Yahoo! UI Library > datasource > DataSource.js (source view)
/**
* The DataSource utility provides a common configurable interface for widgets
* to access a variety of data, from JavaScript arrays to online servers over
* XHR.
*
* @namespace YAHOO.util
* @module datasource
* @requires yahoo, event
* @optional connection
* @title DataSource Utility
* @beta
*/
/****************************************************************************/
/****************************************************************************/
/****************************************************************************/
/**
* The DataSource class defines and manages a live set of data for widgets to
* interact with. Examples of live databases include in-memory
* local data such as a JavaScript array, a JavaScript function, or JSON, or
* remote data such as data retrieved through an XHR connection.
*
* @class DataSource
* @uses YAHOO.util.EventProvider
* @constructor
* @param oLiveData {Object} Pointer to live database.
* @param oConfigs {Object} (optional) Object literal of configuration values.
*/
YAHOO.util.DataSource = function(oLiveData, oConfigs) {
if(!oLiveData) {
YAHOO.log("Could not instantiate DataSource due to invalid live database",
"error", this.toString());
return;
}
this.liveData = oLiveData;
this._oQueue = {interval:null, conn:null, requests:[]};
if(oLiveData.nodeType && oLiveData.nodeType == 9) {
this.dataType = YAHOO.util.DataSource.TYPE_XML;
}
else if(YAHOO.lang.isArray(oLiveData)) {
this.dataType = YAHOO.util.DataSource.TYPE_JSARRAY;
}
else if(YAHOO.lang.isString(oLiveData)) {
this.dataType = YAHOO.util.DataSource.TYPE_XHR;
}
else if(YAHOO.lang.isFunction(oLiveData)) {
this.dataType = YAHOO.util.DataSource.TYPE_JSFUNCTION;
}
else if(oLiveData.nodeName && (oLiveData.nodeName.toLowerCase() == "table")) {
this.dataType = YAHOO.util.DataSource.TYPE_HTMLTABLE;
this.liveData = oLiveData.cloneNode(true);
}
else if(YAHOO.lang.isObject(oLiveData)) {
this.dataType = YAHOO.util.DataSource.TYPE_JSON;
}
else {
this.dataType = YAHOO.util.DataSource.TYPE_UNKNOWN;
}
// Set any config params passed in to override defaults
if(oConfigs && (oConfigs.constructor == Object)) {
for(var sConfig in oConfigs) {
if(sConfig) {
this[sConfig] = oConfigs[sConfig];
}
}
}
// Validate and initialize public configs
var maxCacheEntries = this.maxCacheEntries;
if(!YAHOO.lang.isNumber(maxCacheEntries) || (maxCacheEntries < 0)) {
maxCacheEntries = 0;
}
// Initialize interval tracker
this._aIntervals = [];
this._sName = "DataSource instance" + YAHOO.util.DataSource._nIndex;
YAHOO.util.DataSource._nIndex++;
YAHOO.log("DataSource initialized", "info", this.toString());
/////////////////////////////////////////////////////////////////////////////
//
// Custom Events
//
/////////////////////////////////////////////////////////////////////////////
/**
* Fired when a request is made to the local cache.
*
* @event cacheRequestEvent
* @param oArgs.request {Object} The request object.
* @param oArgs.callback {Function} The callback function.
* @param oArgs.caller {Object} (deprecated) Use callback.scope.
*/
this.createEvent("cacheRequestEvent");
/**
* Fired when data is retrieved from the local cache.
*
* @event cacheResponseEvent
* @param oArgs.request {Object} The request object.
* @param oArgs.response {Object} The response object.
* @param oArgs.callback {Function} The callback function.
* @param oArgs.caller {Object} (deprecated) Use callback.scope.
* @param oArgs.tId {Number} Transaction ID.
*/
this.createEvent("cacheResponseEvent");
/**
* Fired when a request is sent to the live data source.
*
* @event requestEvent
* @param oArgs.request {Object} The request object.
* @param oArgs.callback {Function} The callback function.
* @param oArgs.caller {Object} (deprecated) Use callback.scope.
*/
this.createEvent("requestEvent");
/**
* Fired when live data source sends response.
*
* @event responseEvent
* @param oArgs.request {Object} The request object.
* @param oArgs.response {Object} The raw response object.
* @param oArgs.callback {Function} The callback function.
