001// License: GPL. For details, see LICENSE file.
002package org.openstreetmap.josm.io;
003
004import static org.openstreetmap.josm.tools.I18n.tr;
005
006import java.io.BufferedInputStream;
007import java.io.File;
008import java.io.FileInputStream;
009import java.io.IOException;
010import java.io.InputStream;
011import java.net.HttpURLConnection;
012import java.net.MalformedURLException;
013import java.net.URL;
014import java.nio.charset.StandardCharsets;
015import java.nio.file.Files;
016import java.nio.file.StandardCopyOption;
017import java.util.ArrayList;
018import java.util.Arrays;
019import java.util.Enumeration;
020import java.util.List;
021import java.util.Map;
022import java.util.concurrent.ConcurrentHashMap;
023import java.util.zip.ZipEntry;
024import java.util.zip.ZipFile;
025
026import org.openstreetmap.josm.Main;
027import org.openstreetmap.josm.tools.HttpClient;
028import org.openstreetmap.josm.tools.Pair;
029import org.openstreetmap.josm.tools.Utils;
030
031/**
032 * Downloads a file and caches it on disk in order to reduce network load.
033 *
034 * Supports URLs, local files, and a custom scheme (<code>resource:</code>) to get
035 * resources from the current *.jar file. (Local caching is only done for URLs.)
036 * <p>
037 * The mirrored file is only downloaded if it has been more than 7 days since
038 * last download. (Time can be configured.)
039 * <p>
040 * The file content is normally accessed with {@link #getInputStream()}, but
041 * you can also get the mirrored copy with {@link #getFile()}.
042 */
043public class CachedFile {
044
045    /**
046     * Caching strategy.
047     */
048    public enum CachingStrategy {
049        /**
050         * If cached file on disk is older than a certain time (7 days by default),
051         * consider the cache stale and try to download the file again.
052         */
053        MaxAge,
054        /**
055         * Similar to MaxAge, considers the cache stale when a certain age is
056         * exceeded. In addition, a If-Modified-Since HTTP header is added.
057         * When the server replies "304 Not Modified", this is considered the same
058         * as a full download.
059         */
060        IfModifiedSince
061    }
062
063    protected String name;
064    protected long maxAge;
065    protected String destDir;
066    protected String httpAccept;
067    protected CachingStrategy cachingStrategy;
068
069    protected File cacheFile;
070    protected boolean initialized;
071
072    public static final long DEFAULT_MAXTIME = -1L;
073    public static final long DAYS = 24*60*60; // factor to get caching time in days
074
075    private final Map<String, String> httpHeaders = new ConcurrentHashMap<>();
076
077    /**
078     * Constructs a CachedFile object from a given filename, URL or internal resource.
079     *
080     * @param name can be:<ul>
081     *  <li>relative or absolute file name</li>
082     *  <li>{@code file:///SOME/FILE} the same as above</li>
083     *  <li>{@code http://...} a URL. It will be cached on disk.</li>
084     *  <li>{@code resource://SOME/FILE} file from the classpath (usually in the current *.jar)</li>
085     *  <li>{@code josmdir://SOME/FILE} file inside josm user data directory (since r7058)</li>
086     *  <li>{@code josmplugindir://SOME/FILE} file inside josm plugin directory (since r7834)</li></ul>
087     */
088    public CachedFile(String name) {
089        this.name = name;
090    }
091
092    /**
093     * Set the name of the resource.
094     * @param name can be:<ul>
095     *  <li>relative or absolute file name</li>
096     *  <li>{@code file:///SOME/FILE} the same as above</li>
097     *  <li>{@code http://...} a URL. It will be cached on disk.</li>
098     *  <li>{@code resource://SOME/FILE} file from the classpath (usually in the current *.jar)</li>
099     *  <li>{@code josmdir://SOME/FILE} file inside josm user data directory (since r7058)</li>
100     *  <li>{@code josmplugindir://SOME/FILE} file inside josm plugin directory (since r7834)</li></ul>
101     * @return this object
102     */
103    public CachedFile setName(String name) {
104        this.name = name;
105        return this;
106    }
107
108    /**
109     * Set maximum age of cache file. Only applies to URLs.
