/**
* Extends the IO base class to provide an alternate, Flash transport, for making
* cross-domain requests.
* @module io
* @submodule io-xdr
*/
/**
* @event io:xdrReady
* @description This event is fired by YUI.io when the specified transport is
* ready for use.
* @type Event Custom
*/
var E_XDR_READY = Y.publish('io:xdrReady', { fireOnce: true }),
/**
* @description Object that stores callback handlers for cross-domain requests
* when using Flash as the transport.
*
* @property _fn
* @private
* @static
* @type object
*/
_fn = {},
/**
* @description Map of transaction readyState values used when
* XDomainRequest is the XDR transport.
*
* @property _rS
* @private
* @static
* @type object
*/
_rS = {},
// Document reference
d = Y.config.doc,
// Window reference
w = Y.config.win;
/**
* @description Method that creates the Flash transport swf.
*
* @method _swf
* @private
* @static
* @param {string} uri - location of io.swf.
* @param {string} yid - YUI instance id.
* @return void
*/
function _swf(uri, yid) {
var o = '<object id="yuiIoSwf" type="application/x-shockwave-flash" data="' +
uri + '" width="0" height="0">' +
'<param name="movie" value="' + uri + '">' +
'<param name="FlashVars" value="yid=' + yid + '">' +
'<param name="allowScriptAccess" value="always">' +
'</object>',
c = d.createElement('div');
d.body.appendChild(c);
c.innerHTML = o;
}
/**
* @description Sets event handlers for XDomainRequest transactions.
*
* @method _evt
* @private
* @static
* @param {object} o - Transaction object generated by _create() in io-base.
* @param {object} c - configuration object for the transaction.
* @return void
*/
function _evt(o, c) {
o.c.onprogress = function() { _rS[o.id] = 3; }
o.c.onload = function() {
_rS[o.id] = 4;
Y.io.xdrResponse(o, c, 'success');
};
o.c.onerror = function() {
_rS[o.id] = 4;
Y.io.xdrResponse(o, c, 'failure');
};
if (c.timeout) {
o.c.ontimeout = function() {
_rS[o.id] = 4;
Y.io.xdrResponse(o, c, 'timeout');
};
o.c.timeout = c.timeout;
}
}
/**
* @description Creates a response object for XDR transactions, for success
* and failure cases.
*
* @method _data
* @private
* @static
* @param {object} o - Transaction object generated by _create() in io-base.
* @param {boolean} f - True if Flash was used as the transport.
* @param {boolean} t - DataType value, as defined in the configuration.
*
* @return object
*/
function _data(o, f, t) {
var s, x;
if (!o.e) {
s = f ? decodeURI(o.c.responseText) : o.c.responseText;
x = t === 'xml' ? Y.DataType.XML.parse(s) : null;
return { id: o.id, c: { responseText: s, responseXML: x } };
}
else {
return { id: o.id, status: o.e };
}
}
/**
* @description Method for intiating an XDR transaction abort.
*
* @method _abort
* @private
* @static
* @param {object} o - Transaction object generated by _create() in io-base.
* @param {object} c - configuration object for the transaction.
*/
function _abort(o, c) {
return o.c.abort(o.id, c);
}
/**
* @description Method for determining if an XDR transaction has completed
* and all data are received.
*
* @method _isInProgress.
* @private
* @static
* @param {object} o - Transaction object generated by _create() in io-base.
*/
function _isInProgress(o) {
return w && w.XDomainRequest ? _rS[o.id] !== 4 : o.c.isInProgress(o.id);
}
Y.mix(Y.io, {
/**
* @description Map of io transports.
*
* @property _transport
* @private
* @static
* @type object
*/
_transport: {},
/**
* @description Method for accessing the transport's interface for making a
* cross-domain transaction.
*
* @method xdr
* @private
* @static
* @param {string} uri - qualified path to transaction resource.
* @param {object} o - Transaction object generated by _create() in io-base.
* @param {object} c - configuration object for the transaction.
*/
xdr: function(uri, o, c) {
if (c.on && c.xdr.use === 'flash') {
_fn[o.id] = {
on: c.on,
context: c.context,
arguments: c.arguments
};
// These properties cannot be serialized across Flash's
// ExternalInterface. Doing so will result in exceptions.
c.context = null;
c.form = null;
o.c.send(uri, c, o.id);
}
else if (w && w.XDomainRequest) {
_evt(o, c);
o.c.open(c.method || 'GET', uri);
o.c.send(c.data);
}
else {
o.c.send(uri, o, c);
}
return {
id: o.id,
abort: function() {
return o.c ? _abort(o, c) : false;
},
isInProgress: function() {
return o.c ? _isInProgress(o.id) : false;
}
}
},
/**
* @description Response controller for cross-domain requests when using the
* Flash transport or IE8's XDomainRequest object.
*
* @method xdrResponse
* @private
* @static
* @param {object} o - Transaction object generated by _create() in io-base.
* @param {object} c - configuration object for the transaction.
* @param {string} e - Event name
* @return object
*/
xdrResponse: function(o, c, e) {
var m, fn,
f = c.xdr.use === 'flash' ? true : false,
t = c.xdr.dataType;
c.on = c.on || {};
if (f) {
m = _fn || {};
fn = m[o.id] ? m[o.id] : null;
if (fn) {
c.on = fn.on;
c.context = fn.context;
c.arguments = fn.arguments;
}
}
switch (e.toLowerCase()) {
case 'start':
Y.io.start(o.id, c);
break;
case 'complete':
Y.io.complete(o, c);
break;
case 'success':
Y.io.success(t || f ? _data(o, f, t) : o, c);
f ? delete m[o.id] : delete _rS[o.id];
break;
case 'timeout':
case 'abort':
case 'failure':
if (e === ('abort' || 'timeout')) {
o.e = e;
}
Y.io.failure(t || f ? _data(o, f, t) : o, c);
f ? delete m[o.id] : delete _rS[o.id];
break;
}
},
/**
* @description Fires event "io:xdrReady"
*
* @method xdrReady
* @private
* @static
* @param {number} id - transaction id
* @param {object} c - configuration object for the transaction.
*
* @return void
*/
xdrReady: function(id) {
Y.fire(E_XDR_READY, id);
},
/**
* @description Method to initialize the desired transport.
*
* @method transport
* @public
* @static
* @param {object} o - object of transport configurations.
* @return void
*/
transport: function(o) {
var id = o.yid ? o.yid : Y.id;
o.id = o.id || 'flash';
if (o.id === 'native' || o.id === 'flash') {
_swf(o.src, id);
this._transport.flash = d.getElementById('yuiIoSwf');
}
else {
this._transport[o.id] = o.src;
}
}
});