I just started using Netty. It looks very interesting but I encountered a problem. After the client is connected, a message should be received but that's not happening. For some reason connection works fine; it says Channel Connected.
Server:
this.bossgroup = new NioEventLoopGroup();
ServerBootstrap bootstrap = new ServerBootstrap()
.group(bossgroup)
.channel(NioServerSocketChannel.class)
.childHandler(new ChannelInitializer<SocketChannel>() {
#Override
protected void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast("framer", new DelimiterBasedFrameDecoder(8192, Delimiters.lineDelimiter()))
.addLast("decoder", new StringDecoder())
.addLast("encoder", new StringEncoder())
.addLast("timer", new ReadTimeoutHandler(10))
.addLast("handler", new ChannelHandler());
}
});
ChannelHandler :
public class ChannelHandler extends SimpleChannelInboundHandler<String> {
#Override
public void channelActive(ChannelHandlerContext ctx) throws Exception {
System.out.println("[+] Channel connected: " + ctx.channel().remoteAddress());
new ClientHandler(ctx.channel());
}
#Override
public void channelInactive(ChannelHandlerContext ctx) throws Exception {
System.out.println("Channel disconnected: " + ctx.channel().remoteAddress() + " [-]");
ctx.close();
}
#Override
protected void messageReceived(ChannelHandlerContext ctx, String msg) throws Exception {
System.out.println(ctx.channel().remoteAddress() + ": " + msg);
}
#Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
System.out.println("Exception caught, closing channel." + cause);
ctx.close();
}
}
Solved By:
ChannelInboundHandlerAdapter
Instead Of:SimpleChannelInboundHandler
Related
I'v got no idea about the "read" method of the ChannelOutboundHandle.
why this method occurred in the ChannelOutboundHandle, what's its for?
cause the outboundHandlers are used to handle the output, they are usually
used to write data to wire.
and also I got a problem when I'm using the "read" method.I wrote a EchoServer by netty. here is my code:
public class EchoServer {
public static void main(String[] args) {
// this handler is sharable
final EchoServerInboundHandler echoServerInboundHandler = new EchoServerInboundHandler();
EventLoopGroup eventLoopGroup = new NioEventLoopGroup();
ServerBootstrap serverBootstrap = new ServerBootstrap();
// setup group
serverBootstrap.group(eventLoopGroup)
// setup channelFactory
.channel(NioServerSocketChannel.class)
// listening port
.localAddress(new InetSocketAddress(8080))
.childHandler(new ChannelInitializer<SocketChannel>() {
#Override
protected void initChannel(SocketChannel ch) throws Exception {
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast(echoServerInboundHandler);
pipeline.addLast(new EchoServerOutboundHandler());
}
});
try {
ChannelFuture f = serverBootstrap.bind().sync();
f.addListener(new ChannelFutureListener() {
public void operationComplete(ChannelFuture future) throws Exception {
if (future.isSuccess()) {
System.out.println(future.channel().localAddress()+" started!");
}
}
});
f.channel().closeFuture().sync();
} catch (InterruptedException e) {
e.printStackTrace();
}finally {
// release all threads
eventLoopGroup.shutdownGracefully().syncUninterruptibly();
}
}
}
public class EchoServerOutboundHandler extends ChannelOutboundHandlerAdapter {
#Override
public void read(ChannelHandlerContext ctx) throws Exception {
System.out.println("read");
//super.read(ctx);
}
#Override
public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
System.out.println("msg:"+msg);
super.write(ctx, msg, promise);
}
#Override
public void flush(ChannelHandlerContext ctx) throws Exception {
super.flush(ctx);
}
#Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
}
#ChannelHandler.Sharable
public class EchoServerInboundHandler extends ChannelInboundHandlerAdapter {
#Override
public void channelRead(ChannelHandlerContext ctx, Object msg) {
ctx.writeAndFlush(msg);
}
#Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
cause.printStackTrace();
ctx.close();
}
#Override
public void channelActive(ChannelHandlerContext ctx) {
System.out.println("client:"+ctx.channel().remoteAddress()+" connected!");
}
#Override
public void channelInactive(ChannelHandlerContext ctx) {
System.out.println("client:"+ctx.channel().remoteAddress()+" disconnected!");
}
#Override
public void channelRegistered(ChannelHandlerContext ctx) throws Exception {
System.out.println("EchoServerInboundHandler registered");
super.channelRegistered(ctx);
}
#Override
public void channelUnregistered(ChannelHandlerContext ctx) throws Exception {
System.out.println("EchoServerInboundHandler unregistered");
super.channelUnregistered(ctx);
}
}
as U can see, I comment the super.read(ctx); in the read method of the EchoServerOutboundHandler which cause a problem that it can't write data to the client. and also I found that this method will be called when a client established a connection.
