/javascripts/lib/src/data/JsonReader.js
JavaScript | 358 lines | 151 code | 15 blank | 192 comment | 32 complexity | 7ddba4af509576e414873a90bda14d8f MD5 | raw file
Possible License(s): GPL-3.0
1/*! 2 * Ext JS Library 3.2.1 3 * Copyright(c) 2006-2010 Ext JS, Inc. 4 * licensing@extjs.com 5 * http://www.extjs.com/license 6 */ 7/** 8 * @class Ext.data.JsonReader 9 * @extends Ext.data.DataReader 10 * <p>Data reader class to create an Array of {@link Ext.data.Record} objects 11 * from a JSON packet based on mappings in a provided {@link Ext.data.Record} 12 * constructor.</p> 13 * <p>Example code:</p> 14 * <pre><code> 15var myReader = new Ext.data.JsonReader({ 16 // metadata configuration options: 17 {@link #idProperty}: 'id' 18 {@link #root}: 'rows', 19 {@link #totalProperty}: 'results', 20 {@link Ext.data.DataReader#messageProperty}: "msg" // The element within the response that provides a user-feedback message (optional) 21 22 // the fields config option will internally create an {@link Ext.data.Record} 23 // constructor that provides mapping for reading the record data objects 24 {@link Ext.data.DataReader#fields fields}: [ 25 // map Record's 'firstname' field to data object's key of same name 26 {name: 'name'}, 27 // map Record's 'job' field to data object's 'occupation' key 28 {name: 'job', mapping: 'occupation'} 29 ] 30}); 31</code></pre> 32 * <p>This would consume a JSON data object of the form:</p><pre><code> 33{ 34 results: 2000, // Reader's configured {@link #totalProperty} 35 rows: [ // Reader's configured {@link #root} 36 // record data objects: 37 { {@link #idProperty id}: 1, firstname: 'Bill', occupation: 'Gardener' }, 38 { {@link #idProperty id}: 2, firstname: 'Ben' , occupation: 'Horticulturalist' }, 39 ... 40 ] 41} 42</code></pre> 43 * <p><b><u>Automatic configuration using metaData</u></b></p> 44 * <p>It is possible to change a JsonReader's metadata at any time by including 45 * a <b><tt>metaData</tt></b> property in the JSON data object. If the JSON data 46 * object has a <b><tt>metaData</tt></b> property, a {@link Ext.data.Store Store} 47 * object using this Reader will reconfigure itself to use the newly provided 48 * field definition and fire its {@link Ext.data.Store#metachange metachange} 49 * event. The metachange event handler may interrogate the <b><tt>metaData</tt></b> 50 * property to perform any configuration required.</p> 51 * <p>Note that reconfiguring a Store potentially invalidates objects which may 52 * refer to Fields or Records which no longer exist.</p> 53 * <p>To use this facility you would create the JsonReader like this:</p><pre><code> 54var myReader = new Ext.data.JsonReader(); 55</code></pre> 56 * <p>The first data packet from the server would configure the reader by 57 * containing a <b><tt>metaData</tt></b> property <b>and</b> the data. For 58 * example, the JSON data object might take the form:</p><pre><code> 59{ 60 metaData: { 61 "{@link #idProperty}": "id", 62 "{@link #root}": "rows", 63 "{@link #totalProperty}": "results" 64 "{@link #successProperty}": "success", 65 "{@link Ext.data.DataReader#fields fields}": [ 66 {"name": "name"}, 67 {"name": "job", "mapping": "occupation"} 68 ], 69 // used by store to set its sortInfo 70 "sortInfo":{ 71 "field": "name", 72 "direction": "ASC" 73 }, 74 // {@link Ext.PagingToolbar paging data} (if applicable) 75 "start": 0, 76 "limit": 2, 77 // custom property 78 "foo": "bar" 79 }, 80 // Reader's configured {@link #successProperty} 81 "success": true, 82 // Reader's configured {@link #totalProperty} 83 "results": 2000, 84 // Reader's configured {@link #root} 85 // (this data simulates 2 results {@link Ext.PagingToolbar per page}) 86 "rows": [ // <b>*Note:</b> this must be an Array 87 { "id": 1, "name": "Bill", "occupation": "Gardener" }, 88 { "id": 2, "name": "Ben", "occupation": "Horticulturalist" } 89 ] 90} 91 * </code></pre> 92 * <p>The <b><tt>metaData</tt></b> property in the JSON data object should contain:</p> 93 * <div class="mdetail-params"><ul> 94 * <li>any of the configuration options for this class</li> 95 * <li>a <b><tt>{@link Ext.data.Record#fields fields}</tt></b> property which 96 * the JsonReader will use as an argument to the 97 * {@link Ext.data.Record#create data Record create method} in order to 98 * configure the layout of the Records it will produce.</li> 99 * <li>a <b><tt>{@link Ext.data.Store#sortInfo sortInfo}</tt></b> property 100 * which the JsonReader will use to set the {@link Ext.data.Store}'s 101 * {@link Ext.data.Store#sortInfo sortInfo} property</li> 102 * <li>any custom properties needed</li> 103 * </ul></div> 104 * 105 * @constructor 106 * Create a new JsonReader 107 * @param {Object} meta Metadata configuration options. 