110     * When this time has passed after the last download of the file, the
111     * cache is considered stale and a new download will be attempted.
112     * @param maxAge the maximum cache age in seconds
113     * @return this object
114     */
115    public CachedFile setMaxAge(long maxAge) {
116        this.maxAge = maxAge;
117        return this;
118    }
119
120    /**
121     * Set the destination directory for the cache file. Only applies to URLs.
122     * @param destDir the destination directory
123     * @return this object
124     */
125    public CachedFile setDestDir(String destDir) {
126        this.destDir = destDir;
127        return this;
128    }
129
130    /**
131     * Set the accepted MIME types sent in the HTTP Accept header. Only applies to URLs.
132     * @param httpAccept the accepted MIME types
133     * @return this object
134     */
135    public CachedFile setHttpAccept(String httpAccept) {
136        this.httpAccept = httpAccept;
137        return this;
138    }
139
140    /**
141     * Set the caching strategy. Only applies to URLs.
142     * @param cachingStrategy caching strategy
143     * @return this object
144     */
145    public CachedFile setCachingStrategy(CachingStrategy cachingStrategy) {
146        this.cachingStrategy = cachingStrategy;
147        return this;
148    }
149
150    /**
151     * Sets the http headers. Only applies to URL pointing to http or https resources
152     * @param headers that should be sent together with request
153     * @return this object
154     */
155    public CachedFile setHttpHeaders(Map<String, String> headers) {
156        this.httpHeaders.putAll(headers);
157        return this;
158    }
159
160    public String getName() {
161        return name;
162    }
163
164    public long getMaxAge() {
165        return maxAge;
166    }
167
168    public String getDestDir() {
169        return destDir;
170    }
171
172    public String getHttpAccept() {
173        return httpAccept;
174    }
175
176    public CachingStrategy getCachingStrategy() {
177        return cachingStrategy;
178    }
179
180    /**
181     * Get InputStream to the requested resource.
182     * @return the InputStream
183     * @throws IOException when the resource with the given name could not be retrieved
184     */
185    public InputStream getInputStream() throws IOException {
186        File file = getFile();
187        if (file == null) {
188            if (name.startsWith("resource://")) {
189                InputStream is = getClass().getResourceAsStream(
190                        name.substring("resource:/".length()));
191                if (is == null)
192                    throw new IOException(tr("Failed to open input stream for resource ''{0}''", name));
193                return is;
194            } else {
195                throw new IOException("No file found for: "+name);
196            }
197        }
198        return new FileInputStream(file);
199    }
200
201    /**
202     * Get local file for the requested resource.
203     * @return The local cache file for URLs. If the resource is a local file,
204     * returns just that file.
205     * @throws IOException when the resource with the given name could not be retrieved
206     */
207    public synchronized File getFile() throws IOException {
208        if (initialized)
209            return cacheFile;
210        initialized = true;
211        URL url;
212        try {
213            url = new URL(name);
214            if ("file".equals(url.getProtocol())) {
215                cacheFile = new File(name.substring("file:/".length() - 1));
216                if (!cacheFile.exists()) {
217                    cacheFile = new File(name.substring("file://".length() - 1));
218                }
219            } else {
220                cacheFile = checkLocal(url);
221            }
222        } catch (MalformedURLException e) {
223            if (name.startsWith("resource://")) {
224                return null;
225            } else if (name.startsWith("josmdir://")) {
226                cacheFile = new File(Main.pref.getUserDataDirectory(), name.substring("josmdir://".length()));
227            } else if (name.startsWith("josmplugindir://")) {
228                cacheFile = new File(Main.pref.getPluginsDirectory(), name.substring("josmplugindir://".length()));
229            } else {
230                cacheFile = new File(name);
231            }
232        }
233        if (cacheFile == null)
234            throw new IOException("Unable to get cache file for "+name);
235        return cacheFile;
236    }
237
238    /**
239     * Looks for a certain entry inside a zip file and returns the entry path.
240     *
241     * Replies a file in the top level directory of the ZIP file which has an
242     * extension <code>extension</code>. If more than one files have this
243     * extension, the last file whose name includes <code>namepart</code>
244     * is opened.
