ActionScript: The Definitive Guide

Name

XMLSocket Class — support for a continuous server/client TCP/IP connection

Availability

Flash 5

Constructor

new XMLSocket( )

Methods

close( )

Terminate an open connection to a server application.

connect( )

Attempt to establish a new connection to a server application.

send( )

Send an XML object hierarchy to a server application as a string.

Event handlers

onClose( )

Executes when the server terminates the connection.

onConnect( )

Executes when a connection attempt completes.

onData( )

Executes when data is received but has not yet been parsed as XML.

onXML( )

Executes when data has been received and parsed into an XML object hierarchy.

Description

The majority of connections between Flash and a server have a very short life span. When Flash requests external data via the loadMovie( ), loadVariables( ), or XML.load( ) functions, a temporary communication channel is established. Data is sent over that channel and then the channel is terminated. This kind of short-term communication has many useful applications, but it is also limited in two important ways:

• Once the connection closes, the server has no way of contacting Flash. Flash must always initiate communication with the server.

• Each time Flash obtains information from the server, a new connection must be opened. The time and processor load involved in opening repeated connections prevents Flash from engaging in anything near real-time transactions with a server.

As of Flash 5, we can overcome these limitations with the XMLSocket class, ...