* @param oArgs.caller {Object} (deprecated) Use callback.scope.
*/
this.createEvent("responseEvent");
/**
* Fired when response is parsed.
*
* @event responseParseEvent
* @param oArgs.request {Object} The request object.
* @param oArgs.response {Object} The parsed response object.
* @param oArgs.callback {Function} The callback function.
* @param oArgs.caller {Object} (deprecated) Use callback.scope.
*/
this.createEvent("responseParseEvent");
/**
* Fired when response is cached.
*
* @event responseCacheEvent
* @param oArgs.request {Object} The request object.
* @param oArgs.response {Object} The parsed response object.
* @param oArgs.callback {Function} The callback function.
* @param oArgs.caller {Object} (deprecated) Use callback.scope.
*/
this.createEvent("responseCacheEvent");
/**
* Fired when an error is encountered with the live data source.
*
* @event dataErrorEvent
* @param oArgs.request {Object} The request object.
* @param oArgs.callback {Function} The callback function.
* @param oArgs.caller {Object} (deprecated) Use callback.scope.
* @param oArgs.message {String} The error message.
*/
this.createEvent("dataErrorEvent");
/**
* Fired when the local cache is flushed.
*
* @event cacheFlushEvent
*/
this.createEvent("cacheFlushEvent");
};
YAHOO.augment(YAHOO.util.DataSource, YAHOO.util.EventProvider);
/////////////////////////////////////////////////////////////////////////////
//
// Public constants
//
/////////////////////////////////////////////////////////////////////////////
/**
* Type is unknown.
*
* @property TYPE_UNKNOWN
* @type Number
* @final
* @default -1
*/
YAHOO.util.DataSource.TYPE_UNKNOWN = -1;
/**
* Type is a JavaScript Array.
*
* @property TYPE_JSARRAY
* @type Number
* @final
* @default 0
*/
YAHOO.util.DataSource.TYPE_JSARRAY = 0;
/**
* Type is a JavaScript Function.
*
* @property TYPE_JSFUNCTION
* @type Number
* @final
* @default 1
*/
YAHOO.util.DataSource.TYPE_JSFUNCTION = 1;
/**
* Type is hosted on a server via an XHR connection.
*
* @property TYPE_XHR
* @type Number
* @final
* @default 2
*/
YAHOO.util.DataSource.TYPE_XHR = 2;
/**
* Type is JSON.
*
* @property TYPE_JSON
* @type Number
* @final
* @default 3
*/
YAHOO.util.DataSource.TYPE_JSON = 3;
/**
* Type is XML.
*
* @property TYPE_XML
* @type Number
* @final
* @default 4
*/
YAHOO.util.DataSource.TYPE_XML = 4;
/**
* Type is plain text.
*
* @property TYPE_TEXT
* @type Number
* @final
* @default 5
*/
YAHOO.util.DataSource.TYPE_TEXT = 5;
/**
* Type is an HTML TABLE element.
*
* @property TYPE_HTMLTABLE
* @type Number
* @final
* @default 6
*/
YAHOO.util.DataSource.TYPE_HTMLTABLE = 6;
/**
* Error message for invalid dataresponses.
*
* @property ERROR_DATAINVALID
* @type String
* @final
* @default "Invalid data"
*/
YAHOO.util.DataSource.ERROR_DATAINVALID = "Invalid data";
/**
* Error message for null data responses.
*
* @property ERROR_DATANULL
* @type String
* @final
* @default "Null data"
*/
YAHOO.util.DataSource.ERROR_DATANULL = "Null data";
/////////////////////////////////////////////////////////////////////////////
//
// Private variables
//
/////////////////////////////////////////////////////////////////////////////
/**
* Internal class variable to index multiple DataSource instances.
*
* @property DataSource._nIndex
* @type Number
* @private
* @static
*/
YAHOO.util.DataSource._nIndex = 0;
/**
* Internal class variable to assign unique transaction IDs.
*
* @property DataSource._nTransactionId
* @type Number
* @private
* @static
*/
YAHOO.util.DataSource._nTransactionId = 0;
/**
* Name of DataSource instance.
*
* @property _sName
* @type String
* @private
*/
YAHOO.util.DataSource.prototype._sName = null;
/**
* Local cache of data result object literals indexed chronologically.
