/**
* @author Ed Spencer
*
* 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',
* fields: ['id', 'name', 'email']
* });
*
* var store = Ext.create('Ext.data.Store', {
* model: 'User',
* proxy: {
* type: 'ajax',
* url : 'users.xml',
* reader: {
* type: 'xml',
* record: 'user',
* root: 'users'
* }
* }
* });
*
* 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',
* root: 'users'
* }
*
* 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>
*
* First off there's {@link #root} option to define the root node `<users>` (there should be only one in a well-formed
* XML document). Then 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.
*
* Note that XmlReader doesn't care whether your {@link #root} 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>
*
* If this Reader is being used by a {@link Ext.data.TreeStore TreeStore} to read tree-structured data in which records
* are nested as descendant nodes of other records, then this lenient behaviour must be overridden by using a more specific
* child node selector as your {@link #record} selector which will not select all descendants, such as:
*
* record: '>user'
*
* # 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',
* root: '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',
/**
* @cfg {String} record (required)
* The DomQuery path to the repeated element which contains record information.
*
* By default, the elements which match the selector may be nested at any level below the {@link #root}
*
* If this Reader is being used by a {@link Ext.data.TreeStore TreeStore} to read tree-structured data,
* then only first generation child nodes of the root element must be selected, so the record selector must be
* specified with a more specific selector which will not select all descendants. For example:
*
* record: '>node'
*
*/
/**
* @cfg {String} namespace
* A namespace prefix that will be prepended to the field name when reading a
* field from an XML node. Take, for example, the following Model:
*
* Ext.define('Foo', {
* extend: 'Ext.data.Model',
* fields: ['bar', 'baz']
* });
*
* The reader would need to be configured with a namespace of 'n' in order to read XML
* data in the following format:
*
* <foo>
* <n:bar>bar</n:bar>
* <n:baz>baz</n:baz>
* </foo>
*/
/**
* @private
* Creates a function to return some particular key of data from a response. The totalProperty and
* successProperty are treated as special cases for type casting, everything else is just a simple selector.
* @param {String} key
* @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) {
// overcome a limitation of maximum textnode size
// http://reference.sitepoint.com/javascript/Node/normalize
// https://developer.mozilla.org/En/DOM/Node.normalize
if (typeof node.normalize === 'function') {
node.normalize();
}
node = node.firstChild;
if (node) {
return node.nodeValue;
}
}
return undefined;
},
//inherit docs
getResponseData: function(response) {
var xml = response.responseXML,
error,
msg;
if (!xml) {
msg = 'XML data not found in the response';
error = new Ext.data.ResultSet({
total : 0,
count : 0,
records: [],
success: false,
message: msg
});
this.fireEvent('exception', this, response, error);
Ext.Logger.warn(msg);
return error;
}
return this.readRecords(xml);
},
/**
* Normalizes the data object.
* @param {Object} data The raw data object
* @return {Object} 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.root;
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.record;
//<debug>
if (!recordName) {
Ext.Error.raise('Record is a required parameter');
}
//</debug>
if (recordName != root.nodeName) {
root = Ext.DomQuery.select(recordName, root);
} else {
root = [root];
}
return this.callParent([root]);
},
/**
* @private
* See Ext.data.reader.Reader's getAssociatedDataRoot docs.
* @param {Object} data The raw data object
* @param {String} associationName The name of the association to get data for (uses 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];
}
/**
* @property {Object} xmlData
* Copy of {@link #rawData}.
* @deprecated Will be removed in Ext JS 5.0. Use {@link #rawData} instead.
*/
this.xmlData = doc;
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 collsction 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 namespace = this.namespace,
selector, result;
selector = field.mapping || ((namespace ? namespace + '|' : '') + field.name);
if (typeof selector === 'function') {
result = fieldVarName + '.mapping(' + dataName + ', this)';
} else {
result = 'me.getNodeValue(Ext.DomQuery.selectNode("' + selector + '", ' + dataName + '))';
}
return result;
}
});