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/**
* DSS - Digital Signature Services
* Copyright (C) 2015 European Commission, provided under the CEF programme
*
* This file is part of the "DSS - Digital Signature Services" project.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
package eu.europa.esig.dss.client.http.commons;
import java.io.File;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import eu.europa.esig.dss.DSSCannotFetchDataException;
import eu.europa.esig.dss.DSSException;
import eu.europa.esig.dss.DSSUtils;
import eu.europa.esig.dss.DigestAlgorithm;
import eu.europa.esig.dss.ResourceLoader;
import eu.europa.esig.dss.client.http.DataLoader;
import eu.europa.esig.dss.client.http.Protocol;
import eu.europa.esig.dss.utils.Utils;
/**
* This class provides some caching features to handle the resources. The default cache folder is set to
* {@code java.io.tmpdir}. The urls of the resources is transformed to the
* file name by replacing the special characters by {@code _}
*/
public class FileCacheDataLoader extends CommonsDataLoader implements DataLoader {
private static final Logger LOG = LoggerFactory.getLogger(FileCacheDataLoader.class);
private File fileCacheDirectory = new File(System.getProperty("java.io.tmpdir"));
private ResourceLoader resourceLoader = new ResourceLoader();
private List toBeLoaded;
private List toIgnored;
private Long cacheExpirationTime;
private DataLoader dataLoader;
public FileCacheDataLoader() {
}
public FileCacheDataLoader(DataLoader dataLoader) {
this.dataLoader = dataLoader;
}
public DataLoader getDataLoader() {
return dataLoader;
}
public void setDataLoader(DataLoader dataLoader) {
this.dataLoader = dataLoader;
}
/**
* This method allows to set the file cache directory. If the cache folder does not exists then it's created.
*
* @param fileCacheDirectory
* {@code File} pointing the cache folder to be used.
*/
public void setFileCacheDirectory(final File fileCacheDirectory) {
this.fileCacheDirectory = fileCacheDirectory;
this.fileCacheDirectory.mkdirs();
}
/**
* Sets the expiration time for the cached files in milliseconds.
* If more time has passed from the cache file's last modified time, then a fresh copy is downloaded and cached,
* otherwise a cached copy is used.
*
* If the expiration time is not set, then the cache does not expire.
*
* @param cacheExpirationTimeInMilliseconds
*/
public void setCacheExpirationTime(long cacheExpirationTimeInMilliseconds) {
this.cacheExpirationTime = cacheExpirationTimeInMilliseconds;
}
public void setResourceLoader(final ResourceLoader resourceLoader) {
this.resourceLoader = resourceLoader;
}
/**
* This methods allows to indicate if the resource must be obtained. If this method has been invoked then only the
* provided URL will be processed.
*
* @param url
* to be processed
*/
public void addToBeLoaded(final String url) {
if (toBeLoaded == null) {
toBeLoaded = new ArrayList();
}
if (Utils.isStringNotBlank(url)) {
toBeLoaded.add(url);
}
}
/**
* This methods allows to indicate which resources must be ignored. It is useful in a test environment where some of
* fake sources a not available. It prevents to wait for the
* timeout.
*
* @param urlString
* to be ignored. It can be the original URL or the cache file name
*/
public void addToBeIgnored(final String urlString) {
if (toIgnored == null) {
toIgnored = new ArrayList();
}
if (Utils.isStringNotBlank(urlString)) {
final String normalizedFileName = ResourceLoader.getNormalizedFileName(urlString);
toIgnored.add(normalizedFileName);
}
}
@Override
public byte[] get(final String url, final boolean refresh) throws DSSCannotFetchDataException {
if ((toBeLoaded != null) && !toBeLoaded.contains(url)) {
return null;
}
final String fileName = ResourceLoader.getNormalizedFileName(url);
final File file = getCacheFile(fileName);
final boolean fileExists = file.exists();
final boolean isCacheExpired = isCacheExpired(file);
if (fileExists && !refresh && !isCacheExpired) {
LOG.debug("Cached file was used");
final byte[] bytes = DSSUtils.toByteArray(file);
return bytes;
} else {
if (!fileExists) {
LOG.debug("There is no cached file!");
} else {
LOG.debug("The refresh is forced!");
}
}
final byte[] bytes;
if (!isNetworkProtocol(url)) {
final String resourcePath = resourceLoader.getAbsoluteResourceFolder(url.trim());
final File fileResource = new File(resourcePath);
bytes = DSSUtils.toByteArray(fileResource);
} else {
bytes = super.get(url);
}
if ((bytes != null) && (bytes.length != 0)) {
final File out = getCacheFile(fileName);
DSSUtils.saveToFile(bytes, out);
}
return bytes;
}
@Override
public byte[] get(final String url) throws DSSCannotFetchDataException {
return get(url, false);
}
protected boolean isNetworkProtocol(final String urlString) {
final String normalizedUrl = urlString.trim().toLowerCase();
return Protocol.isHttpUrl(normalizedUrl) || Protocol.isLdapUrl(normalizedUrl) || Protocol.isFtpUrl(normalizedUrl);
}
private File getCacheFile(final String fileName) {
final String trimmedFileName = fileName.trim();
if ((toIgnored != null) && toIgnored.contains(trimmedFileName)) {
throw new DSSException("Part of urls to ignore.");
}
LOG.debug("Cached file: " + fileCacheDirectory + "/" + trimmedFileName);
final File file = new File(fileCacheDirectory, trimmedFileName);
return file;
}
/**
* Allows to load the file for a given file name from the cache folder.
