I try to use Kryonet to create an online game.
When I give the ip adress (hardcoded in the code), connection and sendind/receiving works.
But if I try to discover the server, It's never responding me: the method always return null.
Server:
public static int UDP_PORT = 54723, TCP_PORT = 54722;
public static void main(String args[]) {
/* ***** server starting ***** */
Server server = new Server();
server.start();
try {
server.bind(TCP_PORT, UDP_PORT);
} catch (IOException e) {
System.out.println("server not deployed");
e.printStackTrace();
System.exit(1);
}
System.out.println("server started");
server.addListener(new ServerListener());
}
Client:
public static void main(String[] args) {
Client client = new Client();
client.start();
InetAddress addr = client.discoverHost(UDP_PORT, 10000);
System.out.println(addr);
if(addr == null) {
System.exit(0);
}
try {
client.connect(5000, addr, TCP_PORT, UDP_PORT);
} catch (IOException e) {
e.printStackTrace();
}
for(int i = 0; i < 100; i++) {
client.sendTCP(new String("bouh" + i));
}
client.close();
}
What's wrong in this code?
Note that my tests are launched on localhost. Is it a problem here ?
Thank's for all reponse.
Jonathan
If you are having the same problem I had related to discover hosts (http://code.google.com/p/kryonet/issues/detail?id=29) then checking out the project from SVN (instead of using the 2.20 zip file) fixed the issue for me.
Related
I am new to netty and I am trying to design a solution as below for transfer of file from Server to Client over TCP:
1. Zero copy based file transfer in case of non-ssl based transfer (Using default region of the file)
2. ChunkedFile transfer in case of SSL based transfer.
The Client - Server file transfer works in this way:
1. The client sends the location of the file to be transfered
2. Based on the location (sent by the client) the server transfers the file to the client
The file content could be anything (String /image /pdf etc) and any size.
Now, I get this TooLongFrameException: at the Server side, though the server is just decoding the path received from the client, for running the code mentioned below (Server/Client).
io.netty.handler.codec.TooLongFrameException: Adjusted frame length exceeds 65536: 215542494061 - discarded
at io.netty.handler.codec.LengthFieldBasedFrameDecoder.fail(LengthFieldBasedFrameDecoder.java:522)
at io.netty.handler.codec.LengthFieldBasedFrameDecoder.failIfNecessary(LengthFieldBasedFrameDecoder.java:500)
Now, My question is:
Am I wrong with the order of Encoders and Decoders and its configuration? If so, what is the correct way to configure it to receive a file from the server?
I went through few related StackOverflow posts SO Q1,SO Q2 , SO Q3, SO Q4. I got to know about the LengthFieldBasedDecoder, but I didn't get to know how to configure its corresponding LengthFieldPrepender at the Server (Encoding side). Is it even required at all?
Please point me into the right direction.
FileClient:
public final class FileClient {
static final boolean SSL = System.getProperty("ssl") != null;
static final int PORT = Integer.parseInt(System.getProperty("port", SSL ? "8992" : "8023"));
static final String HOST = System.getProperty("host", "127.0.0.1");
public static void main(String[] args) throws Exception {
// Configure SSL.
final SslContext sslCtx;
if (SSL) {
SelfSignedCertificate ssc = new SelfSignedCertificate();
sslCtx = SslContextBuilder.forServer(ssc.certificate(), ssc.privateKey()).build();
} else {
sslCtx = null;
}
// Configure the client
EventLoopGroup group = new NioEventLoopGroup();
try {
Bootstrap b = new Bootstrap();
b.group(group)
.channel(NioSocketChannel.class)
.option(ChannelOption.SO_KEEPALIVE, true)
.handler(new ChannelInitializer<SocketChannel>() {
#Override
public void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
if (sslCtx != null) {
pipeline.addLast(sslCtx.newHandler(ch.alloc(), HOST, PORT));
}
pipeline.addLast("frameDecoder", new LengthFieldBasedFrameDecoder(64*1024, 0, 8));
pipeline.addLast("frameEncoder", new LengthFieldPrepender(4));
pipeline.addLast(new ObjectDecoder(ClassResolvers.cacheDisabled(null)));
pipeline.addLast(new ObjectEncoder());
pipeline.addLast( new FileClientHandler()); }
});
// Start the server.
