Version 3.18.1
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File: dataschema/js/dataschema-json.js

            /**
            Provides a DataSchema implementation which can be used to work with JSON data.
            
            @module dataschema
            @submodule dataschema-json
            **/
            
            /**
            Provides a DataSchema implementation which can be used to work with JSON data.
            
            See the `apply` method for usage.
            
            @class DataSchema.JSON
            @extends DataSchema.Base
            @static
            **/
            var LANG = Y.Lang,
                isFunction = LANG.isFunction,
                isObject   = LANG.isObject,
                isArray    = LANG.isArray,
                // TODO: I don't think the calls to Base.* need to be done via Base since
                // Base is mixed into SchemaJSON.  Investigate for later.
                Base       = Y.DataSchema.Base,
            
                SchemaJSON;
            
            SchemaJSON = {
            
            /////////////////////////////////////////////////////////////////////////////
            //
            // DataSchema.JSON static methods
            //
            /////////////////////////////////////////////////////////////////////////////
                /**
                 * Utility function converts JSON locator strings into walkable paths
                 *
                 * @method getPath
                 * @param locator {String} JSON value locator.
                 * @return {String[]} Walkable path to data value.
                 * @static
                 */
                getPath: function(locator) {
                    var path = null,
                        keys = [],
                        i = 0;
            
                    if (locator) {
                        // Strip the ["string keys"] and [1] array indexes
                        // TODO: the first two steps can probably be reduced to one with
                        // /\[\s*(['"])?(.*?)\1\s*\]/g, but the array indices would be
                        // stored as strings.  This is not likely an issue.
                        locator = locator.
                            replace(/\[\s*(['"])(.*?)\1\s*\]/g,
                            function (x,$1,$2) {keys[i]=$2;return '.@'+(i++);}).
                            replace(/\[(\d+)\]/g,
                            function (x,$1) {keys[i]=parseInt($1,10)|0;return '.@'+(i++);}).
                            replace(/^\./,''); // remove leading dot
            
                        // Validate against problematic characters.
                        // commented out because the path isn't sent to eval, so it
                        // should be safe. I'm not sure what makes a locator invalid.
                        //if (!/[^\w\.\$@]/.test(locator)) {
                        path = locator.split('.');
                        for (i=path.length-1; i >= 0; --i) {
                            if (path[i].charAt(0) === '@') {
                                path[i] = keys[parseInt(path[i].substr(1),10)];
                            }
                        }
                        /*}
                        else {
                            Y.log("Invalid locator: " + locator, "error", "dataschema-json");
                        }
                        */
                    }
                    return path;
                },
            
                /**
                 * Utility function to walk a path and return the value located there.
                 *
                 * @method getLocationValue
                 * @param path {String[]} Locator path.
                 * @param data {String} Data to traverse.
                 * @return {Object} Data value at location.
                 * @static
                 */
                getLocationValue: function (path, data) {
                    var i = 0,
                        len = path.length;
                    for (;i<len;i++) {
                        if (isObject(data) && (path[i] in data)) {
                            data = data[path[i]];
                        } else {
                            data = undefined;
                            break;
                        }
                    }
                    return data;
                },
            
                /**
                Applies a schema to an array of data located in a JSON structure, returning
                a normalized object with results in the `results` property. Additional
                information can be parsed out of the JSON for inclusion in the `meta`
                property of the response object.  If an error is encountered during
                processing, an `error` property will be added.
            
                The input _data_ is expected to be an object or array.  If it is a string,
                it will be passed through `Y.JSON.parse()`.
            
                If _data_ contains an array of data records to normalize, specify the
                _schema.resultListLocator_ as a dot separated path string just as you would
                reference it in JavaScript.  So if your _data_ object has a record array at
                _data.response.results_, use _schema.resultListLocator_ =
                "response.results". Bracket notation can also be used for array indices or
                object properties (e.g. "response['results']");  This is called a "path
                locator"
            
                Field data in the result list is extracted with field identifiers in
                _schema.resultFields_.  Field identifiers are objects with the following
                properties:
            
                  * `key`   : <strong>(required)</strong> The path locator (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.
            
                If no value parsing is needed, you can use path locators (strings)
                instead of field identifiers (objects) -- see example below.
            
                If no processing of the result list array is needed, _schema.resultFields_
                can be omitted; the `response.results` will point directly to the array.
            
                If the result list contains arrays, `response.results` will contain an
                array of objects with key:value pairs assuming the fields in
                _schema.resultFields_ are ordered in accordance with the data array
                values.
            
                If the result list contains objects, the identified _schema.resultFields_
                will be used to extract a value from those objects for the output result.
            
