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POEstablishing WebSocket connection with Java server and Javascript client
 

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    <p>I'm trying to implement WebSockets with a Javascript-based client and a Java-based server. I think I've done all the correct steps, but for an unknown reason, I can't establish the connection with both.</p> <p>When the server socket receives a connection, it handles to form a websocket-accept response, and it sends back to the client, but the connection in the client socket instantly close, weird that there's no handshake problem.</p> <p>Does anyone have an idea what might be the problem?</p> <p>Here's my server code implemented in java:</p> <pre><code>package server; import java.io.IOException; import java.net.ServerSocket; import java.net.Socket; import java.util.ArrayList; import java.util.List; import server.message.Message; import server.message.SpeakMessage; public class Server implements ConnectionListener { private static final int PORT = 1509; private MessageDispatcher dispatcher = new MessageDispatcher(); private List&lt;ConnectionManager&gt; clients = new ArrayList&lt;&gt;(); public void listen() { try (ServerSocket server = new ServerSocket(PORT)) { System.out.printf("Listening on port %d...%n", PORT); while (true) { System.out.println("Waiting for connection..."); Socket client = server.accept(); System.out.println("Incoming connection - Attempting to establish connection..."); ConnectionManager manager = new ConnectionManager(client, dispatcher, this); manager.start(); } } catch (IOException e) { System.out.println("Unable to start server"); e.printStackTrace(); } System.exit(0); } public void execute() { try { while (true) { if (dispatcher.isEmpty()) { Thread.sleep(100); continue; } Message msg = dispatcher.read(); if (msg instanceof SpeakMessage) broadcast(MessageEncoder.spoke(((SpeakMessage) msg).getText())); } } catch (Exception e) { e.printStackTrace(); System.exit(1); } } public static void main(String[] args) { final Server server = new Server(); new Thread(new Runnable() { @Override public void run() { server.listen(); } }).start(); server.execute(); } public synchronized void broadcast(byte[] message) { for (ConnectionManager client : clients) { client.send(message); } } @Override public synchronized void clientConnected(ConnectionManager who) { clients.add(who); System.out.println("Connected client " + clients.size()); } @Override public synchronized void clientDisconnected(ConnectionManager who) { clients.remove(who); } } </code></pre> <p>Heres subclass ConnectionManager of server:</p> <pre><code>package server; import java.io.DataInputStream; import java.io.DataOutputStream; import java.io.IOException; import java.io.InputStream; import java.lang.reflect.InvocationTargetException; import java.net.Socket; import java.security.MessageDigest; import java.util.Properties; import server.message.HandshakeMessage; import server.message.Message; public class ConnectionManager { private static final int CLIENT_VERSION = 1; private Socket socket; private MessageDecoder decoder = new MessageDecoder(); private MessageDispatcher dispatcher; private ConnectionListener listener; public ConnectionManager(Socket connection, MessageDispatcher dispatcher, ConnectionListener listener) { socket = connection; this.dispatcher = dispatcher; this.listener = listener; } public void start() { Thread t = new Thread(new ChannelReader()); t.setName("Client thread"); t.setDaemon(true); t.start(); } public void send(byte[] data) { if (socket == null) return; try { DataOutputStream dos = new DataOutputStream(socket.getOutputStream()); dos.write(data); dos.flush(); } catch (IOException e) { disconnect("Client closed the connection"); } } private class ChannelReader implements Runnable { private boolean accepted = false; private String ret = null; @Override public void run() { try { DataInputStream in = new DataInputStream(socket.getInputStream()); while (socket != null &amp;&amp; socket.isConnected()) { int len = in.readShort(); if (len &lt; 0) { disconnect("Invalid message length."); } String s; readLine(in); Properties