@Override
protected void configurePipeline(ChannelHandlerContext ctx, String protocol) throws Exception {
    if (ApplicationProtocolNames.HTTP_2.equals(protocol)) {
        ctx.pipeline().addLast(Http2FrameCodecBuilder.forServer().build(), new HelloWorldHttp2Handler());
        return;
    }

    if (ApplicationProtocolNames.HTTP_1_1.equals(protocol)) {
        ctx.pipeline().addLast(new HttpServerCodec(),
                               new HttpObjectAggregator(MAX_CONTENT_LENGTH),
                               new HelloWorldHttp1Handler("ALPN Negotiation"));
        return;
    }

    throw new IllegalStateException("unknown protocol: " + protocol);
}
 

@Override
public void init(final Channel channel) {
    final Http2FrameCodecBuilder multiplexCodecBuilder = forServer()
            // We do not want close to trigger graceful closure (go away), instead when user triggers a graceful
            // close, we do the appropriate go away handling.
            .decoupleCloseAndGoAway(true)
            // We don't want to rely upon Netty to manage the graceful close timeout, because we expect
            // the user to apply their own timeout at the call site.
            .gracefulShutdownTimeoutMillis(-1);

    final BiPredicate<CharSequence, CharSequence> headersSensitivityDetector =
            config.headersSensitivityDetector();
    multiplexCodecBuilder.headerSensitivityDetector(headersSensitivityDetector::test);

    final String frameLoggerName = config.frameLoggerName();
    if (frameLoggerName != null) {
        multiplexCodecBuilder.frameLogger(new Http2FrameLogger(TRACE, frameLoggerName));
    }

    // TODO(scott): more configuration. header validation, settings stream, etc...

    channel.pipeline().addLast(multiplexCodecBuilder.build(), new Http2MultiplexHandler(streamChannelInitializer));
}
 

private InetSocketAddress bindH2Server(ChannelHandler childChannelHandler,
                                       Consumer<ChannelPipeline> parentChannelInitializer) {
    ServerBootstrap sb = new ServerBootstrap();
    sb.group(serverEventLoopGroup);
    sb.channel(serverChannel(serverEventLoopGroup, InetSocketAddress.class));
    sb.childHandler(new ChannelInitializer<Channel>() {
        @Override
        protected void initChannel(final Channel ch) {
            ch.pipeline().addLast(
                    Http2FrameCodecBuilder.forServer().build(),
                    new Http2MultiplexHandler(childChannelHandler));
            parentChannelInitializer.accept(ch.pipeline());
        }
    });
    serverAcceptorChannel = sb.bind(localAddress(0)).syncUninterruptibly().channel();
    return (InetSocketAddress) serverAcceptorChannel.localAddress();
}
 

static void configureHttp2Pipeline(ChannelPipeline p, HttpResponseDecoderSpec decoder, Http2Settings http2Settings,
		ConnectionObserver observer) {
	Http2FrameCodecBuilder http2FrameCodecBuilder =
			Http2FrameCodecBuilder.forClient()
			                      .validateHeaders(decoder.validateHeaders())
			                      .initialSettings(http2Settings);

	if (p.get(NettyPipeline.LoggingHandler) != null) {
		http2FrameCodecBuilder.frameLogger(new Http2FrameLogger(LogLevel.DEBUG,
				"reactor.netty.http.client.h2"));
	}

	p.addBefore(NettyPipeline.ReactiveBridge, NettyPipeline.HttpCodec, http2FrameCodecBuilder.build())
	 .addBefore(NettyPipeline.ReactiveBridge, NettyPipeline.H2MultiplexHandler, new Http2MultiplexHandler(new H2Codec()))
	 .addBefore(NettyPipeline.ReactiveBridge, NettyPipeline.HttpTrafficHandler, new HttpTrafficHandler(observer));
}
 

static void configureH2Pipeline(ChannelPipeline p,
		ServerCookieDecoder cookieDecoder,
		ServerCookieEncoder cookieEncoder,
		boolean forwarded,
		Http2Settings http2Settings,
		ConnectionObserver listener,
		ChannelOperations.OnSetup opsFactory,
		boolean validate) {
	p.remove(NettyPipeline.ReactiveBridge);

