FLASH® LITE™ 2.x - Adobe Help and Support

XMLSocket
Object
|
+-XMLSocket
public class XMLSocket
extends Object
The XMLSocket class implements client sockets that let the device running the Flash Lite
player communicate with a server computer that an IP address or domain name identifies.
The XMLSocket class is useful for client-server applications that require low latency, such as
real-time chat systems. A traditional HTTP-based chat system frequently polls the server and
downloads new messages by using an HTTP request. In contrast, an XMLSocket chat
solution maintains an open connection to the server, which lets the server immediately send
incoming messages without a request from the client.
To use the XMLSocket class, the server computer must run a daemon process that
understands the protocol that the XMLSocket class uses. The following list describes the
protocol:
■ XML messages are sent over a full-duplex TCP/IP stream socket connection.
■ Each XML message is a complete XML document, terminated by a zero (0) byte.
■ An unlimited number of XML messages can be sent and received over a single
XMLSocket connection.
The following restrictions apply to how and where an XMLSocket object can connect to the
server:
■ To connect an XMLSocket to a port lower than 1024, you must first load a policy file
with the System.security.loadPolicyFile() method, even when your application
connects to its own exact domain.
■ The XMLSocket.connect() method can connect only to computers in the same domain
where the SWF file resides. This restriction does not apply to SWF files running on a local
disk. (This restriction is identical to the security rules for the loadVariables() function,
and the XML.sendAndLoad() and XML.load() methods.) To connect to a server daemon
running in a domain other than the one where the SWF file resides, you can create a
security policy file on the server that allows access from specific domains.
Setting up a server to communicate with the XMLSocket object can be challenging. If your
application does not require real-time interactivity, use the loadVariables() function, or
Flash HTTP-based XML server connectivity methods (XML.load(), XML.sendAndLoad(),
XML.send()), instead of the XMLSocket class.
714 ActionScript classes