#

API Docs for: 3.10.3
Show: Inherited Protected Private Deprecated

# File: dataschema/js/dataschema-xml.js

    /**
    Provides a DataSchema implementation which can be used to work with XML data.

    @module dataschema
    @submodule dataschema-xml
    **/

    /**
    Provides a DataSchema implementation which can be used to work with XML data.

    See the `apply` method for usage.

    @class DataSchema.XML
    @extends DataSchema.Base
    @static
    **/
    var Lang = Y.Lang,

        okNodeType = {
            1 : true,
            9 : true,
            11: true
        },

        SchemaXML;

    SchemaXML = {

        ////////////////////////////////////////////////////////////////////////////
        //
        // DataSchema.XML static methods
        //
        ////////////////////////////////////////////////////////////////////////////
        /**
        Applies a schema to an XML data tree, returning a normalized object with
        results in the `results` property. Additional information can be parsed out
        of the XML for inclusion in the `meta` property of the response object.  If
        an error is encountered during processing, an `error` property will be
        added.

        Field data in the nodes captured by the XPath in _schema.resultListLocator_
        is extracted with the field identifiers described in _schema.resultFields_.
        Field identifiers are objects with the following properties:

          * `key`    : <strong>(required)</strong> The desired property name to use
                store the retrieved value in the result object.  If `locator` is
                not specified, `key` is also used as the XPath locator (String)
          * `locator`: The XPath locator to the node or attribute within each
                result node found by _schema.resultListLocator_ containing the
                desired field data (String)
          * `parser` : A function or the name of a function on `Y.Parsers` used
                to convert the input value into a normalized type.  Parser
                functions are passed the value as input and are expected to
                return a value.
          * `schema` : Used to retrieve nested field data into an array for
                assignment as the result field value.  This object follows the same
                conventions as _schema_.

        If no value parsing or nested parsing is needed, you can use XPath locators
        (strings) instead of field identifiers (objects) -- see example below.

        `response.results` will contain an array of objects with key:value pairs.
        The keys are the field identifier `key`s, and the values are the data
        values extracted from the nodes or attributes found by the field `locator`
        (or `key` fallback).

        To extract additional information from the XML, include an array of
        XPath locators in _schema.metaFields_.  The collected values will be
        stored in `response.meta` with the XPath locator as keys.

        @example
            var schema = {
                    resultListLocator: '//produce/item',
                    resultFields: [
                        {
                            locator: 'name',
                            key: 'name'
                        },
                        {
                            locator: 'color',
                            key: 'color',
                            parser: function (val) { return val.toUpperCase(); }
                        }
                    ]
                };

            // Assumes data like
            // <inventory>
            //   <produce>
            //     <item><name>Banana</name><color>yellow</color></item>
            //     <item><name>Orange</name><color>orange</color></item>
            //     <item><name>Eggplant</name><color>purple</color></item>
            //   </produce>
            // </inventory>

            var response = Y.DataSchema.JSON.apply(schema, data);

            // response.results[0] is { name: "Banana", color: "YELLOW" }

        @method apply
        @param {Object} schema Schema to apply.  Supported configuration
            properties are:
          @param {String} [schema.resultListLocator] XPath locator for the
              XML nodes that contain the data to flatten into `response.results`
          @param {Array} [schema.resultFields] Field identifiers to
              locate/assign values in the response records. See above for
              details.
          @param {Array} [schema.metaFields] XPath locators to extract extra
              non-record related information from the XML data
        @param {XMLDoc} data XML data to parse
        @return {Object} An Object with properties `results` and `meta`
        @static
        **/
        apply: function(schema, data) {
            var xmldoc = data, // unnecessary variables
                data_out = { results: [], meta: {} };

            if (xmldoc && okNodeType[xmldoc.nodeType] && schema) {
                // Parse results data
                data_out = SchemaXML._parseResults(schema, xmldoc, data_out);

