Websocket Java client without browser

Question

I am working on a project that requires real-time interaction between users. I want to have an HTML5 web client (fairly simple) as well as a local client (preferably Java), both of which can connect to the server. I did some research and did not find a definitive answer to the question of whether the local client can connect to the server without a browser.

Question: Is there a way to connect from the local Java client to the websocket server without viewing? I saw some browser browsers in other languages ​​that could make this possible. If not, I am open to suggestions.

Thanks.

Answer 1

You might also consider using JSR 356, the Java API for WebSocket . It is part of Java EE 7, but the client can start with simple Java SE without any problems. Several implementations are now available, and the following will work in all of them:

software API:

final WebSocketContainer webSocketContainer = ContainerProvider.getWebSocketContainer(); Session session = webSocketContainer.connectToServer(new Endpoint() { @Override public void onOpen(Session session, EndpointConfig config) { // session.addMessageHandler( ... ); } }, URI.create("ws://some.uri")); 

annotated API:

 public static void main(String[] args) throws IOException, DeploymentException { final WebSocketContainer webSocketContainer = ContainerProvider.getWebSocketContainer(); webSocketContainer.connectToServer(MyEndpoint.class, URI.create("ws://some.uri")); } @ClientEndpoint public static class MyEndpoint { // text @OnMessage void onMessage(Session session, String message) { // ... } // binary @OnMessage void onMessage(Session session, ByteBuffer message) { // ... } // @OnClose, @OnOpen, @OnError } 

see the linked page for more information (full specification).

There are various implementations here, basically every Java container has one. I am working on an implementation of Glassfish / WebLogic and it is called Tyrus , do not hesitate to try (we provide easy-to-use all in one set, see http: //search.maven.org / ... ).

Answer 2

You can, of course, use WebSockets from a Java desktop application, outside of a sandboxed browser program. The idea is that you can create thick clients that create TCP connections, so of course they should be able to create WebSocket connections on top of these TCP connections.

One of the newest and best APIs for this is written by Kaazing, in terms of the fact that WebSocket is similar to a socket and can be created using simple URI files ws: //.

The API is discussed in detail on the Kaazing Gateway 5.0 Java WebSocket documentation website . You can download a simple gateway from Kaazing here.

Create a website:

  import com.kaazing.net.ws.WebSocket; import com.kaazing.net.ws.WebSocketFactory; wsFactory = WebSocketFactory.createWebSocketFactory(); ws = wsFactory.createWebSocket(URI.create("ws://example.com:8001/path")); ws.connect(); // This will block or throw an exception if failed. 

To send messages, add a WebSocketMessageWriter object:

  WebSocketMessageWriter writer = ws.getMessageWriter(); String text = "Hello WebSocket!"; writer.writeText(text); // Send text message 

To receive or consume messages, add WebSocket and WebSocketMessageReader objects:

  wsFactory = WebSocketFactory.createWebSocketFactory(); ws = wsFactory.createWebSocket(URI.create("ws://example.com:8001/path")); ws.connect(); // This will block or throw an exception if failed. WebSocketMessageReader reader = ws.getMessageReader(); WebSocketMessageType type = null; // Block till a message arrives // Loop till the connection goes away while ((type = reader.next()) != WebSocketMessageType.EOS) { switch (type) { // Handle both text and binary messages case TEXT: CharSequence text = reader.getText(); log("RECEIVED TEXT MESSAGE: " + text.toString()); break; case BINARY: ByteBuffer buffer = reader.getBinary(); log("RECEIVED BINARY MESSAGE: " + getHexDump(buffer)); break; } } 

(Full disclosure: I worked at Kaazing Corporation as a server engineer.)

Answer 3

Vert.x has a java web client:

 VertxFactory.newVertx() .createHttpClient() .setHost("localhost") .setPort(8080) .connectWebsocket("/ws", new Handler<WebSocket>() { @Override public void handle(final WebSocket webSocket) { // Listen webSocket.dataHandler(new Handler<Buffer>() { @Override public void handle(Buffer buff) { log.info("Received {}", buff.toString()); } }); // Publish webSocket.writeTextFrame("Heya"); } }); 

