A simple server that can be run inside photoshop, demonstrating how to respond to socket calls

PhotoshopSockets.js

// requires photoshop CS5+
 
// create a new socket
conn = new Socket();
 
var keep_serving = true;
// sample functions. In a real application you'd have handler functions that could accept  more complex inputs
var alrt = alert;                                                                                           // pop a dialog
var newLayer = function () { return app.activeDocument.artLayers.add(); };      // make a layer
var stop = function () { keep_serving = false; };                                           // stop the server
 
// 'register' the commands by putting them into a dictionary
var known_cmds = { 'alert': alrt, 'stop': stop, 'newLayer': newLayer };
 
while (keep_serving) {
    if (conn.listen(8789))  // ... you'd probably want to make this configurable
    {
        // wait forever for a connection
        var incoming;
        do incoming = conn.poll();
        while (incoming == null);
 
        // grab the next non-null communication
        new_cmd = incoming.read();
        try {
            // split the incoming message into cmd on spaces (shell style)
            var command_text = new_cmd.split(" ", 1);
            var args = new_cmd.slice(command_text[0].length + 1, 999).split(" ");
            var requested = known_cmds[command_text];
 
            if (null != requested) {
                result = requested(args);
                incoming.writeln(result + "\nOK\n");
            }
            else {
                incoming.writeln("unknown command\nFAIL\n");
            }
 
        }
        catch (err) {
            incoming.writeln(err + "FAIL\n");
            incoming.close();
            delete incoming;
        }
    } // end if 
} // -- end while