	Http2FrameCodecBuilder http2FrameCodecBuilder =
			Http2FrameCodecBuilder.forServer()
			                      .validateHeaders(validate)
			                      .initialSettings(http2Settings);

	if (p.get(NettyPipeline.LoggingHandler) != null) {
		http2FrameCodecBuilder.frameLogger(new Http2FrameLogger(LogLevel.DEBUG,
				"reactor.netty.http.server.h2"));
	}

	p.addLast(NettyPipeline.HttpCodec, http2FrameCodecBuilder.build())
	 .addLast(NettyPipeline.H2MultiplexHandler,
	          new Http2MultiplexHandler(new H2Codec(opsFactory, listener, forwarded, cookieEncoder, cookieDecoder)));
}
 

Http11OrH2CleartextCodec(
		ServerCookieDecoder cookieDecoder,
		ServerCookieEncoder cookieEncoder,
		boolean debug,
		boolean forwarded,
		Http2Settings http2Settings,
		ConnectionObserver listener,
		ChannelOperations.OnSetup opsFactory,
		boolean validate) {
	this.cookieDecoder = cookieDecoder;
	this.cookieEncoder = cookieEncoder;
	this.forwarded = forwarded;
	Http2FrameCodecBuilder http2FrameCodecBuilder =
			Http2FrameCodecBuilder.forServer()
			                      .validateHeaders(validate)
			                      .initialSettings(http2Settings);

	if (debug) {
		http2FrameCodecBuilder.frameLogger(new Http2FrameLogger(
				LogLevel.DEBUG,
				"reactor.netty.http.server.h2"));
	}
	this.http2FrameCodec = http2FrameCodecBuilder.build();
	this.listener = listener;
	this.opsFactory = opsFactory;
}
 

public static ApplicationProtocolNegotiationHandler getServerAPNHandler() {
    ApplicationProtocolNegotiationHandler serverAPNHandler = new ApplicationProtocolNegotiationHandler(ApplicationProtocolNames.HTTP_2) {

        @Override
        protected void configurePipeline(ChannelHandlerContext ctx, String protocol) throws Exception {
            if (ApplicationProtocolNames.HTTP_2.equals(protocol)) {
                ctx.pipeline()
                    .addLast(Http2FrameCodecBuilder.forServer()
                        .build(), new Http2ServerResponseHandler());
                return;
            }
            throw new IllegalStateException("Protocol: " + protocol + " not supported");
        }
    };
    return serverAPNHandler;

}
 

private void configureHttp2(ChannelPipeline pipeline) {

        // setup the initial stream settings for the server to use.
        Http2Settings settings = new Http2Settings()
                .maxConcurrentStreams(maxConcurrentStreams)
                .initialWindowSize(initialWindowSize)
                .headerTableSize(maxHeaderTableSize)
                .maxHeaderListSize(maxHeaderListSize);

        Http2FrameCodec frameCodec = Http2FrameCodecBuilder.forServer()
                .frameLogger(FRAME_LOGGER)
                .initialSettings(settings)
                .validateHeaders(true)
                .build();

        Http2MultiplexHandler multiplexHandler = new Http2MultiplexHandler(http2StreamHandler);

        // The frame codec MUST be in the pipeline.
        pipeline.addBefore("codec_placeholder", /* name= */ null, frameCodec);
        pipeline.replace("codec_placeholder", HTTP_CODEC_HANDLER_NAME, multiplexHandler);
    }
 

@Override
public UpgradeCodec newUpgradeCodec(CharSequence protocol) {
    if (AsciiString.contentEquals(Http2CodecUtil.HTTP_UPGRADE_PROTOCOL_NAME, protocol)) {
        return new Http2ServerUpgradeCodec(
                Http2FrameCodecBuilder.forServer().build(), new HelloWorldHttp2Handler());
    } else {
        return null;
    }
}
 

@Override
public void init(final Channel channel) {
    final Http2FrameCodecBuilder multiplexCodecBuilder = forClient()
            // We do not want close to trigger graceful closure (go away), instead when user triggers a graceful
            // close, we do the appropriate go away handling.
            .decoupleCloseAndGoAway(true)
            // The max concurrent streams is made available via a publisher and may be consumed asynchronously
            // (e.g. when offloading is enabled), so we manually control the SETTINGS ACK frames.
            .autoAckSettingsFrame(false)
            // We don't want to rely upon Netty to manage the graceful close timeout, because we expect
            // the user to apply their own timeout at the call site.
            .gracefulShutdownTimeoutMillis(-1);