*
* @property _aCache
* @type Object[]
* @private
*/
YAHOO.util.DataSource.prototype._aCache = null;
/**
* Local queue of request connections, enabled if queue needs to be managed.
*
* @property _oQueue
* @type Object
* @private
*/
YAHOO.util.DataSource.prototype._oQueue = null;
/**
* Array of polling interval IDs that have been enabled, needed to clear all intervals.
*
* @property _aIntervals
* @type Array
* @private
*/
YAHOO.util.DataSource.prototype._aIntervals = null;
/////////////////////////////////////////////////////////////////////////////
//
// Private methods
//
/////////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////
//
// Public member variables
//
/////////////////////////////////////////////////////////////////////////////
/**
* Max size of the local cache. Set to 0 to turn off caching. Caching is
* useful to reduce the number of server connections. Recommended only for data
* sources that return comprehensive results for queries or when stale data is
* not an issue.
*
* @property maxCacheEntries
* @type Number
* @default 0
*/
YAHOO.util.DataSource.prototype.maxCacheEntries = 0;
/**
* Pointer to live database.
*
* @property liveData
* @type Object
*/
YAHOO.util.DataSource.prototype.liveData = null;
/**
* Where the live data is held.
*
* @property dataType
* @type Number
* @default YAHOO.util.DataSource.TYPE_UNKNOWN
*
*/
YAHOO.util.DataSource.prototype.dataType = YAHOO.util.DataSource.TYPE_UNKNOWN;
/**
* Format of response.
*
* @property responseType
* @type Number
* @default YAHOO.util.DataSource.TYPE_UNKNOWN
*/
YAHOO.util.DataSource.prototype.responseType = YAHOO.util.DataSource.TYPE_UNKNOWN;
/**
* Response schema object literal takes a combination of the following properties:
*
* <dl>
* <dt>resultsList</dt> <dd>Pointer to array of tabular data</dd>
* <dt>resultNode</dt> <dd>Pointer to node name of row data (XML data only)</dd>
* <dt>recordDelim</dt> <dd>Record delimiter (text data only)</dd>
* <dt>fieldDelim</dt> <dd>Field delimiter (text data only)</dd>
* <dt>fields</dt> <dd>Array of field names (aka keys), or array of object literals
* such as: {key:"fieldname",parser:YAHOO.util.DataSource.parseDate}</dd>
* <dt>metaFields</dt> <dd>Object literal of keys to include in the oParsedResponse.meta collection</dd>
* <dt>metaNode</dt> <dd>Name of the node under which to search for meta information in XML response data</dd>
* </dl>
*
* @property responseSchema
* @type Object
*/
YAHOO.util.DataSource.prototype.responseSchema = null;
/**
* Alias to YUI Connection Manager, to allow implementers to customize the utility.
*
* @property connMgr
* @type Object
* @default YAHOO.util.Connect
*/
YAHOO.util.DataSource.prototype.connMgr = null;
/**
* If data is accessed over XHR via Connection Manager, this setting defines
* request/response management in the following manner:
* <dl>
* <dt>queueRequests</dt>
* <dd>If a request is already in progress, wait until response is returned
* before sending the next request.</dd>
*
* <dt>cancelStaleRequests</dt>
* <dd>If a request is already in progress, cancel it before sending the next
* request.</dd>
*
* <dt>ignoreStaleResponses</dt>
* <dd>Send all requests, but handle only the response for the most recently
* sent request.</dd>
*
* <dt>allowAll</dt>
* <dd>Send all requests and handle all responses.</dd>
*
* </dl>
*
* @property connXhrMode
* @type String
* @default "allowAll"
*/
YAHOO.util.DataSource.prototype.connXhrMode = "allowAll";
/**
* If data is accessed over XHR via Connection Manager, true if data should be
* sent via POST, otherwise data will be sent via GET.
*
* @property connMethodPost
* @type Boolean
* @default false
*/
YAHOO.util.DataSource.prototype.connMethodPost = false;
/**
* If data is accessed over XHR via Connection Manager, the connection timeout
* defines how many milliseconds the XHR connection will wait for a server
* response. Any non-zero value will enable the Connection utility's
* Auto-Abort feature.
