io-base.js revision db6bcdca3c01def23cea443aa1bb08552d696ba6
/**
* Base IO functionality. Provides basic XHR transport support.
* @module io
* @submodule io-base
*/
/**
* The io class is a utility that brokers HTTP requests through a simplified
* interface. Specifically, it allows JavaScript to make HTTP requests to
* a resource without a page reload. The underlying transport for making
* same-domain requests is the XMLHttpRequest object. YUI.io can also use
* Flash, if specified as a transport, for cross-domain requests.
*
* @class io
*/
/**
* @event io:start
* @description This event is fired by YUI.io when a transaction is initiated.
* @type Event Custom
*/
var E_START = 'io:start',
/**
* @event io:complete
* @description This event is fired by YUI.io when a transaction is complete.
* Response status and data are accessible, if available.
* @type Event Custom
*/
E_COMPLETE = 'io:complete',
/**
* @event io:success
* @description This event is fired by YUI.io when a transaction is complete, and
* the HTTP status resolves to HTTP2xx.
* @type Event Custom
*/
E_SUCCESS = 'io:success',
/**
* @event io:failure
* @description This event is fired by YUI.io when a transaction is complete, and
* the HTTP status resolves to HTTP4xx, 5xx and above.
* @type Event Custom
*/
E_FAILURE = 'io:failure',
/**
* @event io:end
* @description This event signifies the end of the transaction lifecycle. The
* transaction transport is destroyed.
* @type Event Custom
*/
E_END = 'io:end',
//--------------------------------------
// Properties
//--------------------------------------
/**
* @description A transaction counter that increments for each transaction.
*
* @property transactionId
* @private
* @static
* @type int
*/
transactionId = 0,
/**
* @description Object of default HTTP headers to be initialized and sent
* for all transactions.
*
* @property _headers
* @private
* @static
* @type object
*/
_headers = {
'X-Requested-With' : 'XMLHttpRequest'
},
/**
* @description Object that stores timeout values for any transaction with
* a defined "timeout" configuration property.
*
* @property _timeOut
* @private
* @static
* @type object
*/
_timeout = {},
// Window reference
//--------------------------------------
// Methods
//--------------------------------------
/**
* @description Method for requesting a transaction. _io() is implemented as
* yui.io(). Each transaction may include a configuration object. Its
* properties are:
*
* method: HTTP method verb (e.g., GET or POST). If this property is not
* not defined, the default value will be GET.
*
* data: This is the name-value string that will be sent as the transaction
* data. If the request is HTTP GET, the data become part of
* querystring. If HTTP POST, the data are sent in the message body.
*
* xdr: Defines the transport to be used for cross-domain requests. By
* setting this property, the transaction will use the specified
* transport instead of XMLHttpRequest. Currently, the only alternate
* transport supported is Flash (e.g., { xdr: 'flash' }).
*
* form: This is a defined object used to process HTML form as data. The
* properties are:
* {
* id: object, //HTML form object or id of HTML form
* useDisabled: boolean, //Allow disabled HTML form field values
* to be sent as part of the data.
* }
*
* on: This is a defined object used to create and handle specific
* events during a transaction lifecycle. These events will fire in
* addition to the global io events. The events are:
* start - This event is fired when a request is sent to a resource.
* complete - This event fires when the transaction is complete.
* success - This event fires when the response status resolves to
* HTTP 2xx.
* failure - This event fires when the response status resolves to
* HTTP 4xx, 5xx; and, for all transaction exceptions,
* including aborted transactions and transaction timeouts.
* end - This even is fired at the conclusion of the transaction
* lifecycle, after a success or failure resolution.
*
* The properties are:
* {
* start: function(id, args){},
* complete: function(id, responseobject, args){},
* success: function(id, responseobject, args){},
* failure: function(id, responseobject, args){},
* end: function(id, args){}
* }
* Each property can reference a function or be written as an
* inline function.
*
* context: Object reference for an event handler when it is implemented
* as a method of a base object. Defining "context" will preserve
* the proper reference of "this" used in the event handler.
* headers: This is a defined object of client headers, as many as.
* desired for the transaction. These headers are sentThe object
* pattern is:
* {
* header: value
* }
*
* timeout: This value, defined as milliseconds, is a time threshold for the
* transaction. When this threshold is reached, and the transaction's
* Complete event has not yet fired, the transaction will be aborted.
* arguments: Object, array, string, or number passed to all registered
* event handlers. This value is available as the second
* argument in the "start" and "abort" event handlers; and, it is
* the third argument in the "complete", "success", and "failure"
* event handlers.