ChannelFuture f = b.connect(HOST,PORT).sync();
// Wait until the server socket is closed.
f.channel().closeFuture().sync();
} finally {
// Shut down all event loops to terminate all threads.
group.shutdownGracefully();
}
}
}
FileClientHandler:
public class FileClientHandler extends ChannelInboundHandlerAdapter{
#Override
public void channelActive(ChannelHandlerContext ctx) {
String filePath = "/Users/Home/Documents/Data.pdf";
ctx.writeAndFlush(Unpooled.wrappedBuffer(filePath.getBytes()));
}
#Override
public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
System.out.println("File Client Handler Read method...");
}
#Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
}
}
FileServer:
/**
* Server that accept the path of a file and echo back its content.
*/
public final class FileServer {
static final boolean SSL = System.getProperty("ssl") != null;
static final int PORT = Integer.parseInt(System.getProperty("port", SSL ? "8992" : "8023"));
public static void main(String[] args) throws Exception {
// Configure SSL.
final SslContext sslCtx;
if (SSL) {
SelfSignedCertificate ssc = new SelfSignedCertificate();
sslCtx = SslContextBuilder.forServer(ssc.certificate(), ssc.privateKey()).build();
} else {
sslCtx = null;
}
// Configure the server.
EventLoopGroup bossGroup = new NioEventLoopGroup(1);
EventLoopGroup workerGroup = new NioEventLoopGroup();
try {
ServerBootstrap b = new ServerBootstrap();
b.group(bossGroup, workerGroup).channel(NioServerSocketChannel.class)
.option(ChannelOption.SO_KEEPALIVE, true).handler(new LoggingHandler(LogLevel.INFO))
.childHandler(new ChannelInitializer<SocketChannel>() {
#Override
public void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
if (sslCtx != null) {
pipeline.addLast(sslCtx.newHandler(ch.alloc()));
}
pipeline.addLast("frameDecoder",new LengthFieldBasedFrameDecoder(64*1024, 0, 8));
pipeline.addLast("frameEncoder", new LengthFieldPrepender(4));
pipeline.addLast(new ObjectDecoder(ClassResolvers.cacheDisabled(null)));
pipeline.addLast(new ObjectEncoder());
pipeline.addLast(new ChunkedWriteHandler());
pipeline.addLast(new FileServerHandler());
}
});
// Start the server.
ChannelFuture f = b.bind(PORT).sync();
// Wait until the server socket is closed.
f.channel().closeFuture().sync();
} finally {
bossGroup.shutdownGracefully();
workerGroup.shutdownGracefully();
}
}
}
FileServerHandler:
public class FileServerHandler extends ChannelInboundHandlerAdapter {
#Override
public void channelRead(ChannelHandlerContext ctx, Object obj) throws Exception {
RandomAccessFile raf = null;
long length = -1;
try {
ByteBuf buff = (ByteBuf)obj;
byte[] bytes = new byte[buff.readableBytes()];
buff.readBytes(bytes);
String msg = new String(bytes);
raf = new RandomAccessFile(msg, "r");
length = raf.length();
} catch (Exception e) {
ctx.writeAndFlush("ERR: " + e.getClass().getSimpleName() + ": " + e.getMessage() + '\n');
return;
} finally {
if (length < 0 && raf != null) {
raf.close();
}
}
if (ctx.pipeline().get(SslHandler.class) == null) {
// SSL not enabled - can use zero-copy file transfer.
ctx.writeAndFlush(new DefaultFileRegion(raf.getChannel(), 0, length));
} else {
// SSL enabled - cannot use zero-copy file transfer.
ctx.writeAndFlush(new ChunkedFile(raf));
}
}
#Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
System.out.println("Exception server.....");
}
}
I referred Netty In Action and code samples from here
There are multiple things wrong with your server/client. First thing the SSL, for the client you don't need to initialize a SslContext for a server instead you would do something like this:
sslCtx = SslContextBuilder.forClient().trustManager(InsecureTrustManagerFactory.INSTANCE).build();
On the server side of things you use a SelfSignedCertificate which in itself isn't wrong but would like to remind you that it should only be used for debugging purposes and not in production. In addition you use the ChannelOption.SO_KEEPALIVE which isn't recommended since the keepalive interval is OS-dependent. Furthermore you added Object En-/Decoder to your pipeline which in your case don't do anything useful so you can remove them.
