Java tutorial
/* * Copyright 2015 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.ssl; import io.netty.channel.Channel; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.ChannelInboundHandlerAdapter; import io.netty.channel.ChannelInitializer; import io.netty.channel.ChannelPipeline; import io.netty.util.internal.ObjectUtil; import io.netty.util.internal.logging.InternalLogger; import io.netty.util.internal.logging.InternalLoggerFactory; /** * Configures a {@link ChannelPipeline} depending on the application-level protocol negotiation result of * {@link SslHandler}. For example, you could configure your HTTP pipeline depending on the result of ALPN: * <pre> * public class MyInitializer extends {@link ChannelInitializer}<{@link Channel}> { * private final {@link SslContext} sslCtx; * * public MyInitializer({@link SslContext} sslCtx) { * this.sslCtx = sslCtx; * } * * protected void initChannel({@link Channel} ch) { * {@link ChannelPipeline} p = ch.pipeline(); * p.addLast(sslCtx.newHandler(...)); // Adds {@link SslHandler} * p.addLast(new MyNegotiationHandler()); * } * } * * public class MyNegotiationHandler extends {@link ApplicationProtocolNegotiationHandler} { * public MyNegotiationHandler() { * super({@link ApplicationProtocolNames}.HTTP_1_1); * } * * protected void configurePipeline({@link ChannelHandlerContext} ctx, String protocol) { * if ({@link ApplicationProtocolNames}.HTTP_2.equals(protocol) { * configureHttp2(ctx); * } else if ({@link ApplicationProtocolNames}.HTTP_1_1.equals(protocol)) { * configureHttp1(ctx); * } else { * throw new IllegalStateException("unknown protocol: " + protocol); * } * } * } * </pre> */ public abstract class ApplicationProtocolNegotiationHandler extends ChannelInboundHandlerAdapter { private static final InternalLogger logger = InternalLoggerFactory .getInstance(ApplicationProtocolNegotiationHandler.class); private final String fallbackProtocol; /** * Creates a new instance with the specified fallback protocol name. * * @param fallbackProtocol the name of the protocol to use when * ALPN/NPN negotiation fails or the client does not support ALPN/NPN */ protected ApplicationProtocolNegotiationHandler(String fallbackProtocol) { this.fallbackProtocol = ObjectUtil.checkNotNull(fallbackProtocol, "fallbackProtocol"); } @Override public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception { if (evt instanceof SslHandshakeCompletionEvent) { try { SslHandshakeCompletionEvent handshakeEvent = (SslHandshakeCompletionEvent) evt; if (handshakeEvent.isSuccess()) { SslHandler sslHandler = ctx.pipeline().get(SslHandler.class); if (sslHandler == null) { throw new IllegalStateException("cannot find an SslHandler in the pipeline (required for " + "application-level protocol negotiation)"); } String protocol = sslHandler.applicationProtocol(); configurePipeline(ctx, protocol != null ? protocol : fallbackProtocol); } else { handshakeFailure(ctx, handshakeEvent.cause()); } } catch (Throwable cause) { exceptionCaught(ctx, cause); } finally { ChannelPipeline pipeline = ctx.pipeline(); if (pipeline.context(this) != null) { pipeline.remove(this); } } } ctx.fireUserEventTriggered(evt); } /** * Invoked on successful initial SSL/TLS handshake. Implement this method to configure your pipeline * for the negotiated application-level protocol. * * @param protocol the name of the negotiated application-level protocol, or * the fallback protocol name specified in the constructor call if negotiation failed or the client * isn't aware of ALPN/NPN extension */ protected abstract void configurePipeline(ChannelHandlerContext ctx, String protocol) throws Exception; /** * Invoked on failed initial SSL/TLS handshake. */ protected void handshakeFailure(ChannelHandlerContext ctx, Throwable cause) throws Exception { logger.warn("{} TLS handshake failed:", ctx.channel(), cause); ctx.close(); } @Override public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception { logger.warn("{} Failed to select the application-level protocol:", ctx.channel(), cause); ctx.fireExceptionCaught(cause); ctx.close(); } }