Java tutorial
/* * Copyright 2019 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.netty.handler.codec.http.websocketx; import io.netty.buffer.Unpooled; import io.netty.channel.Channel; import io.netty.channel.ChannelFutureListener; import io.netty.channel.ChannelHandler; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelInboundHandler; import io.netty.channel.ChannelInboundHandlerAdapter; import io.netty.channel.ChannelPipeline; 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.HttpResponseStatus; import io.netty.util.AttributeKey; import java.util.List; import static io.netty.handler.codec.http.HttpVersion.*; import static io.netty.handler.codec.http.websocketx.WebSocketServerProtocolConfig.DEFAULT; import static io.netty.util.internal.ObjectUtil.*; /** * This handler does all the heavy lifting for you to run a websocket server. * * It takes care of websocket handshaking as well as processing of control frames (Close, Ping, Pong). Text and Binary * data frames are passed to the next handler in the pipeline (implemented by you) for processing. * * See <tt>io.netty.example.http.websocketx.html5.WebSocketServer</tt> for usage. * * The implementation of this handler assumes that you just want to run a websocket server and not process other types * HTTP requests (like GET and POST). If you wish to support both HTTP requests and websockets in the one server, refer * to the <tt>io.netty.example.http.websocketx.server.WebSocketServer</tt> example. * * To know once a handshake was done you can intercept the * {@link ChannelInboundHandler#userEventTriggered(ChannelHandlerContext, Object)} and check if the event was instance * of {@link HandshakeComplete}, the event will contain extra information about the handshake such as the request and * selected subprotocol. */ public class WebSocketServerProtocolHandler extends WebSocketProtocolHandler { /** * Events that are fired to notify about handshake status */ public enum ServerHandshakeStateEvent { /** * The Handshake was completed successfully and the channel was upgraded to websockets. * * @deprecated in favor of {@link HandshakeComplete} class, * it provides extra information about the handshake */ @Deprecated HANDSHAKE_COMPLETE, /** * The Handshake was timed out */ HANDSHAKE_TIMEOUT } /** * The Handshake was completed successfully and the channel was upgraded to websockets. */ public static final class HandshakeComplete { private final String requestUri; private final HttpHeaders requestHeaders; private final String selectedSubprotocol; HandshakeComplete(String requestUri, HttpHeaders requestHeaders, String selectedSubprotocol) { this.requestUri = requestUri; this.requestHeaders = requestHeaders; this.selectedSubprotocol = selectedSubprotocol; } public String requestUri() { return requestUri; } public HttpHeaders requestHeaders() { return requestHeaders; } public String selectedSubprotocol() { return selectedSubprotocol; } } private static final AttributeKey<WebSocketServerHandshaker> HANDSHAKER_ATTR_KEY = AttributeKey .valueOf(WebSocketServerHandshaker.class, "HANDSHAKER"); private final WebSocketServerProtocolConfig serverConfig; /** * Base constructor * * @param serverConfig * Server protocol configuration. */ public WebSocketServerProtocolHandler(WebSocketServerProtocolConfig serverConfig) { super(checkNotNull(serverConfig, "serverConfig").dropPongFrames()); this.serverConfig = serverConfig; } public WebSocketServerProtocolHandler(String websocketPath) { this(websocketPath, DEFAULT.handshakeTimeoutMillis()); } public WebSocketServerProtocolHandler(String websocketPath, long handshakeTimeoutMillis) { this(websocketPath, false, handshakeTimeoutMillis); } public WebSocketServerProtocolHandler(String websocketPath, boolean checkStartsWith) { this(websocketPath, checkStartsWith, DEFAULT.handshakeTimeoutMillis()); } public WebSocketServerProtocolHandler(String websocketPath, boolean checkStartsWith, long handshakeTimeoutMillis) { this(websocketPath, null, false, 65536, false, checkStartsWith, handshakeTimeoutMillis); } public WebSocketServerProtocolHandler(String websocketPath, String subprotocols) { this(websocketPath, subprotocols, DEFAULT.handshakeTimeoutMillis()); } public WebSocketServerProtocolHandler(String websocketPath, String subprotocols, long handshakeTimeoutMillis) { this(websocketPath, subprotocols, false, handshakeTimeoutMillis); } public WebSocketServerProtocolHandler(String websocketPath, String subprotocols, boolean allowExtensions) { this(websocketPath, subprotocols, allowExtensions, DEFAULT.handshakeTimeoutMillis()); } public WebSocketServerProtocolHandler(String websocketPath, String subprotocols, boolean allowExtensions, long handshakeTimeoutMillis) { this(websocketPath, subprotocols, allowExtensions, 65536, handshakeTimeoutMillis); } public WebSocketServerProtocolHandler(String websocketPath, String subprotocols, boolean allowExtensions, int maxFrameSize) { this(websocketPath, subprotocols, allowExtensions, maxFrameSize, DEFAULT.handshakeTimeoutMillis()); } public WebSocketServerProtocolHandler(String websocketPath, String subprotocols, boolean