Very strange problem about flashplayer policy file request

[davy zhang <da...@gmail.com>]

as it well-known flashplayer will request a policy file from the port
843(by default)

I set up my server at that port use mina 1.1.7, I can successfully
receive the message from the flashplayer

it said <policy-file-request/> + "\0"

but the problem is flashplayer disconnected immediately that request
and I can't send the policy data back.

I've been there for days ... sigh~

I tried the pure nio non-block server way, didn't use any external library

the problem still there!

So I guess it's not the mina's fault, right?

I know the adobe claimed the player will disconnect the server when it
received a "\0"

cause by the "contract" from adobe that means the end of policy file data.

Is there any possibility the java sent a "\0" after the message
arrived ?? it's just so wierd~

I managed to solve this problem used the traditional thread-blocking
way in java, it works

so that is said flashplayer can only use block way ?

but that make no sense~, is there any difference to the client whether
the server is working on blocking or non-blocking way???

I've been tried use FreePascal to write the policy server before, it
use non-block and event-driven model too and works fine,

I just so confused about what is going on there....

the reproduct the scene is very easy setup a mina server on localhost:843

write a simple flash code to connect to any port on localhost.

the attachment is the flash swf file and html , it will try to connect
the 80 port on localhost

you can host this files on your machine and start the mina server and
click on the flash connect button.

y

Re: Very strange problem about flashplayer policy file request

[davy zhang <da...@gmail.com>]

I think I know where was wrong now

the older version mina 1.x didn't handle the TransportMetadata like 2.0.x ....

in the code hasFragmentation is used to handle this situation, seems a
bug in mina 1.x

in the 1.x code the read function is pretty simple, when ret < 0 ,
close the client connect

   private void read(T session) {
        IoSessionConfig config = session.getConfig();
        IoBuffer buf = IoBuffer.allocate(config.getReadBufferSize());

        final boolean hasFragmentation =
            session.getTransportMetadata().hasFragmentation();

        try {
            int readBytes = 0;
            int ret;

            try {
                if (hasFragmentation) {
                    while ((ret = read(session, buf)) > 0) {
                        readBytes += ret;
                        if (!buf.hasRemaining()) {
                            break;
                        }
                    }
                } else {
                    ret = read(session, buf);
                    if (ret > 0) {
                        readBytes = ret;
                    }
                }
            } finally {
                buf.flip();
            }

            if (readBytes > 0) {
                session.getFilterChain().fireMessageReceived(buf);
                buf = null;

                if (hasFragmentation) {
                    if (readBytes << 1 < config.getReadBufferSize()) {
                        session.decreaseReadBufferSize();
                    } else if (readBytes == config.getReadBufferSize()) {
                        session.increaseReadBufferSize();
                    }
                }
            }
            if (ret < 0) {
                scheduleRemove(session);
            }
        } catch (Throwable e) {
            if (e instanceof IOException) {
                scheduleRemove(session);
            }
            session.getFilterChain().fireExceptionCaught(e);
        }
    }

but I don't really know what is the fragmentation could be ?

and why the pure nio server code can't work properly, the pure nio code is below

package main;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.ServerSocketChannel;
import java.nio.channels.SocketChannel;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CharsetEncoder;
import java.util.Iterator;
import java.util.Set;

public class ServerMain {

	/**
	 * @param args
	 */
	public static void main(String[] args) throws IOException {
		Charset charset = Charset.forName("UTF-8");
		CharsetEncoder encoder = charset.newEncoder();
		CharsetDecoder decoder = charset.newDecoder();

		ByteBuffer buffer = ByteBuffer.allocate(512);

		Selector selector = Selector.open();

		ServerSocketChannel server = ServerSocketChannel.open();
		server.socket().bind(new java.net.InetSocketAddress(843));
		server.configureBlocking(false);
		SelectionKey serverkey = server.register(selector,
				SelectionKey.OP_ACCEPT);

		for (;;) {
			// wait here for event
			System.out.println("server started at "
					+ server.socket().getLocalPort());
			selector.select();
			Set<SelectionKey> keys = selector.selectedKeys();

			for (Iterator i = keys.iterator(); i.hasNext();) {
				SelectionKey key = (SelectionKey) i.next();
				i.remove();

				if (key == serverkey) {
					if (key.isAcceptable()) {
						SocketChannel client = server.accept();
						client.configureBlocking(false);
						SelectionKey clientkey = client.register(selector,
								SelectionKey.OP_READ);
						clientkey.attach(new Integer(0));
					}
				} else {
					SocketChannel client = (SocketChannel) key.channel();
					if (!key.isReadable())
						continue;
					int bytesread = client.read(buffer);
					if (bytesread == -1) {
						key.cancel();
						client.close();
						continue;
					}
					buffer.flip();
					String request = decoder.decode(buffer).toString();
					System.out.println("msg received: " + request);
					client.write(encoder.encode(CharBuffer.wrap(request)));
					buffer.clear();
					if (request.trim().equals("quit")) {
						client.write(encoder.encode(CharBuffer.wrap("Bye.")));
						key.cancel();
						client.close();
					} else {
						int num = ((Integer) key.attachment()).intValue();
						String response = num + ": " + request.toUpperCase();
						client.write(encoder.encode(CharBuffer.wrap(response)));
						key.attach(new Integer(num + 1));
					}
				}
			}
		}
	}
}




On Sun, Sep 14, 2008 at 7:34 PM, davy zhang <da...@gmail.com> wrote:
> as it well-known flashplayer will request a policy file from the port
> 843(by default)
>
> I set up my server at that port use mina 1.1.7, I can successfully
> receive the message from the flashplayer
>
> it said <policy-file-request/> + "\0"
>
> but the problem is flashplayer disconnected immediately that request
> and I can't send the policy data back.
>
> I've been there for days ... sigh~
>
> I tried the pure nio non-block server way, didn't use any external library
>
> the problem still there!
>
> So I guess it's not the mina's fault, right?
>
> I know the adobe claimed the player will disconnect the server when it
> received a "\0"
>
> cause by the "contract" from adobe that means the end of policy file data.
>
> Is there any possibility the java sent a "\0" after the message
> arrived ?? it's just so wierd~
>
> I managed to solve this problem used the traditional thread-blocking
> way in java, it works
>
> so that is said flashplayer can only use block way ?
>
> but that make no sense~, is there any difference to the client whether
> the server is working on blocking or non-blocking way???
>
> I've been tried use FreePascal to write the policy server before, it
> use non-block and event-driven model too and works fine,
>
> I just so confused about what is going on there....
>
> the reproduct the scene is very easy setup a mina server on localhost:843
>
> write a simple flash code to connect to any port on localhost.
>
> the attachment is the flash swf file and html , it will try to connect
> the 80 port on localhost
>
> you can host this files on your machine and start the mina server and
> click on the flash connect button.
>
> y
>