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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("Error on subscribe request", e);
 121         }
 122     }
 123
 124     private void executeLongPoll(BoschHttpClient httpClient, String subscriptionId) {
 125         scheduler.execute(() -> this.longPoll(httpClient, subscriptionId));
 126     }
 127
 128     /**
 129      * Start long polling the home controller. Once a long poll resolves, a new one is started.
 130      */
 131     private void longPoll(BoschHttpClient httpClient, String subscriptionId) {
 132         logger.debug("Sending long poll request");
 133
 134         JsonRpcRequest requestContent = new JsonRpcRequest("2.0", "RE/longPoll", new String[] { subscriptionId, "20" });
 135         String url = httpClient.getBoschShcUrl("remote/json-rpc");
 136         Request request = httpClient.createRequest(url, POST, requestContent);
 137
 138         // Long polling responds after 20 seconds with an empty response if no update has happened.
 139         // 10 second threshold was added to not time out if response from controller takes a bit longer than 20 seconds.
 140         request.timeout(30, TimeUnit.SECONDS);
 141
 142         this.request = request;
 143         LongPolling longPolling = this;
 144         request.send(new BufferingResponseListener() {
 145             @Override
 146             public void onComplete(@Nullable Result result) {
 147                 Throwable failure = result != null ? result.getFailure() : null;
 148                 if (failure != null) {
 149                     if (failure instanceof ExecutionException) {
 150                         if (failure.getCause() instanceof AbortLongPolling) {
 151                             logger.debug("Canceling long polling for subscription id {} because it was aborted",
 152                                     subscriptionId);
 153                         } else {
 154                             longPolling.handleFailure.accept(new LongPollingFailedException(
 155                                     "Unexpected exception during long polling request", failure));
 156                         }
 157                     } else {
 158                         longPolling.handleFailure.accept(new LongPollingFailedException(
 159                                 "Unexpected exception during long polling request", failure));
 160                     }
 161                 } else {
 162                     longPolling.onLongPollResponse(httpClient, subscriptionId, this.getContentAsString());
 163                 }
 164             }
 165         });
 166     }
 167
 168     private void onLongPollResponse(BoschHttpClient httpClient, String subscriptionId, String content) {
 169         // Check if thing is still online
 170         if (this.aborted) {
 171             logger.debug("Canceling long polling for subscription id {} because it was aborted", subscriptionId);
 172             return;
 173         }
 174
 175         logger.debug("Long poll response: {}", content);
 176
 177         String nextSubscriptionId = subscriptionId;
 178
 179         LongPollResult longPollResult = gson.fromJson(content, LongPollResult.class);
 180         if (longPollResult != null && longPollResult.result != null) {
 181             this.handleResult.accept(longPollResult);
 182         } else {
 183             logger.warn("Long poll response contained no results: {}", content);
 184
 185             // Check if we got a proper result from the SHC
 186             LongPollError longPollError = gson.fromJson(content, LongPollError.class);
 187
 188             if (longPollError != null && longPollError.error != null) {
 189                 logger.warn("Got long poll error: {} (code: {})", longPollError.error.message,
 190                         longPollError.error.code);
 191
 192                 if (longPollError.error.code == LongPollError.SUBSCRIPTION_INVALID) {
 193                     logger.warn("Subscription {} became invalid, subscribing again", subscriptionId);
 194                     try {
 195                         nextSubscriptionId = this.subscribe(httpClient);
 196                     } catch (LongPollingFailedException e) {
 197                         this.handleFailure.accept(e);
 198                         return;
 199                     }
 200                 }
 201             }
 202         }
 203
 204         // Execute next run.
 205         this.executeLongPoll(httpClient, nextSubscriptionId);
 206     }
 207
 208     @SuppressWarnings("serial")
 209     private class AbortLongPolling extends BoschSHCException {
 210     }
 211 }