dataparser-json.js revision 3ab1d84918e2599d8b7cae1fd6632c311c808774
/**
* The DataParser utility provides a common configurable interface for widgets to
* parse a variety of data against a given schema.
*
* @module dataparser
*/
/**
* JSON subclass for the YUI DataParser utility.
* @class DataParser.JSON
* @extends DataParser.Base
* @static
*/
DPJSON = {
/////////////////////////////////////////////////////////////////////////////
//
// DataParser.JSON static methods
//
/////////////////////////////////////////////////////////////////////////////
/**
* Utility function converts JSON locator strings into walkable paths
*
* @method DataParser.JSON.buildPath
* @param locator {String} JSON value locator.
* @return {String[]} Walkable path to data value.
* @static
*/
var path = null,
keys = [],
i = 0;
if (locator) {
// Strip the ["string keys"] and [1] array indexes
replace(/\[(['"])(.*?)\1\]/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.
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", this.toString());
}
}
return path;
},
/**
* Utility function to walk a path and return the value located there.
*
* @method DataParser.JSON.walkPath
* @param path {String[]} Locator path.
* @param data {String} Data to traverse.
* @return {Object} Data value at location.
* @static
*/
walkPath: function (path, data) {
var i = 0,
len = path.length;
for (;i<len;i++) {
data = data[path[i]];
}
return data;
},
/**
* Overriding parse method traverses JSON data according to given schema.
*
* @method _parse
* @param schema {Object} Schema to parse against.
* @param data {Object} Data to parse.
* @return {Object} Schema-parsed data.
* @static
* @protected
*/
_parse: function(schema, data) {
var data_in = (data.responseText && Y.JSON.parse(data.responseText)) || data,
data_out = {results:[],meta:{}};
if(LANG.isObject(data_in) && schema) {
// Parse results data
data_out = this._parseResults(schema, data_in, data_out);
// Parse meta data
if(LANG.isObject(schema.metaFields)) {
data_out = this._parseMeta(schema.metaFields, data_in, data_out);
}
}
else {
Y.log("JSON data could not be parsed: " + Y.dump(data_in), "error", this.toString());
data_out.error = true;
}
return data_out;
},
/**
* Schema-parsed list of results from full data
*
* @method _parseResults
* @param data_out {Object} Data to parse.
* @param data_in {Object} In-progress parsed data to update.
* @return {Array} Array of results.
* @static
* @protected
*/
_parseResults: function(schema, data_in, data_out) {
if(schema.resultsList) {
var bError = false,
results = [],
path;
path = DPJSON.buildPath(schema.resultsList);
if(path) {
results = DPJSON.walkPath(path, data_in);
if (results === undefined) {
bError = true;
}
else {
if(LANG.isArray(schema.fields)) {
if(LANG.isArray(schema.fields)) {
results = this._filterFieldValues(schema.fields, results);
}
else {
bError = true;
}
}
}
}
else {
bError = true;
}
if (bError) {
Y.log("JSON data could not be parsed: " + Y.dump(data_in), "error", this.toString());
data_out.error = true;
}
data_out.results = results;
}
return data_out;
},
/**
* Schema-parse field data out of list of full results
*
* @method _filterFieldValues
* @param fields {Array} Fields to filter against.
* @param results {Array} Results data to parse.
* @return {Array} Array of field-filtered results.
* @static
* @protected
*/
_filterFieldValues: function(fields, results) {
var data_out = [],
len = fields.length,
i, j,
field, key, path, parser,
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
// Validate and store locators for later
path = DPJSON.buildPath(key);
if (path) {
if (path.length === 1) {
simplePaths[simplePaths.length] = {key:key, path:path[0]};
} else {
complexPaths[complexPaths.length] = {key:key, path:path};
}
} else {
Y.log("Invalid key syntax: " + key, "warn", this.toString());
}
// Validate and store parsers for later
parser = (LANG.isFunction(field.parser)) ? field.parser : Y.DataParser[field.parser+''];
if (parser) {
fieldParsers[fieldParsers.length] = {key:key, parser:parser};
}
}
// Traverse list of results, creating records of simple fields,
// complex fields, and applying parsers as necessary
for (i=results.length-1; i>=0; --i) {
record = {};
result = results[i];
if(result) {
// Cycle through simpleLocators
for (j=simplePaths.length-1; j>=0; --j) {
// Bug 1777850: The result might be an array instead of object
record[simplePaths[j].key] =
LANG.isUndefined(result[simplePaths[j].path]) ?
result[j] : result[simplePaths[j].path];
}
// Cycle through complexLocators
for (j=complexPaths.length - 1; j>=0; --j) {
record[complexPaths[j].key] = DPJSON.walkPath(complexPaths[j].path, result);
}
// Cycle through fieldParsers
for (j=fieldParsers.length-1; j>=0; --j) {
key = fieldParsers[j].key;
record[key] = fieldParsers[j].parser(record[key]);
// Safety net
if (LANG.isUndefined(record[key])) {
record[key] = null;
}
}
}
data_out[i] = record;
}
return data_out;
},
/**
* Parses results data according to schema
*
* @method _parseMeta
* @param data_out {Object} Data to parse.
* @param data_in {Object} In-progress parsed data to update.
* @return {Object} Schema-parsed meta data.
* @static
* @protected
*/
_parseMeta: function(metaFields, data_in, data_out) {
var key, path;
for(key in metaFields) {
if (metaFields.hasOwnProperty(key)) {
path = DPJSON.buildPath(metaFields[key]);
if (path && data_in) {
data_out.meta[key] = DPJSON.walkPath(path, data_in);
}
}
}
return data_out;
}
};
Y.mix(DPJSON, Y.DataParser.Base);
Y.DataParser.JSON = DPJSON;