*
* @property connTimeout
* @type Number
* @default 0
*/
YAHOO.util.DataSource.prototype.connTimeout = 0;
/////////////////////////////////////////////////////////////////////////////
//
// Public static methods
//
/////////////////////////////////////////////////////////////////////////////
/**
* Converts data to type String.
*
* @method DataSource.parseString
* @param oData {String | Number | Boolean | Date | Array | Object} Data to parse.
* The special values null and undefined will return null.
* @return {Number} A string, or null.
* @static
*/
YAHOO.util.DataSource.parseString = function(oData) {
// Special case null and undefined
if(!YAHOO.lang.isValue(oData)) {
return null;
}
//Convert to string
var string = oData + "";
// Validate
if(YAHOO.lang.isString(string)) {
return string;
}
else {
YAHOO.log("Could not convert data " + YAHOO.lang.dump(oData) + " to type String", "warn", this.toString());
return null;
}
};
/**
* Converts data to type Number.
*
* @method DataSource.parseNumber
* @param oData {String | Number | Boolean | Null} Data to convert. Beware, null
* returns as 0.
* @return {Number} A number, or null if NaN.
* @static
*/
YAHOO.util.DataSource.parseNumber = function(oData) {
//Convert to number
var number = oData * 1;
// Validate
if(YAHOO.lang.isNumber(number)) {
return number;
}
else {
YAHOO.log("Could not convert data " + YAHOO.lang.dump(oData) + " to type Number", "warn", this.toString());
return null;
}
};
// Backward compatibility
YAHOO.util.DataSource.convertNumber = function(oData) {
YAHOO.log("The method YAHOO.util.DataSource.convertNumber() has been" +
" deprecated in favor of YAHOO.util.DataSource.parseNumber()", "warn",
this.toString());
return YAHOO.util.DataSource.parseNumber(oData);
};
/**
* Converts data to type Date.
*
* @method DataSource.parseDate
* @param oData {Date | String | Number} Data to convert.
* @return {Date} A Date instance.
* @static
*/
YAHOO.util.DataSource.parseDate = function(oData) {
var date = null;
//Convert to date
if(!(oData instanceof Date)) {
date = new Date(oData);
}
else {
return oData;
}
// Validate
if(date instanceof Date) {
return date;
}
else {
YAHOO.log("Could not convert data " + YAHOO.lang.dump(oData) + " to type Date", "warn", this.toString());
return null;
}
};
// Backward compatibility
YAHOO.util.DataSource.convertDate = function(oData) {
YAHOO.log("The method YAHOO.util.DataSource.convertDate() has been" +
" deprecated in favor of YAHOO.util.DataSource.parseDate()", "warn",
this.toString());
return YAHOO.util.DataSource.parseDate(oData);
};
/////////////////////////////////////////////////////////////////////////////
//
// Public methods
//
/////////////////////////////////////////////////////////////////////////////
/**
* Public accessor to the unique name of the DataSource instance.
*
* @method toString
* @return {String} Unique name of the DataSource instance.
*/
YAHOO.util.DataSource.prototype.toString = function() {
return this._sName;
};
/**
* Overridable method passes request to cache and returns cached response if any,
* refreshing the hit in the cache as the newest item. Returns null if there is
* no cache hit.
*
* @method getCachedResponse
* @param oRequest {Object} Request object.
* @param oCallback {Function} Handler function to receive the response.
* @param oCaller {Object} The Calling object that is making the request.
* @return {Object} Cached response object or null.
*/
YAHOO.util.DataSource.prototype.getCachedResponse = function(oRequest, oCallback, oCaller) {
var aCache = this._aCache;
// If cache is enabled...
if(this.maxCacheEntries > 0) {
// Initialize local cache
if(!aCache) {
this._aCache = [];
YAHOO.log("Cache initialized", "info", this.toString());
}
// Look in local cache
else {
var nCacheLength = aCache.length;
if(nCacheLength > 0) {
var oResponse = null;
this.fireEvent("cacheRequestEvent", {request:oRequest,callback:oCallback,caller:oCaller});
// Loop through each cached element
for(var i = nCacheLength-1; i >= 0; i--) {
var oCacheElem = aCache[i];
// Defer cache hit logic to a public overridable method
if(this.isCacheHit(oRequest,oCacheElem.request)) {
// The cache returned a hit!
