TCPSocket: Sockets in the browser
Date : 2008 07 01 Category : Tech & Development
AjaxianMichael Carter of Orbited has written about how he now likes to call Comet sockets in the browser, and has an implementation available that looks like this:
PLAIN TEXT JAVASCRIPT:var conn = new TCPSocket(hostname, port) conn.onopen = function() { alert('connection opened!') } conn.onread = function(data) { alert('RECEIVE: ' + data) } conn.onclose = function(data) { alert('connection closed!') } conn.send('Hello World');
The above code code is all you need to know. It will open a TCP connection to hostname:port, and will send the data “Hello World”. Any data the server sends back will be alerted with the onread handler.
The exact mechanism behind this innovation is pretty straightforward: Orbited is a router and firewall for incoming TCPSocket connections from the browser. It uses Comet techniques to establish bi-directional communication with the browser, then forwards all data over a raw TCP socket to the end point. Configuration allows access control enforcement so that the TCPSocket can only be connected to pre-approved end-points, so that the Orbited server isn’t an open relay.
While this presents a paradigm shift in the way developers are tackling real-time, web-based applications today, it’s actually a return to the original method of writing network applications. Instead of writing applications based on web frameworks and throwing a Comet server in the mix, you can simply use the client-server architecture where the browser is the client, and the server is an arbitrary TCP server.