/*
    * Copyright 2016 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:
    *
    *   https://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.frame.server;
  
  import io.netty.bootstrap.ServerBootstrap;
  import io.netty.channel.Channel;
  import io.netty.channel.ChannelOption;
  import io.netty.channel.EventLoopGroup;
  import io.netty.channel.nio.NioEventLoopGroup;
  import io.netty.channel.socket.nio.NioServerSocketChannel;
  import io.netty.handler.codec.http2.Http2SecurityUtil;
  import io.netty.handler.logging.LogLevel;
  import io.netty.handler.logging.LoggingHandler;
  import io.netty.handler.ssl.ApplicationProtocolConfig;
  import io.netty.handler.ssl.ApplicationProtocolConfig.Protocol;
  import io.netty.handler.ssl.ApplicationProtocolConfig.SelectedListenerFailureBehavior;
  import io.netty.handler.ssl.ApplicationProtocolConfig.SelectorFailureBehavior;
  import io.netty.handler.ssl.ApplicationProtocolNames;
  import io.netty.handler.ssl.OpenSsl;
  import io.netty.handler.ssl.SslContext;
  import io.netty.handler.ssl.SslContextBuilder;
  import io.netty.handler.ssl.SslProvider;
  import io.netty.handler.ssl.SupportedCipherSuiteFilter;
  import io.netty.handler.ssl.util.SelfSignedCertificate;
  
  /**
   * An HTTP/2 Server that responds to requests with a Hello World. Once started, you can test the
   * server with the example client.
   *
   * <p>This example is making use of the "multiplexing" http2 API, where streams are mapped to child
   * Channels. This API is very experimental and incomplete.
   */
  public final class Http2Server {
  
      static final boolean SSL = System.getProperty("ssl") != null;
  
      static final int PORT = Integer.parseInt(System.getProperty("port", SSL? "8443" : "8080"));
  
      public static void main(String[] args) throws Exception {
          // Configure SSL.
          final SslContext sslCtx;
          if (SSL) {
              SslProvider provider = OpenSsl.isAlpnSupported() ? SslProvider.OPENSSL : SslProvider.JDK;
              SelfSignedCertificate ssc = new SelfSignedCertificate();
              sslCtx = SslContextBuilder.forServer(ssc.certificate(), ssc.privateKey())
                  .sslProvider(provider)
                  /* NOTE: the cipher filter may not include all ciphers required by the HTTP/2 specification.
                   * Please refer to the HTTP/2 specification for cipher requirements. */
                  .ciphers(Http2SecurityUtil.CIPHERS, SupportedCipherSuiteFilter.INSTANCE)
                  .applicationProtocolConfig(new ApplicationProtocolConfig(
                      Protocol.ALPN,
                      // NO_ADVERTISE is currently the only mode supported by both OpenSsl and JDK providers.
                      SelectorFailureBehavior.NO_ADVERTISE,
                      // ACCEPT is currently the only mode supported by both OpenSsl and JDK providers.
                      SelectedListenerFailureBehavior.ACCEPT,
                      ApplicationProtocolNames.HTTP_2,
                      ApplicationProtocolNames.HTTP_1_1))
                  .build();
          } else {
              sslCtx = null;
          }
          // Configure the server.
          EventLoopGroup group = new NioEventLoopGroup();
          try {
              ServerBootstrap b = new ServerBootstrap();
              b.option(ChannelOption.SO_BACKLOG, 1024);
              b.group(group)
               .channel(NioServerSocketChannel.class)
               .handler(new LoggingHandler(LogLevel.INFO))
               .childHandler(new Http2ServerInitializer(sslCtx));
  
              Channel ch = b.bind(PORT).sync().channel();
  
              System.err.println("Open your HTTP/2-enabled web browser and navigate to " +
                      (SSL? "https" : "http") + "://127.0.0.1:" + PORT + '/');
  
              ch.closeFuture().sync();
          } finally {
              group.shutdownGracefully();
          }
      }
  }