Yahoo! UI Library

connection 

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

Class YAHOO.util.Connect

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

Properties

_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.

_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_http_headers - private static boolean

Determines if HTTP headers are set.

_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.

_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.

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 was a 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 ( secureUri )
Creates an iframe to be used for form file uploads. It is remove from the document upon completion of the upload transaction.
Parameters:
secureUri <string> Optional 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 sser-defined callback object
isAbort <boolean> Determines if the transaction was aborted.
Returns: void

initHeader

static void initHeader ( label , value )
Public method that stores the custom HTTP headers for each transaction.
Parameters:
label <string> The HTTP header label
value <string> The HTTP header value
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

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

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 HTTP header Content-Type of application/x-www-form-urlencoded.
Parameters:
form <string || object> id or name attribute, or form object.
optional <string> boolean to indicate SSL environment.
optional <string || boolean> qualified path of iframe resource for SSL in IE.
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 )
Uploads HTML form, including files/attachments, to the iframe created in createFrame.
Parameters:
id <int> The transaction id.
callback <object> - User-defined callback object.
uri <string> Fully qualified path of resource.
Returns: void

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