                To extract additional information from the JSON, include an array of
                path locators in _schema.metaFields_.  The collected values will be
                stored in `response.meta`.
            
            
                @example
                    // Process array of arrays
                    var schema = {
                            resultListLocator: 'produce.fruit',
                            resultFields: [ 'name', 'color' ]
                        },
                        data = {
                            produce: {
                                fruit: [
                                    [ 'Banana', 'yellow' ],
                                    [ 'Orange', 'orange' ],
                                    [ 'Eggplant', 'purple' ]
                                ]
                            }
                        };
            
                    var response = Y.DataSchema.JSON.apply(schema, data);
            
                    // response.results[0] is { name: "Banana", color: "yellow" }
            
            
                    // Process array of objects + some metadata
                    schema.metaFields = [ 'lastInventory' ];
            
                    data = {
                        produce: {
                            fruit: [
                                { name: 'Banana', color: 'yellow', price: '1.96' },
                                { name: 'Orange', color: 'orange', price: '2.04' },
                                { name: 'Eggplant', color: 'purple', price: '4.31' }
                            ]
                        },
                        lastInventory: '2011-07-19'
                    };
            
                    response = Y.DataSchema.JSON.apply(schema, data);
            
                    // response.results[0] is { name: "Banana", color: "yellow" }
                    // response.meta.lastInventory is '2001-07-19'
            
            
                    // Use parsers
                    schema.resultFields = [
                        {
                            key: 'name',
                            parser: function (val) { return val.toUpperCase(); }
                        },
                        {
                            key: 'price',
                            parser: 'number' // Uses Y.Parsers.number
                        }
                    ];
            
                    response = Y.DataSchema.JSON.apply(schema, data);
            
                    // Note price was converted from a numeric string to a number
                    // response.results[0] looks like { fruit: "BANANA", price: 1.96 }
            
                @method apply
                @param {Object} [schema] Schema to apply.  Supported configuration
                    properties are:
                  @param {String} [schema.resultListLocator] Path locator for the
                      location of the array of records 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] Path locators to extract extra
                      non-record related information from the data object.
                @param {Object|Array|String} data JSON data or its string serialization.
                @return {Object} An Object with properties `results` and `meta`
                @static
                **/
                apply: function(schema, data) {
                    var data_in = data,
                        data_out = { results: [], meta: {} };
            
                    // Convert incoming JSON strings
                    if (!isObject(data)) {
                        try {
                            data_in = Y.JSON.parse(data);
                        }
                        catch(e) {
                            data_out.error = e;
                            return data_out;
                        }
                    }
            
                    if (isObject(data_in) && schema) {
                        // Parse results data
                        data_out = SchemaJSON._parseResults.call(this, schema, data_in, data_out);
            
                        // Parse meta data
                        if (schema.metaFields !== undefined) {
                            data_out = SchemaJSON._parseMeta(schema.metaFields, data_in, data_out);
                        }
                    }
                    else {
                        Y.log("JSON data could not be schema-parsed: " + Y.dump(data) + " " + Y.dump(data), "error", "dataschema-json");
                        data_out.error = new Error("JSON schema parse failure");
                    }
            
                    return data_out;
                },
            
                /**
                 * Schema-parsed list of results from full data
                 *
                 * @method _parseResults
                 * @param schema {Object} Schema to parse against.
                 * @param json_in {Object} JSON to parse.
                 * @param data_out {Object} In-progress parsed data to update.
                 * @return {Object} Parsed data object.
                 * @static
                 * @protected
                 */
                _parseResults: function(schema, json_in, data_out) {
                    var getPath  = SchemaJSON.getPath,
                        getValue = SchemaJSON.getLocationValue,
                        path     = getPath(schema.resultListLocator),
                        results  = path ?
                                    (getValue(path, json_in) ||
                                     // Fall back to treat resultListLocator as a simple key
                                        json_in[schema.resultListLocator]) :
                                    // Or if no resultListLocator is supplied, use the input
                                    json_in;
            
                    if (isArray(results)) {
                        // if no result fields are passed in, then just take
                        // the results array whole-hog Sometimes you're getting
                        // an array of strings, or want the whole object, so
                        // resultFields don't make sense.
                        if (isArray(schema.resultFields)) {
                            data_out = SchemaJSON._getFieldValues.call(this, schema.resultFields, results, data_out);
                        } else {
                            data_out.results = results;
                        }
                    } else if (schema.resultListLocator) {
                        data_out.results = [];
                        data_out.error = new Error("JSON results retrieval failure");
                        Y.log("JSON data could not be parsed: " + Y.dump(json_in), "error", "dataschema-json");
                    }
            
                    return data_out;
                },
            
                /**
                 * Get field data values out of list of full results
                 *
                 * @method _getFieldValues
                 * @param fields {Array} Fields to find.
                 * @param array_in {Array} Results to parse.
                 * @param data_out {Object} In-progress parsed data to update.
                 * @return {Object} Parsed data object.
                 * @static
                 * @protected
                 */
                _getFieldValues: function(fields, array_in, data_out) {
                    var results = [],
                        len = fields.length,
                        i, j,
                        field, key, locator, path, parser, val,
                        simplePaths = [], complexPaths = [], fieldParsers = [],
                        result, record;
            