// Grab the cached response
oResponse = oCacheElem.response;
this.fireEvent("cacheResponseEvent", {request:oRequest,response:oResponse,callback:oCallback,caller:oCaller});
// Refresh the position of the cache hit
if(i < nCacheLength-1) {
YAHOO.log("Refreshing cache position of the response for \"" + oRequest + "\"", "info", this.toString());
// Remove element from its original location
aCache.splice(i,1);
YAHOO.log("Cleared from cache the response for \"" + oRequest + "\"", "info", this.toString());
// Add as newest
this.addToCache(oRequest, oResponse);
}
break;
}
}
YAHOO.log("The cached response for \"" + YAHOO.lang.dump(oRequest) +
"\" is " + YAHOO.lang.dump(oResponse), "info", this.toString());
return oResponse;
}
}
}
else if(aCache) {
this._aCache = null;
YAHOO.log("Cache destroyed", "info", this.toString());
}
return null;
};
/**
* Default overridable method matches given request to given cached request.
* Returns true if is a hit, returns false otherwise. Implementers should
* override this method to customize the cache-matching algorithm.
*
* @method isCacheHit
* @param oRequest {Object} Request object.
* @param oCachedRequest {Object} Cached request object.
* @return {Boolean} True if given request matches cached request, false otherwise.
*/
YAHOO.util.DataSource.prototype.isCacheHit = function(oRequest, oCachedRequest) {
return (oRequest === oCachedRequest);
};
/**
* Adds a new item to the cache. If cache is full, evicts the stalest item
* before adding the new item.
*
* @method addToCache
* @param oRequest {Object} Request object.
* @param oResponse {Object} Response object to cache.
*/
YAHOO.util.DataSource.prototype.addToCache = function(oRequest, oResponse) {
var aCache = this._aCache;
if(!aCache) {
return;
}
// If the cache is full, make room by removing stalest element (index=0)
while(aCache.length >= this.maxCacheEntries) {
aCache.shift();
}
// Add to cache in the newest position, at the end of the array
var oCacheElem = {request:oRequest,response:oResponse};
aCache[aCache.length] = oCacheElem;
this.fireEvent("responseCacheEvent", {request:oRequest,response:oResponse});
YAHOO.log("Cached the response for \"" + oRequest + "\"", "info", this.toString());
};
/**
* Flushes cache.
*
* @method flushCache
*/
YAHOO.util.DataSource.prototype.flushCache = function() {
if(this._aCache) {
this._aCache = [];
this.fireEvent("cacheFlushEvent");
YAHOO.log("Flushed the cache", "info", this.toString());
}
};
/**
* Sets up a polling mechanism to send requests at set intervals and forward
* responses to given callback.
*
* @method setInterval
* @param nMsec {Number} Length of interval in milliseconds.
* @param oRequest {Object} Request object.
* @param oCallback {Function} Handler function to receive the response.
* @param oCaller {Object} (deprecated) Use oCallback.scope.
* @return {Number} Interval ID.
*/
YAHOO.util.DataSource.prototype.setInterval = function(nMsec, oRequest, oCallback, oCaller) {
if(YAHOO.lang.isNumber(nMsec) && (nMsec >= 0)) {
YAHOO.log("Enabling polling to live data for \"" + oRequest + "\" at interval " + nMsec, "info", this.toString());
var oSelf = this;
var nId = setInterval(function() {
oSelf.makeConnection(oRequest, oCallback, oCaller);
}, nMsec);
this._aIntervals.push(nId);
return nId;
}
else {
YAHOO.log("Could not enable polling to live data for \"" + oRequest + "\" at interval " + nMsec, "info", this.toString());
}
};
/**
* Disables polling mechanism associated with the given interval ID.
*
* @method clearInterval
* @param nId {Number} Interval ID.
*/
YAHOO.util.DataSource.prototype.clearInterval = function(nId) {
// Remove from tracker if there
var tracker = this._aIntervals || [];
for(var i=tracker.length-1; i>-1; i--) {
if(tracker[i] === nId) {
tracker.splice(i,1);
clearInterval(nId);
}
}
};
/**
* Disables all known polling intervals.
*
* @method clearAllIntervals
*/
YAHOO.util.DataSource.prototype.clearAllIntervals = function(nId) {
var tracker = this._aIntervals || [];
for(var i=tracker.length-1; i>-1; i--) {
tracker.splice(i,1);
clearInterval(nId);
}
};
/**
* Executes a configured callback. For object literal callbacks, the third
* param determines whether to execute the success handler or failure handler.
