Http2ClientInitializer.java Source code

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Here is the source code for Http2ClientInitializer.java

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/*
 * 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.
 */

import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.socket.SocketChannel;
import io.netty.handler.codec.http.DefaultFullHttpRequest;
import io.netty.handler.codec.http.HttpClientCodec;
import io.netty.handler.codec.http.HttpClientUpgradeHandler;
import io.netty.handler.codec.http.HttpMethod;
import io.netty.handler.codec.http.HttpVersion;
import io.netty.handler.codec.http2.Http2ClientUpgradeCodec;
import io.netty.handler.ssl.SslContext;

/**
 * Configures the client pipeline to support HTTP/2 frames.
 */
public class Http2ClientInitializer extends ChannelInitializer<SocketChannel> {

    private final SslContext sslCtx;
    private Http2ClientConnectionHandler connectionHandler;

    public Http2ClientInitializer(SslContext sslCtx) {
        this.sslCtx = sslCtx;
    }

    @Override
    public void initChannel(SocketChannel ch) throws Exception {
        connectionHandler = new Http2ClientConnectionHandler(ch.newPromise());
        if (sslCtx != null) {
            configureSsl(ch);
        } else {
            configureClearText(ch);
        }
    }

    public Http2ClientConnectionHandler connectionHandler() {
        return connectionHandler;
    }

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

    /**
     * Configure the pipeline for a cleartext upgrade from HTTP to HTTP/2.
     */
    private void configureClearText(SocketChannel ch) {
        HttpClientCodec sourceCodec = new HttpClientCodec();
        Http2ClientUpgradeCodec upgradeCodec = new Http2ClientUpgradeCodec(connectionHandler);
        HttpClientUpgradeHandler upgradeHandler = new HttpClientUpgradeHandler(sourceCodec, upgradeCodec, 65536);

        ch.pipeline().addLast(sourceCodec);
        ch.pipeline().addLast(upgradeHandler);
        ch.pipeline().addLast(new UpgradeRequestHandler());
        ch.pipeline().addLast(new UserEventLogger());
    }

    /**
     * A handler that triggers the cleartext upgrade to HTTP/2 by sending an initial HTTP request.
     */
    private static class UpgradeRequestHandler extends ChannelHandlerAdapter {

        @Override
        public void channelActive(ChannelHandlerContext ctx) throws Exception {
            DefaultFullHttpRequest upgradeRequest = new DefaultFullHttpRequest(HttpVersion.HTTP_1_1, HttpMethod.GET,
                    "/");
            ctx.writeAndFlush(upgradeRequest);

            super.channelActive(ctx);

            // Done with this handler, remove it from the pipeline.
            ctx.pipeline().remove(ctx.name());
        }
    }

    /**
     * Class that logs any User Events triggered on this channel.
     */
    private static class UserEventLogger extends ChannelHandlerAdapter {

        @Override
        public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
            System.out.println("User Event Triggered: " + evt);
            super.userEventTriggered(ctx, evt);
        }
    }
}