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Java example source code file (Http2ServerInitializer.java)

This example Java source code file (Http2ServerInitializer.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

attempted, channelhandlercontext, channelinboundhandleradapter, channelpipeline, direct, exception, http2serverinitializer, httpobjectaggregator, httpservercodec, httpserverupgradehandler, override, upgradecodecfactory, usereventlogger

The Http2ServerInitializer.java Java example source code

/*
 * Copyright 2014 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.example.http2.helloworld.server;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.http.HttpMessage;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.codec.http.HttpServerUpgradeHandler;
import io.netty.handler.codec.http.HttpServerUpgradeHandler.UpgradeCodec;
import io.netty.handler.codec.http.HttpServerUpgradeHandler.UpgradeCodecFactory;
import io.netty.handler.codec.http2.Http2CodecUtil;
import io.netty.handler.codec.http2.Http2ServerUpgradeCodec;
import io.netty.handler.ssl.SslContext;
import io.netty.util.AsciiString;

/**
 * Sets up the Netty pipeline for the example server. Depending on the endpoint config, sets up the
 * pipeline for NPN or cleartext HTTP upgrade to HTTP/2.
 */
public class Http2ServerInitializer extends ChannelInitializer<SocketChannel> {

    private static final UpgradeCodecFactory upgradeCodecFactory = new UpgradeCodecFactory() {
        @Override
        public UpgradeCodec newUpgradeCodec(CharSequence protocol) {
            if (AsciiString.contentEquals(Http2CodecUtil.HTTP_UPGRADE_PROTOCOL_NAME, protocol)) {
                return new Http2ServerUpgradeCodec(new HelloWorldHttp2HandlerBuilder().build());
            } else {
                return null;
            }
        }
    };

    private final SslContext sslCtx;
    private final int maxHttpContentLength;

    public Http2ServerInitializer(SslContext sslCtx) {
        this(sslCtx, 16 * 1024);
    }

    public Http2ServerInitializer(SslContext sslCtx, int maxHttpContentLength) {
        if (maxHttpContentLength < 0) {
            throw new IllegalArgumentException("maxHttpContentLength (expected >= 0): " + maxHttpContentLength);
        }
        this.sslCtx = sslCtx;
        this.maxHttpContentLength = maxHttpContentLength;
    }

    @Override
    public void initChannel(SocketChannel ch) {
        if (sslCtx != null) {
            configureSsl(ch);
        } else {
            configureClearText(ch);
        }
    }

    /**
     * Configure the pipeline for TLS NPN negotiation to HTTP/2.
     */
    private void configureSsl(SocketChannel ch) {
        ch.pipeline().addLast(sslCtx.newHandler(ch.alloc()), new Http2OrHttpHandler());
    }

    /**
     * Configure the pipeline for a cleartext upgrade from HTTP to HTTP/2.0
     */
    private void configureClearText(SocketChannel ch) {
        final ChannelPipeline p = ch.pipeline();
        final HttpServerCodec sourceCodec = new HttpServerCodec();

        p.addLast(sourceCodec);
        p.addLast(new HttpServerUpgradeHandler(sourceCodec, upgradeCodecFactory));
        p.addLast(new SimpleChannelInboundHandler<HttpMessage>() {
            @Override
            protected void channelRead0(ChannelHandlerContext ctx, HttpMessage msg) throws Exception {
                // If this handler is hit then no upgrade has been attempted and the client is just talking HTTP.
                System.err.println("Directly talking: " + msg.protocolVersion() + " (no upgrade was attempted)");
                ChannelPipeline pipeline = ctx.pipeline();
                ChannelHandlerContext thisCtx = pipeline.context(this);
                pipeline.addAfter(thisCtx.name(), null, new HelloWorldHttp1Handler("Direct. No Upgrade Attempted."));
                pipeline.replace(this, null, new HttpObjectAggregator(maxHttpContentLength));
                ctx.fireChannelRead(msg);
            }
        });

        p.addLast(new UserEventLogger());
    }

    /**
     * Class that logs any User Events triggered on this channel.
     */
    private static class UserEventLogger extends ChannelInboundHandlerAdapter {
        @Override
        public void userEventTriggered(ChannelHandlerContext ctx, Object evt) {
            System.out.println("User Event Triggered: " + evt);
            ctx.fireUserEventTriggered(evt);
        }
    }
}

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