Json2.html
15.5 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>The source code</title>
<link href="../resources/prettify/prettify.css" type="text/css" rel="stylesheet" />
<script type="text/javascript" src="../resources/prettify/prettify.js"></script>
<style type="text/css">
.highlight { display: block; background-color: #ddd; }
</style>
<script type="text/javascript">
function highlight() {
document.getElementById(location.hash.replace(/#/, "")).className = "highlight";
}
</script>
</head>
<body onload="prettyPrint(); highlight();">
<pre class="prettyprint lang-js"><span id='Ext-data-reader-Json'>/**
</span> * @author Ed Spencer
*
* The JSON Reader is used by a Proxy to read a server response that is sent back in JSON format. This usually
* happens as a result of loading a Store - for example we might create something like this:
*
* Ext.define('User', {
* extend: 'Ext.data.Model',
* fields: ['id', 'name', 'email']
* });
*
* var store = Ext.create('Ext.data.Store', {
* model: 'User',
* proxy: {
* type: 'ajax',
* url : 'users.json',
* reader: {
* type: 'json'
* }
* }
* });
*
* The example above creates a 'User' model. Models are explained in the {@link Ext.data.Model Model} docs if you're
* not already familiar with them.
*
* We created the simplest type of JSON Reader possible by simply telling our {@link Ext.data.Store Store}'s
* {@link Ext.data.proxy.Proxy Proxy} that we want a JSON Reader. The Store automatically passes the configured model to the
* Store, so it is as if we passed this instead:
*
* reader: {
* type : 'json',
* model: 'User'
* }
*
* The reader we set up is ready to read data from our server - at the moment it will accept a response like this:
*
* [
* {
* "id": 1,
* "name": "Ed Spencer",
* "email": "ed@sencha.com"
* },
* {
* "id": 2,
* "name": "Abe Elias",
* "email": "abe@sencha.com"
* }
* ]
*
* ## Reading other JSON formats
*
* If you already have your JSON format defined and it doesn't look quite like what we have above, you can usually
* pass JsonReader a couple of configuration options to make it parse your format. For example, we can use the
* {@link #cfg-root} configuration to parse data that comes back like this:
*
* {
* "users": [
* {
* "id": 1,
* "name": "Ed Spencer",
* "email": "ed@sencha.com"
* },
* {
* "id": 2,
* "name": "Abe Elias",
* "email": "abe@sencha.com"
* }
* ]
* }
*
* To parse this we just pass in a {@link #root} configuration that matches the 'users' above:
*
* reader: {
* type: 'json',
* root: 'users'
* }
*
* Sometimes the JSON structure is even more complicated. Document databases like CouchDB often provide metadata
* around each record inside a nested structure like this:
*
* {
* "total": 122,
* "offset": 0,
* "users": [
* {
* "id": "ed-spencer-1",
* "value": 1,
* "user": {
* "id": 1,
* "name": "Ed Spencer",
* "email": "ed@sencha.com"
* }
* }
* ]
* }
*
* In the case above the record data is nested an additional level inside the "users" array as each "user" item has
* additional metadata surrounding it ('id' and 'value' in this case). To parse data out of each "user" item in the
* JSON above we need to specify the {@link #record} configuration like this:
*
* reader: {
* type : 'json',
* root : 'users',
* record: 'user'
* }
*
* ## Response MetaData
*
* The server can return metadata in its response, in addition to the record data, that describe attributes
* of the data set itself or are used to reconfigure the Reader. To pass metadata in the response you simply
* add a `metaData` attribute to the root of the response data. The metaData attribute can contain anything,
* but supports a specific set of properties that are handled by the Reader if they are present:
*
* - {@link #root}: the property name of the root response node containing the record data
* - {@link #idProperty}: property name for the primary key field of the data
* - {@link #totalProperty}: property name for the total number of records in the data
* - {@link #successProperty}: property name for the success status of the response
* - {@link #messageProperty}: property name for an optional response message