allowExtensions, int maxFrameSize, long handshakeTimeoutMillis) { this(websocketPath, subprotocols, allowExtensions, maxFrameSize, false, handshakeTimeoutMillis); } public WebSocketServerProtocolHandler(String websocketPath, String subprotocols, boolean allowExtensions, int maxFrameSize, boolean allowMaskMismatch) { this(websocketPath, subprotocols, allowExtensions, maxFrameSize, allowMaskMismatch, DEFAULT.handshakeTimeoutMillis()); } public WebSocketServerProtocolHandler(String websocketPath, String subprotocols, boolean allowExtensions, int maxFrameSize, boolean allowMaskMismatch, long handshakeTimeoutMillis) { this(websocketPath, subprotocols, allowExtensions, maxFrameSize, allowMaskMismatch, false, handshakeTimeoutMillis); } public WebSocketServerProtocolHandler(String websocketPath, String subprotocols, boolean allowExtensions, int maxFrameSize, boolean allowMaskMismatch, boolean checkStartsWith) { this(websocketPath, subprotocols, allowExtensions, maxFrameSize, allowMaskMismatch, checkStartsWith, DEFAULT.handshakeTimeoutMillis()); } public WebSocketServerProtocolHandler(String websocketPath, String subprotocols, boolean allowExtensions, int maxFrameSize, boolean allowMaskMismatch, boolean checkStartsWith, long handshakeTimeoutMillis) { this(websocketPath, subprotocols, allowExtensions, maxFrameSize, allowMaskMismatch, checkStartsWith, true, handshakeTimeoutMillis); } public WebSocketServerProtocolHandler(String websocketPath, String subprotocols, boolean allowExtensions, int maxFrameSize, boolean allowMaskMismatch, boolean checkStartsWith, boolean dropPongFrames) { this(websocketPath, subprotocols, allowExtensions, maxFrameSize, allowMaskMismatch, checkStartsWith, dropPongFrames, DEFAULT.handshakeTimeoutMillis()); } public WebSocketServerProtocolHandler(String websocketPath, String subprotocols, boolean allowExtensions, int maxFrameSize, boolean allowMaskMismatch, boolean checkStartsWith, boolean dropPongFrames, long handshakeTimeoutMillis) { this(websocketPath, subprotocols, checkStartsWith, dropPongFrames, handshakeTimeoutMillis, WebSocketDecoderConfig.newBuilder().maxFramePayloadLength(maxFrameSize) .allowMaskMismatch(allowMaskMismatch).allowExtensions(allowExtensions).build()); } public WebSocketServerProtocolHandler(String websocketPath, String subprotocols, boolean checkStartsWith, boolean dropPongFrames, long handshakeTimeoutMillis, WebSocketDecoderConfig decoderConfig) { this(WebSocketServerProtocolConfig.newBuilder().websocketPath(websocketPath).subprotocols(subprotocols) .checkStartsWith(checkStartsWith).handshakeTimeoutMillis(handshakeTimeoutMillis) .dropPongFrames(dropPongFrames).decoderConfig(decoderConfig).build()); } @Override public void handlerAdded(ChannelHandlerContext ctx) { ChannelPipeline cp = ctx.pipeline(); if (cp.get(WebSocketServerProtocolHandshakeHandler.class) == null) { // Add the WebSocketHandshakeHandler before this one. cp.addBefore(ctx.name(), WebSocketServerProtocolHandshakeHandler.class.getName(), new WebSocketServerProtocolHandshakeHandler(serverConfig)); } if (serverConfig.decoderConfig().withUTF8Validator() && cp.get(Utf8FrameValidator.class) == null) { // Add the UFT8 checking before this one. cp.addBefore(ctx.name(), Utf8FrameValidator.class.getName(), new Utf8FrameValidator()); } if (serverConfig.sendCloseFrame() != null) { cp.addBefore(ctx.name(), WebSocketCloseFrameHandler.class.getName(), new WebSocketCloseFrameHandler( serverConfig.sendCloseFrame(), serverConfig.forceCloseTimeoutMillis())); } } @Override protected void decode(ChannelHandlerContext ctx, WebSocketFrame frame, List<Object> out) throws Exception { if (serverConfig.handleCloseFrames() && frame instanceof CloseWebSocketFrame) { WebSocketServerHandshaker handshaker = getHandshaker(ctx.channel()); if (handshaker != null) { frame.retain(); handshaker.close(ctx.channel(), (CloseWebSocketFrame) frame); } else { ctx.writeAndFlush(Unpooled.EMPTY_BUFFER).addListener(ChannelFutureListener.CLOSE); } return; } super.decode(ctx, frame, out); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { if (cause instanceof WebSocketHandshakeException) { FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, HttpResponseStatus.BAD_REQUEST, Unpooled.wrappedBuffer(cause.getMessage().getBytes())); ctx.channel().writeAndFlush(response).addListener(ChannelFutureListener.CLOSE); } else { ctx.fireExceptionCaught(cause); ctx.close(); } } static WebSocketServerHandshaker getHandshaker(Channel channel) { return channel.attr(HANDSHAKER_ATTR_KEY).get(); } static void setHandshaker(Channel channel, WebSocketServerHandshaker handshaker) { channel.attr(HANDSHAKER_ATTR_KEY).set(handshaker); } static ChannelHandler forbiddenHttpRequestResponder() { return new ChannelInboundHandlerAdapter() { @Override public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception { if (msg instanceof FullHttpRequest) { ((FullHttpRequest) msg).release(); FullHttpResponse response = new DefaultFullHttpResponse(HTTP_1_1, HttpResponseStatus.FORBIDDEN, ctx.alloc().buffer(0)); ctx.channel().writeAndFlush(response); } else { ctx.fireChannelRead(msg); } } }; } }