At the very least, you need to provide the same code that the parent object would do in the super() method, which is ctx.read()
Which is what the JavaDoc says...
Calls ChannelHandlerContext.read() ...
Otherwise, all you're doing is printing something on your own, and not using Netty to handle anything.
I read the documentation of IdleStateHandlerand from my Server I implemented it same as from the documentation,
but I don't understand on how can I exactly tell if the Client become disconnected for example the Client loses the Wifi Connectivity.
from my understanding, inside my Handler, the method channelInactive() was trigger when the client become disconnected,
then using IdleStateHandler, the IdleState.READER_IDLE will be triggered when no read was performed for the specified period of time,
then after 3 seconds of no read from the client I closed the channel and was expecting that the channelInactive will be trigger but it's not, why?.
Initializer
public class ServerInitializer extends ChannelInitializer<SocketChannel> {
String TAG = "LOG: ";
#Override
protected void initChannel(SocketChannel ch) throws Exception {
System.out.println(TAG + "Starting ServerInitializer class...");
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast("decoder", new ObjectDecoder(ClassResolvers.cacheDisabled(null)));
pipeline.addLast("encoder", new ObjectEncoder());
pipeline.addLast("idleStateHandler", new IdleStateHandler(6, 3, 0, TimeUnit.SECONDS));
pipeline.addLast("handler", new ServerHandler());
}
}
Handler
public class ServerHandler extends ChannelInboundHandlerAdapter {
private String TAG = "LOG: ";
public ServerHandler(){}
#Override
public void channelActive(ChannelHandlerContext ctx) {
Log.w(TAG,"New Client become connected, Sending a message to the Client. Client Socket is: " + ctx.channel().remoteAddress().toString());
List<String> msg = new ArrayList<>();
msg.add(0,"sample message 1");
msg.add(1,"sample message 2");
sendMessage(ctx, msg);
}
public void sendMessage(ChannelHandlerContext ctx, List message){
ctx.write(message);
ctx.flush();
}
#Override
public void channelInactive(ChannelHandlerContext ctx) {
Log.w(TAG,"A Client become disconnected. Client Socket is: " + ctx.channel().remoteAddress().toString() + " id: " + (String.valueOf(ctx.channel().hashCode())));
//COnnection id dead, do something here...
}
#Override
public void channelRead(ChannelHandlerContext ctx, Object object) { // (2)
Log.w(TAG, "CLIENT: "+ ctx.channel().remoteAddress().toString() + " SAYS: " + object);
}
#Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { // (4)
// Close the connection for that client when an exception is raised.
Log.e(TAG,"Something's wrong, CLIENT: "+ ctx.channel().remoteAddress().toString() + " CAUSE: " + cause.toString());
ctx.close();
}
#Override
public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
Log.w(TAG,"LOLO");
if (evt instanceof IdleStateEvent) {
IdleStateEvent e = (IdleStateEvent) evt;
if (e.state() == IdleState.READER_IDLE) {
ctx.close(); //Closed the Channel so that the `channelInactive` will be trigger
} else if (e.state() == IdleState.WRITER_IDLE) {
ctx.writeAndFlush("ping\n"); //Send ping to client
}
}
}
}
Anyone can help me out
IdleStateHandler should always be the first handler in your pipeline.