* - {@link Ext.data.Model#cfg-fields fields}: Config used to reconfigure the Model's fields before converting the
* response data into records
*
* An initial Reader configuration containing all of these properties might look like this ("fields" would be
* included in the Model definition, not shown):
*
* reader: {
* type : 'json',
* root : 'root',
* idProperty : 'id',
* totalProperty : 'total',
* successProperty: 'success',
* messageProperty: 'message'
* }
*
* If you were to pass a response object containing attributes different from those initially defined above, you could
* use the `metaData` attribute to reconifgure the Reader on the fly. For example:
*
* {
* "count": 1,
* "ok": true,
* "msg": "Users found",
* "users": [{
* "userId": 123,
* "name": "Ed Spencer",
* "email": "ed@sencha.com"
* }],
* "metaData": {
* "root": "users",
* "idProperty": 'userId',
* "totalProperty": 'count',
* "successProperty": 'ok',
* "messageProperty": 'msg'
* }
* }
*
* You can also place any other arbitrary data you need into the `metaData` attribute which will be ignored by the Reader,
* but will be accessible via the Reader's {@link #metaData} property (which is also passed to listeners via the Proxy's
* {@link Ext.data.proxy.Proxy#metachange metachange} event (also relayed by the {@link Ext.data.AbstractStore#metachange
* store}). Application code can then process the passed metadata in any way it chooses.
*
* A simple example for how this can be used would be customizing the fields for a Model that is bound to a grid. By passing
* the `fields` property the Model will be automatically updated by the Reader internally, but that change will not be
* reflected automatically in the grid unless you also update the column configuration. You could do this manually, or you
* could simply pass a standard grid {@link Ext.panel.Table#columns column} config object as part of the `metaData` attribute
* and then pass that along to the grid. Here's a very simple example for how that could be accomplished:
*
* // response format:
* {
* ...
* "metaData": {
* "fields": [
* { "name": "userId", "type": "int" },
* { "name": "name", "type": "string" },
* { "name": "birthday", "type": "date", "dateFormat": "Y-j-m" },
* ],
* "columns": [
* { "text": "User ID", "dataIndex": "userId", "width": 40 },
* { "text": "User Name", "dataIndex": "name", "flex": 1 },
* { "text": "Birthday", "dataIndex": "birthday", "flex": 1, "format": 'Y-j-m', "xtype": "datecolumn" }
* ]
* }
* }
*
* The Reader will automatically read the meta fields config and rebuild the Model based on the new fields, but to handle
* the new column configuration you would need to handle the metadata within the application code. This is done simply enough
* by handling the metachange event on either the store or the proxy, e.g.:
*
* var store = Ext.create('Ext.data.Store', {
* ...
* listeners: {
* 'metachange': function(store, meta) {
* myGrid.reconfigure(store, meta.columns);
* }
* }
* });
*
*/
Ext.define('Ext.data.reader.Json', {
extend: 'Ext.data.reader.Reader',
alternateClassName: 'Ext.data.JsonReader',
alias : 'reader.json',
root: '',
<span id='Ext-data-reader-Json-cfg-record'> /**
</span> * @cfg {String} record The optional location within the JSON response that the record data itself can be found at.
* See the JsonReader intro docs for more details. This is not often needed.
*/
<span id='Ext-data-reader-Json-cfg-useSimpleAccessors'> /**
</span> * @cfg {Boolean} useSimpleAccessors True to ensure that field names/mappings are treated as literals when
* reading values.
*
* For example, by default, using the mapping "foo.bar.baz" will try and read a property foo from the root, then a property bar
* from foo, then a property baz from bar. Setting the simple accessors to true will read the property with the name
* "foo.bar.baz" direct from the root object.
*/
useSimpleAccessors: false,
<span id='Ext-data-reader-Json-method-readRecords'> /**
</span> * Reads a JSON object and returns a ResultSet. Uses the internal getTotal and getSuccess extractors to
* retrieve meta data from the response, and extractData to turn the JSON data into model instances.