                    // First collect hashes of simple paths, complex paths, and parsers
                    for (i=0; i<len; i++) {
                        field = fields[i]; // A field can be a simple string or a hash
                        key = field.key || field; // Find the key
                        locator = field.locator || key; // Find the locator
            
                        // Validate and store locators for later
                        path = SchemaJSON.getPath(locator);
                        if (path) {
                            if (path.length === 1) {
                                simplePaths.push({
                                    key : key,
                                    path: path[0]
                                });
                            } else {
                                complexPaths.push({
                                    key    : key,
                                    path   : path,
                                    locator: locator
                                });
                            }
                        } else {
                            Y.log("Invalid key syntax: " + key, "warn", "dataschema-json");
                        }
            
                        // Validate and store parsers for later
                        //TODO: use Y.DataSchema.parse?
                        parser = (isFunction(field.parser)) ?
                                    field.parser :
                                    Y.Parsers[field.parser + ''];
            
                        if (parser) {
                            fieldParsers.push({
                                key   : key,
                                parser: parser
                            });
                        }
                    }
            
                    // Traverse list of array_in, creating records of simple fields,
                    // complex fields, and applying parsers as necessary
                    for (i=array_in.length-1; i>=0; --i) {
                        record = {};
                        result = array_in[i];
                        if(result) {
                            // Cycle through complexLocators
                            for (j=complexPaths.length - 1; j>=0; --j) {
                                path = complexPaths[j];
                                val = SchemaJSON.getLocationValue(path.path, result);
                                if (val === undefined) {
                                    val = SchemaJSON.getLocationValue([path.locator], result);
                                    // Fail over keys like "foo.bar" from nested parsing
                                    // to single token parsing if a value is found in
                                    // results["foo.bar"]
                                    if (val !== undefined) {
                                        simplePaths.push({
                                            key:  path.key,
                                            path: path.locator
                                        });
                                        // Don't try to process the path as complex
                                        // for further results
                                        complexPaths.splice(i,1);
                                        continue;
                                    }
                                }
            
                                record[path.key] = Base.parse.call(this,
                                    (SchemaJSON.getLocationValue(path.path, result)), path);
                            }
            
                            // Cycle through simpleLocators
                            for (j = simplePaths.length - 1; j >= 0; --j) {
                                path = simplePaths[j];
                                // Bug 1777850: The result might be an array instead of object
                                record[path.key] = Base.parse.call(this,
                                        ((result[path.path] === undefined) ?
                                        result[j] : result[path.path]), path);
                            }
            
                            // Cycle through fieldParsers
                            for (j=fieldParsers.length-1; j>=0; --j) {
                                key = fieldParsers[j].key;
                                record[key] = fieldParsers[j].parser.call(this, record[key]);
                                // Safety net
                                if (record[key] === undefined) {
                                    record[key] = null;
                                }
                            }
                            results[i] = record;
                        }
                    }
                    data_out.results = results;
                    return data_out;
                },
            
                /**
                 * Parses results data according to schema
                 *
                 * @method _parseMeta
                 * @param metaFields {Object} Metafields definitions.
                 * @param json_in {Object} JSON to parse.
                 * @param data_out {Object} In-progress parsed data to update.
                 * @return {Object} Schema-parsed meta data.
                 * @static
                 * @protected
                 */
                _parseMeta: function(metaFields, json_in, data_out) {
                    if (isObject(metaFields)) {
                        var key, path;
                        for(key in metaFields) {
                            if (metaFields.hasOwnProperty(key)) {
                                path = SchemaJSON.getPath(metaFields[key]);
                                if (path && json_in) {
                                    data_out.meta[key] = SchemaJSON.getLocationValue(path, json_in);
                                }
                            }
                        }
                    }
                    else {
                        data_out.error = new Error("JSON meta data retrieval failure");
                    }
                    return data_out;
                }
            };
            
            // TODO: Y.Object + mix() might be better here
            Y.DataSchema.JSON = Y.mix(SchemaJSON, Base);