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   1 /**
   2  * Copyright (c) 2010-2020 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.*;
  16 import java.util.Date;
  17 import java.util.List;
  18 import java.util.Optional;
  19 import java.util.Set;
  20 import java.util.concurrent.*;
  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.Authentication;
  26 import org.eclipse.jetty.client.api.AuthenticationStore;
  27 import org.openhab.binding.http.internal.Util;
  28 import org.openhab.binding.http.internal.config.HttpThingConfig;
  29 import org.slf4j.Logger;
  30 import org.slf4j.LoggerFactory;
  31
  32 /**
  33  * The {@link RefreshingUrlCache} is responsible for requesting from a single URL and passing the content to the
  34  * channels
  35  *
  36  * @author Jan N. Klug - Initial contribution
  37  */
  38 @NonNullByDefault
  39 public class RefreshingUrlCache {
  40     private final Logger logger = LoggerFactory.getLogger(RefreshingUrlCache.class);
  41
  42     private final String url;
  43     private final RateLimitedHttpClient httpClient;
  44     private final int timeout;
  45     private final int bufferSize;
  46     private final @Nullable String fallbackEncoding;
  47     private final Set<Consumer<Content>> consumers = ConcurrentHashMap.newKeySet();
  48     private final List<String> headers;
  49
  50     private final ScheduledFuture<?> future;
  51     private @Nullable Content lastContent;
  52
  53     public RefreshingUrlCache(ScheduledExecutorService executor, RateLimitedHttpClient httpClient, String url,
  54             HttpThingConfig thingConfig) {
  55         this.httpClient = httpClient;
  56         this.url = url;
  57         this.timeout = thingConfig.timeout;
  58         this.bufferSize = thingConfig.bufferSize;
  59         this.headers = thingConfig.headers;
  60         fallbackEncoding = thingConfig.encoding;
  61
  62         future = executor.scheduleWithFixedDelay(this::refresh, 0, thingConfig.refresh, TimeUnit.SECONDS);
  63         logger.trace("Started refresh task for URL '{}' with interval {}s", url, thingConfig.refresh);
  64     }
  65
  66     private void refresh() {
  67         refresh(false);
  68     }
  69
  70     private void refresh(boolean isRetry) {
  71         if (consumers.isEmpty()) {
  72             // do not refresh if we don't have listeners
  73             return;
  74         }
  75
  76         // format URL
  77         try {
  78             URI uri = Util.uriFromString(String.format(this.url, new Date()));
  79             logger.trace("Requesting refresh (retry={}) from '{}' with timeout {}ms", isRetry, uri, timeout);
  80
  81             httpClient.newRequest(uri).thenAccept(request -> {
  82                 request.timeout(timeout, TimeUnit.MILLISECONDS);
  83
  84                 headers.forEach(header -> {
  85                     String[] keyValuePair = header.split("=", 2);
  86                     if (keyValuePair.length == 2) {
  87                         request.header(keyValuePair[0].trim(), keyValuePair[1].trim());
  88                     } else {
  89                         logger.warn("Splitting header '{}' failed. No '=' was found. Ignoring", header);
  90                     }
  91                 });
  92
  93                 CompletableFuture<@Nullable Content> response = new CompletableFuture<>();
  94                 response.exceptionally(e -> {
  95                     if (e instanceof HttpAuthException) {
  96                         if (isRetry) {
  97                             logger.warn("Retry after authentication  failure failed again for '{}', failing here", uri);
  98                         } else {
  99                             AuthenticationStore authStore = httpClient.getAuthenticationStore();
 100                             Authentication.Result authResult = authStore.findAuthenticationResult(uri);
 101                             if (authResult != null) {
 102                                 authStore.removeAuthenticationResult(authResult);
 103                                 logger.debug("Cleared authentication result for '{}', retrying immediately", uri);
 104                                 refresh(true);
 105                             } else {
 106                                 logger.warn("Could not find authentication result for '{}', failing here", uri);
 107                             }
 108                         }
 109                     }
 110                     return null;
 111                 }).thenAccept(this::processResult);
 112
 113                 if (logger.isTraceEnabled()) {
 114                     logger.trace("Sending to '{}': {}", uri, Util.requestToLogString(request));
 115                 }
 116
 117                 request.send(new HttpResponseListener(response, fallbackEncoding, bufferSize));
 118             }).exceptionally(e -> {
 119                 if (e instanceof CancellationException) {
 120                     logger.debug("Request to URL {} was cancelled by thing handler.", uri);
 121                 } else {
 122                     logger.warn("Request to URL {} failed: {}", uri, e.getMessage());
 123                 }
 124                 return null;
 125             });
 126         } catch (IllegalArgumentException | URISyntaxException | MalformedURLException e) {
 127             logger.warn("Creating request for '{}' failed: {}", url, e.getMessage());
 128         }
 129     }
 130
 131     public void stop() {
 132         // clearing all listeners to prevent further updates
 133         consumers.clear();
 134         future.cancel(false);
 135         logger.trace("Stopped refresh task for URL '{}'", url);
 136     }
 137
 138     public void addConsumer(Consumer<Content> consumer) {
 139         consumers.add(consumer);
 140     }
 141
 142     public Optional<Content> get() {
 143         final Content content = lastContent;
 144         if (content == null) {
 145             return Optional.empty();
 146         } else {
 147             return Optional.of(content);
 148         }
 149     }
 150
 151     private void processResult(@Nullable Content content) {
 152         if (content != null) {
 153             for (Consumer<Content> consumer : consumers) {
 154                 try {
 155                     consumer.accept(content);
 156                 } catch (IllegalArgumentException | IllegalStateException e) {
 157                     logger.warn("Failed processing result for URL {}: {}", url, e.getMessage());
 158                 }
 159             }
 160         }
 161         lastContent = content;
 162     }
 163 }