HelloUdpServer.java

/*
 *
 * Copyright 2014 Netflix, Inc.
 *
 * Licensed 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 com.netflix.ribbon.transport.netty.udp;

import io.netty.buffer.ByteBuf;
import io.netty.channel.socket.DatagramPacket;
import io.reactivex.netty.RxNetty;
import io.reactivex.netty.channel.ConnectionHandler;
import io.reactivex.netty.channel.ObservableConnection;
import io.reactivex.netty.protocol.udp.server.UdpServer;
import rx.Observable;
import rx.functions.Func1;

import java.net.InetSocketAddress;
import java.nio.charset.Charset;
import java.util.concurrent.TimeUnit;

/**
 * Created by awang on 8/5/14.
 */
public final class HelloUdpServer {

    static final int DEFAULT_PORT = 8098;
    static final String WELCOME_MSG = "Welcome to the broadcast world!";
    static final byte[] WELCOME_MSG_BYTES = WELCOME_MSG.getBytes(Charset.defaultCharset());

    public final int port;
    public final int delay;

    public HelloUdpServer(int port, int delay) {
        this.port = port;
        this.delay = delay;
    }

    public HelloUdpServer(int port) {
        this.port = port;
        this.delay = 0;
    }

    public UdpServer<DatagramPacket, DatagramPacket> createServer() {
        UdpServer<DatagramPacket, DatagramPacket> server = RxNetty.createUdpServer(port, new ConnectionHandler<DatagramPacket, DatagramPacket>() {
            @Override
            public Observable<Void> handle(final ObservableConnection<DatagramPacket, DatagramPacket> newConnection) {
                return newConnection.getInput().flatMap(new Func1<DatagramPacket, Observable<Void>>() {
                    @Override
                    public Observable<Void> call(final DatagramPacket received) {
                        return Observable.interval(delay, TimeUnit.MILLISECONDS).take(1).flatMap(new Func1<Long, Observable<Void>>() {
                            @Override
                            public Observable<Void> call(Long aLong) {
                                InetSocketAddress sender = received.sender();
                                System.out.println("Received datagram. Sender: " + sender);
                                ByteBuf data = newConnection.getChannel().alloc().buffer(WELCOME_MSG_BYTES.length);
                                data.writeBytes(WELCOME_MSG_BYTES);
                                return newConnection.writeAndFlush(new DatagramPacket(data, sender));
                            }
                        });
                    }
                });
            }
        });
        System.out.println("UDP hello server started at port: " + port);
        return server;
    }

    public static void main(String[] args) {
        new HelloUdpServer(DEFAULT_PORT, 0).createServer().startAndWait();
    }
}