                // Parse meta data
                data_out = SchemaXML._parseMeta(schema.metaFields, xmldoc, data_out);
            } else {
                Y.log("XML data could not be schema-parsed: " + Y.dump(data) + " " + Y.dump(data), "error", "dataschema-xml");
                data_out.error = new Error("XML schema parse failure");
            }

            return data_out;
        },

        /**
         * Get an XPath-specified value for a given field from an XML node or document.
         *
         * @method _getLocationValue
         * @param field {String | Object} Field definition.
         * @param context {Object} XML node or document to search within.
         * @return {Object} Data value or null.
         * @static
         * @protected
         */
        _getLocationValue: function(field, context) {
            var locator = field.locator || field.key || field,
                xmldoc = context.ownerDocument || context,
                result, res, value = null;

            try {
                result = SchemaXML._getXPathResult(locator, context, xmldoc);
                while ((res = result.iterateNext())) {
                    value = res.textContent || res.value || res.text || res.innerHTML || res.innerText || null;
                }

                // FIXME: Why defer to a method that is mixed into this object?
                // DSchema.Base is mixed into DSchema.XML (et al), so
                // DSchema.XML.parse(...) will work.  This supports the use case
                // where DSchema.Base.parse is changed, and that change is then
                // seen by all DSchema.* implementations, but does not support the
                // case where redefining DSchema.XML.parse changes behavior. In
                // fact, DSchema.XML.parse is never even called.
                return Y.DataSchema.Base.parse.call(this, value, field);
            } catch (e) {
                Y.log('SchemaXML._getLocationValue failed: ' + e.message);
            }

            return null;
        },

        /**
         * Fetches the XPath-specified result for a given location in an XML node
         * or document.
         *
         * @method _getXPathResult
         * @param locator {String} The XPath location.
         * @param context {Object} XML node or document to search within.
         * @param xmldoc {Object} XML document to resolve namespace.
         * @return {Object} Data collection or null.
         * @static
         * @protected
         */
        _getXPathResult: function(locator, context, xmldoc) {
            // Standards mode
            if (! Lang.isUndefined(xmldoc.evaluate)) {
                return xmldoc.evaluate(locator, context, xmldoc.createNSResolver(context.ownerDocument ? context.ownerDocument.documentElement : context.documentElement), 0, null);

            }
            // IE mode
            else {
                var values=[], locatorArray = locator.split(/\b\/\b/), i=0, l=locatorArray.length, location, subloc, m, isNth;

                // XPath is supported
                try {
                    // this fixes the IE 5.5+ issue where childnode selectors begin at 0 instead of 1
                    try {
                       xmldoc.setProperty("SelectionLanguage", "XPath");
                    } catch (e) {}

                    values = context.selectNodes(locator);
                }
                // Fallback for DOM nodes and fragments
                catch (e) {
                    // Iterate over each locator piece
                    for (; i<l && context; i++) {
                        location = locatorArray[i];

                        // grab nth child []
                        if ((location.indexOf("[") > -1) && (location.indexOf("]") > -1)) {
                            subloc = location.slice(location.indexOf("[")+1, location.indexOf("]"));
                            //XPath is 1-based while DOM is 0-based
                            subloc--;
                            context = context.children[subloc];
                            isNth = true;
                        }
                        // grab attribute value @
                        else if (location.indexOf("@") > -1) {
                            subloc = location.substr(location.indexOf("@"));
                            context = subloc ? context.getAttribute(subloc.replace('@', '')) : context;
                        }
                        // grab that last instance of tagName
                        else if (-1 < location.indexOf("//")) {
                            subloc = context.getElementsByTagName(location.substr(2));
                            context = subloc.length ? subloc[subloc.length - 1] : null;
                        }
                        // find the last matching location in children
                        else if (l != i + 1) {
                            for (m=context.childNodes.length-1; 0 <= m; m-=1) {
                                if (location === context.childNodes[m].tagName) {
                                    context = context.childNodes[m];
                                    m = -1;
                                }
                            }
                        }
                    }

                    if (context) {
                        // attribute
                        if (Lang.isString(context)) {
                            values[0] = {value: context};
                        }
                        // nth child
                        else if (isNth) {
                            values[0] = {value: context.innerHTML};
                        }
                        // all children
                        else {
                            values = Y.Array(context.childNodes, 0, true);
                        }
                    }
                }

