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   1 /**
   2  * Copyright (c) 2010-2021 Contributors to the openHAB project
   3  *
   4  * See the NOTICE file(s) distributed with this work for additional
   5  * information.
   6  *
   7  * This program and the accompanying materials are made available under the
   8  * terms of the Eclipse Public License 2.0 which is available at
   9  * http://www.eclipse.org/legal/epl-2.0
  10  *
  11  * SPDX-License-Identifier: EPL-2.0
  12  */
  13 package org.openhab.binding.bigassfan.internal.discovery;
  14
  15 import static org.openhab.binding.bigassfan.internal.BigAssFanBindingConstants.BAF_PORT;
  16
  17 import java.io.IOException;
  18 import java.net.DatagramPacket;
  19 import java.net.DatagramSocket;
  20 import java.net.InetAddress;
  21 import java.net.SocketException;
  22 import java.net.SocketTimeoutException;
  23 import java.net.UnknownHostException;
  24 import java.nio.charset.StandardCharsets;
  25
  26 import org.slf4j.Logger;
  27 import org.slf4j.LoggerFactory;
  28
  29 /**
  30  * The {@link DiscoveryListener} is responsible for listening on the UDP socket for fan discovery messages.
  31  *
  32  * @author Mark Hilbush - Initial contribution
  33  */
  34 public class DiscoveryListener {
  35     private final Logger logger = LoggerFactory.getLogger(DiscoveryListener.class);
  36
  37     private final String BCAST_ADDRESS = "255.255.255.255";
  38     private final int SOCKET_RECEIVE_TIMEOUT = 500;
  39
  40     private final String POLL_MESSAGE = "<ALL;DEVICE;ID;GET>";
  41
  42     DatagramSocket dSocket;
  43     DatagramPacket rcvPacket;
  44     byte[] rcvBuffer;
  45     InetAddress bcastAddress;
  46     byte[] bcastBuffer;
  47     DatagramPacket bcastPacket;
  48
  49     BigAssFanDevice device;
  50
  51     public DiscoveryListener() throws IOException, SocketException {
  52         logger.debug("DiscoveryListener opening UDP broadcast socket");
  53         dSocket = null;
  54         device = new BigAssFanDevice();
  55         try {
  56             // Create a socket on the UDP port and get send & receive buffers
  57             dSocket = new DatagramSocket(BAF_PORT);
  58             dSocket.setSoTimeout(SOCKET_RECEIVE_TIMEOUT);
  59             dSocket.setBroadcast(true);
  60             rcvBuffer = new byte[256];
  61             rcvPacket = new DatagramPacket(rcvBuffer, rcvBuffer.length);
  62             bcastAddress = InetAddress.getByName(BCAST_ADDRESS);
  63             bcastBuffer = POLL_MESSAGE.getBytes(StandardCharsets.US_ASCII);
  64             bcastPacket = new DatagramPacket(bcastBuffer, bcastBuffer.length, bcastAddress, BAF_PORT);
  65         } catch (UnknownHostException uhe) {
  66             logger.warn("UnknownHostException sending poll request for fans: {}", uhe.getMessage(), uhe);
  67         }
  68     }
  69
  70     public BigAssFanDevice waitForMessage() throws IOException, SocketTimeoutException {
  71         // Wait to receive a packet
  72         rcvPacket.setLength(rcvBuffer.length);
  73         dSocket.receive(rcvPacket);
  74
  75         // Process the received packet
  76         device.reset();
  77         device.setIpAddress(rcvPacket.getAddress().getHostAddress());
  78         String message = (new String(rcvBuffer, 0, rcvPacket.getLength()));
  79         device.setDiscoveryMessage(message);
  80         logger.debug("RECEIVED packet of length {} from {}: {}", message.length(), device.getIpAddress(), message);
  81
  82         return device;
  83     }
  84
  85     public void pollForDevices() {
  86         if (dSocket == null) {
  87             logger.debug("Socket is null in discoveryListener.pollForDevices()");
  88             return;
  89         }
  90
  91         logger.debug("Sending poll request for fans: {}", POLL_MESSAGE);
  92         try {
  93             dSocket.send(bcastPacket);
  94         } catch (IOException ioe) {
  95             logger.warn("IOException sending poll request for fans: {}", ioe.getMessage(), ioe);
  96         }
  97     }
  98
  99     public void shutdown() {
 100         logger.debug("DiscoveryListener closing socket");
 101         if (dSocket != null) {
 102             dSocket.close();
 103             dSocket = null;
 104         }
 105     }
 106 }