001// License: GPL. For details, see LICENSE file. 002package org.openstreetmap.josm.data.cache; 003 004import java.io.FileNotFoundException; 005import java.io.IOException; 006import java.net.HttpURLConnection; 007import java.net.URL; 008import java.net.URLConnection; 009import java.util.HashSet; 010import java.util.List; 011import java.util.Map; 012import java.util.Random; 013import java.util.Set; 014import java.util.concurrent.ConcurrentHashMap; 015import java.util.concurrent.ConcurrentMap; 016import java.util.concurrent.LinkedBlockingDeque; 017import java.util.concurrent.ThreadPoolExecutor; 018import java.util.concurrent.TimeUnit; 019import java.util.logging.Level; 020import java.util.logging.Logger; 021 022import org.apache.commons.jcs.access.behavior.ICacheAccess; 023import org.apache.commons.jcs.engine.behavior.ICacheElement; 024import org.openstreetmap.gui.jmapviewer.FeatureAdapter; 025import org.openstreetmap.josm.Main; 026import org.openstreetmap.josm.data.cache.ICachedLoaderListener.LoadResult; 027import org.openstreetmap.josm.data.preferences.IntegerProperty; 028import org.openstreetmap.josm.tools.Utils; 029 030/** 031 * @author Wiktor Niesiobędzki 032 * 033 * @param <K> cache entry key type 034 * @param <V> cache value type 035 * 036 * Generic loader for HTTP based tiles. Uses custom attribute, to check, if entry has expired 037 * according to HTTP headers sent with tile. If so, it tries to verify using Etags 038 * or If-Modified-Since / Last-Modified. 039 * 040 * If the tile is not valid, it will try to download it from remote service and put it 041 * to cache. If remote server will fail it will try to use stale entry. 042 * 043 * This class will keep only one Job running for specified tile. All others will just finish, but 044 * listeners will be gathered and notified, once download job will be finished 045 * 046 * @since 8168 047 */ 048public abstract class JCSCachedTileLoaderJob<K, V extends CacheEntry> implements ICachedLoaderJob<K>, Runnable { 049 private static final Logger log = FeatureAdapter.getLogger(JCSCachedTileLoaderJob.class.getCanonicalName()); 050 protected static final long DEFAULT_EXPIRE_TIME = 1000L * 60 * 60 * 24 * 7; // 7 days 051 // Limit for the max-age value send by the server. 052 protected static final long EXPIRE_TIME_SERVER_LIMIT = 1000L * 60 * 60 * 24 * 28; // 4 weeks 053 // Absolute expire time limit. Cached tiles that are older will not be used, 054 // even if the refresh from the server fails. 055 protected static final long ABSOLUTE_EXPIRE_TIME_LIMIT = 1000L * 60 * 60 * 24 * 365; // 1 year 056 057 /** 058 * maximum download threads that will be started 059 */ 060 public static final IntegerProperty THREAD_LIMIT = new IntegerProperty("cache.jcs.max_threads", 10); 061 062 /* 063 * ThreadPoolExecutor starts new threads, until THREAD_LIMIT is reached. Then it puts tasks into LinkedBlockingDeque. 064 * 065 * The queue works FIFO, so one needs to take care about ordering of the entries submitted 066 * 067 * There is no point in canceling tasks, that are already taken by worker threads (if we made so much effort, we can at least cache 068 * the response, so later it could be used). We could actually cancel what is in LIFOQueue, but this is a tradeoff between simplicity 069 * and performance (we do want to have something to offer to worker threads before tasks will be resubmitted by class consumer) 070 */ 071 072 private static ThreadPoolExecutor DEFAULT_DOWNLOAD_JOB_DISPATCHER = new ThreadPoolExecutor( 073 2, // we have a small queue, so threads will be quickly started (threads are started only, when queue is full) 074 THREAD_LIMIT.get().intValue(), // do not this number of threads 075 30, // keepalive for thread 076 TimeUnit.SECONDS, 077 // make queue of LIFO type - so recently requested tiles will be loaded first (assuming that these are which user is waiting to see) 078 new LinkedBlockingDeque<Runnable>(), 079 