Java tutorial
/* * Copyright 2014-2016 the original author or authors. * * 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 org.springframework.cloud.stream.app.websocket.sink; 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.HttpVersion.HTTP_1_1; import java.util.LinkedHashMap; import java.util.Map; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.springframework.boot.actuate.trace.TraceRepository; import io.netty.buffer.ByteBuf; import io.netty.buffer.Unpooled; 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; /** * Handles handshakes and messages. Based on the Netty <a href="http://bit.ly/1jVBj5T">websocket examples</a>. * * @author Netty Project * @author Oliver Moser * @author Gary Russell */ class WebsocketSinkServerHandler extends SimpleChannelInboundHandler<Object> { private static final Log logger = LogFactory.getLog(WebsocketSinkServerHandler.class); private final boolean traceEnabled; private final TraceRepository websocketTraceRepository; private final WebsocketSinkProperties properties; private WebSocketServerHandshaker handshaker; public WebsocketSinkServerHandler(TraceRepository websocketTraceRepository, WebsocketSinkProperties properties, boolean traceEnabled) { this.websocketTraceRepository = websocketTraceRepository; this.properties = properties; this.traceEnabled = traceEnabled; } @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(); } private void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest req) { // Handle a bad request. if (!req.getDecoderResult().isSuccess()) { logger.warn(String.format("Bad request: %s", req.getUri())); sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, BAD_REQUEST)); return; } // Allow only GET methods. if (req.getMethod() != GET) { logger.warn(String.format("Unsupported HTTP method: %s", req.getMethod())); sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, FORBIDDEN)); return; } // enable subclasses to do additional processing 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); WebsocketSinkServer.channels.add(ctx.channel()); } } private void handleWebSocketFrame(ChannelHandlerContext ctx, WebSocketFrame frame) { // Check for closing frame if (frame instanceof CloseWebSocketFrame) { addTraceForFrame(frame, "close"); handshaker.close(ctx.channel(), (CloseWebSocketFrame) frame.retain()); return; } if (frame instanceof PingWebSocketFrame) { addTraceForFrame(frame, "ping"); 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())); } // todo [om] think about BinaryWebsocketFrame handleTextWebSocketFrameInternal((TextWebSocketFrame) frame, ctx); } private boolean additionalHttpRequestHandler(ChannelHandlerContext ctx, FullHttpRequest req) { // implement other HTTP request logic return true; // continue processing } // simple echo implementation private void handleTextWebSocketFrameInternal(TextWebSocketFrame frame, ChannelHandlerContext ctx) { if (logger.isTraceEnabled()) { logger.trace(String.format("%s received %s", ctx.channel(), frame.text())); } addTraceForFrame(frame, "text"); ctx.channel().write(new TextWebSocketFrame("Echo: " + frame.text())); } // add trace information for received frame private void addTraceForFrame(WebSocketFrame frame, String type) { Map<String, Object> trace = new LinkedHashMap<>(); trace.put("type", type); trace.put("direction", "in"); if (frame instanceof TextWebSocketFrame) { trace.put("payload", ((TextWebSocketFrame) frame).text()); } if (traceEnabled) { websocketTraceRepository.add(trace); } } private 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) { logger.error("Websocket error", cause); cause.printStackTrace(); ctx.close(); } private String getWebSocketLocation(FullHttpRequest req) { String location = req.headers().get(HOST) + properties.getPath(); if (properties.isSsl()) { return "wss://" + location; } else { return "ws://" + location; } } }