/**
* Copyright (C) 2012-2013 Selventa, Inc.
*
* This file is part of the OpenBEL Framework.
*
* This program 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 3 of the License, or
* (at your option) any later version.
*
* The OpenBEL Framework 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 the OpenBEL Framework. If not, see <http://www.gnu.org/licenses/>.
*
* Additional Terms under LGPL v3:
*
* This license does not authorize you and you are prohibited from using the
* name, trademarks, service marks, logos or similar indicia of Selventa, Inc.,
* or, in the discretion of other licensors or authors of the program, the
* name, trademarks, service marks, logos or similar indicia of such authors or
* licensors, in any marketing or advertising materials relating to your
* distribution of the program or any covered product. This restriction does
* not waive or limit your obligation to keep intact all copyright notices set
* forth in the program as delivered to you.
*
* If you distribute the program in whole or in part, or any modified version
* of the program, and you assume contractual liability to the recipient with
* respect to the program or modified version, then you will indemnify the
* authors and licensors of the program for any liabilities that these
* contractual assumptions directly impose on those licensors and authors.
*/
package org.openbel.framework.core.df.cache;
import static org.apache.commons.io.FileUtils.readFileToString;
import static org.openbel.framework.common.BELUtilities.asPath;
import static org.openbel.framework.common.BELUtilities.deleteDirectory;
import static org.openbel.framework.common.BELUtilities.hasItems;
import static org.openbel.framework.common.BELUtilities.sizedArrayList;
import static org.openbel.framework.common.PathConstants.SHA256_EXTENSION;
import static org.openbel.framework.common.Strings.UTF_8;
import static org.openbel.framework.common.cfg.SystemConfiguration.getSystemConfiguration;
import static org.openbel.framework.core.df.cache.CacheUtil.*;
import java.io.File;
import java.io.IOException;
import java.util.Collections;
import java.util.List;
import java.util.UUID;
import org.openbel.framework.common.cfg.SystemConfiguration;
import org.openbel.framework.core.protocol.ResourceDownloadError;
/**
* DefaultCacheableResourceService implements a cacheable resource service that
* handles BELFramework resource locations.
* <p>
* This service manages the cache at
* {@link SystemConfiguration#getCacheDirectory()}.
* </p>
*
* @author Anthony Bargnesi {@code <abargnesi@selventa.com>}
*/
public class DefaultCacheableResourceService extends
DefaultResourceService implements
CacheableResourceService {
/**
* Defines the temporary resource {@link File} list to be clean up after
* use.
*/
private final List<File> tempResources;
public DefaultCacheableResourceService() {
final List<File> fl = sizedArrayList(128);
tempResources = Collections.synchronizedList(fl);
Runtime.getRuntime().addShutdownHook(new ResourceCleanupThread());
}
/**
* {@inheritDoc}
*/
@Override
public ResolvedResource resolveResource(ResourceType type, String location)
throws ResourceDownloadError {
String resFolderPath = getResourceFolderPath(type);
String encLocation = encodeLocation(location);
String cachePath = asPath(resFolderPath, encLocation);
String cacheFile = CacheLookupService.DEFAULT_RESOURCE_FILE_NAME
+ type.getResourceExtension();
String cacheLocation = asPath(cachePath, cacheFile);
File resource = new File(cacheLocation);
if (resource.exists()) {
// cached resource exists, compare against remote hash
HashState hashState = hashCompare(location, resource);
switch (hashState) {
case HASH_MISMATCH:
File newResource = downloadResourceForUse(location, type);
return new ResolvedResource(newResource, true);
case HASH_MATCH:
case MISSING_REMOTE_HASH:
default:
File copiedFile = copyResource(resource, location);
return new ResolvedResource(copiedFile, false);
}
}
// download the latest version because it is not in the cache
File newResource = downloadResourceForUse(location, type);
return new ResolvedResource(newResource, true);
}
/**
* Compare hashes of the remote resource to the local resource. The
* comparison can result in the following:
* <ul>
* <li>If the resource's remote hash does not exist then return
* {@link HashState#MISSING_REMOTE_HASH}.</li>
* <li>If the resource's remote hash matches the local resource's hash then
* return {@link HashState#HASH_MATCH}</li>
* <li>If the resource's remote hash does not match the local resource's
* hash then return {@link HashState#HASH_MISMATCH}.</li>
* </ul>
*
* @param location {@link String}, the remote resource location
