Yahoo! UI Library

connection  2.8.0r4

Yahoo! UI Library > connection > YAHOO.util.Connect
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Class YAHOO.util.Connect

The Connection Manager singleton provides methods for creating and managing asynchronous transactions.

Properties

_customEvents - private static object

A reference table that maps callback custom events members to its specific event name.

_default_form_header - private static boolean

The default header used for transactions involving the use of HTML forms.

_default_post_header - private static boolean

The default header used for POST transactions.

_default_xhr_header - private static boolean

The default header value for the label "X-Requested-With". This is sent with each transaction, by default, to identify the request as being made by YUI Connection Manager.

_has_default_header - private static boolean

Determines if custom, default headers are set for each transaction.

_has_http_headers - private static boolean

Determines if HTTP headers are set.

_http_header - private static object

Object literal of HTTP header(s)

_msxml_progid - private static array

Array of MSFT ActiveX ids for XMLHttpRequest.

_poll - private static object

Collection of polling references to the polling mechanism in handleReadyState.

_polling_interval - private static int

The polling frequency, in milliseconds, for HandleReadyState. when attempting to determine a transaction's XHR readyState. The default is 50 milliseconds.

_timeOut - private static object

Queue of timeout values for each transaction callback with a defined timeout value.

_transaction_id - private static int

A transaction counter that increments the transaction id for each transaction.

_use_default_post_header - private static boolean

Determines if a default header of Content-Type of 'application/x-www-form-urlencoded' will be added to any client HTTP headers sent for POST transactions.

_use_default_xhr_header - private static boolean

Determines if a default header of 'X-Requested-With: XMLHttpRequest' will be added to each transaction.

abortEvent - private static CustomEvent

Custom event that fires when a transaction is successfully aborted.

completeEvent - private static CustomEvent

Custom event that fires when a transaction response has completed.

failureEvent - private static CustomEvent

Custom event that fires when handleTransactionResponse() determines a response in the HTTP 4xx/5xx range.

startEvent - private static CustomEvent

Custom event that fires at the start of a transaction

successEvent - private static CustomEvent

Custom event that fires when handleTransactionResponse() determines a response in the HTTP 2xx range.

Methods

abort

static boolean abort ( o , callback , isTimeout )
Method to terminate a transaction, if it has not reached readyState 4.
Parameters:
o <object> The connection object returned by asyncRequest.
callback <object> User-defined callback object.
isTimeout <string> boolean to indicate if abort resulted from a callback timeout.
Returns: boolean

asyncRequest

static object asyncRequest ( method , uri , callback , postData )
Method for initiating an asynchronous request via the XHR object.
Parameters:
method <string> HTTP transaction method
uri <string> Fully qualified path of resource
callback <callback> User-defined callback function or object
postData <string> POST body
Returns: object
Returns the connection object

createExceptionObject

private static object createExceptionObject ( tId , callbackArg , isAbort )
If a transaction cannot be completed due to dropped or closed connections, there may be not be enough information to build a full response object. The failure callback will be fired and this specific condition can be identified by a status property value of 0. If an abort was successful, the status property will report a value of -1.
Parameters:
tId <int> The Transaction Id
callbackArg <callbackArg> The user-defined argument or arguments to be passed to the callback
isAbort <boolean> Determines if the exception case is caused by a transaction abort
Returns: object

createResponseObject

private static object createResponseObject ( o , callbackArg )
This method evaluates the server response, creates and returns the results via its properties. Success and failure cases will differ in the response object's property values.
Parameters:
o <object> The connection object
callbackArg <callbackArg> The user-defined argument or arguments to be passed to the callback
Returns: object

createXhrObject

private static createXhrObject ( transactionId )
Instantiates a XMLHttpRequest object and returns an object with two properties: the XMLHttpRequest instance and the transaction id.
Parameters:
transactionId <int> Property containing the transaction id for this transaction.

getConnectionObject

private static object getConnectionObject ( )
This method is called by asyncRequest to create a valid connection object for the transaction. It also passes a transaction id and increments the transaction id counter.
Returns: object

handleReadyState

private static void handleReadyState ( o , callback )
This method serves as a timer that polls the XHR object's readyState property during a transaction, instead of binding a callback to the onreadystatechange event. Upon readyState 4, handleTransactionResponse will process the response, and the timer will be cleared.
Parameters:
o <object> The connection object
callback <callback> The user-defined callback object
Returns: void

handleTransactionResponse

private static void handleTransactionResponse ( o , callback , isAbort )
This method attempts to interpret the server response and determine whether the transaction was successful, or if an error or exception was encountered.
Parameters:
o <object> The connection object
callback <object> The user-defined callback object
isAbort <boolean> Determines if the transaction was terminated via abort().
Returns: void

initCustomEvents

private static void initCustomEvents ( o , callback )
This method creates and subscribes custom events, specific to each transaction
Parameters:
o <object> The connection object
callback <callback> The user-defined callback object
Returns: void

initHeader

static void initHeader ( label , value , isDefault )
Method that initializes the custom HTTP headers for the each transaction.
Parameters:
label <string> The HTTP header label
value <string> The HTTP header value
isDefault <string> Determines if the specific header is a default header automatically sent with each transaction.
Returns: void

isCallInProgress

static boolean isCallInProgress ( o )
Determines if the transaction is still being processed.
Parameters:
o <object> The connection object returned by asyncRequest
Returns: boolean

releaseObject

private static void releaseObject ( o )
Dereference the XHR instance and the connection object after the transaction is completed.
Parameters:
o <object> The connection object
Returns: void

resetDefaultHeaders

static void resetDefaultHeaders ( )
Resets the default HTTP headers object
Returns: void

setDefaultPostHeader

static setDefaultPostHeader ( b )
Member to override the default POST header.
Parameters:
b <boolean> Set and use default header - true or false .

setDefaultXhrHeader

static setDefaultXhrHeader ( b )
Member to override the default transaction header..
Parameters:
b <boolean> Set and use default header - true or false .

setHeader

private static void setHeader ( o )
Accessor that sets the HTTP headers for each transaction.
Parameters:
o <object> The connection object for the transaction.
Returns: void

setPollingInterval

static setPollingInterval ( i )
Member to modify the default polling interval.
Parameters:
i <int> The polling interval in milliseconds.

setProgId

static setProgId ( id )
Member to add an ActiveX id to the existing xml_progid array. In the event(unlikely) a new ActiveX id is introduced, it can be added without internal code modifications.
Parameters:
id <string> The ActiveX id to be added to initialize the XHR object.
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