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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.boschshc.internal.devices.bridge;
  14
  15 import static org.eclipse.jetty.http.HttpMethod.POST;
  16
  17 import java.util.concurrent.ExecutionException;
  18 import java.util.concurrent.ScheduledExecutorService;
  19 import java.util.concurrent.TimeUnit;
  20 import java.util.concurrent.TimeoutException;
  21 import java.util.function.Consumer;
  22
  23 import org.eclipse.jdt.annotation.NonNullByDefault;
  24 import org.eclipse.jdt.annotation.Nullable;
  25 import org.eclipse.jetty.client.api.Request;
  26 import org.eclipse.jetty.client.api.Result;
  27 import org.eclipse.jetty.client.util.BufferingResponseListener;
  28 import org.openhab.binding.boschshc.internal.devices.bridge.dto.LongPollError;
  29 import org.openhab.binding.boschshc.internal.devices.bridge.dto.LongPollResult;
  30 import org.openhab.binding.boschshc.internal.devices.bridge.dto.SubscribeResult;
  31 import org.openhab.binding.boschshc.internal.exceptions.BoschSHCException;
  32 import org.openhab.binding.boschshc.internal.exceptions.LongPollingFailedException;
  33 import org.slf4j.Logger;
  34 import org.slf4j.LoggerFactory;
  35
  36 import com.google.gson.Gson;
  37
  38 /**
  39  * Handles the long polling to the Smart Home Controller.
  40  *
  41  * @author Christian Oeing - Initial contribution
  42  */
  43 @NonNullByDefault
  44 public class LongPolling {
  45
  46     private final Logger logger = LoggerFactory.getLogger(LongPolling.class);
  47
  48     /**
  49      * gson instance to convert a class to json string and back.
  50      */
  51     private final Gson gson = new Gson();
  52
  53     /**
  54      * Executor to schedule long polls.
  55      */
  56     private final ScheduledExecutorService scheduler;
  57
  58     /**
  59      * Handler for long poll results.
  60      */
  61     private final Consumer<LongPollResult> handleResult;
  62
  63     /**
  64      * Handler for unrecoverable.
  65      */
  66     private final Consumer<Throwable> handleFailure;
  67
  68     /**
  69      * Current running long polling request.
  70      */
  71     private @Nullable Request request;
  72
  73     /**
  74      * Indicates if long polling was aborted.
  75      */
  76     private boolean aborted = false;
  77
  78     public LongPolling(ScheduledExecutorService scheduler, Consumer<LongPollResult> handleResult,
  79             Consumer<Throwable> handleFailure) {
  80         this.scheduler = scheduler;
  81         this.handleResult = handleResult;
  82         this.handleFailure = handleFailure;
  83     }
  84
  85     public void start(BoschHttpClient httpClient) throws LongPollingFailedException {
  86         // Subscribe to state updates.
  87         String subscriptionId = this.subscribe(httpClient);
  88         this.executeLongPoll(httpClient, subscriptionId);
  89     }
  90
  91     public void stop() {
  92         // Abort long polling.
  93         this.aborted = true;
  94         Request request = this.request;
  95         if (request != null) {
  96             request.abort(new AbortLongPolling());
  97             this.request = null;
  98         }
  99     }
 100
 101     /**
 102      * Subscribe to events and store the subscription ID needed for long polling.
 103      *
 104      * @param httpClient Http client to use for sending subscription request
 105      * @return Subscription id
 106      */
 107     private String subscribe(BoschHttpClient httpClient) throws LongPollingFailedException {
 108         try {
 109             String url = httpClient.getBoschShcUrl("remote/json-rpc");
 110             JsonRpcRequest request = new JsonRpcRequest("2.0", "RE/subscribe",
 111                     new String[] { "com/bosch/sh/remote/*", null });
 112             logger.debug("Subscribe: Sending request: {} - using httpClient {}", gson.toJson(request), httpClient);
 113             Request httpRequest = httpClient.createRequest(url, POST, request);
 114             SubscribeResult response = httpClient.sendRequest(httpRequest, SubscribeResult.class);
 115
 116             logger.debug("Subscribe: Got subscription ID: {} {}", response.getResult(), response.getJsonrpc());
 117             String subscriptionId = response.getResult();
 118             return subscriptionId;
 119         } catch (TimeoutException | ExecutionException e) {
 120             throw new LongPollingFailedException(
 121                     String.format("Error on subscribe (Http client: %s): %s", httpClient.toString(), e.getMessage()),
 122                     e);
 123         } catch (InterruptedException e) {
 124             Thread.currentThread().interrupt();
 125             throw new LongPollingFailedException(
 126                     String.format("Interrupted subscribe (Http client: %s): %s", httpClient.toString(), e.getMessage()),
 127                     e);
 128         }
 129     }
 130
 131     /**
 132      * Create a new subscription for long polling.