* @method issueCallback
* @param callback {Function|Object} the callback to execute
* @param params {Array} params to be passed to the callback method
* @param error {Boolean} whether an error occurred
* @param scope {Object} the scope from which to execute the callback
* (deprecated - use an object literal callback)
*/
YAHOO.util.DataSource.issueCallback = function (callback,params,error,scope) {
if (YAHOO.lang.isFunction(callback)) {
callback.apply(scope, params);
} else if (YAHOO.lang.isObject(callback)) {
scope = callback.scope || scope || window;
var callbackFunc = callback.success;
if (error) {
callbackFunc = callback.failure;
}
if (callbackFunc) {
callbackFunc.apply(scope, params.concat([callback.argument]));
}
}
};
/**
* First looks for cached response, then sends request to live data.
*
* @method sendRequest
* @param oRequest {Object} Request object.
* @param oCallback {Object} An object literal with the following properties:
* <dl>
* <dt><code>success</code></dt>
* <dd>The function to call when the data is ready.</dd>
* <dt><code>failure</code></dt>
* <dd>The function to call upon a response failure condition.</dd>
* <dt><code>scope</code></dt>
* <dd>The object to serve as the scope for the success and failure handlers.</dd>
* <dt><code>argument</code></dt>
* <dd>Arbitrary data that will be passed back to the success and failure handlers.</dd>
* </dl>
* @param oCaller {Object} (deprecated) Use oCallback.scope.
* @return {Number} Transaction ID, or null if response found in cache.
*/
YAHOO.util.DataSource.prototype.sendRequest = function(oRequest, oCallback, oCaller) {
// First look in cache
var oCachedResponse = this.getCachedResponse(oRequest, oCallback, oCaller);
if(oCachedResponse) {
YAHOO.util.DataSource.issueCallback(oCallback,[oRequest,oCachedResponse],false,oCaller);
return null;
}
// Not in cache, so forward request to live data
YAHOO.log("Making connection to live data for \"" + oRequest + "\"", "info", this.toString());
return this.makeConnection(oRequest, oCallback, oCaller);
};
/**
* Overridable method provides default functionality to make a connection to
* live data in order to send request. The response coming back is then
* forwarded to the handleResponse function. This method should be customized
* to achieve more complex implementations.
*
* @method makeConnection
* @param oRequest {Object} Request object.
* @param oCallback {Object} Callback object literal.
* @param oCaller {Object} (deprecated) Use oCallback.scope.
* @return {Number} Transaction ID.
*/
YAHOO.util.DataSource.prototype.makeConnection = function(oRequest, oCallback, oCaller) {
this.fireEvent("requestEvent", {request:oRequest,callback:oCallback,caller:oCaller});
var oRawResponse = null;
var tId = YAHOO.util.DataSource._nTransactionId++;
// How to make the connection depends on the type of data
switch(this.dataType) {
// If the live data is a JavaScript Function
// pass the request in as a parameter and
// forward the return value to the handler
case YAHOO.util.DataSource.TYPE_JSFUNCTION:
oRawResponse = this.liveData(oRequest);
this.handleResponse(oRequest, oRawResponse, oCallback, oCaller, tId);
break;
// If the live data is over Connection Manager
// set up the callback object and
// pass the request in as a URL query and
// forward the response to the handler
case YAHOO.util.DataSource.TYPE_XHR:
var oSelf = this;
var oConnMgr = this.connMgr || YAHOO.util.Connect;
var oQueue = this._oQueue;
/**
* Define Connection Manager success handler
*
* @method _xhrSuccess
* @param oResponse {Object} HTTPXMLRequest object
* @private
*/
var _xhrSuccess = function(oResponse) {
// If response ID does not match last made request ID,
// silently fail and wait for the next response
if(oResponse && (this.connXhrMode == "ignoreStaleResponses") &&
(oResponse.tId != oQueue.conn.tId)) {
YAHOO.log("Ignored stale response", "warn", this.toString());
return null;
}
// Error if no response
else if(!oResponse) {
this.fireEvent("dataErrorEvent", {request:oRequest,
callback:oCallback, caller:oCaller,
message:YAHOO.util.DataSource.ERROR_DATANULL});
YAHOO.log(YAHOO.util.DataSource.ERROR_DATANULL, "error", this.toString());
// Send error response back to the caller with the error flag on
// TODO: should this send oResponse, considering the fork?
