<p>
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* Using the <b><tt>metaData</tt></b> property, and the Store's {@link Ext.data.Store#metachange metachange} event,
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* it is possible to have a Store-driven control initialize itself. The metachange
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* event handler may interrogate the <b><tt>metaData</tt></b> property (which
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* may contain any user-defined properties needed) and the <b><tt>metaData.fields</tt></b>
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* property to perform any configuration required.</p>
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*
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* <p>To use this facility to send the same data as the above example without
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* having to code the creation of the Record constructor, you would create the
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* JsonReader like this:</p><pre><code>
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var myReader = new Ext.data.JsonReader();
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</code></pre>
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* <p>The first data packet from the server would configure the reader by
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* containing a metaData property as well as the data:</p><pre><code>
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{
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metaData: {
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totalProperty: 'results',
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root: 'rows',
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id: 'id',
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fields: [
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{name: 'name'},
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{name: 'occupation'}
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]
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},
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results: 2,
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rows: [
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{ 'id': 1, 'name': 'Bill', occupation: 'Gardener' },
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{ 'id': 2, 'name': 'Ben', occupation: 'Horticulturalist' }
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]
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}
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</code></pre>
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* @cfg {String} totalProperty Name of the property from which to retrieve the total number of records
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* in the dataset. This is only needed if the whole dataset is not passed in one go, but is being
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* paged from the remote server.
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* @cfg {String} successProperty Name of the property from which to retrieve the success attribute used by forms.
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* @cfg {String} root name of the property which contains the Array of row objects.
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* @cfg {String} id Name of the property within a row object that contains a record identifier value.
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* @constructor
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* Create a new JsonReader
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* @param {Object} meta Metadata configuration options.
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* @param {Object} recordType Either an Array of field definition objects as passed to
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* {@link Ext.data.Record#create}, or a {@link Ext.data.Record Record} constructor created using {@link Ext.data.Record#create}.
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*/
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Ext.data.JsonReader = function(meta, recordType){
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meta = meta || {};
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Ext.data.JsonReader.superclass.constructor.call(this, meta, recordType || meta.fields);
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};
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Ext.extend(Ext.data.JsonReader, Ext.data.DataReader, {
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/**
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* This JsonReader's metadata as passed to the constructor, or as passed in
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* the last data packet's <b><tt>metaData</tt></b> property.
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* @type Mixed
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* @property meta
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*/
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/**
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* This method is only used by a DataProxy which has retrieved data from a remote server.
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* @param {Object} response The XHR object which contains the JSON data in its responseText.
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* @return {Object} data A data block which is used by an Ext.data.Store object as
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* a cache of Ext.data.Records.
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*/
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read : function(response){
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var json = response.responseText;
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var o = eval("("+json+")");
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if(!o) {
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throw {message: "JsonReader.read: Json object not found"};
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}
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return this.readRecords(o);
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},
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// private function a store will implement
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onMetaChange : function(meta, recordType, o){
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},
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/**
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* @ignore
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*/
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simpleAccess: function(obj, subsc) {
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return obj[subsc];
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},
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/**
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* @ignore
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*/
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getJsonAccessor: function(){
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var re = /[\[\.]/;
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return function(expr) {
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try {
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return(re.test(expr))
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? new Function("obj", "return obj." + expr)
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: function(obj){
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return obj[expr];
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};
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} catch(e){}
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return Ext.emptyFn;
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};
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}(),
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/**
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* Create a data block containing Ext.data.Records from a JSON object.
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* @param {Object} o An object which contains an Array of row objects in the property specified
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* in the config as 'root, and optionally a property, specified in the config as 'totalProperty'
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* which contains the total size of the dataset.
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* @return {Object} data A data block which is used by an Ext.data.Store object as
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* a cache of Ext.data.Records.
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*/
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readRecords : function(o){
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/**
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* After any data loads, the raw JSON data is available for further custom processing. If no data is
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* loaded or there is a load exception this property will be undefined.
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* @type Object
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*/
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this.jsonData = o;
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if(o.metaData){
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delete this.ef;
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this.meta = o.metaData;
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this.recordType = Ext.data.Record.create(o.metaData.fields);
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this.onMetaChange(this.meta, this.recordType, o);
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}
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var s = this.meta, Record = this.recordType,
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f = Record.prototype.fields, fi = f.items, fl = f.length;
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// Generate extraction functions for the totalProperty, the root, the id, and for each field
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if (!this.ef) {
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if(s.totalProperty) {
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this.getTotal = this.getJsonAccessor(s.totalProperty);
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}
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if(s.successProperty) {
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this.getSuccess = this.getJsonAccessor(s.successProperty);
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}
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this.getRoot = s.root ? this.getJsonAccessor(s.root) : function(p){return p;};
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if (s.id) {
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var g = this.getJsonAccessor(s.id);
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this.getId = function(rec) {
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var r = g(rec);
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return (r === undefined || r === "") ? null : r;
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};
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} else {
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this.getId = function(){return null;};
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}
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this.ef = [];
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for(var i = 0; i < fl; i++){
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f = fi[i];
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var map = (f.mapping !== undefined && f.mapping !== null) ? f.mapping : f.name;
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this.ef[i] = this.getJsonAccessor(map);
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}
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}
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var root = this.getRoot(o), c = root.length, totalRecords = c, success = true;
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if(s.totalProperty){
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var v = parseInt(this.getTotal(o), 10);
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if(!isNaN(v)){
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totalRecords = v;
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}
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}
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if(s.successProperty){
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var v = this.getSuccess(o);
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if(v === false || v === 'false'){
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success = false;
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}
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}
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var records = [];
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for(var i = 0; i < c; i++){
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var n = root[i];
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var values = {};
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var id = this.getId(n);
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for(var j = 0; j < fl; j++){
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f = fi[j];
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var v = this.ef[j](n);
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values[f.name] = f.convert((v !== undefined) ? v : f.defaultValue, n);
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}
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var record = new Record(values, id);
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record.json = n;
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records[i] = record;
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}
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return {
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success : success,
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records : records,
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totalRecords : totalRecords
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};
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}
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});
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