108 * @param {Array/Object} recordType 109 * <p>Either an Array of {@link Ext.data.Field Field} definition objects (which 110 * will be passed to {@link Ext.data.Record#create}, or a {@link Ext.data.Record Record} 111 * constructor created from {@link Ext.data.Record#create}.</p> 112 */ 113Ext.data.JsonReader = function(meta, recordType){ 114 meta = meta || {}; 115 /** 116 * @cfg {String} idProperty [id] Name of the property within a row object 117 * that contains a record identifier value. Defaults to <tt>id</tt> 118 */ 119 /** 120 * @cfg {String} successProperty [success] Name of the property from which to 121 * retrieve the success attribute. Defaults to <tt>success</tt>. See 122 * {@link Ext.data.DataProxy}.{@link Ext.data.DataProxy#exception exception} 123 * for additional information. 124 */ 125 /** 126 * @cfg {String} totalProperty [total] Name of the property from which to 127 * retrieve the total number of records in the dataset. This is only needed 128 * if the whole dataset is not passed in one go, but is being paged from 129 * the remote server. Defaults to <tt>total</tt>. 130 */ 131 /** 132 * @cfg {String} root [undefined] <b>Required</b>. The name of the property 133 * which contains the Array of row objects. Defaults to <tt>undefined</tt>. 134 * An exception will be thrown if the root property is undefined. The data 135 * packet value for this property should be an empty array to clear the data 136 * or show no data. 137 */ 138 Ext.applyIf(meta, { 139 idProperty: 'id', 140 successProperty: 'success', 141 totalProperty: 'total' 142 }); 143 144 Ext.data.JsonReader.superclass.constructor.call(this, meta, recordType || meta.fields); 145}; 146Ext.extend(Ext.data.JsonReader, Ext.data.DataReader, { 147 /** 148 * This JsonReader's metadata as passed to the constructor, or as passed in 149 * the last data packet's <b><tt>metaData</tt></b> property. 150 * @type Mixed 151 * @property meta 152 */ 153 /** 154 * This method is only used by a DataProxy which has retrieved data from a remote server. 155 * @param {Object} response The XHR object which contains the JSON data in its responseText. 156 * @return {Object} data A data block which is used by an Ext.data.Store object as 157 * a cache of Ext.data.Records. 158 */ 159 read : function(response){ 160 var json = response.responseText; 161 var o = Ext.decode(json); 162 if(!o) { 163 throw {message: 'JsonReader.read: Json object not found'}; 164 } 165 return this.readRecords(o); 166 }, 167 168 /* 169 * TODO: refactor code between JsonReader#readRecords, #readResponse into 1 method. 170 * there's ugly duplication going on due to maintaining backwards compat. with 2.0. It's time to do this. 171 */ 172 /** 173 * Decode a JSON response from server. 174 * @param {String} action [Ext.data.Api.actions.create|read|update|destroy] 175 * @param {Object} response The XHR object returned through an Ajax server request. 176 * @return {Response} A {@link Ext.data.Response Response} object containing the data response, and also status information. 177 */ 178 readResponse : function(action, response) { 179 var o = (response.responseText !== undefined) ? Ext.decode(response.responseText) : response; 180 if(!o) { 181 throw new Ext.data.JsonReader.Error('response'); 182 } 183 184 var root = this.getRoot(o); 185 if (action === Ext.data.Api.actions.create) { 186 var def = Ext.isDefined(root); 187 if (def && Ext.isEmpty(root)) { 188 throw new Ext.data.JsonReader.Error('root-empty', this.meta.root); 189 } 190 else if (!def) { 191 throw new Ext.data.JsonReader.Error('root-undefined-response', this.meta.root); 192 } 193 } 194 195 // instantiate response object 196 var res = new Ext.data.Response({ 197 action: action, 198 success: this.getSuccess(o), 199 data: (root) ? this.extractData(root, false) : [], 200 message: this.getMessage(o), 201 raw: o 202 }); 203 204 // blow up if no successProperty 205 if (Ext.isEmpty(res.success)) { 206 throw new Ext.data.JsonReader.Error('successProperty-response', this.meta.successProperty); 207 } 208 return res; 209 }, 210 211 /** 212 * Create a data block containing Ext.data.Records from a JSON object. 213 * @param {Object} o An object which contains an Array of row objects in the property specified 214 * in the config as 'root, and optionally a property, specified in the config as 'totalProperty' 215 * which contains the total size of the dataset. 