YAHOO.util.DataSource.issueCallback(oCallback,[oRequest, {error:true}], true, oCaller);
return null;
}
// Forward to handler
else {
this.handleResponse(oRequest, oResponse, oCallback, oCaller, tId);
}
};
/**
* Define Connection Manager failure handler
*
* @method _xhrFailure
* @param oResponse {Object} HTTPXMLRequest object
* @private
*/
var _xhrFailure = function(oResponse) {
this.fireEvent("dataErrorEvent", {request:oRequest,
callback:oCallback, caller:oCaller,
message:YAHOO.util.DataSource.ERROR_DATAINVALID});
YAHOO.log(YAHOO.util.DataSource.ERROR_DATAINVALID + ": " +
oResponse.statusText, "error", this.toString());
// Backward compatibility
if((this.liveData.lastIndexOf("?") !== this.liveData.length-1) &&
(oRequest.indexOf("?") !== 0)){
YAHOO.log("DataSources using XHR no longer supply a \"?\"" +
" between the host and query parameters" +
" -- please check that the request URL is correct", "warn", this.toString());
}
// Send failure response back to the caller with the error flag on
oResponse = oResponse || {};
oResponse.error = true;
YAHOO.util.DataSource.issueCallback(oCallback,[oRequest,oResponse],true, oCaller);
return null;
};
/**
* Define Connection Manager callback object
*
* @property _xhrCallback
* @param oResponse {Object} HTTPXMLRequest object
* @private
*/
var _xhrCallback = {
success:_xhrSuccess,
failure:_xhrFailure,
scope: this
};
// Apply Connection Manager timeout
if(YAHOO.lang.isNumber(this.connTimeout)) {
_xhrCallback.timeout = this.connTimeout;
}
// Cancel stale requests
if(this.connXhrMode == "cancelStaleRequests") {
// Look in queue for stale requests
if(oQueue.conn) {
if(oConnMgr.abort) {
oConnMgr.abort(oQueue.conn);
oQueue.conn = null;
YAHOO.log("Canceled stale request", "warn", this.toString());
}
else {
YAHOO.log("Could not find Connection Manager abort() function", "error", this.toString());
}
}
}
// Get ready to send the request URL
if(oConnMgr && oConnMgr.asyncRequest) {
var sLiveData = this.liveData;
var isPost = this.connMethodPost;
var sMethod = (isPost) ? "POST" : "GET";
var sUri = (isPost) ? sLiveData : sLiveData+oRequest;
var sRequest = (isPost) ? oRequest : null;
// Send the request right away
if(this.connXhrMode != "queueRequests") {
oQueue.conn = oConnMgr.asyncRequest(sMethod, sUri, _xhrCallback, sRequest);
}
// Queue up then send the request
else {
// Found a request already in progress
if(oQueue.conn) {
// Add request to queue
oQueue.requests.push({request:oRequest, callback:_xhrCallback});
// Interval needs to be started
if(!oQueue.interval) {
oQueue.interval = setInterval(function() {
// Connection is in progress
if(oConnMgr.isCallInProgress(oQueue.conn)) {
return;
}
else {
// Send next request
if(oQueue.requests.length > 0) {
sUri = (isPost) ? sLiveData : sLiveData+oQueue.requests[0].request;
sRequest = (isPost) ? oQueue.requests[0].request : null;
oQueue.conn = oConnMgr.asyncRequest(sMethod, sUri, oQueue.requests[0].callback, sRequest);
// Remove request from queue
oQueue.requests.shift();
}
// No more requests
else {
clearInterval(oQueue.interval);
oQueue.interval = null;
}
}
}, 50);
}
}
// Nothing is in progress
else {
oQueue.conn = oConnMgr.asyncRequest(sMethod, sUri, _xhrCallback, sRequest);
}
}
}
else {
YAHOO.log("Could not find Connection Manager asyncRequest() function", "error", this.toString());
// Send null response back to the caller with the error flag on
YAHOO.util.DataSource.issueCallback(oCallback,[oRequest,{error:true}],true,oCaller);
}
break;
// Simply forward the entire data object to the handler
default:
/* accounts for the following cases:
YAHOO.util.DataSource.TYPE_UNKNOWN:
YAHOO.util.DataSource.TYPE_JSARRAY:
YAHOO.util.DataSource.TYPE_JSON:
YAHOO.util.DataSource.TYPE_HTMLTABLE:
YAHOO.util.DataSource.TYPE_XML:
*/
oRawResponse = this.liveData;
this.handleResponse(oRequest, oRawResponse, oCallback, oCaller, tId);
break;
}
return tId;
};
/**
* Receives raw data response and type converts to XML, JSON, etc as necessary.
