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/**
* Simple XML DOM implementation based on sax that works with Strings.
*
* If you have an XML string and want a DOM this utility is convenient.
*
* var domjs = new DomJS();
* domjs.parse(xmlString, function(err, dom) {
*
* });
*
* If you want to compile C there are versions based on libxml2
* and jsdom is full featured but complicated.
*
* This is "lightweight" meaning simple and serves my purpose, it does not support namespaces or all
* of the features of XML 1.0 it just takes a string and returns a JavaScript object graph.
*
* There are only 5 types of object supported
* Element, Text, ProcessingInstruction, CDATASection and Comment.
*
* e.g.
*
* take <xml><elem att="val1"/><elem att="val1"/><elem att="val1"/></xml>
*
* return { name : "xml",
* attributes : {}
* children [
* { name : "elem", attributes : {att:'val1'}, children [] },
* { name : "elem", attributes : {att:'val1'}, children [] },
* { name : "elem", attributes : {att:'val1'}, children [] }
* ]
* }
*
* The object returned is an instance of Element and can be serialized back out with obj.toXml();
*
*
* @constructor DomJS
*/
var DomJS = function() {
/**
* The root element of the XML document currently being parsed.
*/
this.root = null;
this.stack = new Array();
this.currElement = null;
/**
* Flag that is set to true if there was a Sax error parsing the XML.
*/
this.error = false;
/**
* Use strict parsing, this value is passed to the sax parser.
*/
this.strict = true;
/**
* Set to true to parse and write ProcessingInstructions
* By default false for backwards comatability
*/
this.parseProcessingInstructions = false;
// undefined by default
// this.processingInstructions = new Array();
};
DomJS.prototype.parse = function(string, cb) {
if (typeof string != 'string') {
cb(true, 'Data is not a string');
return;
}
var self = this;
var parser = sax.parser(this.strict);
parser.onerror = function (err) {
self.error = true;
cb(true, err);
};
parser.ontext = function (text) {
if (self.currElement == null) {
// console.log("Content in the prolog " + text);
return;
}
var textNode = new Text(text);
self.currElement.children.push(textNode);
};
parser.onopencdata = function () {
var cdataNode = new CDATASection();
self.currElement.children.push(cdataNode);
};
parser.oncdata = function (data) {
var cdataNode = self.currElement.children[self.currElement.children.length - 1];
cdataNode.appendData(data);
};
// do nothing on parser.onclosecdata
parser.onopentag = function (node) {
var elem = new Element(node.name, node.attributes);
if (self.root == null) {
self.root = elem;
if ( self.processingInstructions ) {
elem.processingInstructions = self.processingInstructions;
}
}
if (self.currElement != null) {
self.currElement.children.push(elem);
}
self.currElement = elem;
self.stack.push(self.currElement);
};
parser.onclosetag = function (node) {
self.stack.pop();
self.currElement = self.stack[self.stack.length - 1 ];// self.stack.peek();
};
parser.oncomment = function (comment) {
if (self.currElement == null) {
//console.log("Comments in the prolog discarded " + comment);
return;
}
var commentNode = new Comment(comment);
self.currElement.children.push(commentNode);
};
parser.onprocessinginstruction = function (node) {
if (self.parseProcessingInstructions === true) {
if ( self.processingInstructions === undefined) {
self.processingInstructions = new Array();
}
var pi = new ProcessingInstruction(node.name, node.body);
self.processingInstructions.push(pi);
}
};
parser.onend = function () {
if ( self.error == false) {
cb(false, self.root);
}
};
parser.write(string).close();
};
DomJS.prototype.reset = function() {
this.root = null;
this.stack = new Array();
this.currElement = null;
this.error = false;
};
var escape = function(string) {
return string.replace(/&/g, '&amp;')
.replace(/>/g, '&gt;')
.replace(/</g, '&lt;')
.replace(/"/g, '&quot;')
.replace(/'/g, '&apos;');
};
/**
*
* @constructor Element
*/
var Element = function(name, attributes, children ) {
this.name = name;
this.attributes = attributes || [];
this.children = children || [];
// undefined by default
// this.processingInstructions = new Array();
};
Element.prototype.toXml = function(sb) {
if (typeof sb == 'undefined') {
sb = {buf:''}; // Strings are pass by value in JS it seems
}
if (this.processingInstructions) {
for (var i = 0 ; i < this.processingInstructions.length ; i++) {
sb.buf += '<?' + this.processingInstructions[i].name + ' ' + this.processingInstructions[i].body + '?>\n';
}
}
sb.buf += '<' + this.name;
for (att in this.attributes) {
sb.buf += ' ' + att + '="' + escape(this.attributes[att]) + '"';
}
if (this.children.length != 0) {
sb.buf += '>';
for (var i = 0 ; i < this.children.length ; i++) {
this.children[i].toXml(sb);
}
sb.buf += '</' + this.name + '>';
}
else {
sb.buf += '/>';
}
return sb.buf;
};
Element.prototype.firstChild = function() {
if ( this.children.length > 0) {
return this.children[0];
}
return null;
};
Element.prototype.text = function() {
if ( this.children.length > 0) {
if (typeof this.children[0].text == 'string') {
return this.children[0].text;
};
}
return null;
};
var Text = function(data){
this.text = data;
};
Text.prototype.toXml = function(sb) {
sb.buf += escape(this.text);
};
var Comment = function(comment) {
this.comment = comment;
};
Comment.prototype.toXml = function(sb) {
sb.buf += '<!--' + this.comment + '-->';
};
var ProcessingInstruction = function(name, body) {
this.name = name;
this.body = body;
};
ProcessingInstruction.prototype.toXml = function(sb) {
sb.buf += '<?' + this.name + ' ' + this.body + '?>';
};
var CDATASection = function(data){
this.text = data || '';
};
CDATASection.prototype.toXml = function(sb) {
sb.buf += '<![CDATA[' + this.text + ']]>';
};
CDATASection.prototype.appendData = function(data) {
this.text += data;
};