Java tutorial
/* * #%L * ACS AEM Tools Bundle * %% * Copyright (C) 2013 Adobe * %% * Licensed 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. * #L% */ package com.adobe.acs.livereload.impl; import static com.adobe.acs.livereload.impl.LiveReloadConstants.*; import static io.netty.handler.codec.http.HttpHeaders.*; import static io.netty.handler.codec.http.HttpHeaders.Names.*; import static io.netty.handler.codec.http.HttpMethod.*; import static io.netty.handler.codec.http.HttpResponseStatus.*; import static io.netty.handler.codec.http.HttpVersion.*; 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.channel.group.ChannelGroup; 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.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.io.InputStream; import java.net.URI; import java.net.URISyntaxException; import java.util.Map; import javax.servlet.http.HttpServletResponse; import org.apache.commons.io.IOUtils; import org.apache.sling.commons.json.JSONArray; import org.apache.sling.commons.json.JSONException; import org.apache.sling.commons.json.JSONObject; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /** * See http://feedback.livereload.com/knowledgebase/articles/86174-livereload- * protocol. */ public final class WebSocketServerHandler extends SimpleChannelInboundHandler<Object> { private ChannelGroup group; private Map<Channel, ChannelInfo> infos; public WebSocketServerHandler(ChannelGroup group, Map<Channel, ChannelInfo> infos) { this.group = group; this.infos = infos; } private static final Logger log = LoggerFactory.getLogger(WebSocketServerHandler.class); private static final String WEBSOCKET_PATH = "/websocket"; private WebSocketServerHandshaker handshaker; @Override public void channelRead0(ChannelHandlerContext ctx, Object msg) throws Exception { if (msg instanceof FullHttpRequest) { handleHttpRequest(ctx, (FullHttpRequest) msg); } else if (msg instanceof WebSocketFrame) { handleWebSocketFrame(ctx, (WebSocketFrame) msg); } } @Override public void channelReadComplete(ChannelHandlerContext ctx) throws Exception { ctx.flush(); } private void handleHttpRequest(ChannelHandlerContext ctx, FullHttpRequest req) throws Exception { // Handle a bad request. if (!req.getDecoderResult().isSuccess()) { sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, BAD_REQUEST)); return; } // Allow only GET methods. if (req.getMethod() != GET) { sendHttpResponse(ctx, req, new DefaultFullHttpResponse(HTTP_1_1, FORBIDDEN)); return; } if ("/".equals(req.getUri()) || "/favicon.ico".equals(req.getUri())) { FullHttpResponse res = new DefaultFullHttpResponse(HTTP_1_1, NOT_FOUND); sendHttpResponse(ctx, req, res); return; } if (req.getUri().startsWith("/livereload.js")) { InputStream is = getClass().getResourceAsStream("/livereload.js"); byte[] data = IOUtils.toByteArray(is); ByteBuf content = Unpooled.wrappedBuffer(data); FullHttpResponse res = new DefaultFullHttpResponse(HTTP_1_1, OK, content); res.headers().set(CONTENT_TYPE, "application/javascript"); setContentLength(res, content.readableBytes()); sendHttpResponse(ctx, req, res); return; } // Handshake WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory(getWebSocketLocation(req), null, false); handshaker = wsFactory.newHandshaker(req); if (handshaker == null) { WebSocketServerHandshakerFactory.sendUnsupportedWebSocketVersionResponse(ctx.channel()); } else { handshaker.handshake(ctx.channel(), req); } } private 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())); } String request = ((TextWebSocketFrame) frame).text(); try { JSONObject obj = new JSONObject(request); handleCommand(obj, ctx); } catch (JSONException e) { throw new IllegalArgumentException(String.format("%s is not a valid JSON object", request)); } } private void handleCommand(JSONObject obj, ChannelHandlerContext ctx) throws JSONException { String cmd = obj.getString(COMMAND); Channel channel = ctx.channel(); if (CMD_HELLO.equals(cmd)) { JSONObject result = new JSONObject(); result.put(COMMAND, CMD_HELLO); JSONArray protocols = new JSONArray(); protocols.put(PROTOCOL_VERSION_7); result.put(PROTOCOLS, protocols); result.put("serverName", "AEM Live Reload Server"); channel.write(new TextWebSocketFrame(result.toString())); if (isSupported(obj)) { log.info("adding LiveReload channel"); group.add(channel); } ChannelInfo info = new ChannelInfo(isSupported(obj)); infos.put(channel, info); } else if (CMD_INFO.equals(cmd)) { ChannelInfo info = infos.get(channel); if (info != null) { String url = obj.getString(URL); try { URI uri = new URI(url); info.setUri(uri); log.info("added uri to channel info {}", info); } catch (URISyntaxException e) { log.warn("Unable to store uri " + url, e); } } } else { log.warn("Unknown command {}", cmd); log.info(obj.toString(2)); } } private boolean isSupported(JSONObject obj) { try { if (obj.has(PROTOCOLS)) { JSONArray protocols = obj.getJSONArray(PROTOCOLS); for (int i = 0; i < protocols.length(); i++) { String protocol = protocols.getString(i); if (PROTOCOL_VERSION_7.equals(protocol)) { return true; } } } } catch (JSONException e) { } return false; } private static void sendHttpResponse(ChannelHandlerContext ctx, FullHttpRequest req, FullHttpResponse res) { // Generate an error page if response getStatus code is not OK (200). if (res.getStatus().code() != HttpServletResponse.SC_OK) { ByteBuf buf = Unpooled.copiedBuffer(res.getStatus().toString(), CharsetUtil.UTF_8); res.content().writeBytes(buf); buf.release(); setContentLength(res, res.content().readableBytes()); } // Send the response and close the connection if necessary. ChannelFuture f = ctx.channel().writeAndFlush(res); if (!isKeepAlive(req) || res.getStatus().code() != HttpServletResponse.SC_OK) { f.addListener(ChannelFutureListener.CLOSE); } } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { log.error("caught exception", cause); ctx.close(); } private static String getWebSocketLocation(FullHttpRequest req) { return "ws://" + req.headers().get(HOST) + WEBSOCKET_PATH; } }