Also you configured your LengthFieldBasedFrameDecoder wrong due to an incomplete and wrong parameter list. In the netty docs you need the version of the constructor which defines the lengthFieldLength and initialBytesToStrip. Besides the not stripping the length field you also defined the wrong lengthFieldLength which should be the same as your LengthFieldPrepender's lengthFieldLength which is 4 bytes. In conlusion you could use the constructor like this:
new LengthFieldBasedFrameDecoder(64 * 1024, 0, 4, 0, 4)
In both your handler you don't specify a Charset when en-/decoding your String which could lead to problems because if no ´Charset´ is defined the systems default will be used which could vary. You could do something like this:
//to encode the String
string.getBytes(StandardCharsets.UTF_8);
//to decode the String
new String(bytes, StandardCharsets.UTF_8);
Additionally you tried to use the DefaultFileRegion if no SslHandler was added to the pipeline which would have been fine if you didn't added the LengthFieldHandler since they would need a memory copy of the byte[] to send to added the length field. Moreover I would recommend using the ChunkedNioFile instead of the ChunkedFile because it's nonblocking which is always a good thing. You would do this like that:
new ChunkedNioFile(randomAccessFile.getChannel())
One final thing on how to decode a ChunkedFile as it's split in chunks you can simply assamble them tougether with a simple OutputStream. Here's an old file handler of mine:
public class FileTransferHandler extends SimpleChannelInboundHandler<ByteBuf> {
private final Path path;
private final int size;
private final int hash;
private OutputStream outputStream;
private int writtenBytes = 0;
private byte[] buffer = new byte[0];
protected FileTransferHandler(Path path, int size, int hash) {
this.path = path;
this.size = size;
this.hash = hash;
}
#Override
protected void channelRead0(ChannelHandlerContext ctx, ByteBuf byteBuf) throws Exception {
if(this.outputStream == null) {
Files.createDirectories(this.path.getParent());
if(Files.exists(this.path))
Files.delete(this.path);
this.outputStream = Files.newOutputStream(this.path, StandardOpenOption.CREATE, StandardOpenOption.APPEND);
}
int size = byteBuf.readableBytes();
if(size > this.buffer.length)
this.buffer = new byte[size];
byteBuf.readBytes(this.buffer, 0, size);
this.outputStream.write(this.buffer, 0, size);
this.writtenBytes += size;
if(this.writtenBytes == this.size && MurMur3.hash(this.path) != this.hash) {
System.err.println("Received file has wrong hash");
return;
}
}
#Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
if(this.outputStream != null)
this.outputStream.close();
}
}
I am receiving strings from my server that I want to append into a Textarea on the client side (Think chat window). Problem is, when I receive the string, the client freezes.
insertUserNameButton.setOnAction((event) -> {
userName=userNameField.getText();
try {
connect();
} catch (IOException e) {
e.printStackTrace();
}
});
public Client() {
userInput.setOnAction((event) -> {
out.println(userInput.getText());
userInput.setText("");
});
}
private void connect() throws IOException {
String serverAddress = hostName;
Socket socket = new Socket(serverAddress, portNumber);
in = new BufferedReader(new InputStreamReader(
socket.getInputStream()));
out = new PrintWriter(socket.getOutputStream(), true);
while (true) {
String line = in.readLine();
if (line.startsWith("SUBMITNAME")) {
out.println(userName);
} else if (line.startsWith("MESSAGE")) {
Platform.runLater(()->serverOutput.appendText(line.substring(8) + "\n"));
} else if (line.startsWith("QUESTION")) {
Platform.runLater(()->serverOutput.appendText(line.substring(8) + "\n"));
} else if (line.startsWith("CORRECTANSWER")) {
Platform.runLater(()->serverOutput.appendText(line.substring(14) + "\n"));
}
}
}
public static void main(String[] args) {
launch(args);
}
I have done some research and it seems that using Platform.runLater on each append should fix the problem. It doesn't for me.
Anyone has an idea of what it can be caused by? Thank you!
You are calling connect() on the FX Application Thread. Since it blocks indefinitely via the
while(true) {
String line = in.readLine();
// ...
