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   1 /**
   2  * Copyright (c) 2010-2023 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.webthing.internal;
  14
  15 import java.io.IOException;
  16 import java.net.URI;
  17 import java.time.Duration;
  18 import java.time.Instant;
  19 import java.util.Map;
  20 import java.util.Optional;
  21 import java.util.concurrent.ConcurrentHashMap;
  22 import java.util.concurrent.ScheduledFuture;
  23 import java.util.concurrent.TimeUnit;
  24 import java.util.concurrent.atomic.AtomicBoolean;
  25 import java.util.concurrent.atomic.AtomicReference;
  26
  27 import org.eclipse.jdt.annotation.NonNullByDefault;
  28 import org.eclipse.jdt.annotation.Nullable;
  29 import org.eclipse.jetty.client.HttpClient;
  30 import org.eclipse.jetty.websocket.client.WebSocketClient;
  31 import org.openhab.binding.webthing.internal.channel.Channels;
  32 import org.openhab.binding.webthing.internal.client.ConsumedThing;
  33 import org.openhab.binding.webthing.internal.client.ConsumedThingFactory;
  34 import org.openhab.binding.webthing.internal.link.ChannelToPropertyLink;
  35 import org.openhab.binding.webthing.internal.link.PropertyToChannelLink;
  36 import org.openhab.binding.webthing.internal.link.UnknownPropertyException;
  37 import org.openhab.core.thing.ChannelUID;
  38 import org.openhab.core.thing.Thing;
  39 import org.openhab.core.thing.ThingStatus;
  40 import org.openhab.core.thing.ThingStatusDetail;
  41 import org.openhab.core.thing.binding.BaseThingHandler;
  42 import org.openhab.core.types.Command;
  43 import org.openhab.core.types.RefreshType;
  44 import org.openhab.core.types.State;
  45 import org.slf4j.Logger;
  46 import org.slf4j.LoggerFactory;
  47
  48 /**
  49  * The {@link WebThingHandler} is responsible for handling commands, which are
  50  * sent to one of the channels.
  51  *
  52  * @author Gregor Roth - Initial contribution
  53  */
  54 @NonNullByDefault
  55 public class WebThingHandler extends BaseThingHandler implements ChannelHandler {
  56     private static final Duration RECONNECT_PERIOD = Duration.ofHours(23);
  57     private static final Duration HEALTH_CHECK_PERIOD = Duration.ofSeconds(70);
  58     private static final ItemChangedListener EMPTY_ITEM_CHANGED_LISTENER = (channelUID, stateCommand) -> {
  59     };
  60
  61     private final Logger logger = LoggerFactory.getLogger(WebThingHandler.class);
  62     private final HttpClient httpClient;
  63     private final WebSocketClient webSocketClient;
  64     private final AtomicBoolean isActivated = new AtomicBoolean(true);
  65     private final Map<ChannelUID, ItemChangedListener> itemChangedListenerMap = new ConcurrentHashMap<>();
  66     private final AtomicReference<Optional<ConsumedThing>> webThingConnectionRef = new AtomicReference<>(
  67             Optional.empty());
  68     private final AtomicReference<Instant> lastReconnect = new AtomicReference<>(Instant.now());
  69     private final AtomicReference<Optional<ScheduledFuture<?>>> watchdogHandle = new AtomicReference<>(
  70             Optional.empty());
  71     private @Nullable URI webThingURI = null;
  72
  73     public WebThingHandler(Thing thing, HttpClient httpClient, WebSocketClient webSocketClient) {
  74         super(thing);
  75         this.httpClient = httpClient;
  76         this.webSocketClient = webSocketClient;
  77     }
  78
  79     private boolean isOnline() {
  80         return getThing().getStatus() == ThingStatus.ONLINE;
  81     }
  82
  83     private boolean isDisconnected() {
  84         return (getThing().getStatus() == ThingStatus.OFFLINE) || (getThing().getStatus() == ThingStatus.UNKNOWN);
  85     }
  86
  87     private boolean isAlive() {
  88         return webThingConnectionRef.get().map(ConsumedThing::isAlive).orElse(false);
  89     }
  90
  91     @Override
  92     public void initialize() {
  93         updateStatus(ThingStatus.UNKNOWN);
  94         isActivated.set(true); // set with true, even though the connect may fail. In this case retries will be
  95                                // triggered
  96
  97         // perform connect in background
  98         scheduler.execute(() -> {
  99             // WebThing URI present?
