xmljs/XmlParser.js

A small and simple package which can traverse a XML document

module.exports = (function() {
    "use strict";
    var $o = require("./core.js");
    var sax = require("sax");

    var parser = $o.Object.extend({
        saxParser: null,
        currentNode: null,
        attributes: null, // storage for attributes for the next node
        nodeStack: null, // stack of nodes

        // oPar.strict: Whenever or not to use a strict parser
        // oPar.noTrim : Do not trimtext and comment nodes
        // oPar.noNormalizeWhitespaces: Do not normalize whitespaces in text
        // oPar.lowercaseTagnames: Turn the tagsNames to lowercase
        // oPar.noTracing: Disable position tracing of sax
        // oPar.strictEntities: Allow only predefined entities
        create: function(oPar) {
            this.nodeStack = [];
            this.saxParser = sax.parser(!!oPar.strict, {
                trim: !oPar.noTrim,
                normalize: !oPar.noNormalizeWhitespaces,
                lowercase: !!oPar.lowercaseTagnames,
                xmlns: !oPar.noNamespaces,
                position: !oPar.noTracing,
                strictEntities: !!oPar.strictEntities
            });
            this.errors = [];
            this.attributes = [];
            this.continueOnError = !!oPar.continueOnError;

            this._createEvents();
        },

        _createEvents: function() {
            var self = this;
            this.saxParser.onopentag = function(n) {
                var node = new XmlNode(n);
                self.attributes.forEach(function(attr) {
                    node.addAttribute(attr);
                });
                self.currentNode.addNode(node);

                self.attributes.length = 0;
                self.pushStack(node);
            };
            this.saxParser.onclosetag = function() {
                self.popStack();
            };
            this.saxParser.onattribute = function(attr) {
                if (attr.prefix === "xmlns") return; // ignore namespace attributes
                self.attributes.push(attr);
            };
            this.saxParser.ontext = function(txt) {
                self.currentNode.setText(txt);
            };
            this.saxParser.onerror = function(err) {
                self.errors.push(err);
                if (self.continueOnError) self.saxParser.resume();
            };
        },
        parseString: function(str, cb) {
            this.nodeStack.length = 0;
            this.errors.length = 0;
            this.root = new Node();
            this.currentNode = this.root;

            try {
                this.saxParser.write(str.toString());
                this.saxParser.close();
            } catch (e) {
                this.errors.push(e);
            }

            var err = this.errors.length === 0 ? null : this.errors;
            cb(err, this.root);

            return this.errors.length === 0;
        },
        pushStack: function(node) {
            this.nodeStack.push(this.currentNode);
            this.currentNode = node;

            return node;
        },
        popStack: function() {
            this.currentNode = this.nodeStack.pop();
            return this.currentNode;
        }
    });
    parser.isXmlNode = function(n) {
        return n instanceof XmlNode;
    };

    var Attribute = $o.Object.extend({
        name: null,
        text: null,
        create: function(name, value) {
            this.name = name;
            this.text = value;
        }
    });

    var XmlAttribute = Attribute.extend({
        ns: null,
        create: function(xml) {
            _super(XmlAttribute).create.call(this, xml.local, xml.value);
            this.ns = xml.namespace;
        }
    });

    // generic node
    var Node = $o.Object.extend({
        children: null, // dictionary of children nodes
        children_lower: null,
        attributes: null, // dictionary of attributes
        attributes_lower: null, // dictionary of attributes
        create: function() {
            this.children = {};
            this.children_lower = {};

            this.attributes = {};
            this.attributes_lower = {};
        },
        getAttribute: function(attr, ignoreCase) {
            return ignoreCase
                ? this.attributes_lower[attr.toLowerCase()]
                : this.attributes[attr];
        },
        addAttribute: function(xmlAttr) {
            var attr = new XmlAttribute(xmlAttr);
            this.attributes[attr.name] = attr;
            this.attributes_lower[attr.name.toLowerCase()] = attr;
        },
        addNode: function(n) {
            if (!this.children[n.localName]) this.children[n.localName] = [];
            if (!this.children_lower[n.localName.toLowerCase()])
                this.children_lower[n.localName.toLowerCase()] = [];

            this.children[n.localName].push(n);
            this.children_lower[n.localName.toLowerCase()].push(n);

            return n;
        },

        path: function(arr, ignoreCase) {
            var nodes = [];

            function next(parNode, left) {
                if (left.length === 0) {
                    nodes.push(parNode);
                    return;
                }
                var name = left[0];
                var arr = parNode.children[name] || [];

                arr.forEach(function(n) {
                    next(n, left.slice(1));
                });
            }

            function next_caseinvar(parNode, left) {
                if (left.length === 0) {
                    nodes.push(parNode);
                    return;
                }
                var name = left[0];
                var arr = parNode.children_lower[name.toLowerCase()] || [];

                arr.forEach(function(n) {
                    next_caseinvar(n, left.slice(1));
                });
            }

            if (ignoreCase) next_caseinvar(this, arr);
            else next(this, arr);
            return nodes;
        },
        visit: function(fn) {
            fn(this);
            for (var k in this.children) this.children[k].visit(fn);
        }
    });

    var XmlNode = Node.extend({
        name: "",
        ns: "",
        prefix: "",
        localName: "",
        text: "",

        _n: null,
        create: function(n) {
            _super(XmlNode).create.call(this);
            this._n = n;

            this.name = n.name;
            this.prefix = n.prefix;
            this.localName = n.local;
            this.ns = n.ns[this.prefix];
        },
        setText: function(txt) {
            this.text = txt;
        }
    });

    return parser;
})();