 133      *
 134      * @param httpClient Http client to send requests to
 135      */
 136     private void resubscribe(BoschHttpClient httpClient) {
 137         try {
 138             String subscriptionId = this.subscribe(httpClient);
 139             this.executeLongPoll(httpClient, subscriptionId);
 140         } catch (LongPollingFailedException e) {
 141             this.handleFailure.accept(e);
 142             return;
 143         }
 144     }
 145
 146     private void executeLongPoll(BoschHttpClient httpClient, String subscriptionId) {
 147         scheduler.execute(() -> this.longPoll(httpClient, subscriptionId));
 148     }
 149
 150     /**
 151      * Start long polling the home controller. Once a long poll resolves, a new one is started.
 152      */
 153     private void longPoll(BoschHttpClient httpClient, String subscriptionId) {
 154         logger.debug("Sending long poll request");
 155
 156         JsonRpcRequest requestContent = new JsonRpcRequest("2.0", "RE/longPoll", new String[] { subscriptionId, "20" });
 157         String url = httpClient.getBoschShcUrl("remote/json-rpc");
 158         Request request = httpClient.createRequest(url, POST, requestContent);
 159
 160         // Long polling responds after 20 seconds with an empty response if no update has happened.
 161         // 10 second threshold was added to not time out if response from controller takes a bit longer than 20 seconds.
 162         request.timeout(30, TimeUnit.SECONDS);
 163
 164         this.request = request;
 165         LongPolling longPolling = this;
 166         request.send(new BufferingResponseListener() {
 167             @Override
 168             public void onComplete(@Nullable Result result) {
 169                 // NOTE: This handler runs inside the HTTP thread, so we schedule the response handling in a new thread
 170                 // because the HTTP thread is terminated after the timeout expires.
 171                 scheduler.execute(() -> longPolling.onLongPollComplete(httpClient, subscriptionId, result,
 172                         this.getContentAsString()));
 173             }
 174         });
 175     }
 176
 177     /**
 178      * This is the handler for responses of long poll requests.
 179      *
 180      * @param httpClient HTTP client which received the response
 181      * @param subscriptionId Id of subscription the response is for
 182      * @param result Complete result of the response
 183      * @param content Content of the response
 184      */
 185     private void onLongPollComplete(BoschHttpClient httpClient, String subscriptionId, @Nullable Result result,
 186             String content) {
 187         // Check if thing is still online
 188         if (this.aborted) {
 189             logger.debug("Canceling long polling for subscription id {} because it was aborted", subscriptionId);
 190             return;
 191         }
 192
 193         // Check if response was failure or success
 194         Throwable failure = result != null ? result.getFailure() : null;
 195         if (failure != null) {
 196             if (failure instanceof ExecutionException) {
 197                 if (failure.getCause() instanceof AbortLongPolling) {
 198                     logger.debug("Canceling long polling for subscription id {} because it was aborted",
 199                             subscriptionId);
 200                 } else {
 201                     this.handleFailure.accept(new LongPollingFailedException(
 202                             "Unexpected exception during long polling request", failure));
 203                 }
 204             } else {
 205                 this.handleFailure.accept(
 206                         new LongPollingFailedException("Unexpected exception during long polling request", failure));
 207             }
 208         } else {
 209             logger.debug("Long poll response: {}", content);
 210
 211             String nextSubscriptionId = subscriptionId;
 212
 213             LongPollResult longPollResult = gson.fromJson(content, LongPollResult.class);
 214             if (longPollResult != null && longPollResult.result != null) {
 215                 this.handleResult.accept(longPollResult);
 216             } else {
 217                 logger.debug("Long poll response contained no result: {}", content);
 218
 219                 // Check if we got a proper result from the SHC
 220                 LongPollError longPollError = gson.fromJson(content, LongPollError.class);
 221
 222                 if (longPollError != null && longPollError.error != null) {
 223                     logger.debug("Got long poll error: {} (code: {})", longPollError.error.message,
 224                             longPollError.error.code);
 225
 226                     if (longPollError.error.code == LongPollError.SUBSCRIPTION_INVALID) {
 227                         logger.debug("Subscription {} became invalid, subscribing again", subscriptionId);
 228                         this.resubscribe(httpClient);
 229                         return;
 230                     }
 231                 }
 232             }
 233
 234             // Execute next run
 235             this.longPoll(httpClient, nextSubscriptionId);
 236         }
 237     }
 238
 239     @SuppressWarnings("serial")
 240     private class AbortLongPolling extends BoschSHCException {
 241     }
 242 }