 100             if (getWebThingURI() != null) {
 101                 logger.debug("try to connect WebThing {}", webThingURI);
 102                 var connected = tryReconnect();
 103                 if (connected) {
 104                     logger.debug("WebThing {} connected", getWebThingLabel());
 105                 }
 106             } else {
 107                 updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.CONFIGURATION_ERROR,
 108                         "webThing uri has not been set");
 109                 logger.warn("could not initialize WebThing. URI is not set or invalid. {}", this.webThingURI);
 110             }
 111         });
 112
 113         // starting watchdog that checks the healthiness of the WebThing connection, periodically
 114         watchdogHandle
 115                 .getAndSet(Optional.of(scheduler.scheduleWithFixedDelay(this::checkWebThingConnection,
 116                         HEALTH_CHECK_PERIOD.getSeconds(), HEALTH_CHECK_PERIOD.getSeconds(), TimeUnit.SECONDS)))
 117                 .ifPresent(future -> future.cancel(true));
 118     }
 119
 120     private @Nullable URI getWebThingURI() {
 121         if (webThingURI == null) {
 122             webThingURI = toUri(getConfigAs(WebThingConfiguration.class).webThingURI);
 123         }
 124         return webThingURI;
 125     }
 126
 127     private @Nullable URI toUri(@Nullable String uri) {
 128         try {
 129             if (uri != null) {
 130                 return URI.create(uri);
 131             }
 132         } catch (IllegalArgumentException illegalURIException) {
 133             return null;
 134         }
 135         return null;
 136     }
 137
 138     @Override
 139     public void dispose() {
 140         try {
 141             isActivated.set(false); // set to false to avoid reconnecting
 142
 143             // terminate WebThing connection as well as the alive watchdog
 144             webThingConnectionRef.getAndSet(Optional.empty()).ifPresent(ConsumedThing::close);
 145             watchdogHandle.getAndSet(Optional.empty()).ifPresent(future -> future.cancel(true));
 146         } finally {
 147             super.dispose();
 148         }
 149     }
 150
 151     private boolean tryReconnect() {
 152         if (isActivated.get()) { // will try reconnect only, if activated
 153             try {
 154                 // create the client-side WebThing representation
 155                 var uri = getWebThingURI();
 156                 if (uri != null) {
 157                     var webThing = ConsumedThingFactory.instance().create(webSocketClient, httpClient, uri, scheduler,
 158                             this::onError);
 159                     this.webThingConnectionRef.getAndSet(Optional.of(webThing)).ifPresent(ConsumedThing::close);
 160
 161                     // update the Thing structure based on the WebThing description
 162                     thingStructureChanged(webThing);
 163
 164                     // link the Thing's channels with the WebThing properties to forward properties/item updates
 165                     establishWebThingChannelLinks(webThing);
 166
 167                     lastReconnect.set(Instant.now());
 168                     updateStatus(ThingStatus.ONLINE);
 169                     return true;
 170                 }
 171             } catch (IOException e) {
 172                 var msg = e.getMessage();
 173                 if (msg == null) {
 174                     msg = "";
 175                 }
 176                 onError(msg);
 177             }
 178         }
 179         return false;
 180     }
 181
 182     public void onError(String reason) {
 183         var wasConnectedBefore = isOnline();
 184         updateStatus(ThingStatus.OFFLINE, ThingStatusDetail.COMMUNICATION_ERROR, reason);
 185
 186         // close the WebThing connection. If the handler is still active, the WebThing connection
 187         // will be re-established within the periodically watchdog task
 188         webThingConnectionRef.getAndSet(Optional.empty()).ifPresent(ConsumedThing::close);
 189
 190         if (wasConnectedBefore) { // to reduce log messages, just log in case of connection state changed
 191             logger.debug("WebThing {} disconnected {}. Try reconnect (each {} sec)", getWebThingLabel(), reason,
 192                     HEALTH_CHECK_PERIOD.getSeconds());
 193         } else {
 194             logger.debug("WebThing {} is offline {}. Try reconnect (each {} sec)", getWebThingLabel(), reason,
 195                     HEALTH_CHECK_PERIOD.getSeconds());
 196         }
 197     }
 198
 199     private String getWebThingLabel() {
 200         if (getThing().getLabel() == null) {
 201             return "" + webThingURI;
 202         } else {
 203             return "'" + getThing().getLabel() + "' (" + webThingURI + ")";
 204         }
 205     }
 206
 207     /**
