/*
 * 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:
 *
 *   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.multiplex.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;

A HTTP/2 Server that responds to requests with a Hello World. Once started, you can test the
server with the example client.
This example is making use of the "multiplexing" http2 API, where streams are mapped to child
Channels. This API is very experimental and incomplete.
/**
 * A 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();
        }
    }
}