Use the ReadTimeoutHandler instead of IdleStateHandler and override the exceptionCaught method.
This question already has answers here:
Official reasons for "Software caused connection abort: socket write error"
(14 answers)
Closed 5 years ago.
I'm trying to go through the SSL example and EchoServer example in Netty and for some reason, when I add my sslContext on the client side, I keep getting, an established connection was aborted by the software in your host machine.
EchoServerBootstrap
public class EchoServerBootstrap {
private final int port;
public EchoServerBootstrap(int port) {
this.port = port;
}
public static void main(String[] args) throws Exception {
new EchoServerBootstrap(3000).start();
}
public void start() throws Exception {
SelfSignedCertificate ssc = new SelfSignedCertificate();
final SslContext sslContext = SslContextBuilder.forServer(ssc.certificate(), ssc.privateKey()).build();
EventLoopGroup group = new NioEventLoopGroup();
try {
ServerBootstrap b = new ServerBootstrap();
b.group(group)
.channel(NioServerSocketChannel.class)
.localAddress(new InetSocketAddress(port))
.handler(new LoggingHandler(LogLevel.INFO))
.childHandler(new ChannelInitializer<SocketChannel>() {
#Override
protected void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast(sslContext.newHandler(ch.alloc()));
ch.pipeline().addLast(new EchoServerHandler());
}
});
ChannelFuture f = b.bind().sync();
f.channel().closeFuture().sync();
} finally {
group.shutdownGracefully().sync();
}
}
}
EchoServerHandler
public class EchoServerHandler extends ChannelInboundHandlerAdapter {
#Override
public void channelRead(ChannelHandlerContext ctx, Object msg) {
ByteBuf in = (ByteBuf) msg;
System.out.println("Received: " + in.toString(CharsetUtil.UTF_8));
ctx.write(in);
}
#Override
public void channelReadComplete(ChannelHandlerContext ctx) {
System.out.println("channel read complete");
ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(ChannelFutureListener.CLOSE);
}
#Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
ctx.close();
}
}
EchoClientHandler
public class EchoClientHandler extends SimpleChannelInboundHandler<ByteBuf> {
#Override
public void channelActive(ChannelHandlerContext ctx) {
ctx.writeAndFlush(Unpooled.copiedBuffer("Netty rocks", CharsetUtil.UTF_8));
}
#Override
public void channelRead0(ChannelHandlerContext ctx, ByteBuf in) {
System.out.println("Client receive: " + in.toString(CharsetUtil.UTF_8));
}
#Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
ctx.close();
}
}
EchoClientBootstrap
public class EchoClientBootstrap {
private final String host;
private final int port;
public EchoClientBootstrap(String host, int port) {
this.port = port;
this.host = host;
}
public void start() throws Exception {
EventLoopGroup group = new NioEventLoopGroup();
final SslContext sslContext = SslContextBuilder.forClient().trustManager(InsecureTrustManagerFactory.INSTANCE).build();
try {
Bootstrap b = new Bootstrap();
b.group(group)
.channel(NioSocketChannel.class)
.remoteAddress(new InetSocketAddress(host, port))
.handler(new ChannelInitializer<SocketChannel>() {
#Override
public void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast(sslContext.newHandler(ch.alloc(), host, port)); // WHEN I ADD THIS LINE IT FAILS WITH I/O EXCEPTION 'an established connection was aborted...'
ch.pipeline().addLast(new EchoClientHandler());
}
});
ChannelFuture f = b.connect(host, port).sync();
f.channel().closeFuture().sync();
} finally {
group.shutdownGracefully().sync();
}
}
public static void main(String[] args) throws Exception {
new EchoClientBootstrap("localhost", 3000).start();
}
}
Is there something obvious I'm missing? I tried following this example and altering it a bit (http://netty.io/4.1/xref/io/netty/example/securechat/package-summary.html), but I keep getting that exception when I add the sslContext to the client channel. Any thoughts?