}
construct, you block the FX Application Thread and prevent it from doing any of its usual work (rendering the UI, responding to user events, etc).
You need to run this on a background thread. It's best to use a Executor to manage the threads:
private final Executor exec = Executors.newCachedThreadPool(runnable -> {
Thread t = new Thread(runnable);
t.setDaemon(true);
return t ;
});
and then do
insertUserNameButton.setOnAction((event) -> {
userName=userNameField.getText();
exec.execute(() -> {
try {
connect();
} catch (IOException e) {
e.printStackTrace();
}
});
});
I'm using this to install my application as a windows service. Everything works fine except the service does not stop;
#Override
public int serviceMain(String[] strings) throws ServiceException {
try {
System.out.println("BootService: init");
System.out.println("BootService: service loop start");
while (ws.isServiceRunning()) {
System.out.println("BootService: loop");
ws.serviceHandler();
}
System.out.println("BootService: stopped");
return 0;
} catch (Exception ex) {
throw new ServiceException(ex);
}
}
#Override
public int serviceRequest(int control) throws ServiceException {
try {
switch (control) {
case SERVICE_CONTROL_SHUTDOWN:
case SERVICE_CONTROL_STOP:
if (ws!=null) {
ws.stopService();
}
break;
}
return 0;
} catch (WindowsServiceException ex) {
throw new ServiceException(ex);
}
}
My service backend code is stopped by the call to serviceRequest(), which in turn makes the loop in serviceMain() exit. I see the message "BootService: stopped" in my logs, yet the Window Control Panel Services Applet just sits says "Stopping service...", but it never does.
What would stop the service from stopping even though I'm sure it has exited the serviceMain() without error?
I don´t know if you could solve it, but I had a simmilar problem and I fixed it by adding a timer that called System.exit(0)
public int serviceMain(String[] args) throws ServiceException {
while (!shutdown) {
try {
if (!myservice.isRunning()) {
(new Thread(new LaucherRunnable(args))).start();
}
Thread.sleep(6000);
} catch (InterruptedException e) {
}
}
periodicRunner.stop();
Timer t = new Timer(1000, new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
t.setRepeats(false);
t.start();
return 0;
}
I'm trying to access a XML file from client side in GWT. But it looks like the sendRequest method is not getting fired at all.
I'm able to see the xml in the browser. Do I need to do any thing in the server side?
Any help is appreciated.
Here's my code
String xmlurl = "http://localhost:8888/test.xml";
RequestBuilder builder = new RequestBuilder(RequestBuilder.GET, URL.encode(xmlurl));
try {
Request request = builder.sendRequest(null, new RequestCallback() {
public void onError(Request request, Throwable exception) {
System.out.println(exception);
}
public void onResponseReceived(Request request, Response response) {
if (200 == response.getStatusCode()) {
System.out.println(response.getText());
} else {
System.out.println(response.getStatusCode());
}
}
});
} catch (RequestException e) {
System.out.println("exception"+e);
}
I tried the following code too, but have the same problem. The developer tool shows response status as 200 and correct response text. Only, its not working in the code.
String xmlurl = "http://127.0.0.1:8888/test.xml";
httpGetFile(xmlurl, new AsyncCallback<String>() {
public void onFailure(Throwable caught) {
xmlData = "Error";
}
public void onSuccess(String xmlText) {
xmlData = xmlText;
}
});
public static void httpGetFile(final String url, final AsyncCallback<String> callback) {
final RequestBuilder rb = new RequestBuilder(RequestBuilder.GET, url);
rb.setCallback(new RequestCallback() {
public void onResponseReceived(Request request, Response response) {
try {
System.out.println("dafadfdf");
final int responseCode = response.getStatusCode() / 100;
if (url.startsWith("file:/") || (responseCode == 2)) {
callback.onSuccess(response.getText());
} else {
callback.onFailure(new IllegalStateException("HttpError#" + response.getStatusCode() + " - " + response.getStatusText()));
}
} catch (Throwable e) {
callback.onFailure(e);
}
}
public void onError(Request request, Throwable exception) {
callback.onFailure(exception);
}
});
try {
rb.send();
} catch (RequestException e) {
callback.onFailure(e);
}
}
Always Use logging instead of System.out.print statements https://developers.google.com/web-toolkit/doc/latest/DevGuideLogging
Step 1 - Add logging statements to failure, success and try catch statements. Clean up the exception.
