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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 | InterruptedException e) {
 120             throw new LongPollingFailedException(
 121                     String.format("Error on subscribe (Http client: %s): %s", httpClient.toString(), e.getMessage()),
 122                     e);
 123         }
 124     }
 125
 126     /**
 127      * Create a new subscription for long polling.
 128      *
 129      * @param httpClient Http client to send requests to
 130      */
 131     private void resubscribe(BoschHttpClient httpClient) {
 132         try {
 133             String subscriptionId = this.subscribe(httpClient);
 134             this.executeLongPoll(httpClient, subscriptionId);
 135         } catch (LongPollingFailedException e) {
 136             this.handleFailure.accept(e);
 137             return;
 138         }
 139     }
 140
 141     private void executeLongPoll(BoschHttpClient httpClient, String subscriptionId) {
 142         scheduler.execute(() -> this.longPoll(httpClient, subscriptionId));
 143     }
 144
 145     /**
 146      * Start long polling the home controller. Once a long poll resolves, a new one is started.
 147      */
 148     private void longPoll(BoschHttpClient httpClient, String subscriptionId) {
 149         logger.debug("Sending long poll request");
 150
 151         JsonRpcRequest requestContent = new JsonRpcRequest("2.0", "RE/longPoll", new String[] { subscriptionId, "20" });
 152         String url = httpClient.getBoschShcUrl("remote/json-rpc");
 153         Request request = httpClient.createRequest(url, POST, requestContent);
 154
 155         // Long polling responds after 20 seconds with an empty response if no update has happened.
 156         // 10 second threshold was added to not time out if response from controller takes a bit longer than 20 seconds.
 157         request.timeout(30, TimeUnit.SECONDS);
 158
 159         this.request = request;
 160         LongPolling longPolling = this;
 161         request.send(new BufferingResponseListener() {
 162             @Override
 163             public void onComplete(@Nullable Result result) {
 164                 // NOTE: This handler runs inside the HTTP thread, so we schedule the response handling in a new thread
 165                 // because the HTTP thread is terminated after the timeout expires.
 166                 scheduler.execute(() -> longPolling.onLongPollComplete(httpClient, subscriptionId, result,
 167                         this.getContentAsString()));
 168             }
 169         });
 170     }
 171
 172     /**
 173      * This is the handler for responses of long poll requests.
 174      *
 175      * @param httpClient HTTP client which received the response
 176      * @param subscriptionId Id of subscription the response is for
 177      * @param result Complete result of the response
 178      * @param content Content of the response
 179      */
 180     private void onLongPollComplete(BoschHttpClient httpClient, String subscriptionId, @Nullable Result result,
 181             String content) {
 182         // Check if thing is still online
 183         if (this.aborted) {
 184             logger.debug("Canceling long polling for subscription id {} because it was aborted", subscriptionId);
 185             return;
 186         }
 187
 188         // Check if response was failure or success
 189         Throwable failure = result != null ? result.getFailure() : null;
 190         if (failure != null) {
 191             if (failure instanceof ExecutionException) {
 192                 if (failure.getCause() instanceof AbortLongPolling) {
 193                     logger.debug("Canceling long polling for subscription id {} because it was aborted",
 194                             subscriptionId);
 195                 } else {
 196                     this.handleFailure.accept(new LongPollingFailedException(
 197                             "Unexpected exception during long polling request", failure));
 198                 }
 199             } else {
 200                 this.handleFailure.accept(
 201                         new LongPollingFailedException("Unexpected exception during long polling request", failure));
 202             }
 203         } else {
 204             logger.debug("Long poll response: {}", content);
 205
 206             String nextSubscriptionId = subscriptionId;
 207
 208             LongPollResult longPollResult = gson.fromJson(content, LongPollResult.class);
 209             if (longPollResult != null && longPollResult.result != null) {
 210                 this.handleResult.accept(longPollResult);
 211             } else {
 212                 logger.debug("Long poll response contained no result: {}", content);
 213
 214                 // Check if we got a proper result from the SHC
 215                 LongPollError longPollError = gson.fromJson(content, LongPollError.class);
 216
 217                 if (longPollError != null && longPollError.error != null) {
 218                     logger.debug("Got long poll error: {} (code: {})", longPollError.error.message,
 219                             longPollError.error.code);
 220
 221                     if (longPollError.error.code == LongPollError.SUBSCRIPTION_INVALID) {
 222                         logger.debug("Subscription {} became invalid, subscribing again", subscriptionId);
 223                         this.resubscribe(httpClient);
 224                         return;
 225                     }
 226                 }
 227             }
 228
 229             // Execute next run
 230             this.longPoll(httpClient, nextSubscriptionId);
 231         }
 232     }
 233
 234     @SuppressWarnings("serial")
 235     private class AbortLongPolling extends BoschSHCException {
 236     }
 237 }