Scratch

archmage wrote:

I seem to have absolutely no problems with receiving the messages. Its the sending that is giving me a hard time.

I believe what you need to do is send Scratch a 4-byte size field (that tells it the size of the message) followed by the actual message.

http://s3.amazonaws.com/jef.mindtouch.com/10053343/7/1?AWSAccessKeyId=1TDEJCXAPFCDHW56MSG2&Signature=/GsaCH6Gexn3CHX84PbFovlwWOY%3d&Expires=1232837274

so, for example, in Python, here is the way you would do it, and I think you'll see what it's doing even if you haven't done a lot of python.

def sendScratchCommand(cmd):
    n = len(cmd)
    a = array('c')
    a.append(chr((n >> 24) & 0xFF))
    a.append(chr((n >> 16) & 0xFF))
    a.append(chr((n >>  8) & 0xFF))
    a.append(chr(n & 0xFF))
    scratchSock.send(a.tostring() + cmd)

Or, in Java/Processing, it looks like this (though is less general):

void sendtoscratch(String dataOut) {                              
byte [] sizeBytes = { 0, 0, 0, 0 };
  sizeBytes[3] = byte(dataOut.length());
  for (int i=0; i<4; i++) {                  
    ScratchClient.write(sizeBytes[i]);
  }
  ScratchClient.write(dataOut);
}

I'm hopeless with Actionscript, so I'm probably no help in figuring out the exact syntax. The basic idea is: 1. figure out how big the message to scratch is, 2. build four bytes indicating the length, 3. concatenate the actual message, 4. send the combined string to scratch.

Hope this helps.

Last edited by chalkmarrow (2009-01-24 17:57:44)

archmage: Your code looks good to me. I'm thinking there might be a data type issue -- i.e., scratch expects a series of four bytes (which are generally 8-bit signed two's-complement integers),  which of course is not necessarily the same as an array of integers (which I think may be 16 or 32 bits). I'm not sure what sort of primitive data types actionscript has, but that may be the issue. In the python example above, this is accomplished by using the "chr" function (which returns 8 bits). in Java, you can just use the byte data type. I'll fish around and see what I can find out.

archmage wrote:

Oh thats really bad news for me then if that is the case. I don't think you can assign a variable to a byte in actionscript.

Actionscript only has 3 variable types: number,boolean, and string.

I'm wondering about the WriteByte method in flash.utils, or something like it:

http://help.adobe.com/en_US/AS3LCR/Flash_10.0/flash/utils/IDataOutput.html

update: I noticed that bytearrays are a part of AS3, but not AS2, if that is the version you're using.

Last edited by chalkmarrow (2009-01-25 00:07:33)

I'm wondering if the "chr" function in AS2 might work, much in the same way chr works in the Python code above.

Hmm, I tried moving this thread as chalkmarrow suggested, but apparently didn't succeed, could someone smarter than me try again? Thanks!

archmage: I just realized I had a copy of CS3, so I might be able take a look at the A3 code, though as I said I know nothing about Flash. Is the script pasted above the entire code?

Thanks. I'll see if I can play with it this weekend. One thing that is likely a problem, I just noticed, is that the xmlSocket class is used, rather than the Socket class. Looking around, it appears that this class send and receives full xml-formatted objects. If I were to set up the socket, I would use something like the following, and then play around with the socket methods, such as writeBytes, writeUTFBytes, or the like. I'm not sure how exactly I would do that, but you'll probably have a better idea than I do once you look at the socket class methods, etc.

var s=new Socket();
var sizeBytes:ByteArray = new ByteArray();
var dataOut:String;
s.connect("localhost",42001);
s.addEventListener(Event.CONNECT,socket);
s.addEventListener(Event.CLOSE,socket);
s.addEventListener(IOErrorEvent.IO_ERROR,socket);
function socket(Event):void {
    switch (Event.type) {
        case 'ioError' :
            trace("can't connect");
            break;
        case 'connect' :
            trace("connected");
            break;
        case 'close' :
            trace("can't connect");
            break;
    }
}

I think I need a bit more help because it isn't working.

This is the error flash gives me

ReferenceError: Error #1069: Property send not found on flash.net.Socket and there is no default value.
    at sockets_fla::MainTimeline/sendtoscratch()
    at sockets_fla::MainTimeline/sockets_fla::frame1()
connected


Here is my AS3 code

var s=new Socket();
var sizeBytes:ByteArray = new ByteArray();
var dataOut:String;
s.connect("localhost",42001);
s.addEventListener(Event.CONNECT,socket);
s.addEventListener(Event.CLOSE,socket);
s.addEventListener(IOErrorEvent.IO_ERROR,socket);
function socket(Event):void {
    switch (Event.type) {
        case 'ioError' :
            trace("can't connect");
            break;
        case 'connect' :
            trace("connected");
            break;
        case 'close' :
            trace("can't connect");
            break;
    }
}
sendtoscratch('broadcast "test"');
function sendtoscratch(dataOut:String) {
    sizeBytes[0]=0;
    sizeBytes[1]=0;
    sizeBytes[2]=0;
    sizeBytes[3] = dataOut.length;
    for (var i:Number=0; i<4; i++) {
        s.send(sizeBytes[i]);//send each element in the array to scratch
    }
    s.send(dataOut);//This will send the dataOut variable to scratch
}

I am not familiar with AS3 or sockets so this is kinda hard for me.

Last edited by archmage (2009-01-30 14:00:18)

Thanks for the encouragement Magnie 

If you want to program in a text language easily then try downloading and installing a cool program called hackity hack which lets you code in Ruby and comes with lessons.

Cool I'll Check It Out. 

Oh wow it worked! Thanks so much Chalkmarrow!

Now all I have to do is get it to read data in from scratch which hopefully won't be too difficult.

Yeah. That's why I think Adobe AIR is going to be the way to deliver Flash programs in the future.

btw: Here's a variation of the code that reads from the socket (adding an event handler, and a function at the end):

var s=new Socket();
var dataOut:String;
s.connect("localhost",42001);
s.addEventListener(Event.CONNECT,socket);
s.addEventListener(Event.CLOSE,socket);
s.addEventListener(IOErrorEvent.IO_ERROR,socket);
s.addEventListener(ProgressEvent.SOCKET_DATA, dataInHandler);

function socket(Event):void {
    switch (Event.type) {
        case 'ioError' :
            trace("can't connect");
            break;
        case 'connect' :
            trace("connected");
            break;
        case 'close' :
            trace("can't connect");
            break;
    }
}
sendToScratch('broadcast "test"');

function sendToScratch(dataOut:String) {
    var sizeBytes:ByteArray = new ByteArray();
    sizeBytes[0]=0;
    sizeBytes[1]=0;
    sizeBytes[2]=0;
    sizeBytes[3] = dataOut.length;
    s.writeBytes(sizeBytes);
    s.writeMultiByte(dataOut, "us-ascii");
    s.flush();
}

function dataInHandler(event:ProgressEvent):void {
        var inString:String = s.readUTF();
        trace(inString);      
}