 208      * updates the thing structure. Refer https://www.openhab.org/docs/developer/bindings/#updating-the-thing-structure
 209      *
 210      * @param webThing the WebThing that is used for the new structure
 211      */
 212     private void thingStructureChanged(ConsumedThing webThing) {
 213         var thingBuilder = editThing().withLabel(webThing.getThingDescription().title);
 214
 215         // create a channel for each WebThing property
 216         for (var entry : webThing.getThingDescription().properties.entrySet()) {
 217             var channel = Channels.createChannel(thing.getUID(), entry.getKey(), entry.getValue());
 218             // add channel (and remove a previous one, if exist)
 219             thingBuilder.withoutChannel(channel.getUID()).withChannel(channel);
 220         }
 221         var thing = thingBuilder.build();
 222
 223         // and update the thing
 224         updateThing(thing);
 225     }
 226
 227     /**
 228      * connects each WebThing property with a corresponding openHAB channel. After this changes will be synchronized
 229      * between a WebThing property and the openHAB channel
 230      *
 231      * @param webThing the WebThing to be connected
 232      * @throws IOException if the channels can not be connected
 233      */
 234     private void establishWebThingChannelLinks(ConsumedThing webThing) throws IOException {
 235         // remove all registered listeners
 236         itemChangedListenerMap.clear();
 237
 238         // create new links (listeners will be registered, implicitly)
 239         for (var namePropertyPair : webThing.getThingDescription().properties.entrySet()) {
 240             try {
 241                 // determine the name of the associated channel
 242                 var channelUID = Channels.createChannelUID(getThing().getUID(), namePropertyPair.getKey());
 243
 244                 // will try to establish a link, if channel is present
 245                 var channel = getThing().getChannel(channelUID);
 246                 if (channel != null) {
 247                     // establish downstream link
 248                     PropertyToChannelLink.establish(webThing, namePropertyPair.getKey(), this, channel);
 249
 250                     // establish upstream link
 251                     if (!namePropertyPair.getValue().readOnly) {
 252                         ChannelToPropertyLink.establish(this, channel, webThing, namePropertyPair.getKey());
 253                     }
 254                 }
 255             } catch (UnknownPropertyException upe) {
 256                 logger.warn("WebThing {} property {} could not be linked with a channel", getWebThingLabel(),
 257                         namePropertyPair.getKey(), upe);
 258             }
 259         }
 260     }
 261
 262     @Override
 263     public void handleCommand(ChannelUID channelUID, Command command) {
 264         if (command instanceof State stateCommand) {
 265             itemChangedListenerMap.getOrDefault(channelUID, EMPTY_ITEM_CHANGED_LISTENER).onItemStateChanged(channelUID,
 266                     stateCommand);
 267         } else if (command instanceof RefreshType) {
 268             tryReconnect();
 269         }
 270     }
 271
 272     /////////////
 273     // ChannelHandler methods
 274     @Override
 275     public void observeChannel(ChannelUID channelUID, ItemChangedListener listener) {
 276         itemChangedListenerMap.put(channelUID, listener);
 277     }
 278
 279     @Override
 280     public void updateItemState(ChannelUID channelUID, Command command) {
 281         if (isActivated.get()) {
 282             postCommand(channelUID, command);
 283         }
 284     }
 285     //
 286     /////////////
 287
 288     private void checkWebThingConnection() {
 289         // try reconnect, if necessary
 290         if (isDisconnected() || (isOnline() && !isAlive())) {
 291             logger.debug("try reconnecting WebThing {}", getWebThingLabel());
 292             if (tryReconnect()) {
 293                 logger.debug("WebThing {} reconnected", getWebThingLabel());
 294             }
 295
 296         } else {
 297             // force reconnecting periodically, to fix erroneous states that occurs for unknown reasons
 298             var elapsedSinceLastReconnect = Duration.between(lastReconnect.get(), Instant.now());
 299             if (isOnline() && (elapsedSinceLastReconnect.getSeconds() > RECONNECT_PERIOD.getSeconds())) {
 300                 if (tryReconnect()) {
 301                     logger.debug("WebThing {} reconnected. Initiated by periodic reconnect", getWebThingLabel());
 302                 } else {
 303                     logger.debug("could not reconnect WebThing {} (periodic reconnect failed). Next trial in {} sec",
 304                             getWebThingLabel(), HEALTH_CHECK_PERIOD.getSeconds());
 305                 }
 306
 307             }
 308         }
 309     }
 310 }