dataparser-json.js revision 9eb0c723ed90ba9c691cd35c025115b361da3eb4
/**
* The DataParser utility provides a common configurable interface for widgets to
* parse a variety of data against a given schema.
*
* @module dataparser-json
* @requires json, dataparser-base
* @title DataParser JSON Submodule
*/
/**
* JSON subclass for the YUI DataParser utility.
* @class DataParser.JSON
* @extends DataParser.Base
* @constructor
*/
JSON = function() {
};
/////////////////////////////////////////////////////////////////////////////
//
// DataParser.JSON static properties
//
/////////////////////////////////////////////////////////////////////////////
/**
* Class name.
*
* @property NAME
* @type String
* @static
* @final
* @value "DataParser.JSON"
*/
NAME: "DataParser.JSON",
/////////////////////////////////////////////////////////////////////////////
//
// DataSource.XHR Attributes
//
/////////////////////////////////////////////////////////////////////////////
ATTRS: {
/**
* @attribute schema
* @description Object literal schema definition:
<dl>
<dt>resultsList {String}</dt>
<dd>Pointer to array of tabular data</dd>
<dt>fields {String[] | Object []}</dt>
<dd>Array of field names (aka keys), or array of object literals such as:
{key:"fieldname", parser:Date.parse}</dd>
<dt>metaFields {Object}</dt>
<dd>Hash of field names (aka keys) to include in the
oParsedResponse.meta collection</dd>
</dl>
* @type Object
* @default {}
*/
schema: {
value: {}
}
}
});
/**
* Overriding parse method traverses JSON data according to given schema.
*
* @method _parse
* @protected
* @param e {Event.Facade} Custom Event Facade for requestEvent.
* @param e.data {MIXED} Data to parse.
*/
results = [],
fieldParsers = [],
fieldPaths = [],
simpleFields = [],
bError = false,
// Function to convert the schema's fields into walk paths
if (needle) {
// 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
// If the cleaned needle contains invalid characters, the
// path is invalid
if (!/[^\w\.\$@]/.test(needle)) {
path = needle.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: " + needle, "error", this.toString());
}
}
return path;
};
// Function to walk a path and return the pot of gold
var walkPath = function (path, origin) {
var v=origin,i=0,len=path.length;
for (;i<len && v;++i) {
v = v[path[i]];
}
return v;
};
// Parse the response
// Step 1. Pull the resultsList from data_in (default assumes
// data_in IS the resultsList)
path = buildPath(schema.resultsList);
if (path) {
resultsList = walkPath(path, data_in);
if (resultsList === undefined) {
bError = true;
}
} else {
bError = true;
}
if (!resultsList) {
resultsList = [];
}
if (!LANG.isArray(resultsList)) {
resultsList = [resultsList];
}
if (!bError) {
// Step 2. Parse out field data if identified
if(schema.fields) {
var field;
// Build the field parser map and location paths
for (i=0, len=fields.length; i<len; i++) {
field = fields[i];
key = field.key || field;
parser = ((typeof field.parser === 'function') ?
field.parser :
Y.DataParser[field.parser+'']) || field.converter;
path = buildPath(key);
if (parser) {
fieldParsers[fieldParsers.length] = {key:key,parser:parser};
}
if (path) {
if (path.length > 1) {
fieldPaths[fieldPaths.length] = {key:key,path:path};
} else {
simpleFields[simpleFields.length] = {key:key,path:path[0]};
}
} else {
Y.log("Invalid key syntax: " + key,"warn",this.toString());
}
}
for (i = resultsList.length - 1; i >= 0; --i) {
var r = resultsList[i], rec = {};
if(r) {
for (j = simpleFields.length - 1; j >= 0; --j) {
// Bug 1777850: data might be held in an array
rec[simpleFields[j].key] =
(r[simpleFields[j].path] !== undefined) ?
r[simpleFields[j].path] : r[j];
}
for (j = fieldPaths.length - 1; j >= 0; --j) {
rec[fieldPaths[j].key] = walkPath(fieldPaths[j].path,r);
}
for (j = fieldParsers.length - 1; j >= 0; --j) {
var p = fieldParsers[j].key;
rec[p] = fieldParsers[j].parser(rec[p]);
if (rec[p] === undefined) {
rec[p] = null;
}
}
}
results[i] = rec;
}
}
else {
results = resultsList;
}
// Step 3. Parse out meta data if identified
for (key in metaFields) {
if (LANG.hasOwnProperty(metaFields,key)) {
path = buildPath(metaFields[key]);
if (path) {
v = walkPath(path, data_in);
data_out.meta[key] = v;
}
}
}
} else {
Y.log("JSON data could not be parsed: " +
Y.dump(data_in), "error", this.toString());
data_out.error = true;
}
data_out.results = results;
}
else {
Y.log("JSON data could not be parsed: " +
Y.dump(data_in), "error", this.toString());
data_out.error = true;
}
return data_out;
}
});
Y.DataParser.JSON = JSON;