*
* @method _io
* @private
* @static
* @param {string} uri - qualified path to transaction resource.
* @param {object} c - configuration object for the transaction.
* @param {number} i - transaction id, if already set by queue.
* @return object
*/
var u, f, o, m, d;
c = c || {};
i = i || null;
/* Determine configuration properties */
// If config.form is defined, perform data operations.
if (c.form) {
return u;
}
// Serialize the HTML form into a string of name-value pairs.
// If config.data is defined, concatenate the data to the form string.
if (d) {
f += "&" + d;
}
if (m === 'POST') {
d = f;
}
else if (m === 'GET') {
}
}
else if (d && m === 'POST') {
}
if (c.xdr) {
}
if (c.xdr.credentials) {
o.c.withCredentials = true;
}
}
// If config.timeout is defined, and the request is standard XHR,
// initialize timeout polling.
if (c.timeout) {
_startTimeout(o, c.timeout);
}
/* End Configuration Properties */
o.c.onreadystatechange = function() { _readyState(o, c); };
if (c.header) {
_setHeaders(o.c, c.headers);
}
// Do not pass null, in the absence of data, as this
// will result in a POST request with no Content-Length
// defined.
_async(o, d, c);
return {
isInProgress: function() {
}
}
}
/**
* @description Method for creating and subscribing transaction events.
*
* @method _subscribe
* @private
* @static
* @param {string} e - event to be published
* @param {object} c - configuration data subset for event subscription.
*
* @return void
*/
function _subscribe(e, c){
return evt;
}
/**
* @description Fires event "io:start" and creates, fires a
* transaction-specific start event, if config.on.start is
* defined.
*
* @method _ioStart
* @private
* @static
* @param {number} id - transaction id
* @param {object} c - configuration object for the transaction.
*
* @return void
*/
var evt;
// Set default value of argument c, property "on" to Object if
// the property is null or undefined.
}
}
/**
* @description Fires event "io:complete" and creates, fires a
* transaction-specific "complete" event, if config.on.complete is
* defined.
*
* @method _ioComplete
* @private
* @static
* @param {object} o - transaction object.
* @param {object} c - configuration object for the transaction.
*
* @return void
*/
function _ioComplete(o, c) {
var r, evt;
// Set default value of argument c, property "on" to Object if
// the property is null or undefined.
}
}
/**
* @description Fires event "io:success" and creates, fires a
* transaction-specific "success" event, if config.on.success is
* defined.
*
* @method _ioSuccess
* @private
* @static
* @param {object} o - transaction object.
* @param {object} c - configuration object for the transaction.
*
* @return void
*/
function _ioSuccess(o, c) {
var evt;
// Set default value of argument c, property "on" to Object if
// the property is null or undefined.
}
_ioEnd(o, c);
}
/**
* @description Fires event "io:failure" and creates, fires a
* transaction-specific "failure" event, if config.on.failure is
* defined.
*
* @method _ioFailure
* @private
* @static
* @param {object} o - transaction object.
* @param {object} c - configuration object for the transaction.
*
* @return void
*/
function _ioFailure(o, c) {
evt;
// Set default value of argument c, property "on" to Object if
// the property is null or undefined.
}
_ioEnd(o, c);
}
/**
* @description Fires event "io:end" and creates, fires a
* transaction-specific "end" event, if config.on.end is
* defined.
*
* @method _ioEnd
* @private
* @static
* @param {object} o - transaction object.
* @param {object} c - configuration object for the transaction.
*
* @return void
*/
function _ioEnd(o, c) {
var evt;
// Set default value of argument c, property "on" to Object if
// the property is null or undefined.
}
}
/**
* @description Terminates a transaction due to an explicit abort or
* timeout.
*
* @method _ioCancel
* @private
* @static
* @param {object} o - Transaction object generated by _create().
* @param {string} s - Identifies timed out or aborted transaction.
*
* @return void
*/
function _ioCancel(o, s) {
if (o && o.c) {
o.status = s;
o.c.abort();
}
}
function _response(s) {
}
/**
* @description Method that increments _transactionId for each transaction.
*
* @method _id
* @private
* @static
* @return int
*/
function _id() {
var id = transactionId;
return id;
}
/**
* @description Method that creates a unique transaction object for each
* request.