    // Notify server that this client does not support server push and request it to be disabled.
    multiplexCodecBuilder.initialSettings().pushEnabled(false).maxConcurrentStreams(0L);

    final BiPredicate<CharSequence, CharSequence> headersSensitivityDetector =
            config.headersSensitivityDetector();
    multiplexCodecBuilder.headerSensitivityDetector(headersSensitivityDetector::test);

    final String frameLoggerName = config.frameLoggerName();
    if (frameLoggerName != null) {
        multiplexCodecBuilder.frameLogger(new Http2FrameLogger(TRACE, frameLoggerName));
    }

    // TODO(scott): more configuration. header validation, settings stream, etc...

    channel.pipeline().addLast(multiplexCodecBuilder.build(),
            new Http2MultiplexHandler(H2PushStreamHandler.INSTANCE));
}
 

@Override
protected void initChannel(SocketChannel ch) {
    Http2FrameCodec codec = Http2FrameCodecBuilder.forServer()
            .autoAckPingFrame(true)
            .initialSettings(new Http2Settings()
                .initialWindowSize(16384)
                .maxFrameSize(16384)
                .maxConcurrentStreams(5))
            .build();

    ch.pipeline().addLast(codec);
    ch.pipeline().addLast(handlerSupplier.get());
}
 

@Override
protected void initChannel(SocketChannel ch) {
    Http2FrameCodec codec = Http2FrameCodecBuilder.forServer()
            .initialSettings(new Http2Settings()
                    .maxConcurrentStreams(5))
            .build();

    ch.pipeline().addLast(codec);
    ch.pipeline().addLast(handlerSupplier.get());
}
 

public static EmbeddedChannel newHttp2Channel(ChannelHandler channelHandler) {
    Http2FrameCodec http2FrameCodec = Http2FrameCodecBuilder.forClient().initialSettings(
        Http2Settings.defaultSettings().initialWindowSize(INITIAL_WINDOW_SIZE))
                                                            .frameLogger(new Http2FrameLogger(LogLevel.DEBUG)).build();
    EmbeddedChannel channel = new EmbeddedChannel(http2FrameCodec,
                                                  new Http2MultiplexHandler(channelHandler));

    channel.attr(ChannelAttributeKey.HTTP2_CONNECTION).set(http2FrameCodec.connection());
    channel.attr(ChannelAttributeKey.HTTP2_INITIAL_WINDOW_SIZE).set(INITIAL_WINDOW_SIZE);
    channel.attr(ChannelAttributeKey.PROTOCOL_FUTURE).set(CompletableFuture.completedFuture(Protocol.HTTP2));
    return channel;
}
 

@Override
public void channelCreated(Channel ch) throws Exception {
  ChannelPipeline pipeline = ch.pipeline();
  SslHandler sslHandler = new SslHandler(sslFactory.createSSLEngine(host, port, SSLFactory.Mode.CLIENT));
  pipeline.addLast(sslHandler);
  pipeline.addLast(Http2FrameCodecBuilder.forClient()
      .initialSettings(Http2Settings.defaultSettings()
          .maxFrameSize(http2ClientConfig.http2FrameMaxSize)
          .initialWindowSize(http2ClientConfig.http2InitialWindowSize))
      .frameLogger(new Http2FrameLogger(LogLevel.DEBUG, "client"))
      .build());
  pipeline.addLast(new Http2MultiplexHandler(new ChannelInboundHandlerAdapter()));
}
 

@Override
protected void initChannel(SocketChannel ch) throws Exception {
  // To honor http2 window size, WriteBufferWaterMark.high() should be greater or equal to http2 window size.
  // Also see: https://github.com/netty/netty/issues/10193
  // https://stackoverflow.com/questions/25281124/netty-4-high-and-low-write-watermarks
  ch.config()
      .setSendBufferSize(http2ClientConfig.nettySendBufferSize)
      .setReceiveBufferSize(http2ClientConfig.nettyReceiveBufferSize)
      .setWriteBufferWaterMark(new WriteBufferWaterMark(http2ClientConfig.http2InitialWindowSize,
          2 * http2ClientConfig.http2InitialWindowSize));
  // If channel handler implementations are not annotated with @Sharable, Netty creates a new instance of every class
  // in the pipeline for every connection.
  // i.e. if there are a 1000 active connections there will be a 1000 NettyMessageProcessor instances.
  ChannelPipeline pipeline = ch.pipeline();
  // connection stats handler to track connection related metrics
  pipeline.addLast("ConnectionStatsHandler", connectionStatsHandler);
  InetSocketAddress peerAddress = ch.remoteAddress();
  String peerHost = peerAddress.getHostName();
  int peerPort = peerAddress.getPort();
  SslHandler sslHandler = new SslHandler(sslFactory.createSSLEngine(peerHost, peerPort, SSLFactory.Mode.SERVER));
  pipeline.addLast("SslHandler", sslHandler);
  pipeline.addLast("SecurityChecker", serverSecurityHandler);
  pipeline.addLast("Http2FrameCodec", Http2FrameCodecBuilder.forServer()
      .initialSettings(Http2Settings.defaultSettings()
          .maxFrameSize(http2ClientConfig.http2FrameMaxSize)
          .initialWindowSize(http2ClientConfig.http2InitialWindowSize))
      .frameLogger(new Http2FrameLogger(LogLevel.DEBUG, "server"))
      .build());
  pipeline.addLast("Http2MultiplexHandler", new Http2MultiplexHandler(http2ServerStreamHandler));
  pipeline.addLast("CloseOnExceptionHandler", closeOnExceptionHandler);
}
 