245     *
246     * @param extension  the extension of the file we're looking for
247     * @param namepart the name part
248     * @return The zip entry path of the matching file. Null if this cached file
249     * doesn't represent a zip file or if there was no matching
250     * file in the ZIP file.
251     */
252    public String findZipEntryPath(String extension, String namepart) {
253        Pair<String, InputStream> ze = findZipEntryImpl(extension, namepart);
254        if (ze == null) return null;
255        return ze.a;
256    }
257
258    /**
259     * Like {@link #findZipEntryPath}, but returns the corresponding InputStream.
260     * @param extension  the extension of the file we're looking for
261     * @param namepart the name part
262     * @return InputStream to the matching file. Null if this cached file
263     * doesn't represent a zip file or if there was no matching
264     * file in the ZIP file.
265     * @since 6148
266     */
267    public InputStream findZipEntryInputStream(String extension, String namepart) {
268        Pair<String, InputStream> ze = findZipEntryImpl(extension, namepart);
269        if (ze == null) return null;
270        return ze.b;
271    }
272
273    private Pair<String, InputStream> findZipEntryImpl(String extension, String namepart) {
274        File file = null;
275        try {
276            file = getFile();
277        } catch (IOException ex) {
278            Main.warn(ex, false);
279        }
280        if (file == null)
281            return null;
282        Pair<String, InputStream> res = null;
283        try {
284            ZipFile zipFile = new ZipFile(file, StandardCharsets.UTF_8);
285            ZipEntry resentry = null;
286            Enumeration<? extends ZipEntry> entries = zipFile.entries();
287            while (entries.hasMoreElements()) {
288                ZipEntry entry = entries.nextElement();
289                if (entry.getName().endsWith('.' + extension)) {
290                    /* choose any file with correct extension. When more than
291                        one file, prefer the one which matches namepart */
292                    if (resentry == null || entry.getName().indexOf(namepart) >= 0) {
293                        resentry = entry;
294                    }
295                }
296            }
297            if (resentry != null) {
298                InputStream is = zipFile.getInputStream(resentry);
299                res = Pair.create(resentry.getName(), is);
300            } else {
301                Utils.close(zipFile);
302            }
303        } catch (Exception e) {
304            if (file.getName().endsWith(".zip")) {
305                Main.warn(tr("Failed to open file with extension ''{2}'' and namepart ''{3}'' in zip file ''{0}''. Exception was: {1}",
306                        file.getName(), e.toString(), extension, namepart));
307            }
308        }
309        return res;
310    }
311
312    /**
313     * Clear the cache for the given resource.
314     * This forces a fresh download.
315     * @param name the URL
316     */
317    public static void cleanup(String name) {
318        cleanup(name, null);
319    }
320
321    /**
322     * Clear the cache for the given resource.
323     * This forces a fresh download.
324     * @param name the URL
325     * @param destDir the destination directory (see {@link #setDestDir(java.lang.String)})
326     */
327    public static void cleanup(String name, String destDir) {
328        URL url;
329        try {
330            url = new URL(name);
331            if (!"file".equals(url.getProtocol())) {
332                String prefKey = getPrefKey(url, destDir);
333                List<String> localPath = new ArrayList<>(Main.pref.getCollection(prefKey));
334                if (localPath.size() == 2) {
335                    File lfile = new File(localPath.get(1));
336                    if (lfile.exists()) {
337                        Utils.deleteFile(lfile);
338                    }
339                }
340                Main.pref.putCollection(prefKey, null);
341            }
342        } catch (MalformedURLException e) {
343            Main.warn(e);
344        }
345    }
346
347    /**
348     * Get preference key to store the location and age of the cached file.
349     * 2 resources that point to the same url, but that are to be stored in different
350     * directories will not share a cache file.