I added some logging to figure out what was going on, and without encryption, EchoClient sends over the "Netty rocks" message and the server reads the message and closes the channel. But for some reason if SSL is enabled, the EchoServerHandler calls channelReadComplete before the EchoClient can send "Netty rocks" which is essentially this method
#Override
public void channelReadComplete(ChannelHandlerContext ctx) {
System.out.println("channel read complete");
ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(ChannelFutureListener.CLOSE);
}
which was closing my channel. I am not sure why there is that discrepancy when using SSL.
I implemented a very basic EchoClient and EchoServer using the Netty package in JAVA. I am very much new to Netty . Below are the codes for my client , clientHandler , server and serverHandler.
My Client
public class EchoClient {
private final String host;
private final int port;
public EchoClient(String host, int port) {
this.host = host;
this.port = port;
}
public static void main(String[] args) throws Exception {
new EchoClient("127.0.0.1", 11235).start();
}
public void start() throws Exception {
EventLoopGroup group = new NioEventLoopGroup();
try {
Bootstrap b = new Bootstrap();
b.group(group).channel(NioSocketChannel.class)
.remoteAddress(new InetSocketAddress(host, port))
.handler(new ChannelInitializer<SocketChannel>() {
#Override
public void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast(new EchoClientHandler());
}
});
ChannelFuture future = b.connect().sync();
future.channel().closeFuture().sync();
} finally {
group.shutdownGracefully().sync();
}
}
}
My ClientHandler
public class EchoClientHandler extends SimpleChannelInboundHandler<ByteBuf>{
#Override
public void channelActive(ChannelHandlerContext ctx) {
System.out.println("Connected");
int i = 0;
while (i < 1000) {
ctx.writeAndFlush(Unpooled.copiedBuffer("Netty MAY rock!\n", CharsetUtil.UTF_8));
i++;
}
}
#Override
protected void channelRead0(ChannelHandlerContext ctx, ByteBuf in) throws Exception {
System.out.println(
"Client received: " + in.toString(CharsetUtil.UTF_8));
}
#Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause){
cause.printStackTrace();
ctx.close();
}
}
My Server
public class EchoServer {
private final int port;
public EchoServer(int port) {
this.port = port;
}
public static void main(String[] args) throws Exception {
new EchoServer(11235).start();
}
public void start() throws Exception {
EventLoopGroup group = new NioEventLoopGroup();
try {
ServerBootstrap b = new ServerBootstrap();
b.group(group)
.channel(NioServerSocketChannel.class)
.localAddress(new InetSocketAddress(port))
.childHandler(new ChannelInitializer<SocketChannel>() {
#Override
public void initChannel(SocketChannel ch) throws Exception {
System.out.println("New client connected: " + ch.localAddress());
ch.pipeline().addLast(new EchoServerHandler());
}
});
ChannelFuture f = b.bind().sync();
f.channel().closeFuture().sync();
} finally {
group.shutdownGracefully().sync();
}
}
}
My SeverHandler
public class EchoServerHandler extends ChannelInboundHandlerAdapter {
#Override
public void channelRead(ChannelHandlerContext ctx, Object msg) {
ByteBuf in = (ByteBuf) msg;
System.out.println("Server received: " + n.toString(CharsetUtil.UTF_8));
ctx.write(in);
}
#Override
public void channelReadComplete(ChannelHandlerContext ctx) {
ctx.writeAndFlush(Unpooled.EMPTY_BUFFER)
.addListener(ChannelFutureListener.CLOSE);
}
#Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
ctx.close();
}
}
Now the problem is : when I write the while loop in the ClientHandler as i<10 or i<100 both the Server and Client can receive the sent messages but if I increase the iterations upto 1000 and 10000, the Sever is receiving message but not the client. Even the server is unable to receive 10000 messages(only some of the messages are received).
