/**
* @author Ed Spencer
* @class Ext.data.reader.Xml
* @extends Ext.data.reader.Reader
*
* The XML Reader is used by a Proxy to read a server response that is sent back in XML 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',
* config: {
* fields: ['id', 'name', 'email']
* }
* });
*
* var store = Ext.create('Ext.data.Store', {
* model: 'User',
* proxy: {
* type: 'ajax',
* url : 'users.xml',
* reader: {
* type: 'xml',
* record: 'user'
* }
* }
* });
*
* 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 XML Reader possible by simply telling our {@link Ext.data.Store Store}'s
* {@link Ext.data.proxy.Proxy Proxy} that we want a XML Reader. The Store automatically passes the configured model to the
* Store, so it is as if we passed this instead:
*
* reader: {
* type : 'xml',
* model: 'User',
* record: 'user'
* }
*
* The reader we set up is ready to read data from our server - at the moment it will accept a response like this:
*
* <?xml version="1.0" encoding="UTF-8"?>
* <users>
* <user>
* <id>1</id>
* <name>Ed Spencer</name>
* <email>ed@sencha.com</email>
* </user>
* <user>
* <id>2</id>
* <name>Abe Elias</name>
* <email>abe@sencha.com</email>
* </user>
* </users>
*
* The XML Reader uses the configured {@link #record} option to pull out the data for each record - in this case we
* set record to 'user', so each `<user>` above will be converted into a User model.
*
* ## Reading other XML formats
*
* If you already have your XML format defined and it doesn't look quite like what we have above, you can usually
* pass XmlReader a couple of configuration options to make it parse your format. For example, we can use the
* {@link #rootProperty} configuration to parse data that comes back like this:
*
* <?xml version="1.0" encoding="UTF-8"?>
* <users>
* <user>
* <id>1</id>
* <name>Ed Spencer</name>
* <email>ed@sencha.com</email>
* </user>
* <user>
* <id>2</id>
* <name>Abe Elias</name>
* <email>abe@sencha.com</email>
* </user>
* </users>
*
* To parse this we just pass in a {@link #rootProperty} configuration that matches the 'users' above:
*
* reader: {
* type: 'xml',
* record: 'user',
* rootProperty: 'users'
* }
*
* Note that XmlReader doesn't care whether your {@link #rootProperty} and {@link #record} elements are nested deep
* inside a larger structure, so a response like this will still work:
*
* <?xml version="1.0" encoding="UTF-8"?>
* <deeply>
* <nested>
* <xml>
* <users>
* <user>
* <id>1</id>
* <name>Ed Spencer</name>
* <email>ed@sencha.com</email>
* </user>
* <user>
* <id>2</id>
* <name>Abe Elias</name>
* <email>abe@sencha.com</email>
* </user>
* </users>
* </xml>
* </nested>
* </deeply>
*
* ## Response metadata
*
* The server can return additional data in its response, such as the {@link #totalProperty total number of records}
* and the {@link #successProperty success status of the response}. These are typically included in the XML response
* like this:
*
* <?xml version="1.0" encoding="UTF-8"?>
* <users>
* <total>100</total>
* <success>true</success>
* <user>
* <id>1</id>
* <name>Ed Spencer</name>
* <email>ed@sencha.com</email>
* </user>
* <user>
* <id>2</id>
* <name>Abe Elias</name>
* <email>abe@sencha.com</email>
* </user>
* </users>
*
* If these properties are present in the XML response they can be parsed out by the XmlReader and used by the
* Store that loaded it. We can set up the names of these properties by specifying a final pair of configuration
* options:
*
* reader: {
* type: 'xml',
* rootProperty: 'users',
* totalProperty : 'total',
* successProperty: 'success'
* }
*
* These final options are not necessary to make the Reader work, but can be useful when the server needs to report
* an error or if it needs to indicate that there is a lot of data available of which only a subset is currently being
* returned.
*
* ## Response format
*
* __Note:__ In order for the browser to parse a returned XML document, the Content-Type header in the HTTP
* response must be set to "text/xml" or "application/xml". This is very important - the XmlReader will not
* work correctly otherwise.
*/
Ext.define('Ext.data.reader.Xml', {
extend: 'Ext.data.reader.Reader',
alternateClassName: 'Ext.data.XmlReader',
alias: 'reader.xml',
config: {
/**
* @cfg {String} record The DomQuery path to the repeated element which contains record information.
*/
record: null
},
/**
* @private
* Creates a function to return some particular key of data from a response. The {@link #totalProperty} and
* {@link #successProperty} are treated as special cases for type casting, everything else is just a simple selector.