private EmbeddedChannel newHttp2Channel() {
    EmbeddedChannel channel = new EmbeddedChannel(Http2FrameCodecBuilder.forClient().build(),
                                                  new Http2MultiplexHandler(new NoOpHandler()));
    channel.attr(ChannelAttributeKey.PROTOCOL_FUTURE).set(CompletableFuture.completedFuture(Protocol.HTTP2));
    return channel;
}
 

static void configureHttp11OrH2CleartextPipeline(
		ChannelPipeline p,
		boolean acceptGzip,
		HttpResponseDecoderSpec decoder,
		Http2Settings http2Settings,
		@Nullable Supplier<? extends ChannelMetricsRecorder> metricsRecorder,
		ConnectionObserver observer,
		ChannelOperations.OnSetup opsFactory,
		@Nullable Function<String, String> uriTagValue) {
	HttpClientCodec httpClientCodec =
			new HttpClientCodec(
					decoder.maxInitialLineLength(),
					decoder.maxHeaderSize(),
					decoder.maxChunkSize(),
					decoder.failOnMissingResponse,
					decoder.validateHeaders(),
					decoder.initialBufferSize(),
					decoder.parseHttpAfterConnectRequest);

	Http2FrameCodecBuilder http2FrameCodecBuilder =
			Http2FrameCodecBuilder.forClient()
					.validateHeaders(decoder.validateHeaders())
					.initialSettings(http2Settings);

	if (p.get(NettyPipeline.LoggingHandler) != null) {
		http2FrameCodecBuilder.frameLogger(new Http2FrameLogger(LogLevel.DEBUG,
				"reactor.netty.http.client.h2"));
	}

	Http2FrameCodec http2FrameCodec = http2FrameCodecBuilder.build();

	Http2ClientUpgradeCodec upgradeCodec = new Http2ClientUpgradeCodec(http2FrameCodec, new H2CleartextCodec(http2FrameCodec, opsFactory));

	HttpClientUpgradeHandler upgradeHandler = new HttpClientUpgradeHandler(httpClientCodec, upgradeCodec, decoder.h2cMaxContentLength());

	p.addBefore(NettyPipeline.ReactiveBridge, null, httpClientCodec)
	 .addBefore(NettyPipeline.ReactiveBridge, NettyPipeline.H2CUpgradeHandler, upgradeHandler)
	 .addBefore(NettyPipeline.ReactiveBridge, NettyPipeline.HttpTrafficHandler, new HttpTrafficHandler(observer));

	if (acceptGzip) {
		p.addAfter(NettyPipeline.HttpCodec, NettyPipeline.HttpDecompressor, new HttpContentDecompressor());
	}

	if (metricsRecorder != null) {
		ChannelMetricsRecorder channelMetricsRecorder = metricsRecorder.get();
		if (channelMetricsRecorder instanceof HttpClientMetricsRecorder) {
			p.addBefore(NettyPipeline.ReactiveBridge,
					NettyPipeline.HttpMetricsHandler,
					new HttpClientMetricsHandler((HttpClientMetricsRecorder) channelMetricsRecorder, uriTagValue));
		}
	}

}
 

static EmbeddedChannel newHttp2Channel() {
  EmbeddedChannel channel =
      new EmbeddedChannel(Http2FrameCodecBuilder.forClient().build(), new Http2MultiplexHandler(new NoOpHandler()));
  return channel;
}