Utils.newThreadFactory("JCS-downloader-%d", Thread.NORM_PRIORITY) 080 ); 081 082 083 084 private static ConcurrentMap<String, Set<ICachedLoaderListener>> inProgress = new ConcurrentHashMap<>(); 085 private static ConcurrentMap<String, Boolean> useHead = new ConcurrentHashMap<>(); 086 087 protected long now; // when the job started 088 089 private ICacheAccess<K, V> cache; 090 private ICacheElement<K, V> cacheElement; 091 protected V cacheData; 092 protected CacheEntryAttributes attributes; 093 094 // HTTP connection parameters 095 private int connectTimeout; 096 private int readTimeout; 097 private Map<String, String> headers; 098 private ThreadPoolExecutor downloadJobExecutor; 099 private Runnable finishTask; 100 private boolean force; 101 102 /** 103 * @param cache cache instance that we will work on 104 * @param headers HTTP headers to be sent together with request 105 * @param readTimeout when connecting to remote resource 106 * @param connectTimeout when connecting to remote resource 107 * @param downloadJobExecutor that will be executing the jobs 108 */ 109 public JCSCachedTileLoaderJob(ICacheAccess<K, V> cache, 110 int connectTimeout, int readTimeout, 111 Map<String, String> headers, 112 ThreadPoolExecutor downloadJobExecutor) { 113 114 this.cache = cache; 115 this.now = System.currentTimeMillis(); 116 this.connectTimeout = connectTimeout; 117 this.readTimeout = readTimeout; 118 this.headers = headers; 119 this.downloadJobExecutor = downloadJobExecutor; 120 } 121 122 /** 123 * @param cache cache instance that we will work on 124 * @param headers HTTP headers to be sent together with request 125 * @param readTimeout when connecting to remote resource 126 * @param connectTimeout when connecting to remote resource 127 */ 128 public JCSCachedTileLoaderJob(ICacheAccess<K, V> cache, 129 int connectTimeout, int readTimeout, 130 Map<String, String> headers) { 131 this(cache, connectTimeout, readTimeout, 132 headers, DEFAULT_DOWNLOAD_JOB_DISPATCHER); 133 } 134 135 private void ensureCacheElement() { 136 if (cacheElement == null && getCacheKey() != null) { 137 cacheElement = cache.getCacheElement(getCacheKey()); 138 if (cacheElement != null) { 139 attributes = (CacheEntryAttributes) cacheElement.getElementAttributes(); 140 cacheData = cacheElement.getVal(); 141 } 142 } 143 } 144 145 public V get() { 146 ensureCacheElement(); 147 return cacheData; 148 } 149 150 @Override 151 public void submit(ICachedLoaderListener listener, boolean force) throws IOException { 152 this.force = force; 153 boolean first = false; 154 URL url = getUrl(); 155 String deduplicationKey = null; 156 if (url != null) { 157 // url might be null, for example when Bing Attribution is not loaded yet 158 deduplicationKey = url.toString(); 159 } 160 if (deduplicationKey == null) { 161 log.log(Level.WARNING, "No url returned for: {0}, skipping", getCacheKey()); 162 throw new IllegalArgumentException("No url returned"); 163 } 164 synchronized (inProgress) { 165 Set<ICachedLoaderListener> newListeners = inProgress.get(deduplicationKey); 166 if (newListeners == null) { 167 newListeners = new HashSet<>(); 168 inProgress.put(deduplicationKey, newListeners); 169 first = true; 170 } 171 newListeners.add(listener); 172 } 173 174 if (first || force) { 175 // submit all jobs to separate thread, so calling thread is not blocked with IO when loading from disk 176 log.log(Level.FINE, "JCS - Submitting job for execution for url: {0}", getUrlNoException()); 177 downloadJobExecutor.execute(this); 178 } 179 } 180 181 /** 182 * This method is run when job has finished 183 */ 184 protected void executionFinished() { 185 if (finishTask != null) { 186 finishTask.run(); 187 } 188 } 189 190 /** 191 * 192 * @return checks if object from cache has sufficient data to be returned 193 */ 194 protected boolean isObjectLoadable() { 195 if (cacheData == null) { 196 return false; 197 } 198 byte[] content = cacheData.getContent(); 199 return content != null && content.length > 0; 200 } 201 202 /** 203 * Simple implementation. All errors should be cached as empty. Though some JDK (JDK8 on Windows for example) 204 * doesn't return 4xx error codes, instead they do throw an FileNotFoundException or IOException 205 * 206 * @return true if we should put empty object into cache, regardless of what remote resource has returned 207 */ 208 protected boolean cacheAsEmpty() { 209 return attributes.getResponseCode() < 500; 210 } 211 212 /** 213 * @return key under which discovered server settings will be kept 214 */ 215 protected String getServerKey() { 216 return getUrlNoException().getHost(); 217 } 218 219 @Override 220 public void run() { 221 final Thread currentThread = Thread.currentThread(); 222 final String oldName = currentThread.getName(); 223 currentThread.setName("JCS Downloading: " + getUrlNoException()); 224 log.log(Level.FINE, "JCS - starting fetch of url: {0} ", getUrlNoException()); 225 ensureCacheElement(); 226 try { 227 // try to fetch from cache 228 if (!force && cacheElement != null && isCacheElementValid() && isObjectLoadable()) { 229 // we got something in cache, and it's valid, so lets return it 230 log.log(Level.FINE, "JCS - Returning object from cache: {0}", getCacheKey()); 231 finishLoading(LoadResult.SUCCESS); 232 return; 233 } 234 235 // try to load object from remote resource 236 if (loadObject()) { 237 finishLoading(LoadResult.SUCCESS); 238 } else { 239 // if loading failed - check if we can return stale entry 240 if (isObjectLoadable()) { 241 // try to get stale entry in cache 242 finishLoading(LoadResult.SUCCESS); 243 log.log(Level.FINE, "JCS - found stale object in cache: {0}", getUrlNoException()); 244 } else { 245 // failed completely 246 finishLoading(LoadResult.FAILURE); 247 } 248 } 249 } finally { 250 executionFinished(); 251 currentThread.setName(oldName); 252 } 253 } 254 255 private void finishLoading(LoadResult result) { 256 Set<ICachedLoaderListener> listeners = null; 257 synchronized (inProgress) { 258 listeners = inProgress.remove(getUrlNoException().toString()); 259 } 260 if (listeners == null) { 261 log.log(Level.WARNING, "Listener not found for URL: {0}. Listener not notified!", getUrlNoException()); 262 return; 263 } 264 for (ICachedLoaderListener l: listeners) { 265 l.loadingFinished(cacheData, attributes, result); 266 } 267 } 268 269 protected boolean isCacheElementValid() { 270 long expires = attributes.getExpirationTime(); 271 272 // check by expire date set by server 273 if (expires != 0L) { 274 // put a limit to the expire time (some servers send a value 275 // that is too large) 276 expires = Math.min(expires, attributes.getCreateTime() + EXPIRE_TIME_SERVER_LIMIT); 277 if (now > expires) { 278 log.log(Level.FINE, "JCS - Object {0} has expired -> valid to {1}, now is: {2}", 279 new Object[]{getUrlNoException(), Long.toString(expires), Long.toString(now)}); 280 return false; 281 } 282 } else if (attributes.getLastModification() > 0 && 283 now - attributes.getLastModification() > DEFAULT_EXPIRE_TIME) { 284 // check by file modification date 285 log.log(Level.FINE, "JCS - Object has expired, maximum file age reached {0}", getUrlNoException()); 286 return false; 287 } else if (now - attributes.getCreateTime() > DEFAULT_EXPIRE_TIME) { 288 log.log(Level.FINE, "JCS - Object has expired, maximum time since object creation reached {0}", getUrlNoException()); 289 return false; 290 } 291 return true; 292 } 293 294 /** 295 * @return true if object was successfully downloaded, false, if there was a loading failure 296 */ 297 298 private boolean loadObject() { 299 if (attributes == null) { 300 attributes = new CacheEntryAttributes(); 301 } 302 try { 303 // if we have object in cache, and host doesn't support If-Modified-Since nor If-None-Match 304 // then just use HEAD request and check returned values 305 if (isObjectLoadable() && 306 Boolean.TRUE.equals(useHead.get(getServerKey())) && 307 isCacheValidUsingHead()) { 308 log.log(Level.FINE, "JCS - cache entry verified using HEAD request: {0}", getUrl()); 309 return true; 310 } 311 312 HttpURLConnection urlConn = getURLConnection(getUrl()); 313 314 if (isObjectLoadable() && 315 (now - attributes.getLastModification()) <= ABSOLUTE_EXPIRE_TIME_LIMIT) { 316 urlConn.setIfModifiedSince(attributes.getLastModification()); 317 } 318 if (isObjectLoadable() && attributes.getEtag() != null) { 319 urlConn.addRequestProperty("If-None-Match", attributes.getEtag()); 320 } 321 322 log.log(Level.INFO, "GET {0} -> {1}", new Object[]{getUrl(), urlConn.getResponseCode()}); 323 324 // follow redirects 325 for (int i = 0; i < 5; i++) { 326 if (urlConn.getResponseCode() == 302) { 327 urlConn = getURLConnection(new URL(urlConn.getHeaderField("Location"))); 328 } else { 329 break; 330 } 331 } 332 if (urlConn.getResponseCode() == 304) { 333 // If isModifiedSince or If-None-Match has been set 334 // and the server answers with a HTTP 304 = "Not Modified" 335 log.log(Level.FINE, "JCS - IfModifiedSince/Etag test: local version is up to date: {0}", getUrl()); 336 return true; 337 } else if (isObjectLoadable() // we have an object in cache, but we haven't received 304 resposne code 338 && ( 339 (attributes.getEtag() != null && attributes.getEtag().equals(urlConn.getRequestProperty("ETag"))) || 340 attributes.getLastModification() == urlConn.getLastModified()) 341 ) { 342 // we sent ETag or If-Modified-Since, but didn't get 304 response code 343 // for further requests - use HEAD 344 String serverKey = getServerKey(); 345 log.log(Level.INFO, "JCS - Host: {0} found not to return 304 codes for If-Modifed-Since or If-None-Match headers", 346 serverKey); 347 useHead.put(serverKey, Boolean.TRUE); 348 } 349 350 351 attributes = parseHeaders(urlConn); 352 353 for (int i = 0; i < 5; ++i) { 354 if (urlConn.getResponseCode() == 503) { 355 Thread.sleep(5000+(new Random()).nextInt(5000)); 356 continue; 357 } 358 359 attributes.setResponseCode(urlConn.getResponseCode()); 360 byte[] raw; 361 if (urlConn.getResponseCode() == 200) { 362 raw = Utils.readBytesFromStream(urlConn.getInputStream()); 363 } else { 364 raw = new byte[]{}; 365 } 366 367 if (isResponseLoadable(urlConn.getHeaderFields(), urlConn.getResponseCode(), raw)) { 368 // we need to check cacheEmpty, so for cases, when data is returned, but we want to store 369 // as empty (eg. empty tile images) to save some space 370 cacheData = createCacheEntry(raw); 371 cache.put(getCacheKey(), cacheData, attributes); 372 log.log(Level.FINE, "JCS - downloaded key: {0}, length: {1}, url: {2}", 373 new Object[] {getCacheKey(), raw.length, getUrl()}); 374 return true; 375 } else if (cacheAsEmpty()) { 376 cacheData = createCacheEntry(new byte[]{}); 377 cache.put(getCacheKey(), cacheData, attributes); 378 log.log(Level.FINE, "JCS - Caching empty object {0}", getUrl()); 379 return true; 380 } else { 381 log.log(Level.FINE, "JCS - failure during load - reponse is not loadable nor cached as empty"); 382 return false; 383 } 384 } 385 } catch (FileNotFoundException e) { 386 log.log(Level.FINE, "JCS - Caching empty object as server returned 404 for: {0}", getUrlNoException()); 387 attributes.setResponseCode(404); 388 attributes.setErrorMessage(e.toString()); 389 boolean doCache = isResponseLoadable(null, 404, null) || cacheAsEmpty(); 390 if (doCache) { 391 cacheData = createCacheEntry(new byte[]{}); 392 cache.put(getCacheKey(), cacheData, attributes); 393 } 394 return doCache; 395 } catch (IOException e) { 396 log.log(Level.FINE, "JCS - IOExecption during communication with server for: {0}", getUrlNoException()); 397 attributes.setErrorMessage(e.toString()); 398 attributes.setResponseCode(499); // set dummy error code 399 boolean doCache = isResponseLoadable(null, 499, null) || cacheAsEmpty(); //generic 499 error code returned 400 if (doCache) { 401 cacheData = createCacheEntry(new byte[]{}); 402 cache.put(getCacheKey(), createCacheEntry(new byte[]{}), attributes); 403 } 404 return doCache; 405 } catch (Exception e) { 406 attributes.setErrorMessage(e.toString()); 407 log.log(Level.WARNING, "JCS - Exception during download {0}", getUrlNoException()); 408 Main.warn(e); 409 } 410 log.log(Level.WARNING, "JCS - Silent failure during download: {0}", getUrlNoException()); 411 return false; 412 413 } 414 415 /** 416 * Check if the object is loadable. This means, if the data will be parsed, and if this response 417 * will finish as successful retrieve. 