Step 2 - "Parsing the XML" should be done inside the "onSuccess" method of the rb callback.
You do not need a RequestBuilder at all to access an XML file. You can use an ExternalTextResource for this:
https://developers.google.com/web-toolkit/doc/latest/DevGuideClientBundle#TextResource
I'm trying to connect to SSH Unix server on button click (code written in actionPerformed() method). I'm using JSch for connecting to SSH server. The code is written in SwingWorker class as it is a network operation.
private void testConnectionButtonActionPerformed(java.awt.event.ActionEvent evt) {
SwingWorker<Boolean, Void> sw = new SwingWorker<Boolean, Void>(){
#Override
protected Boolean doInBackground() throws Exception {
JSch jsch = new JSch();
String host = "ServerHost";
String username = "username";
String password = "password";
Session session = jsch.getSession(username, host);
session.setPassword(password);
session.setTimeout(20000);
System.out.println("Connecting to server...");
session.connect();
return true;
}
#Override
public void done(){
try {
System.out.println(get().toString());
} catch (Exception ex) {
System.out.err(ex);
}
}
};
sw.execute();
}
But after running the with correct host, username and password details, I get the below error all the time:
com.jcraft.jsch.JSchException: timeout: socket is not established
at java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:222)
at java.util.concurrent.FutureTask.get(FutureTask.java:83)
at javax.swing.SwingWorker.get(SwingWorker.java:583)
But whenever I run the same code in standalone program, I mean instead for writing actionPerformed() method, If I write it in normal method and calling from main() method. It will work. when I integrate the same code with Button Click's actionPerformed() method, it will give me above exception.
Can anyone suggest what I'm doing wrong here or any modification should be made to the code.
I tried to connect to SSH Server using "SSHJ" implementation, but I get the below error:
java.net.SocketException: Connection reset
at java.util.concurrent.FutureTask$Sync.innerGet(FutureTask.java:222)
at java.util.concurrent.FutureTask.get(FutureTask.java:83)
at javax.swing.SwingWorker.get(SwingWorker.java:583)
Can someone help me - how to move forward?
I took your code, wrapped it in some GUI code (and converted it to non-generics to be able to compile it with the same settings as the rest of the JSch examples). It works for me. Try this, and report what exception you get (it has a bit more exception logging).
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
import com.jcraft.jsch.*;
class SwingWorkerExample {
JTextField hostField;
JTextField userNameField;
JTextField passwordField;
JPanel panel;
public SwingWorkerExample() {
JPanel p = panel = new JPanel(new GridLayout(0,2));
hostField = new JTextField(20);
userNameField = new JTextField(20);
passwordField = new JPasswordField(20);
JButton testButton = new JButton("connect!");
testButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ev) {
testConnectionButtonActionPerformed(ev);
}
});
p.add(new JLabel("host:"));
p.add(hostField);
p.add(new JLabel("user:"));
p.add(userNameField);
p.add(new JLabel("password:"));
p.add(passwordField);
p.add(testButton);
}
public JPanel getPanel() {
return panel;
}
private void testConnectionButtonActionPerformed(ActionEvent evt) {
SwingWorker sw = new SwingWorker(){
protected Object doInBackground() throws Exception {
try {
JSch jsch = new JSch();
String host = hostField.getText();
String username = userNameField.getText();
String password = passwordField.getText();
Session session = jsch.getSession(username, host);
session.setPassword(password);
session.setConfig("StrictHostKeyChecking", "no");
session.setTimeout(20000);
System.out.println("Connecting to server...");
session.connect();
return session;
}
catch(Exception ex) {
ex.printStackTrace();
throw ex;
}
}
public void done(){
try {
System.out.println(get());
} catch (Exception ex) {
ex.printStackTrace();
}
}
};
sw.execute();
}
public static void main(String[] egal) {
EventQueue.invokeLater(new Runnable(){public void run() {
SwingWorkerExample ex = new SwingWorkerExample();
JFrame f = new JFrame("bla");
f.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
f.setContentPane(ex.getPanel());
f.pack();
f.setVisible(true);
}});
}
}