* @param {Object} data The raw JSON data
* @return {Ext.data.ResultSet} A ResultSet containing model instances and meta data about the results
*/
readRecords: function(data) {
//this has to be before the call to super because we use the meta data in the superclass readRecords
if (data.metaData) {
this.onMetaChange(data.metaData);
}
<span id='Ext-data-reader-Json-property-jsonData'> /**
</span> * @property {Object} jsonData
* A copy of this.rawData.
* @deprecated Will be removed in Ext JS 5.0. This is just a copy of this.rawData - use that instead.
*/
this.jsonData = data;
return this.callParent([data]);
},
//inherit docs
getResponseData: function(response) {
var data, error;
try {
data = Ext.decode(response.responseText);
return this.readRecords(data);
} catch (ex) {
error = new Ext.data.ResultSet({
total : 0,
count : 0,
records: [],
success: false,
message: ex.message
});
this.fireEvent('exception', this, response, error);
Ext.Logger.warn('Unable to parse the JSON returned by the server');
return error;
}
},
//inherit docs
buildExtractors : function() {
var me = this;
me.callParent(arguments);
if (me.root) {
me.getRoot = me.createAccessor(me.root);
} else {
me.getRoot = function(root) {
return root;
};
}
},
<span id='Ext-data-reader-Json-method-extractData'> /**
</span> * @private
* We're just preparing the data for the superclass by pulling out the record objects we want. If a {@link #record}
* was specified we have to pull those out of the larger JSON object, which is most of what this function is doing
* @param {Object} root The JSON root node
* @return {Ext.data.Model[]} The records
*/
extractData: function(root) {
var recordName = this.record,
data = [],
length, i;
if (recordName) {
length = root.length;
if (!length && Ext.isObject(root)) {
length = 1;
root = [root];
}
for (i = 0; i < length; i++) {
data[i] = root[i][recordName];
}
} else {
data = root;
}
return this.callParent([data]);
},
<span id='Ext-data-reader-Json-method-createAccessor'> /**
</span> * @private
* @method
* Returns an accessor function for the given property string. Gives support for properties such as the following:
*
* - 'someProperty'
* - 'some.property'
* - 'some["property"]'
*
* This is used by buildExtractors to create optimized extractor functions when casting raw data into model instances.
*/
createAccessor: (function() {
var re = /[\[\.]/;
return function(expr) {
if (Ext.isEmpty(expr)) {
return Ext.emptyFn;
}
if (Ext.isFunction(expr)) {
return expr;
}
if (this.useSimpleAccessors !== true) {
var i = String(expr).search(re);
if (i >= 0) {
return Ext.functionFactory('obj', 'return obj' + (i > 0 ? '.' : '') + expr);
}
}
return function(obj) {
return obj[expr];
};
};
}()),
<span id='Ext-data-reader-Json-method-createFieldAccessExpression'> /**
</span> * @private
* @method
* Returns an accessor expression for the passed Field. Gives support for properties such as the following:
*
* - 'someProperty'
* - 'some.property'
* - 'some["property"]'
*
* This is used by buildExtractors to create optimized on extractor function which converts raw data into model instances.
*/
createFieldAccessExpression: (function() {
var re = /[\[\.]/;
return function(field, fieldVarName, dataName) {
var me = this,
hasMap = (field.mapping !== null),
map = hasMap ? field.mapping : field.name,
result,
operatorSearch;
if (typeof map === 'function') {
result = fieldVarName + '.mapping(' + dataName + ', this)';
} else if (this.useSimpleAccessors === true || ((operatorSearch = String(map).search(re)) < 0)) {
if (!hasMap || isNaN(map)) {
// If we don't provide a mapping, we may have a field name that is numeric
map = '"' + map + '"';
}
result = dataName + "[" + map + "]";
} else {
result = dataName + (operatorSearch > 0 ? '.' : '') + map;
}
return result;
};
}())
});
</pre>
</body>
</html>