216 * @return {Object} data A data block which is used by an Ext.data.Store object as 217 * a cache of Ext.data.Records. 218 */ 219 readRecords : function(o){ 220 /** 221 * After any data loads, the raw JSON data is available for further custom processing. If no data is 222 * loaded or there is a load exception this property will be undefined. 223 * @type Object 224 */ 225 this.jsonData = o; 226 if(o.metaData){ 227 this.onMetaChange(o.metaData); 228 } 229 var s = this.meta, Record = this.recordType, 230 f = Record.prototype.fields, fi = f.items, fl = f.length, v; 231 232 var root = this.getRoot(o), c = root.length, totalRecords = c, success = true; 233 if(s.totalProperty){ 234 v = parseInt(this.getTotal(o), 10); 235 if(!isNaN(v)){ 236 totalRecords = v; 237 } 238 } 239 if(s.successProperty){ 240 v = this.getSuccess(o); 241 if(v === false || v === 'false'){ 242 success = false; 243 } 244 } 245 246 // TODO return Ext.data.Response instance instead. @see #readResponse 247 return { 248 success : success, 249 records : this.extractData(root, true), // <-- true to return [Ext.data.Record] 250 totalRecords : totalRecords 251 }; 252 }, 253 254 // private 255 buildExtractors : function() { 256 if(this.ef){ 257 return; 258 } 259 var s = this.meta, Record = this.recordType, 260 f = Record.prototype.fields, fi = f.items, fl = f.length; 261 262 if(s.totalProperty) { 263 this.getTotal = this.createAccessor(s.totalProperty); 264 } 265 if(s.successProperty) { 266 this.getSuccess = this.createAccessor(s.successProperty); 267 } 268 if (s.messageProperty) { 269 this.getMessage = this.createAccessor(s.messageProperty); 270 } 271 this.getRoot = s.root ? this.createAccessor(s.root) : function(p){return p;}; 272 if (s.id || s.idProperty) { 273 var g = this.createAccessor(s.id || s.idProperty); 274 this.getId = function(rec) { 275 var r = g(rec); 276 return (r === undefined || r === '') ? null : r; 277 }; 278 } else { 279 this.getId = function(){return null;}; 280 } 281 var ef = []; 282 for(var i = 0; i < fl; i++){ 283 f = fi[i]; 284 var map = (f.mapping !== undefined && f.mapping !== null) ? f.mapping : f.name; 285 ef.push(this.createAccessor(map)); 286 } 287 this.ef = ef; 288 }, 289 290 /** 291 * @ignore 292 * TODO This isn't used anywhere?? Don't we want to use this where possible instead of complex #createAccessor? 293 */ 294 simpleAccess : function(obj, subsc) { 295 return obj[subsc]; 296 }, 297 298 /** 299 * @ignore 300 */ 301 createAccessor : function(){ 302 var re = /[\[\.]/; 303 return function(expr) { 304 if(Ext.isEmpty(expr)){ 305 return Ext.emptyFn; 306 } 307 if(Ext.isFunction(expr)){ 308 return expr; 309 } 310 var i = String(expr).search(re); 311 if(i >= 0){ 312 return new Function('obj', 'return obj' + (i > 0 ? '.' : '') + expr); 313 } 314 return function(obj){ 315 return obj[expr]; 316 }; 317 318 }; 319 }(), 320 321 /** 322 * type-casts a single row of raw-data from server 323 * @param {Object} data 324 * @param {Array} items 325 * @param {Integer} len 326 * @private 327 */ 328 extractValues : function(data, items, len) { 329 var f, values = {}; 330 for(var j = 0; j < len; j++){ 331 f = items[j]; 332 var v = this.ef[j](data); 333 values[f.name] = f.convert((v !== undefined) ? v : f.defaultValue, data); 334 } 335 return values; 336 } 337}); 338 339/** 340 * @class Ext.data.JsonReader.Error 341 * Error class for JsonReader 342 */ 343Ext.data.JsonReader.Error = Ext.extend(Ext.Error, { 344 constructor : function(message, arg) { 345 this.arg = arg; 346 Ext.Error.call(this, message); 347 }, 348 name : 'Ext.data.JsonReader' 349}); 350Ext.apply(Ext.data.JsonReader.Error.prototype, { 351 lang: { 352 'response': 'An error occurred while json-decoding your server response', 353 'successProperty-response': 'Could not locate your "successProperty" in your server response. Please review your JsonReader config to ensure the config-property "successProperty" matches the property in your server-response. See the JsonReader docs.', 354 'root-undefined-config': 'Your JsonReader was configured without a "root" property. Please review your JsonReader config and make sure to define the root property. See the JsonReader docs.', 355 'idProperty-undefined' : 'Your JsonReader was configured without an "idProperty" Please review your JsonReader configuration and ensure the "idProperty" is set (e.g.: "id"). See the JsonReader docs.', 356 'root-empty': 'Data was expected to be returned by the server in the "root" property of the response. Please review your JsonReader configuration to ensure the "root" property matches that returned in the server-response. See JsonReader docs.' 357 } 358});