Java tutorial
/* * Copyright 2005-2014 Red Hat, Inc. * Red Hat licenses this file to you under the Apache License, version * 2.0 (the "License"); you may not use this file except in compliance * with the License. You may obtain a copy of the License at * http://www.apache.org/licenses/LICENSE-2.0 * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or * implied. See the License for the specific language governing * permissions and limitations under the License. */ package org.hornetq.core.protocol.stomp; import java.nio.charset.StandardCharsets; import io.netty.buffer.ByteBuf; import io.netty.channel.ChannelFuture; import io.netty.channel.ChannelFutureListener; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelOutboundHandlerAdapter; import io.netty.channel.ChannelPromise; import io.netty.channel.SimpleChannelInboundHandler; import io.netty.handler.codec.http.DefaultFullHttpResponse; import io.netty.handler.codec.http.FullHttpRequest; import io.netty.handler.codec.http.FullHttpResponse; import io.netty.handler.codec.http.HttpHeaders; import io.netty.handler.codec.http.HttpRequest; import io.netty.handler.codec.http.websocketx.BinaryWebSocketFrame; import io.netty.handler.codec.http.websocketx.CloseWebSocketFrame; import io.netty.handler.codec.http.websocketx.PingWebSocketFrame; import io.netty.handler.codec.http.websocketx.PongWebSocketFrame; import io.netty.handler.codec.http.websocketx.TextWebSocketFrame; import io.netty.handler.codec.http.websocketx.WebSocketFrame; import io.netty.handler.codec.http.websocketx.WebSocketServerHandshaker; import io.netty.handler.codec.http.websocketx.WebSocketServerHandshakerFactory; import static io.netty.handler.codec.http.HttpHeaders.isKeepAlive; import static io.netty.handler.codec.http.HttpHeaders.setContentLength; import static io.netty.handler.codec.http.HttpMethod.GET; import static io.netty.handler.codec.http.HttpResponseStatus.FORBIDDEN; import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1; /** * @author <a href="http://www.jboss.org/netty/">The Netty Project</a> * @author <a href="http://gleamynode.net/">Trustin Lee</a> * @author <a href="http://jmesnil.net/">Jeff Mesnil</a * @author <a href="mailto:nmaurer@redhat.com">Norman Maurer</a> */ public class WebSocketServerHandler extends SimpleChannelInboundHandler<Object> { private static final String WEBSOCKET_PATH = "/stomp"; private WebSocketServerHandshaker handshaker; private static final BinaryWebSocketEncoder BINARY_WEBSOCKET_ENCODER = new BinaryWebSocketEncoder(); @Override public void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception { if (msg instanceof FullHttpRequest) { handleHttpRequest(ctx, (FullHttpRequest) msg); } else if (msg instanceof WebSocketFrame) { WebSocketFrame frame = (WebSocketFrame) msg; boolean handle = handleWebSocketFrame(ctx, frame); if (handle) { ctx.fireChannelRead(frame.content().retain()); } } } private void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest req) throws Exception { // Allow only GET methods. if (req.getMethod() != GET) { sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, FORBIDDEN)); return; } // Handshake WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory( this.getWebSocketLocation(req), "v10.stomp,v11.stomp", false); this.handshaker = wsFactory.newHandshaker(req); if (this.handshaker == null) { WebSocketServerHandshakerFactory.sendUnsupportedWebSocketVersionResponse(ctx.channel()); } else { ChannelFuture handshake = this.handshaker.handshake(ctx.channel(), req); handshake.addListener(new ChannelFutureListener() { @Override public void operationComplete(ChannelFuture future) throws Exception { if (future.isSuccess()) { // we need to insert an encoder that takes the underlying ChannelBuffer of a StompFrame.toHornetQBuffer and // wrap it in a binary web socket frame before letting the wsencoder send it on the wire future.channel().pipeline().addAfter("wsencoder", "binary-websocket-encoder", BINARY_WEBSOCKET_ENCODER); } else { // Handshake failed, fire an exceptionCaught event future.channel().pipeline().fireExceptionCaught(future.cause()); } } }); } } private boolean handleWebSocketFrame(ChannelHandlerContext ctx, WebSocketFrame frame) { // Check for closing frame if (frame instanceof CloseWebSocketFrame) { this.handshaker.close(ctx.channel(), ((CloseWebSocketFrame) frame).retain()); return false; } else if (frame instanceof PingWebSocketFrame) { ctx.writeAndFlush(new PongWebSocketFrame(frame.content().retain())); return false; } else if (!(frame instanceof TextWebSocketFrame)) { throw new UnsupportedOperationException( String.format("%s frame types not supported", frame.getClass().getName())); } return true; } private void sendHttpResponse(ChannelHandlerContext ctx, HttpRequest req, FullHttpResponse res) { // Generate an error page if response status code is not OK (200). if (res.getStatus().code() != 200) { res.content().writeBytes(res.getStatus().toString().getBytes(StandardCharsets.UTF_8)); setContentLength(res, res.content().readableBytes()); } // Send the response and close the connection if necessary. ChannelFuture f = ctx.writeAndFlush(res); if (!isKeepAlive(req) || res.getStatus().code() != 200) { f.addListener(ChannelFutureListener.CLOSE); } } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { cause.printStackTrace(); ctx.close(); } private String getWebSocketLocation(HttpRequest req) { return "ws://" + req.headers().get(HttpHeaders.Names.HOST) + WEBSOCKET_PATH; } @Sharable private static final class BinaryWebSocketEncoder extends ChannelOutboundHandlerAdapter { @Override public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception { if (msg instanceof ByteBuf) { msg = new BinaryWebSocketFrame((ByteBuf) msg); } ctx.write(msg, promise); } } }