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 com.lm; 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 static com.lm.WebSocketServer.CLIENT_NAMES; import static com.lm.WebSocketServer.PROPERTIES; import static com.lm.WebSocketServer.SSL; import static io.netty.handler.codec.http.HttpHeaders.Names.CONTENT_TYPE; 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.HttpResponseStatus.OK; import static io.netty.handler.codec.http.HttpVersion.HTTP_1_1; /** * Handles handshakes and messages */ public class WebSocketServerHandler extends SimpleChannelInboundHandler<Object> { private WebSocketServerHandshaker handshaker; @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()) { 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; } // Send the demo page and favicon.ico if ("/".equals(req.getUri())) { ByteBuf content = WebSocketServerIndexPage.getContent(getWebSocketLocation(req)); FullHttpResponse res = new DefaultFullHttpResponse(HTTP_1_1, OK, content); res.headers().set(CONTENT_TYPE, "text/html; charset=UTF-8"); HttpHeaders.setContentLength(res, content.readableBytes()); sendHttpResponse(ctx, req, res); return; } if (!req.getUri().startsWith(PROPERTIES.getProperty("websocket_path"))) { FullHttpResponse res = new DefaultFullHttpResponse(HTTP_1_1, NOT_FOUND); sendHttpResponse(ctx, req, res); return; } // Handshake WebSocketServerHandshakerFactory wsFactory = new WebSocketServerHandshakerFactory(getWebSocketLocation(req), null, false); handshaker = wsFactory.newHandshaker(req); if (handshaker == null) { WebSocketServerHandshakerFactory.sendUnsupportedVersionResponse(ctx.channel()); } else { handshaker.handshake(ctx.channel(), req); } } private void handleWebSocketFrame(ChannelHandlerContext ctx, WebSocketFrame frame) { Channel channel = ctx.channel(); // Check for closing frame if (frame instanceof CloseWebSocketFrame) { closeFrame(channel, (CloseWebSocketFrame) frame.retain()); return; } if (frame instanceof PingWebSocketFrame) { 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 { switch (getPartOfString(request, 1)) { case "bye": closeFrame(channel, new CloseWebSocketFrame()); break; case "login": login(channel, request); break; case "plus": calculate(channel, request, new Operation() { @Override public long operate(int a, int b) { return a + b; } }); break; case "minus": calculate(channel, request, new Operation() { @Override public long operate(int a, int b) { return a - b; } }); break; case "multiply": calculate(channel, request, new Operation() { @Override public long operate(int a, int b) { return a * b; } }); break; case "divide": calculate(channel, request, new Operation() { @Override public long operate(int a, int b) { return a / b; } }); break; case "version": sendVersion(channel); break; default: throw new IncorrectFormatException(); } } catch (IncorrectFormatException | NumberFormatException | ArithmeticException e) { channel.write(new TextWebSocketFrame("01:? ??")); } catch (InternalException e) { channel.write(new TextWebSocketFrame("02: ?")); } } 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() != 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(); } @Override public void channelUnregistered(ChannelHandlerContext ctx) throws Exception { CLIENT_NAMES.remove(ctx.channel()); super.channelUnregistered(ctx); } private static String getWebSocketLocation(FullHttpRequest req) { String location = req.headers().get(HOST) + PROPERTIES.getProperty("websocket_path"); if (SSL) { return "wss://" + location; } else { return "ws://" + location; } } private static String getPartOfString(String str, int index) { String result = ""; int count = 0; for (int i = 0; i < str.length(); i++) { if (PROPERTIES.getProperty("delimiter").charAt(0) == str.charAt(i)) { count++; if (count == index) { break; } } else { if (count == index - 1) { result += str.charAt(i); } } } return result; } private void closeFrame(Channel channel, CloseWebSocketFrame frame) { handshaker.close(channel, frame); } private void login(Channel channel, String request) throws InternalException { String accessKey = PROPERTIES.getProperty("access_key"); if (accessKey == null) { throw new InternalException(); } if (!accessKey.equals(getPartOfString(request, 3))) { channel.write(new TextWebSocketFrame("11:? ")); return; } if (CLIENT_NAMES.containsKey(channel)) { channel.write(new TextWebSocketFrame("12: ")); return; } String login = getPartOfString(request, 2); if (login.isEmpty()) { channel.write(new TextWebSocketFrame("13: ?")); return; } if (CLIENT_NAMES.containsValue(login)) { channel.write(new TextWebSocketFrame("14: ?")); return; } CLIENT_NAMES.put(channel, login); channel.write(new TextWebSocketFrame("10: ? " + login + ". ? ? .")); } private void calculate(Channel channel, String request, Operation operation) { if (!CLIENT_NAMES.containsKey(channel)) { channel.write(new TextWebSocketFrame("21:? ??")); return; } int a = Integer.parseInt(getPartOfString(request, 2)); int b = Integer.parseInt(getPartOfString(request, 3)); channel.write(new TextWebSocketFrame("20:" + operation.operate(a, b))); } private void sendVersion(Channel channel) throws InternalException { String version = PROPERTIES.getProperty("version"); if (version == null) { throw new InternalException(); } channel.write(new TextWebSocketFrame("30:" + version)); } private class IncorrectFormatException extends Exception { } private class InternalException extends Exception { } }