props = new Properties(); while((s=readLine(in)) != null &amp;&amp; !s.equals("")) { String[] q = s.split(": "); props.put(q[0], q[1]); } if(props.get("Upgrade").equals("websocket") &amp;&amp; props.get("Sec-WebSocket-Version").equals("13")) { // check if is websocket 8 String key = (String) props.get("Sec-WebSocket-Key"); String r = key + "" + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11"; // magic key MessageDigest md = MessageDigest.getInstance("SHA-1"); md.reset(); md.update(r.getBytes()); byte[] sha1hash = md.digest(); String returnBase = base64(sha1hash); ret = "HTTP/1.1 101 Switching Protocols\r\n"; ret+="Upgrade: websocket\r\n"; ret+="Connection: Upgrade\r\n"; ret+="Sec-WebSocket-Accept: "+returnBase; } else { disconnect("Client got wrong version of websocket"); } Message msg = decoder.decode((String) props.get("Sec-WebSocket-Protocol")); if (!accepted) { doHandshake(msg); } else if (dispatcher != null) { dispatcher.dispatch(msg); } } } catch (Exception e) { disconnect(e.getMessage()); e.printStackTrace(); } } private void doHandshake(Message msg) { if (!(msg instanceof HandshakeMessage)) { disconnect("Missing handshake message"); return; } HandshakeMessage handshake = (HandshakeMessage) msg; if (handshake.getVersion() != CLIENT_VERSION) { disconnect("Client failed in handshake."); return; } send(ret.getBytes()); accepted = true; listener.clientConnected(ConnectionManager.this); } private String base64(byte[] input) throws ClassNotFoundException, SecurityException, NoSuchMethodException, IllegalArgumentException, IllegalAccessException, InvocationTargetException, InstantiationException { Class&lt;?&gt; c = Class.forName("sun.misc.BASE64Encoder"); java.lang.reflect.Method m = c.getMethod("encode", new Class&lt;?&gt;[]{byte[].class}); String s = (String) m.invoke(c.newInstance(), input); return s; } private String readLine(InputStream in) { try{ String line = ""; int pread; int read = 0; while(true) { pread = read; read = in.read(); if(read!=13&amp;&amp;read!=10) line += (char) read; if(pread==13&amp;&amp;read==10) break; } return line; }catch(IOException ex){ } return null; } } public synchronized void disconnect(String message) { System.err.println(message); if (socket != null) { try { socket.close(); } catch (IOException e) { } } socket = null; listener.clientDisconnected(ConnectionManager.this); } } </code></pre> <p>And the MessageDispatcher:</p> <pre><code>package server; import java.util.Queue; import java.util.concurrent.LinkedBlockingDeque; import server.message.Message; public class MessageDispatcher { Queue&lt;Message&gt; messageQueue = new LinkedBlockingDeque&lt;&gt;(); public void dispatch(Message message) { messageQueue.offer(message); } public Message read() { return messageQueue.poll(); } public boolean isEmpty() { return messageQueue.isEmpty(); } } </code></pre> <p>And heres my client code implemented in javascript:</p> <pre><code>var canvas, // Canvas DOM element ctx, // Canvas rendering context socket; // Socket connection function init() { // Initialise the canvas canvas = document.getElementById("gameCanvas"); ctx = canvas.getContext("2d"); // Maximise the canvas canvas.width = window.innerWidth; canvas.height = window.innerHeight; // Initialise socket connection if (window.WebSocket) { socket = new WebSocket("ws://localhost:1509/", ["1", "YURI"]); socket.onopen = onSocketConnected(); socket.onclose = onSocketDisconnect(); socket.onmessage = onSocketMessage(); socket.onerror = onSocketError(); } else { alert("The browser does not support websocket."); } }; // Socket message function onSocketMessage(message) { console.log('Message: ' + message.data); }; // Socket error function onSocketError(error) { console.log('Error: ' + error.data); }; // Socket connected function onSocketConnected() { console.log("Connected to socket server"); }; // Socket disconnected function onSocketDisconnect() { console.log("Disconnected from socket server"); }; </code></pre>
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    1. COdid u manage to find solution. I need to build something like this so will be usefull to reuse your example.
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