*
* @return the content of the file or {@code null} if the file does not exist
*/
public byte[] loadFileFromCache(final String urlString) {
final String fileName = ResourceLoader.getNormalizedFileName(urlString);
final File file = getCacheFile(fileName);
if (file.exists()) {
final byte[] bytes = DSSUtils.toByteArray(file);
return bytes;
}
return null;
}
/**
* Allows to add a given array of {@code byte} as a cache file representing by the {@code urlString}.
*
* @param urlString
* the URL to add to the cache
* @param bytes
* the content of the cache file
*/
public void saveBytesInCache(final String urlString, final byte[] bytes) {
final String fileName = ResourceLoader.getNormalizedFileName(urlString);
final File out = getCacheFile(fileName);
DSSUtils.saveToFile(bytes, out);
}
@Override
public byte[] post(final String urlString, final byte[] content) throws DSSException {
final String fileName = ResourceLoader.getNormalizedFileName(urlString);
// The length for the InputStreamEntity is needed, because some receivers (on the other side) need this
// information.
// To determine the length, we cannot read the content-stream up to the end and re-use it afterwards.
// This is because, it may not be possible to reset the stream (= go to position 0).
// So, the solution is to cache temporarily the complete content data (as we do not expect much here) in a
// byte-array.
final byte[] digest = DSSUtils.digest(DigestAlgorithm.MD5, content);
final String digestHexEncoded = DSSUtils.toHex(digest);
final String cacheFileName = fileName + "." + digestHexEncoded;
final File file = getCacheFile(cacheFileName);
if (file.exists()) {
LOG.debug("Cached file was used");
final byte[] byteArray = DSSUtils.toByteArray(file);
return byteArray;
} else {
LOG.debug("There is no cached file!");
}
final byte[] returnedBytes;
if (!isNetworkProtocol(urlString)) {
final String resourcePath = resourceLoader.getAbsoluteResourceFolder(urlString.trim());
final File fileResource = new File(resourcePath);
returnedBytes = DSSUtils.toByteArray(fileResource);
return returnedBytes;
}
returnedBytes = dataLoader.post(urlString, content);
if (returnedBytes.length != 0) {
final File cacheFile = getCacheFile(cacheFileName);
DSSUtils.saveToFile(returnedBytes, cacheFile);
}
return returnedBytes;
}
private boolean isCacheExpired(File file) {
if (cacheExpirationTime == null) {
return false;
}
if (!file.exists()) {
return true;
}
long currentTime = new Date().getTime();
if (file.lastModified() + cacheExpirationTime < currentTime) {
LOG.debug("Cache is expired");
return true;
}
return false;
}
@Override
public DataAndUrl get(final List urlStrings) {
final int numberOfUrls = urlStrings.size();
int ii = 0;
for (final String urlString : urlStrings) {
try {
ii++;
final byte[] bytes = get(urlString);
if (bytes == null) {
continue;
}
return new DataAndUrl(bytes, urlString);
} catch (Exception e) {
if (ii == numberOfUrls) {
if (e instanceof DSSException) {
throw (DSSException) e;
}
throw new DSSException(e);
}
LOG.warn("Impossible to obtain data using {}", urlString, e);
}
}
return null;
}
@Override
public void setContentType(String contentType) {
dataLoader.setContentType(contentType);
}
}
