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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.http.internal.http;
  14
  15 import java.net.MalformedURLException;
  16 import java.net.URI;
  17 import java.net.URISyntaxException;
  18 import java.util.Date;
  19 import java.util.List;
  20 import java.util.Optional;
  21 import java.util.Set;
  22 import java.util.concurrent.CancellationException;
  23 import java.util.concurrent.CompletableFuture;
  24 import java.util.concurrent.ConcurrentHashMap;
  25 import java.util.concurrent.ScheduledExecutorService;
  26 import java.util.concurrent.ScheduledFuture;
  27 import java.util.concurrent.TimeUnit;
  28 import java.util.function.Consumer;
  29
  30 import org.eclipse.jdt.annotation.NonNullByDefault;
  31 import org.eclipse.jdt.annotation.Nullable;
  32 import org.eclipse.jetty.client.api.Authentication;
  33 import org.eclipse.jetty.client.api.AuthenticationStore;
  34 import org.eclipse.jetty.http.HttpMethod;
  35 import org.openhab.binding.http.internal.Util;
  36 import org.openhab.binding.http.internal.config.HttpThingConfig;
  37 import org.slf4j.Logger;
  38 import org.slf4j.LoggerFactory;
  39
  40 /**
  41  * The {@link RefreshingUrlCache} is responsible for requesting from a single URL and passing the content to the
  42  * channels
  43  *
  44  * @author Jan N. Klug - Initial contribution
  45  */
  46 @NonNullByDefault
  47 public class RefreshingUrlCache {
  48     private final Logger logger = LoggerFactory.getLogger(RefreshingUrlCache.class);
  49
  50     private final String url;
  51     private final RateLimitedHttpClient httpClient;
  52     private final int timeout;
  53     private final int bufferSize;
  54     private final @Nullable String fallbackEncoding;
  55     private final Set<Consumer<Content>> consumers = ConcurrentHashMap.newKeySet();
  56     private final List<String> headers;
  57     private final HttpMethod httpMethod;
  58     private final String httpContent;
  59
  60     private final ScheduledFuture<?> future;
  61     private @Nullable Content lastContent;
  62
  63     public RefreshingUrlCache(ScheduledExecutorService executor, RateLimitedHttpClient httpClient, String url,
  64             HttpThingConfig thingConfig, String httpContent) {
  65         this.httpClient = httpClient;
  66         this.url = url;
  67         this.timeout = thingConfig.timeout;
  68         this.bufferSize = thingConfig.bufferSize;
  69         this.headers = thingConfig.headers;
  70         this.httpMethod = thingConfig.stateMethod;
  71         this.httpContent = httpContent;
  72         fallbackEncoding = thingConfig.encoding;
  73
  74         future = executor.scheduleWithFixedDelay(this::refresh, 1, thingConfig.refresh, TimeUnit.SECONDS);
  75         logger.trace("Started refresh task for URL '{}' with interval {}s", url, thingConfig.refresh);
  76     }
  77
  78     private void refresh() {
  79         refresh(false);
  80     }
  81
  82     private void refresh(boolean isRetry) {
  83         if (consumers.isEmpty()) {
  84             // do not refresh if we don't have listeners
  85             return;
  86         }
  87
  88         // format URL
  89         try {
  90             URI uri = Util.uriFromString(String.format(this.url, new Date()));
  91             logger.trace("Requesting refresh (retry={}) from '{}' with timeout {}ms", isRetry, uri, timeout);
  92
  93             httpClient.newRequest(uri, httpMethod, httpContent).thenAccept(request -> {
  94                 request.timeout(timeout, TimeUnit.MILLISECONDS);
  95
  96                 headers.forEach(header -> {
  97                     String[] keyValuePair = header.split("=", 2);
  98                     if (keyValuePair.length == 2) {
  99                         request.header(keyValuePair[0].trim(), keyValuePair[1].trim());
 100                     } else {
 101                         logger.warn("Splitting header '{}' failed. No '=' was found. Ignoring", header);
 102                     }
 103                 });
 104
 105                 CompletableFuture<@Nullable Content> response = new CompletableFuture<>();
 106                 response.exceptionally(e -> {
 107                     if (e instanceof HttpAuthException) {
 108                         if (isRetry) {
 109                             logger.warn("Retry after authentication failure failed again for '{}', failing here", uri);
 110                         } else {
 111                             AuthenticationStore authStore = httpClient.getAuthenticationStore();
 112                             Authentication.Result authResult = authStore.findAuthenticationResult(uri);
 113                             if (authResult != null) {
 114                                 authStore.removeAuthenticationResult(authResult);
 115                                 logger.debug("Cleared authentication result for '{}', retrying immediately", uri);
 116                                 refresh(true);
 117                             } else {
 118                                 logger.warn("Could not find authentication result for '{}', failing here", uri);
 119                             }
 120                         }
 121                     }
 122                     return null;
 123                 }).thenAccept(this::processResult);
 124
 125                 if (logger.isTraceEnabled()) {
 126                     logger.trace("Sending to '{}': {}", uri, Util.requestToLogString(request));
 127                 }
 128
 129                 request.send(new HttpResponseListener(response, fallbackEncoding, bufferSize));
 130             }).exceptionally(e -> {
 131                 if (e instanceof CancellationException) {
 132                     logger.debug("Request to URL {} was cancelled by thing handler.", uri);
 133                 } else {
 134                     logger.warn("Request to URL {} failed: {}", uri, e.getMessage());
 135                 }
 136                 return null;
 137             });
 138         } catch (IllegalArgumentException | URISyntaxException | MalformedURLException e) {
 139             logger.warn("Creating request for '{}' failed: {}", url, e.getMessage());
 140         }
 141     }
 142
 143     public void stop() {
 144         // clearing all listeners to prevent further updates
 145         consumers.clear();
 146         future.cancel(false);
 147         logger.trace("Stopped refresh task for URL '{}'", url);
 148     }
 149
 150     public void addConsumer(Consumer<Content> consumer) {
 151         consumers.add(consumer);
 152     }
 153
 154     public Optional<Content> get() {
 155         final Content content = lastContent;
 156         if (content == null) {
 157             return Optional.empty();
 158         } else {
 159             return Optional.of(content);
 160         }
 161     }
 162
 163     private void processResult(@Nullable Content content) {
 164         if (content != null) {
 165             for (Consumer<Content> consumer : consumers) {
 166                 try {
 167                     consumer.accept(content);
 168                 } catch (IllegalArgumentException | IllegalStateException e) {
 169                     logger.warn("Failed processing result for URL {}: {}", url, e.getMessage());
 170                 }
 171             }
 172         }
 173         lastContent = content;
 174     }
 175 }