*
* @method _create
* @private
* @static
* @param {number} xdr - XDR configuration object
* @param {number} i - transaction id
* @return object
*/
var o = {};
if (!xdr) {
o.c = _xhr();
}
else if (xdr) {
}
o.c = new XDomainRequest();
}
else {
o.c = _xhr();
}
}
else {
o.c = {};
}
return o;
};
/**
* @description Method that creates the XMLHttpRequest transport
*
* @method _xhr
* @private
* @static
* @return object
*/
function _xhr() {
}
/**
* @description Method that concatenates string data for HTTP GET transactions.
*
* @method _concat
* @private
* @static
* @param {string} s - URI or root data.
* @param {string} d - data to be concatenated onto URI.
* @return int
*/
function _concat(s, d) {
return s;
}
/**
* @description Method that stores default client headers for all transactions.
* If a label is passed with no value argument, the header will be deleted.
*
* @method _setHeader
* @private
* @static
* @param {string} l - HTTP header
* @param {string} v - HTTP header value
* @return int
*/
function _setHeader(l, v) {
if (v) {
_headers[l] = v;
}
else {
delete _headers[l];
}
}
/**
* @description Method that sets all HTTP headers to be sent in a transaction.
*
* @method _setHeaders
* @private
* @static
* @param {object} o - XHR instance for the specific transaction.
* @param {object} h - HTTP headers for the specific transaction, as defined
* in the configuration object passed to YUI.io().
* @return void
*/
function _setHeaders(o, h) {
var p;
for (p in _headers) {
if (_headers.hasOwnProperty(p)) {
if (h[p]) {
// Configuration headers will supersede IO preset headers,
// if headers match.
break;
}
else {
h[p] = _headers[p];
}
}
}
for (p in h) {
if (h.hasOwnProperty(p)) {
o.setRequestHeader(p, h[p]);
}
}
}
}
/**
* @description Method that sends the transaction request.
*
* @method _async
* @private
* @static
* @param {object} o - Transaction object generated by _create().
* @param {string} d - Transaction data.
* @param {object} c - Configuration object passed to YUI.io().
* @return void
*/
function _async(o, d, c) {
o.c.send(d);
}
/**
* @description Starts timeout count if the configuration object
* has a defined timeout property.
*
* @method _startTimeout
* @private
* @static
* @param {object} o - Transaction object generated by _create().
* @param {object} c - Configuration object passed to YUI.io().
* @return void
*/
function _startTimeout(o, timeout) {
}
/**
* @description Clears the timeout interval started by _startTimeout().
*
* @method _clearTimeout
* @private
* @static
* @param {number} id - Transaction id.
* @return void
*/
function _clearTimeout(id) {
}
/**
* @description Event handler bound to onreadystatechange.
*
* @method _readyState
* @private
* @static
* @param {object} o - Transaction object generated by _create().
* @param {object} c - Configuration object passed to YUI.io().
* @return void
*/
function _readyState(o, c) {
if (o.c.readyState === 4) {
if (c.timeout) {
_clearTimeout(o.id);
}
w.setTimeout(
function() {
_ioComplete(o, c);
_handleResponse(o, c);
}, 0);
}
}
/**
* @description Method that determines if a transaction response qualifies
* as success or failure, based on the response HTTP status code, and
* fires the appropriate success or failure events.
*
* @method _handleResponse
* @private
* @static
* @param {object} o - Transaction object generated by _create().
* @param {object} c - Configuration object passed to io().
* @return void
*/
function _handleResponse(o, c) {
var status;
try{
}
else {
status = 0;
}
}
catch(e) {
status = 0;
}
// IE reports HTTP 204 as HTTP 1223.
_ioSuccess(o, c);
}
else {
_ioFailure(o, c);
}
}
function _destroy(o, isTransport) {
// IE, when using XMLHttpRequest as an ActiveX Object, will throw
// a "Type Mismatch" error if the event handler is set to "null".
if(w.XMLHttpRequest && !isTransport) {
if (o.c) {
o.c.onreadystatechange = null;
}
}
o.c = null;
o = null;
}
//--------------------------------------
// Begin public interface definition
//--------------------------------------
/**
* @description Method that stores default client headers for all transactions.
* If a label is passed with no value argument, the header will be deleted.
* This is the interface for _setHeader().
*
* @method header
* @public
* @static
* @param {string} l - HTTP header
* @param {string} v - HTTP header value
* @return int
*/
/**
* @description Method for requesting a transaction. This
* is the interface for _io().
*
* @method io
* @public
* @static
* @param {string} uri - qualified path to transaction resource.
* @param {object} c - configuration object for the transaction.
* @return object
*/