You close your server channel immediately after the first reading. Please remove .addListener(ChannelFutureListener.CLOSE) in channelReadComplete of your EchoServerHandler class.
I'm trying to write a simple echo server with Netty. I'm reading Netty in Action MEAP v8 to get down some theory and learn the core basics of Netty. The client connects successfully, but no messages get through from the client. I am able to telnet a message to the server and receive the response, so I guess the issue is on the client, I just have no idea what is wrong, due to me being new to Netty.
Here is the client:
public class Client {
private final String host;
private final int port;
public Client(String host, int port) {
this.host = host;
this.port = port;
}
public void start() throws Exception {
EventLoopGroup group = new NioEventLoopGroup();
try {
Bootstrap b = new Bootstrap();
b.group(group).channel(NioSocketChannel.class)
.remoteAddress(new InetSocketAddress(host, port))
.handler(new ChannelInitializer<SocketChannel>() {
#Override
public void initChannel(SocketChannel ch) throws Exception {
ch.pipeline().addLast(new EchoClientHandler());
}
});
ChannelFuture f = b.connect().sync();
f.channel().closeFuture().sync();
} finally {
group.shutdownGracefully().sync();
}
}
public static void main (String [] args) throws Exception {
new Client("127.0.0.1", 11235).start();
}
}
And the Client handler: (I did try appending '\r\n' to the sent message, but that did not make a difference, which I found here: Netty Client to Server message)
#Sharable
public class EchoClientHandler extends SimpleChannelInboundHandler<ByteBuf> {
public void channelActive(ChannelHandlerContext ctx) {
System.out.println("Connected");
ctx.write(Unpooled.copiedBuffer("Netty MAY rock!", CharsetUtil.UTF_8));
}
protected void channelRead0(ChannelHandlerContext ctx, ByteBuf in) throws Exception {
System.out.println(
"Client received: " + in.toString(CharsetUtil.UTF_8));
}
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
ctx.close();
}
}
The server:
public class EchoServer {
private final int port;
public EchoServer(int port) {
this.port = port;
}
public void start() throws Exception {
EventLoopGroup group = new NioEventLoopGroup();
try {
ServerBootstrap b = new ServerBootstrap();
b.group(group)
.channel(NioServerSocketChannel.class)
.localAddress(new InetSocketAddress(port))
.childHandler(new ChannelInitializer<SocketChannel>() {
#Override
public void initChannel(SocketChannel ch) throws Exception {
System.out.println("New client connected: " + ch.localAddress());
ch.pipeline().addLast(new EchoServerHandler());
}
});
ChannelFuture f = b.bind().sync();
f.channel().closeFuture().sync();
} finally {
group.shutdownGracefully().sync();
}
}
public static void main (String [] args) throws Exception {
new EchoServer(11235).start();
}
}
The server handler:
#Sharable
public class EchoServerHandler extends ChannelInboundHandlerAdapter {
public void channelRead(ChannelHandlerContext ctx, Object msg) {
ByteBuf in = (ByteBuf) msg;
System.out.println(
"Server received: " + in.toString(CharsetUtil.UTF_8));
ctx.write(in);
}
public void channelReadComplete(ChannelHandlerContext ctx) {
ctx.writeAndFlush(Unpooled.EMPTY_BUFFER)
.addListener(ChannelFutureListener.CLOSE);
}
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
ctx.close();
}
}
It must be something small I'm missing, so any help will preserve my fleeting sanity and will be much appreciated!
Instead of write use writeAndFlush in your ClientHandler:
public void channelActive(ChannelHandlerContext ctx) {
System.out.println("Connected");
ctx.writeAndFlush(Unpooled.copiedBuffer("Netty MAY rock!", CharsetUtil.UTF_8));
}