Java tutorial
/* * Copyright 2012 The Netty Project * * The Netty Project 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 io.riox.springxd.sinks.websocket; import static io.netty.handler.codec.http.HttpHeaders.Names.HOST; import static io.netty.handler.codec.http.HttpMethod.GET; import static io.netty.handler.codec.http.HttpResponseStatus.BAD_REQUEST; import static io.netty.handler.codec.http.HttpResponseStatus.FORBIDDEN; import static io.netty.handler.codec.http.HttpResponseStatus.NOT_FOUND; import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1; import io.netty.buffer.ByteBuf; import io.netty.buffer.Unpooled; import io.netty.channel.Channel; import io.netty.channel.ChannelFuture; import io.netty.channel.ChannelFutureListener; import io.netty.channel.ChannelHandlerContext; 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.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 io.netty.util.CharsetUtil; import java.util.List; import java.util.Map; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * Handles handshakes and messages */ public class NettyWebSocketServerHandler extends SimpleChannelInboundHandler<Object> { private static final Logger log = LoggerFactory.getLogger(NettyWebSocketServerHandler.class); private static final String WEBSOCKET_PATH = "/websocket"; private WebSocketServerHandshaker handshaker; private boolean ssl; public NettyWebSocketServerHandler(boolean ssl) { this.ssl = ssl; } @Override public void channelRead0(ChannelHandlerContext ctx, Object msg) { if (msg instanceof FullHttpRequest) { handleHttpRequest(ctx, (FullHttpRequest) msg); } else if (msg instanceof WebSocketFrame) { handleWebSocketFrame(ctx, (WebSocketFrame) msg); } } @Override public void channelReadComplete(ChannelHandlerContext ctx) { ctx.flush(); } protected void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest req) { // Handle a bad request. if (!req.getDecoderResult().isSuccess()) { log.warn("Bad request: {}", req.getUri()); sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, BAD_REQUEST)); return; } // Allow only GET methods. if (req.getMethod() != GET) { log.warn("Unsupported HTTP method: {}", req.getMethod()); sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, FORBIDDEN)); return; } if (!additionalHttpRequestHandler(ctx, req)) { return; } // Handshake WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory(getWebSocketLocation(req), null, true); handshaker = wsFactory.newHandshaker(req); if (handshaker == null) { WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel()); } else { handshaker.handshake(ctx.channel(), req); Map<String, List<Channel>> pathsToChannels = NettyWebSocketServer.getPathsToChannels(); List<Channel> existing = pathsToChannels.get(req.getUri()); if (existing == null) { sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, NOT_FOUND)); } else { existing.add(ctx.channel()); } } } protected void handleWebSocketFrame(ChannelHandlerContext ctx, WebSocketFrame frame) { // Check for closing frame if (frame instanceof CloseWebSocketFrame) { handshaker.close(ctx.channel(), (CloseWebSocketFrame) frame.retain()); return; } if (frame instanceof PingWebSocketFrame) { ctx.channel().write(new PongWebSocketFrame(frame.content().retain())); return; } if (!(frame instanceof TextWebSocketFrame)) { throw new UnsupportedOperationException( String.format("%s frame types not supported", frame.getClass().getName())); } handleTextWebSocketFrameInternal((TextWebSocketFrame) frame, ctx); } protected boolean additionalHttpRequestHandler(ChannelHandlerContext ctx, FullHttpRequest req) { // implement other HTTP request logic return true; // continue processing } // simple echo implementation protected void handleTextWebSocketFrameInternal(TextWebSocketFrame frame, ChannelHandlerContext ctx) { log.debug("%s received %s%n", ctx.channel(), frame.text()); ctx.channel().write(new TextWebSocketFrame("You said: " + frame.text())); } void sendHttpResponse(ChannelHandlerContext ctx, FullHttpRequest req, FullHttpResponse res) { // Generate an error page if response getStatus code is not OK (200). if (res.getStatus().code() != 200) { ByteBuf buf = Unpooled.copiedBuffer(res.getStatus().toString(), CharsetUtil.UTF_8); res.content().writeBytes(buf); buf.release(); HttpHeaders.setContentLength(res, res.content().readableBytes()); } // Send the response and close the connection if necessary. ChannelFuture f = ctx.channel().writeAndFlush(res); if (!HttpHeaders.isKeepAlive(req) || res.getStatus().code() != 200) { f.addListener(ChannelFutureListener.CLOSE); } } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { cause.printStackTrace(); ctx.close(); } String getWebSocketLocation(FullHttpRequest req) { String location = req.headers().get(HOST) + WEBSOCKET_PATH; if (ssl) { return "wss://" + location; } else { return "ws://" + location; } } }