Netty server and javafx services
Hi my server seems to stop without me telling it to 😦
The object of the Server class isn't getting garbage collected but it's channel does get magically stopped
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public class Server {
private static final StringDecoder DECODER = new StringDecoder();
private static final ChatMessageEncoder ENCODER = new ChatMessageEncoder();
private boolean running;
private EventLoopGroup bossGroup;
private EventLoopGroup workerGroup;
private Channel channel;
public Server() {}
public void start(int port) throws InterruptedException {
if (running)
throw new IllegalStateException("Server is already running");
running = true;
bossGroup = new NioEventLoopGroup(1);
workerGroup = new NioEventLoopGroup();
ServerBootstrap b = new ServerBootstrap();
b.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.childOption(ChannelOption.SO_KEEPALIVE, true)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) {
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast(
DECODER,
ENCODER,
new ServerHandler()
);
}
});
channel = b.bind(port).sync().channel();
channel.closeFuture().addListener(_ -> {
System.out.println("Server is shutting down...");
stop(); // Gracefully stop the server when channel is closed
});
}
public void stop() {
if (running) {
channel.close().awaitUninterruptibly();
bossGroup.shutdownGracefully().awaitUninterruptibly();
workerGroup.shutdownGracefully().awaitUninterruptibly();
} else {
throw new IllegalStateException("Server isn't running");
}
}
public Channel getChannel() {
return channel;
}
}
public class Server {
private static final StringDecoder DECODER = new StringDecoder();
private static final ChatMessageEncoder ENCODER = new ChatMessageEncoder();
private boolean running;
private EventLoopGroup bossGroup;
private EventLoopGroup workerGroup;
private Channel channel;
public Server() {}
public void start(int port) throws InterruptedException {
if (running)
throw new IllegalStateException("Server is already running");
running = true;
bossGroup = new NioEventLoopGroup(1);
workerGroup = new NioEventLoopGroup();
ServerBootstrap b = new ServerBootstrap();
b.group(bossGroup, workerGroup)
.channel(NioServerSocketChannel.class)
.childOption(ChannelOption.SO_KEEPALIVE, true)
.childHandler(new ChannelInitializer<SocketChannel>() {
@Override
protected void initChannel(SocketChannel ch) {
ChannelPipeline pipeline = ch.pipeline();
pipeline.addLast(
DECODER,
ENCODER,
new ServerHandler()
);
}
});
channel = b.bind(port).sync().channel();
channel.closeFuture().addListener(_ -> {
System.out.println("Server is shutting down...");
stop(); // Gracefully stop the server when channel is closed
});
}
public void stop() {
if (running) {
channel.close().awaitUninterruptibly();
bossGroup.shutdownGracefully().awaitUninterruptibly();
workerGroup.shutdownGracefully().awaitUninterruptibly();
} else {
throw new IllegalStateException("Server isn't running");
}
}
public Channel getChannel() {
return channel;
}
}
public class ServerService extends Service<Server> {
private final int port;
public ServerService(int port) {
this.port = port;
}
@Override
protected Task<Server> createTask() {
return new Task<>() {
@Override
protected Server call() throws Exception {
Server server = new Server();
updateMessage("Starting server...");
server.start(port);
updateMessage("Server started on port " + port);
return server;
}
};
}
}
public class ServerService extends Service<Server> {
private final int port;
public ServerService(int port) {
this.port = port;
}
@Override
protected Task<Server> createTask() {
return new Task<>() {
@Override
protected Server call() throws Exception {
Server server = new Server();
updateMessage("Starting server...");
server.start(port);
updateMessage("Server started on port " + port);
return server;
}
};
}
}
public class ServerHandler extends SimpleChannelInboundHandler<String> {
private final Map<Channel, User> connectedUsers = new HashMap<>();
@Override
public void channelInactive(ChannelHandlerContext ctx) {
System.err.println("Connection closed " + ctx.channel().isOpen());
}
@Override
public void handlerAdded(ChannelHandlerContext ctx) {
connectedUsers.put(
ctx.channel(),
null
);
}
@Override
public void handlerRemoved(ChannelHandlerContext ctx) {
User user = connectedUsers.remove(ctx.channel());
if (user != null) {
broadcast(new LeaveMessage(user));
}
}
@Override
protected void channelRead0(ChannelHandlerContext ctx, String msg) {
User sender = connectedUsers.get(ctx.channel());
if (sender == null) {
String username = msg.trim();
User user = new User(String.valueOf(connectedUsers.size()), username);
connectedUsers.put(ctx.channel(), user);
broadcast(new JoinMessage(user));
return;
}
broadcast(new UserMessage(msg, sender, LocalDateTime.now()));
}
private void broadcast(ChatMessage message) {
for (Channel client : connectedUsers.keySet()) {
if (client.isActive() && client.isWritable()) {
client.writeAndFlush(message);
}
}
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
ctx.close();
}
}
public class ServerHandler extends SimpleChannelInboundHandler<String> {
private final Map<Channel, User> connectedUsers = new HashMap<>();
@Override
public void channelInactive(ChannelHandlerContext ctx) {
System.err.println("Connection closed " + ctx.channel().isOpen());
}
@Override
public void handlerAdded(ChannelHandlerContext ctx) {
connectedUsers.put(
ctx.channel(),
null
);
}
@Override
public void handlerRemoved(ChannelHandlerContext ctx) {
User user = connectedUsers.remove(ctx.channel());
if (user != null) {
broadcast(new LeaveMessage(user));
}
}
@Override
protected void channelRead0(ChannelHandlerContext ctx, String msg) {
User sender = connectedUsers.get(ctx.channel());
if (sender == null) {
String username = msg.trim();
User user = new User(String.valueOf(connectedUsers.size()), username);
connectedUsers.put(ctx.channel(), user);
broadcast(new JoinMessage(user));
return;
}
broadcast(new UserMessage(msg, sender, LocalDateTime.now()));
}
private void broadcast(ChatMessage message) {
for (Channel client : connectedUsers.keySet()) {
if (client.isActive() && client.isWritable()) {
client.writeAndFlush(message);
}
}
}
@Override
public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
cause.printStackTrace();
ctx.close();
}
}
Are you getting an exception?
How do you see it being stopped?
Maybe a client just disconnects?
is
handlerRemoved() called?No exception
handlerRemoved is getting called
I'll investigate further
fixed
it was the client 🫣
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