* @param resource {@link File}, the resource's local copy in the cache
* @return {@link HashState} the state of the hash comparison which is
* useful for deciding how to deal further with the resource
* @throws IOException Thrown if there was an IO error in handling hash
* files
*/
private HashState hashCompare(String location, File resource)
throws ResourceDownloadError {
String tmpPath = getSystemConfiguration().getCacheDirectory()
.getAbsolutePath();
String remoteHashLocation = location + SHA256_EXTENSION;
String tempHashPath = asPath(
ResourceType.TMP_FILE.getResourceFolderName(),
encodeLocation(location),
CacheLookupService.DEFAULT_RESOURCE_FILE_NAME
+ SHA256_EXTENSION);
// download resource hash
File remoteHashFile = null;
try {
remoteHashFile = resolveResource(remoteHashLocation, tmpPath,
tempHashPath);
} catch (ResourceDownloadError e) {
return HashState.MISSING_REMOTE_HASH;
}
String absPath = resource.getAbsolutePath();
File localHashFile = new File(absPath + SHA256_EXTENSION);
if (!localHashFile.exists() || !localHashFile.canRead()) {
localHashFile = createLocalHash(resource, location);
}
// compare hash files
try {
if (areHashFilesEqual(localHashFile, remoteHashFile, location)) {
// hashes are equal, so cached resource is the latest
// return cached resource
return HashState.HASH_MATCH;
}
// hashes are not equal
return HashState.HASH_MISMATCH;
} finally {
// delete the downloaded temporary hash
if (!remoteHashFile.delete()) {
remoteHashFile.deleteOnExit();
}
}
}
/**
* Download and copy the resource for use.
*
* @param resourceLocation {@link String}, the resource location
* @param type {@link ResourceType}, the type of resource
* @return the resource copy {@link File} ready for processing
* @throws ResourceDownloadError Throw if an error occurred resolving or
* copying the resource
*/
private File downloadResourceForUse(String resourceLocation,
ResourceType type)
throws ResourceDownloadError {
File downloadResource = downloadResource(resourceLocation, type);
return copyResource(downloadResource, resourceLocation);
}
/**
* Copy the resource to the system's temporary resources.
*
* @param resource {@link File}, the resource to copy from
* @param resourceLocation {@link String}, the resource location
* @return the resource copy {@link File} ready for processing
* @throws ResourceDownloadError Throw if an error occurred copying the
* resource
*/
private File
copyResource(final File resource, final String resourceLocation)
throws ResourceDownloadError {
final String tmpPath = asPath(getSystemConfiguration()
.getCacheDirectory().getAbsolutePath(),
ResourceType.TMP_FILE.getResourceFolderName());
final String uuidDirName = UUID.randomUUID().toString();
// load copy file and create parent directories
final File copyFile = new File(asPath(tmpPath, uuidDirName,
resource.getName()));
// copy to temp directory
File resourceCopy =
copyToDirectory(resource, resourceLocation, copyFile);
// hash uuid temp directory for cleanup later
tempResources.add(new File(asPath(tmpPath, uuidDirName)));
return resourceCopy;
}
/**
* Compares the hashes contained in the resource files. The hashes in the
* files are compared case-insensitively in order to support hexadecimal
* variations on a-f and A-F.
*
* @param hashFile1 {@link File}, the first hash file
* @param hashFile2 {@link File}, the second hash file
* @param remoteLocation {@link String}, the resource remote location
* @return <tt>boolean</tt> indicating <tt>true</tt>, if the hash files are
* equal, or <tt>false</tt> if the hash files are not equal
* @throws IOException Thrown if an IO error occurred reading the resource
* hashes
*/
private boolean areHashFilesEqual(File hashFile1, File hashFile2,
String remoteLocation) throws ResourceDownloadError {
try {
String resource1Hash = readFileToString(hashFile1, UTF_8);
String resource2Hash = readFileToString(hashFile2, UTF_8);
return resource1Hash.trim().equalsIgnoreCase(resource2Hash.trim());
} catch (IOException e) {
throw new ResourceDownloadError(remoteLocation, e.getMessage());
}
}
/**
* ResourceCleanupThread defines a {@link Thread} to delete all temporary
* resource directories created through this cacheable resource service.
*
* @author Anthony Bargnesi {@code <abargnesi@selventa.com>}
*/
private class ResourceCleanupThread extends Thread {
/**
* {@inheritDoc}
*/
@Override
public void run() {
if (hasItems(tempResources)) {
for (final File tempDir : tempResources) {
deleteDirectory(tempDir);
}
}
}
}
/**
* Defines different states with resolving a hashed resource.
*
* @author Anthony Bargnesi {@code <abargnesi@selventa.com>}
*/
private enum HashState {
MISSING_REMOTE_HASH,
HASH_MATCH,
HASH_MISMATCH;
}
}