/**
* Provides a DataSchema implementation which can be used to work with JSON data.
*
* @module dataschema
* @submodule dataschema-json
*/
/**
* JSON subclass for the DataSchema Utility.
* @class DataSchema.JSON
* @extends DataSchema.Base
* @static
*/
var LANG = Y.Lang,
SchemaJSON = {
/////////////////////////////////////////////////////////////////////////////
//
// DataSchema.JSON static methods
//
/////////////////////////////////////////////////////////////////////////////
/**
* Utility function converts JSON locator strings into walkable paths
*
* @method DataSchema.JSON.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
locator = locator.
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", "dataschema-json");
}
}
return path;
},
/**
* Utility function to walk a path and return the value located there.
*
* @method DataSchema.JSON.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(!LANG.isUndefined(data[path[i]])) {
data = data[path[i]];
}
else {
data = undefined;
break;
}
}
return data;
},
/**
* Applies a given schema to given JSON data.
*
* @method apply
* @param schema {Object} Schema to apply.
* @param data {Object} JSON data.
* @return {Object} Schema-parsed data.
* @static
*/
apply: function(schema, data) {
var data_in = data,
data_out = {results:[],meta:{}};
// Convert incoming JSON strings
if(!LANG.isObject(data)) {
try {
data_in = Y.JSON.parse(data);
}
catch(e) {
data_out.error = e;
return data_out;
}
}
if(LANG.isObject(data_in) && schema) {
// Parse results data
if(!LANG.isUndefined(schema.resultListLocator)) {
data_out = SchemaJSON._parseResults(schema, data_in, data_out);
}
// Parse meta data
if(!LANG.isUndefined(schema.metaFields)) {
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 results = [],
path,
error;
if(schema.resultListLocator) {
path = SchemaJSON.getPath(schema.resultListLocator);
if(path) {
results = SchemaJSON.getLocationValue(path, json_in);
if (results === undefined) {
data_out.results = [];
error = new Error("JSON results retrieval failure");
}
else {
if(LANG.isArray(schema.resultFields) && LANG.isArray(results)) {
data_out = SchemaJSON._getFieldValues(schema.resultFields, results, data_out);
}
else {
data_out.results = [];
error = new Error("JSON Schema fields retrieval failure");
}
}
}
else {
error = new Error("JSON Schema results locator failure");
}
if (error) {
Y.log("JSON data could not be parsed: " + Y.dump(json_in), "error", "dataschema-json");
data_out.error = error;
}
}
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, 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 = SchemaJSON.getPath(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", "dataschema-json");
}
// Validate and store parsers for later
//TODO: use Y.DataSchema.parse?
parser = (LANG.isFunction(field.parser)) ? field.parser : Y.Parsers[field.parser+''];
if (parser) {
fieldParsers[fieldParsers.length] = {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 simpleLocators
for (j=simplePaths.length-1; j>=0; --j) {
// Bug 1777850: The result might be an array instead of object
record[simplePaths[j].key] = Y.DataSchema.Base.parse(
(LANG.isUndefined(result[simplePaths[j].path]) ?
result[j] : result[simplePaths[j].path]), simplePaths[j]);
}
// Cycle through complexLocators
for (j=complexPaths.length - 1; j>=0; --j) {
record[complexPaths[j].key] = Y.DataSchema.Base.parse(
(SchemaJSON.getLocationValue(complexPaths[j].path, result)), complexPaths[j] );
}
// 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;
}
}
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(LANG.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;
}
};
Y.DataSchema.JSON = Y.mix(SchemaJSON, Y.DataSchema.Base);