                // returning a mock-standard object for IE
                return {
                    index: 0,

                    iterateNext: function() {
                        if (this.index >= this.values.length) {return undefined;}
                        var result = this.values[this.index];
                        this.index += 1;
                        return result;
                    },

                    values: values
                };
            }
        },

        /**
         * Schema-parsed result field.
         *
         * @method _parseField
         * @param field {String | Object} Required. Field definition.
         * @param result {Object} Required. Schema parsed data object.
         * @param context {Object} Required. XML node or document to search within.
         * @static
         * @protected
         */
        _parseField: function(field, result, context) {
            var key = field.key || field,
                parsed;

            if (field.schema) {
                parsed = { results: [], meta: {} };
                parsed = SchemaXML._parseResults(field.schema, context, parsed);

                result[key] = parsed.results;
            } else {
                result[key] = SchemaXML._getLocationValue(field, context);
            }
        },

        /**
         * Parses results data according to schema
         *
         * @method _parseMeta
         * @param xmldoc_in {Object} XML document parse.
         * @param data_out {Object} In-progress schema-parsed data to update.
         * @return {Object} Schema-parsed data.
         * @static
         * @protected
         */
        _parseMeta: function(metaFields, xmldoc_in, data_out) {
            if(Lang.isObject(metaFields)) {
                var key,
                    xmldoc = xmldoc_in.ownerDocument || xmldoc_in;

                for(key in metaFields) {
                    if (metaFields.hasOwnProperty(key)) {
                        data_out.meta[key] = SchemaXML._getLocationValue(metaFields[key], xmldoc);
                    }
                }
            }
            return data_out;
        },

        /**
         * Schema-parsed result to add to results list.
         *
         * @method _parseResult
         * @param fields {Array} Required. A collection of field definition.
         * @param context {Object} Required. XML node or document to search within.
         * @return {Object} Schema-parsed data.
         * @static
         * @protected
         */
        _parseResult: function(fields, context) {
            var result = {}, j;

            // Find each field value
            for (j=fields.length-1; 0 <= j; j--) {
                SchemaXML._parseField(fields[j], result, context);
            }

            return result;
        },

        /**
         * Schema-parsed list of results from full data
         *
         * @method _parseResults
         * @param schema {Object} Schema to parse against.
         * @param context {Object} XML node or document to parse.
         * @param data_out {Object} In-progress schema-parsed data to update.
         * @return {Object} Schema-parsed data.
         * @static
         * @protected
         */
        _parseResults: function(schema, context, data_out) {
            if (schema.resultListLocator && Lang.isArray(schema.resultFields)) {
                var xmldoc = context.ownerDocument || context,
                    fields = schema.resultFields,
                    results = [],
                    node, nodeList, i=0;

                if (schema.resultListLocator.match(/^[:\-\w]+$/)) {
                    nodeList = context.getElementsByTagName(schema.resultListLocator);

                    // loop through each result node
                    for (i = nodeList.length - 1; i >= 0; --i) {
                        results[i] = SchemaXML._parseResult(fields, nodeList[i]);
                    }
                } else {
                    nodeList = SchemaXML._getXPathResult(schema.resultListLocator, context, xmldoc);

                    // loop through the nodelist
                    while ((node = nodeList.iterateNext())) {
                        results[i] = SchemaXML._parseResult(fields, node);
                        i += 1;
                    }
                }

                if (results.length) {
                    data_out.results = results;
                } else {
                    data_out.error = new Error("XML schema result nodes retrieval failure");
                }
            }
            return data_out;
        }
    };

    Y.DataSchema.XML = Y.mix(SchemaXML, Y.DataSchema.Base);