* @param {String} expr
* @return {Function}
*/
createAccessor: function(expr) {
var me = this;
if (Ext.isEmpty(expr)) {
return Ext.emptyFn;
}
if (Ext.isFunction(expr)) {
return expr;
}
return function(root) {
return me.getNodeValue(Ext.DomQuery.selectNode(expr, root));
};
},
getNodeValue: function(node) {
if (node && node.firstChild) {
return node.firstChild.nodeValue;
}
return undefined;
},
//inherit docs
getResponseData: function(response) {
// Check to see if the response is already an xml node.
if (response.nodeType === 1 || response.nodeType === 9) {
return response;
}
var xml = response.responseXML;
//<debug>
if (!xml) {
/**
* @event exception Fires whenever the reader is unable to parse a response.
* @param {Ext.data.reader.Xml} reader A reference to this reader.
* @param {XMLHttpRequest} response The XMLHttpRequest response object.
* @param {String} error The error message.
*/
this.fireEvent('exception', this, response, 'XML data not found in the response');
Ext.Logger.warn('XML data not found in the response');
}
//</debug>
return xml;
},
/**
* Normalizes the data object.
* @param {Object} data The raw data object.
* @return {Object} Returns the `documentElement` property of the data object if present, or the same object if not.
*/
getData: function(data) {
return data.documentElement || data;
},
/**
* @private
* Given an XML object, returns the Element that represents the root as configured by the Reader's meta data.
* @param {Object} data The XML data object.
* @return {XMLElement} The root node element.
*/
getRoot: function(data) {
var nodeName = data.nodeName,
root = this.getRootProperty();
if (!root || (nodeName && nodeName == root)) {
return data;
} else if (Ext.DomQuery.isXml(data)) {
// This fix ensures we have XML data
// Related to TreeStore calling getRoot with the root node, which isn't XML
// Probably should be resolved in TreeStore at some point
return Ext.DomQuery.selectNode(root, data);
}
},
* @private
* We're just preparing the data for the superclass by pulling out the record nodes we want.
* @param {XMLElement} root The XML root node.
* @return {Ext.data.Model[]} The records.
*/
extractData: function(root) {
var recordName = this.getRecord();
//<debug>
if (!recordName) {
Ext.Logger.error('Record is a required parameter');
}
//</debug>
if (recordName != root.nodeName && recordName !== root.localName) {
root = Ext.DomQuery.select(recordName, root);
} else {
root = [root];
}
return this.callParent([root]);
},
/**
* @private
* See {@link Ext.data.reader.Reader#getAssociatedDataRoot} docs.
* @param {Object} data The raw data object.
* @param {String} associationName The name of the association to get data for (uses {@link Ext.data.association.Association#associationKey} if present).
* @return {XMLElement} The root.
*/
getAssociatedDataRoot: function(data, associationName) {
return Ext.DomQuery.select(associationName, data)[0];
},
/**
* Parses an XML document and returns a ResultSet containing the model instances.
* @param {Object} doc Parsed XML document.
* @return {Ext.data.ResultSet} The parsed result set.
*/
readRecords: function(doc) {
//it's possible that we get passed an array here by associations. Make sure we strip that out (see Ext.data.reader.Reader#readAssociated)
if (Ext.isArray(doc)) {
doc = doc[0];
}
return this.callParent([doc]);
},
/**
* @private
* Returns an accessor expression for the passed Field from an XML element using either the Field's mapping, or
* its ordinal position in the fields collection as the index.
*
* This is used by `buildExtractors` to create optimized on extractor function which converts raw data into model instances.
*/
createFieldAccessExpression: function(field, fieldVarName, dataName) {
var selector = field.getMapping() || field.getName(),
result;
if (typeof selector === 'function') {
result = fieldVarName + '.getMapping()(' + dataName + ', this)';
} else {
selector = selector.split('@');
if (selector.length === 2 && selector[0]) {
result = 'me.getNodeValue(Ext.DomQuery.selectNode("@' + selector[1] + '", Ext.DomQuery.selectNode("' + selector[0] + '", ' + dataName + ')))';
} else if (selector.length === 2) {
result = 'me.getNodeValue(Ext.DomQuery.selectNode("@' + selector[1] + '", ' + dataName + '))';
} else if (selector.length === 1) {
result = 'me.getNodeValue(Ext.DomQuery.selectNode("' + selector[0] + '", ' + dataName + '))';
} else {
throw "Unsupported query - too many queries for attributes in " + selector.join('@');
}
}
return result;
}
});