418 * 419 * This simple implementation doesn't load empty response, nor client (4xx) and server (5xx) errors 420 * 421 * @param headerFields headers sent by server 422 * @param responseCode http status code 423 * @param raw data read from server 424 * @return true if object should be cached and returned to listener 425 */ 426 protected boolean isResponseLoadable(Map<String, List<String>> headerFields, int responseCode, byte[] raw) { 427 if (raw == null || raw.length == 0 || responseCode >= 400) { 428 return false; 429 } 430 return true; 431 } 432 433 protected abstract V createCacheEntry(byte[] content); 434 435 protected CacheEntryAttributes parseHeaders(URLConnection urlConn) { 436 CacheEntryAttributes ret = new CacheEntryAttributes(); 437 438 Long lng = urlConn.getExpiration(); 439 if (lng.equals(0L)) { 440 try { 441 String str = urlConn.getHeaderField("Cache-Control"); 442 if (str != null) { 443 for (String token: str.split(",")) { 444 if (token.startsWith("max-age=")) { 445 lng = Long.parseLong(token.substring(8)) * 1000 + 446 System.currentTimeMillis(); 447 } 448 } 449 } 450 } catch (NumberFormatException e) { 451 // ignore malformed Cache-Control headers 452 if (Main.isTraceEnabled()) { 453 Main.trace(e.getMessage()); 454 } 455 } 456 } 457 458 ret.setExpirationTime(lng); 459 ret.setLastModification(now); 460 ret.setEtag(urlConn.getHeaderField("ETag")); 461 return ret; 462 } 463 464 private HttpURLConnection getURLConnection(URL url) throws IOException { 465 HttpURLConnection urlConn = (HttpURLConnection) url.openConnection(); 466 urlConn.setRequestProperty("Accept", "text/html, image/png, image/jpeg, image/gif, */*"); 467 urlConn.setReadTimeout(readTimeout); // 30 seconds read timeout 468 urlConn.setConnectTimeout(connectTimeout); 469 if (headers != null) { 470 for (Map.Entry<String, String> e: headers.entrySet()) { 471 urlConn.setRequestProperty(e.getKey(), e.getValue()); 472 } 473 } 474 475 if (force) { 476 urlConn.setUseCaches(false); 477 } 478 return urlConn; 479 } 480 481 private boolean isCacheValidUsingHead() throws IOException { 482 HttpURLConnection urlConn = getURLConnection(getUrl()); 483 urlConn.setRequestMethod("HEAD"); 484 for (int i = 0; i < 5; i++) { 485 if (urlConn.getResponseCode() == 302) { 486 urlConn = getURLConnection(new URL(urlConn.getHeaderField("Location"))); 487 } else { 488 break; 489 } 490 } 491 long lastModified = urlConn.getLastModified(); 492 return (attributes.getEtag() != null && attributes.getEtag().equals(urlConn.getRequestProperty("ETag"))) || 493 (lastModified != 0 && lastModified <= attributes.getLastModification()); 494 } 495 496 /** 497 * TODO: move to JobFactory 498 * cancels all outstanding tasks in the queue. 499 */ 500 public void cancelOutstandingTasks() { 501 for (Runnable r: downloadJobExecutor.getQueue()) { 502 if (downloadJobExecutor.remove(r) && r instanceof JCSCachedTileLoaderJob) { 503 ((JCSCachedTileLoaderJob<?, ?>) r).handleJobCancellation(); 504 } 505 } 506 } 507 508 /** 509 * Sets a job, that will be run, when job will finish execution 510 * @param runnable that will be executed 511 */ 512 public void setFinishedTask(Runnable runnable) { 513 this.finishTask = runnable; 514 515 } 516 517 /** 518 * Marks this job as canceled 519 */ 520 public void handleJobCancellation() { 521 finishLoading(LoadResult.CANCELED); 522 } 523 524 private URL getUrlNoException() { 525 try { 526 return getUrl(); 527 } catch (IOException e) { 528 return null; 529 } 530 } 531}