Answer 4

Netty is a good choice for this task, it is a high-performance network application infrastructure and it elegantly supports SSL, here is an example of the netty websocket client from netty github:

 public final class WebSocketClient { static final String URL = System.getProperty("url", "ws://127.0.0.1:8080/websocket"); public static void main(String[] args) throws Exception { URI uri = new URI(URL); String scheme = uri.getScheme() == null? "ws" : uri.getScheme(); final String host = uri.getHost() == null? "127.0.0.1" : uri.getHost(); final int port; if (uri.getPort() == -1) { if ("ws".equalsIgnoreCase(scheme)) { port = 80; } else if ("wss".equalsIgnoreCase(scheme)) { port = 443; } else { port = -1; } } else { port = uri.getPort(); } if (!"ws".equalsIgnoreCase(scheme) && !"wss".equalsIgnoreCase(scheme)) { System.err.println("Only WS(S) is supported."); return; } final boolean ssl = "wss".equalsIgnoreCase(scheme); final SslContext sslCtx; if (ssl) { sslCtx = SslContextBuilder.forClient() .trustManager(InsecureTrustManagerFactory.INSTANCE).build(); } else { sslCtx = null; } EventLoopGroup group = new NioEventLoopGroup(); try { // Connect with V13 (RFC 6455 aka HyBi-17). You can change it to V08 or V00. // If you change it to V00, ping is not supported and remember to change // HttpResponseDecoder to WebSocketHttpResponseDecoder in the pipeline. final WebSocketClientHandler handler = new WebSocketClientHandler( WebSocketClientHandshakerFactory.newHandshaker( uri, WebSocketVersion.V13, null, true, new DefaultHttpHeaders())); Bootstrap b = new Bootstrap(); b.group(group) .channel(NioSocketChannel.class) .handler(new ChannelInitializer<SocketChannel>() { @Override protected void initChannel(SocketChannel ch) { ChannelPipeline p = ch.pipeline(); if (sslCtx != null) { p.addLast(sslCtx.newHandler(ch.alloc(), host, port)); } p.addLast( new HttpClientCodec(), new HttpObjectAggregator(8192), WebSocketClientCompressionHandler.INSTANCE, handler); } }); Channel ch = b.connect(uri.getHost(), port).sync().channel(); handler.handshakeFuture().sync(); BufferedReader console = new BufferedReader(new InputStreamReader(System.in)); while (true) { String msg = console.readLine(); if (msg == null) { break; } else if ("bye".equals(msg.toLowerCase())) { ch.writeAndFlush(new CloseWebSocketFrame()); ch.closeFuture().sync(); break; } else if ("ping".equals(msg.toLowerCase())) { WebSocketFrame frame = new PingWebSocketFrame(Unpooled.wrappedBuffer(new byte[] { 8, 1, 8, 1 })); ch.writeAndFlush(frame); } else { WebSocketFrame frame = new TextWebSocketFrame(msg); ch.writeAndFlush(frame); } } } finally { group.shutdownGracefully(); } } } public class WebSocketClientHandler extends SimpleChannelInboundHandler<Object> { private final WebSocketClientHandshaker handshaker; private ChannelPromise handshakeFuture; public WebSocketClientHandler(WebSocketClientHandshaker handshaker) { this.handshaker = handshaker; } public ChannelFuture handshakeFuture() { return handshakeFuture; } @Override public void handlerAdded(ChannelHandlerContext ctx) { handshakeFuture = ctx.newPromise(); } @Override public void channelActive(ChannelHandlerContext ctx) { handshaker.handshake(ctx.channel()); } @Override public void channelInactive(ChannelHandlerContext ctx) { System.out.println("WebSocket Client disconnected!"); } @Override public void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception { Channel ch = ctx.channel(); if (!handshaker.isHandshakeComplete()) { handshaker.finishHandshake(ch, (FullHttpResponse) msg); System.out.println("WebSocket Client connected!"); handshakeFuture.setSuccess(); return; } if (msg instanceof FullHttpResponse) { FullHttpResponse response = (FullHttpResponse) msg; throw new IllegalStateException( "Unexpected FullHttpResponse (getStatus=" + response.status() + ", content=" + response.content().toString(CharsetUtil.UTF_8) + ')'); } WebSocketFrame frame = (WebSocketFrame) msg; if (frame instanceof TextWebSocketFrame) { TextWebSocketFrame textFrame = (TextWebSocketFrame) frame; System.out.println("WebSocket Client received message: " + textFrame.text()); } else if (frame instanceof PongWebSocketFrame) { System.out.println("WebSocket Client received pong"); } else if (frame instanceof CloseWebSocketFrame) { System.out.println("WebSocket Client received closing"); ch.close(); } } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { cause.printStackTrace(); if (!handshakeFuture.isDone()) { handshakeFuture.setFailure(cause); } ctx.close(); } }