/**
+ * @author Ed Spencer
+ * @class Ext.data.writer.Writer
+ * @extends Object
+ *
+ * <p>Base Writer class used by most subclasses of {@link Ext.data.proxy.Server}. This class is
+ * responsible for taking a set of {@link Ext.data.Operation} objects and a {@link Ext.data.Request}
+ * object and modifying that request based on the Operations.</p>
+ *
+ * <p>For example a Ext.data.writer.Json would format the Operations and their {@link Ext.data.Model}
+ * instances based on the config options passed to the JsonWriter's constructor.</p>
+ *
+ * <p>Writers are not needed for any kind of local storage - whether via a
+ * {@link Ext.data.proxy.WebStorage Web Storage proxy} (see {@link Ext.data.proxy.LocalStorage localStorage}
+ * and {@link Ext.data.proxy.SessionStorage sessionStorage}) or just in memory via a
+ * {@link Ext.data.proxy.Memory MemoryProxy}.</p>
+ *
+ * @constructor
+ * @param {Object} config Optional config object
+ */
+Ext.define('Ext.data.writer.Writer', {
+ alias: 'writer.base',
+ alternateClassName: ['Ext.data.DataWriter', 'Ext.data.Writer'],
+
+ /**
+ * @cfg {Boolean} writeAllFields True to write all fields from the record to the server. If set to false it
+ * will only send the fields that were modified. Defaults to <tt>true</tt>. Note that any fields that have
+ * {@link Ext.data.Field#persist} set to false will still be ignored.
+ */
+ writeAllFields: true,
+
+ /**
+ * @cfg {String} nameProperty This property is used to read the key for each value that will be sent to the server.
+ * For example:
+ * <pre><code>
+Ext.define('Person', {
+ extend: 'Ext.data.Model',
+ fields: [{
+ name: 'first',
+ mapping: 'firstName'
+ }, {
+ name: 'last',
+ mapping: 'lastName'
+ }, {
+ name: 'age'
+ }]
+});
+new Ext.data.writer.Writer({
+ writeAllFields: true,
+ nameProperty: 'mapping'
+});
+
+// This will be sent to the server
+{
+ firstName: 'first name value',
+ lastName: 'last name value',
+ age: 1
+}
+
+ * </code></pre>
+ * Defaults to <tt>name</tt>. If the value is not present, the field name will always be used.
+ */
+ nameProperty: 'name',
+
+ constructor: function(config) {
+ Ext.apply(this, config);
+ },
+
+ /**
+ * Prepares a Proxy's Ext.data.Request object
+ * @param {Ext.data.Request} request The request object
+ * @return {Ext.data.Request} The modified request object
+ */
+ write: function(request) {
+ var operation = request.operation,
+ records = operation.records || [],
+ len = records.length,
+ i = 0,
+ data = [];
+
+ for (; i < len; i++) {
+ data.push(this.getRecordData(records[i]));
+ }
+ return this.writeRecords(request, data);
+ },
+
+ /**
+ * Formats the data for each record before sending it to the server. This
+ * method should be overridden to format the data in a way that differs from the default.
+ * @param {Object} record The record that we are writing to the server.
+ * @return {Object} An object literal of name/value keys to be written to the server.
+ * By default this method returns the data property on the record.
+ */
+ getRecordData: function(record) {
+ var isPhantom = record.phantom === true,
+ writeAll = this.writeAllFields || isPhantom,
+ nameProperty = this.nameProperty,
+ fields = record.fields,
+ data = {},
+ changes,
+ name,
+ field,
+ key;
+
+ if (writeAll) {
+ fields.each(function(field){
+ if (field.persist) {
+ name = field[nameProperty] || field.name;
+ data[name] = record.get(field.name);
+ }
+ });
+ } else {
+ // Only write the changes
+ changes = record.getChanges();
+ for (key in changes) {
+ if (changes.hasOwnProperty(key)) {
+ field = fields.get(key);
+ name = field[nameProperty] || field.name;
+ data[name] = changes[key];
+ }
+ }
+ if (!isPhantom) {
+ // always include the id for non phantoms
+ data[record.idProperty] = record.getId();
+ }
+ }
+ return data;
+ }
+});
+