code: // Licensed to the Software Freedom Conservancy (SFC) under one
  // or more contributor license agreements.  See the NOTICE file
  // distributed with this work for additional information
  // regarding copyright ownership.  The SFC 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 org.openqa.selenium.netty.server;
  
  import io.netty.channel.ChannelInitializer;
  import io.netty.channel.socket.SocketChannel;
  import io.netty.handler.codec.http.HttpServerCodec;
  import io.netty.handler.codec.http.HttpServerKeepAliveHandler;
  import io.netty.handler.codec.http.websocketx.extensions.compression.WebSocketServerCompressionHandler;
  import io.netty.handler.ssl.SslContext;
  import io.netty.handler.stream.ChunkedWriteHandler;
  import io.netty.util.AttributeKey;
  import java.util.Optional;
  import java.util.function.BiFunction;
  import java.util.function.Consumer;
  import org.openqa.selenium.internal.Require;
  import org.openqa.selenium.remote.http.HttpHandler;
  import org.openqa.selenium.remote.http.Message;
  
  class SeleniumHttpInitializer extends ChannelInitializer<SocketChannel> {
  
    private static AttributeKey<Consumer<Message>> KEY = AttributeKey.newInstance("se-ws-handler");
    private HttpHandler seleniumHandler;
    private final BiFunction<String, Consumer<Message>, Optional<Consumer<Message>>> webSocketHandler;
    private SslContext sslCtx;
    private final boolean allowCors;
  
    SeleniumHttpInitializer(
        SslContext sslCtx,
        HttpHandler seleniumHandler,
        BiFunction<String, Consumer<Message>, Optional<Consumer<Message>>> webSocketHandler,
        boolean allowCors) {
      this.sslCtx = sslCtx;
      this.seleniumHandler = Require.nonNull("HTTP handler", seleniumHandler);
      this.webSocketHandler = Require.nonNull("WebSocket handler", webSocketHandler);
      this.allowCors = allowCors;
    }
  
    @Override
    protected void initChannel(SocketChannel ch) {
      if (sslCtx != null) {
        ch.pipeline().addLast("ssl", sslCtx.newHandler(ch.alloc()));
      }
      ch.pipeline().addLast("codec", new HttpServerCodec());
      ch.pipeline().addLast("keep-alive", new HttpServerKeepAliveHandler());
      ch.pipeline().addLast("chunked-write", new ChunkedWriteHandler());
  
      // Websocket magic
      ch.pipeline().addLast("ws-compression", new WebSocketServerCompressionHandler());
      ch.pipeline().addLast("ws-protocol", new WebSocketUpgradeHandler(KEY, webSocketHandler));
      ch.pipeline().addLast("netty-to-se-messages", new MessageInboundConverter());
      ch.pipeline().addLast("se-to-netty-messages", new MessageOutboundConverter());
      ch.pipeline().addLast("se-websocket-handler", new WebSocketMessageHandler(KEY));
  
      // Regular HTTP magic
      ch.pipeline().addLast("se-request", new RequestConverter());
      ch.pipeline().addLast("se-response", new ResponseConverter(allowCors));
      ch.pipeline().addLast("se-handler", new SeleniumHandler(seleniumHandler));
    }
  }
  