Yahoo! UI Library

connection  2.5.0

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_post_header - private static boolean

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

_formNode - private static object

Property modified by setForm() to set a reference to the HTML form node if the desired action is file upload.

_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.

_hasSubmitListener - private static object

Determines whether YAHOO.util.Event is available and returns true or false. If true, an event listener is bound at the document level to trap click events that resolve to a target type of "Submit". This listener will enable setForm() to determine the clicked "Submit" value in a multi-Submit button, HTML form.

_http_header - private static object

Object literal of HTTP header(s)

_isFileUpload - private static boolean

Property modified by setForm() to determine if a file(s) upload is expected.

_isFormSubmit - private static boolean

Property modified by setForm() to determine if the data should be submitted as an HTML form.

_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.

_sFormData - private static string

Property modified by setForm() to set the HTML form data for each transaction.

_submitElementValue - private static string

Tracks the name-value pair of the "clicked" submit button if multiple submit buttons are present in an HTML form; and, if YAHOO.util.Event is available.

_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

appendPostData

private static array appendPostData ( postData )
Parses the POST data and creates hidden form elements for each key-value, and appends them to the HTML form object.
Parameters:
postData <string> The HTTP POST data
Returns: array
formElements Collection of hidden fields.

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

createFrame

private static void createFrame ( optional )
Creates an iframe to be used for form file uploads. It is remove from the document upon completion of the upload transaction.
Parameters:
optional <string> qualified path of iframe resource for SSL in IE.
Returns: void

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 void 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.
Returns: void
object

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 )
Public method to check 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

resetFormState

private static void resetFormState ( )
Resets HTML form properties when an HTML form or HTML form with file upload transaction is sent.
Returns: void

setDefaultPostHeader

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

setDefaultXhrHeader

static void setDefaultXhrHeader ( b )
Member to enable or disable the default POST header.
Parameters:
b <boolean> Set and use default header - true or false .
Returns: void
void

setForm

static string setForm ( form , optional )
This method assembles the form label and value pairs and constructs an encoded string. asyncRequest() will automatically initialize the transaction with a a HTTP header Content-Type of application/x-www-form-urlencoded.
Parameters:
form <string || object> id or name attribute, or form object.
optional <boolean> enable file upload.
optional <boolean> enable file upload over SSL in IE only.
Returns: string
string of the HTML form field name and value pairs..

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

setProgId

static void 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.
Returns: void
void

uploadFile

private static void uploadFile ( id , callback , uri , postData )
Uploads HTML form, inclusive of files/attachments, using the iframe created in createFrame to facilitate the transaction.
Parameters:
id <int> The transaction id.
callback <object> User-defined callback object.
uri <string> Fully qualified path of resource.
postData <string> POST data to be submitted in addition to HTML form.
Returns: void

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