Working with external data in Flash

XMLSocket class in ActionScript lets you open a continuous connection with a server. A socket connection lets the server publish, or  push, information to the client as soon as that information is available. The data is sent over the socket connection as one string and should be formatted as XML. You can use the XML class to structure the data.

The methods of XMLSocket Class create and use TCP/IP socket connections to send and load information as XML.

You can use the connect()and send()methods of the XMLSocket class to transfer XML to and from a server over a socket connection. The connect()method establishes a socket connection with a Web server port. The send()method passes an XML object to the server specified in the socket connection.

Now let us see an example that shows how to use the XMLSocket Class.

Example:

// Create XMLSocket object

var sample_socket:XMLSocket = new XMLSocket();

// Connects to localhost server with port number 1024

sample_socket.connect("localhost", 1024);

// Displays connection status information

sample_socket.onConnect = function(status) {

 if (status) {

   conn_txt.text = "connection successful";

 } else {

   conn_txt.text = "no connection made";

 }

};

// Function that creates data to send it to the server using

send() method

function sendData() {

 var data:XML = new XML();

 var send = data.createElement("user");

 send.attributes.id = "asp123";

 data.appendChild(send);

 sample_socket.send(data);

}

// onData event handler function to track the data returned from

socket connection and perform actions based on that data

sample_socket.onData = function(msg:String):Void {

 trace(msg);

};

Note:The XMLSocket.connect()method can connect only to TCP port numbers greater than or equal to 1024. Port numbers below 1024 are often used by system services such as FTP, Telnet, and HTTP, so XMLSocket objects are barred from these ports for security reasons.