351     * @param url URL
352     * @param destDir destination directory
353     * @return Preference key
354     */
355    private static String getPrefKey(URL url, String destDir) {
356        StringBuilder prefKey = new StringBuilder("mirror.");
357        if (destDir != null) {
358            prefKey.append(destDir).append('.');
359        }
360        prefKey.append(url.toString());
361        return prefKey.toString().replaceAll("=", "_");
362    }
363
364    private File checkLocal(URL url) throws IOException {
365        String prefKey = getPrefKey(url, destDir);
366        String urlStr = url.toExternalForm();
367        long age = 0L;
368        long lMaxAge = maxAge;
369        Long ifModifiedSince = null;
370        File localFile = null;
371        List<String> localPathEntry = new ArrayList<>(Main.pref.getCollection(prefKey));
372        boolean offline = false;
373        try {
374            checkOfflineAccess(urlStr);
375        } catch (OfflineAccessException e) {
376            offline = true;
377        }
378        if (localPathEntry.size() == 2) {
379            localFile = new File(localPathEntry.get(1));
380            if (!localFile.exists()) {
381                localFile = null;
382            } else {
383                if (maxAge == DEFAULT_MAXTIME
384                        || maxAge <= 0 // arbitrary value <= 0 is deprecated
385                ) {
386                    lMaxAge = Main.pref.getInteger("mirror.maxtime", 7*24*60*60); // one week
387                }
388                age = System.currentTimeMillis() - Long.parseLong(localPathEntry.get(0));
389                if (offline || age < lMaxAge*1000) {
390                    return localFile;
391                }
392                if (cachingStrategy == CachingStrategy.IfModifiedSince) {
393                    ifModifiedSince = Long.valueOf(localPathEntry.get(0));
394                }
395            }
396        }
397        if (destDir == null) {
398            destDir = Main.pref.getCacheDirectory().getPath();
399        }
400
401        File destDirFile = new File(destDir);
402        if (!destDirFile.exists()) {
403            destDirFile.mkdirs();
404        }
405
406        // No local file + offline => nothing to do
407        if (offline) {
408            return null;
409        }
410
411        String a = urlStr.replaceAll("[^A-Za-z0-9_.-]", "_");
412        String localPath = "mirror_" + a;
413        destDirFile = new File(destDir, localPath + ".tmp");
414        try {
415            final HttpClient.Response con = HttpClient.create(url)
416                    .setAccept(httpAccept)
417                    .setIfModifiedSince(ifModifiedSince == null ? 0L : ifModifiedSince)
418                    .setHeaders(httpHeaders)
419                    .connect();
420            if (ifModifiedSince != null && con.getResponseCode() == HttpURLConnection.HTTP_NOT_MODIFIED) {
421                if (Main.isDebugEnabled()) {
422                    Main.debug("304 Not Modified ("+urlStr+')');
423                }
424                if (localFile == null)
425                    throw new AssertionError();
426                Main.pref.putCollection(prefKey,
427                        Arrays.asList(Long.toString(System.currentTimeMillis()), localPathEntry.get(1)));
428                return localFile;
429            }
430            try (InputStream bis = new BufferedInputStream(con.getContent())) {
431                Files.copy(bis, destDirFile.toPath(), StandardCopyOption.REPLACE_EXISTING);
432            }
433            localFile = new File(destDir, localPath);
434            if (Main.platform.rename(destDirFile, localFile)) {
435                Main.pref.putCollection(prefKey,
436                        Arrays.asList(Long.toString(System.currentTimeMillis()), localFile.toString()));
437            } else {
438                Main.warn(tr("Failed to rename file {0} to {1}.",
439                destDirFile.getPath(), localFile.getPath()));
440            }
441        } catch (IOException e) {
442            if (age >= lMaxAge*1000 && age < lMaxAge*1000*2) {
443                Main.warn(tr("Failed to load {0}, use cached file and retry next time: {1}", urlStr, e));
444                return localFile;
445            } else {
446                throw e;
447            }
448        }
449
450        return localFile;
451    }
452
453    private static void checkOfflineAccess(String urlString) {
454        OnlineResource.JOSM_WEBSITE.checkOfflineAccess(urlString, Main.getJOSMWebsite());
455        OnlineResource.OSM_API.checkOfflineAccess(urlString, Main.pref.get("osm-server.url", OsmApi.DEFAULT_API_URL));
456    }
457
458}