* Forwards oFullResponse to appropriate parsing function to get turned into
* oParsedResponse. Calls doBeforeCallback() and adds oParsedResponse to
* the cache when appropriate before calling issueCallback().
*
* The oParsedResponse object literal has the following properties:
* <dl>
* <dd><dt>tId {Number}</dt> Unique transaction ID</dd>
* <dd><dt>results {Array}</dt> Array of parsed data results</dd>
* <dd><dt>error {Boolean}</dt> True if there was an error</dd>
* <dd><dt>totalRecords {Number}</dt> Total number of records (if available)</dd>
* </dl>
*
* @method handleResponse
* @param oRequest {Object} Request object
* @param oRawResponse {Object} The raw response from the live database.
* @param oCallback {Object} Callback object literal.
* @param oCaller {Object} (deprecated) Use oCallback.scope.
* @param tId {Number} Transaction ID.
*/
YAHOO.util.DataSource.prototype.handleResponse = function(oRequest, oRawResponse, oCallback, oCaller, tId) {
this.fireEvent("responseEvent", {request:oRequest, response:oRawResponse,
callback:oCallback, caller:oCaller, tId: tId});
YAHOO.log("Received live data response for \"" + oRequest + "\"", "info", this.toString());
var xhr = (this.dataType == YAHOO.util.DataSource.TYPE_XHR) ? true : false;
var oParsedResponse = null;
var oFullResponse = oRawResponse;
switch(this.responseType) {
case YAHOO.util.DataSource.TYPE_JSARRAY:
if(xhr && oRawResponse.responseText) {
oFullResponse = oRawResponse.responseText;
}
oFullResponse = this.doBeforeParseData(oRequest, oFullResponse);
oParsedResponse = this.parseArrayData(oRequest, oFullResponse);
break;
case YAHOO.util.DataSource.TYPE_JSON:
if(xhr && oRawResponse.responseText) {
oFullResponse = oRawResponse.responseText;
}
try {
// Convert to JSON object if it's a string
if(YAHOO.lang.isString(oFullResponse)) {
// Check for YUI JSON Util
if(YAHOO.lang.JSON) {
oFullResponse = YAHOO.lang.JSON.parse(oFullResponse);
}
// Look for JSON parsers using an API similar to json2.js
else if(window.JSON && JSON.parse) {
oFullResponse = JSON.parse(oFullResponse);
}
// Look for JSON parsers using an API similar to json.js
else if(oFullResponse.parseJSON) {
oFullResponse = oFullResponse.parseJSON();
}
// No JSON lib found so parse the string
else {
// Trim leading spaces
while (oFullResponse.length > 0 &&
(oFullResponse.charAt(0) != "{") &&
(oFullResponse.charAt(0) != "[")) {
oFullResponse = oFullResponse.substring(1, oFullResponse.length);
}
if(oFullResponse.length > 0) {
// Strip extraneous stuff at the end
var objEnd = Math.max(oFullResponse.lastIndexOf("]"),oFullResponse.lastIndexOf("}"));
oFullResponse = oFullResponse.substring(0,objEnd+1);
// Turn the string into an object literal...
// ...eval is necessary here
oFullResponse = eval("(" + oFullResponse + ")");
}
}
}
}
catch(e) {
}
oFullResponse = this.doBeforeParseData(oRequest, oFullResponse);
oParsedResponse = this.parseJSONData(oRequest, oFullResponse);
break;
case YAHOO.util.DataSource.TYPE_HTMLTABLE:
if(xhr && oRawResponse.responseText) {
oFullResponse = oRawResponse.responseText;
}
oFullResponse = this.doBeforeParseData(oRequest, oFullResponse);
oParsedResponse = this.parseHTMLTableData(oRequest,