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/*
* Copyright 2010-2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file is distributed
* on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied. See the License for the specific language governing
* permissions and limitations under the License.
* According to cos feature, we modify some class，comment, field name, etc.
*/
package com.qcloud.cos.utils;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.SocketException;
import java.util.Arrays;
import javax.net.ssl.SSLProtocolException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import com.qcloud.cos.exception.CosClientException;
import com.qcloud.cos.exception.FileLockException;
import com.qcloud.cos.internal.FileLocks;
import com.qcloud.cos.internal.SkipMd5CheckStrategy;
import com.qcloud.cos.model.COSObject;
import com.qcloud.cos.model.ObjectMetadata;
public class ServiceUtils {
private static final Logger log = LoggerFactory.getLogger(ServiceUtils.class);
private static final SkipMd5CheckStrategy skipMd5CheckStrategy = SkipMd5CheckStrategy.INSTANCE;
public static final boolean APPEND_MODE = true;
public static final boolean OVERWRITE_MODE = false;
/**
* Same as {@link #downloadObjectToFile(COSObject, File, boolean, boolean)}
* but has an additional expected file length parameter for integrity
* checking purposes.
*
* @param expectedFileLength
* applicable only when appendData is true; the expected length
* of the file to append to.
*/
public static void downloadToFile(COSObject cosObject,
final File dstfile, boolean performIntegrityCheck,
final boolean appendData,
final long expectedFileLength)
{
// attempt to create the parent if it doesn't exist
File parentDirectory = dstfile.getParentFile();
if ( parentDirectory != null && !parentDirectory.exists() ) {
if (!(parentDirectory.mkdirs())) {
throw new CosClientException(
"Unable to create directory in the path"
+ parentDirectory.getAbsolutePath());
}
}
if (!FileLocks.lock(dstfile)) {
throw new FileLockException("Fail to lock " + dstfile
+ " for appendData=" + appendData);
}
OutputStream outputStream = null;
try {
final long actualLen = dstfile.length();
if (appendData && actualLen != expectedFileLength) {
// Fail fast to prevent data corruption
throw new IllegalStateException(
"Expected file length to append is "
+ expectedFileLength + " but actual length is "
+ actualLen + " for file " + dstfile);
}
outputStream = new BufferedOutputStream(new FileOutputStream(
dstfile, appendData));
byte[] buffer = new byte[1024*10];
int bytesRead;
while ((bytesRead = cosObject.getObjectContent().read(buffer)) > -1) {
outputStream.write(buffer, 0, bytesRead);
}
} catch (IOException e) {
cosObject.getObjectContent().abort();
throw new CosClientException(
"Unable to store object contents to disk: " + e.getMessage(), e);
} finally {
IOUtils.closeQuietly(outputStream, log);
FileLocks.unlock(dstfile);
IOUtils.closeQuietly(cosObject.getObjectContent(), log);
}
if (performIntegrityCheck) {
byte[] clientSideHash = null;
byte[] serverSideHash = null;
try {
final ObjectMetadata metadata = cosObject.getObjectMetadata();
if (!skipMd5CheckStrategy.skipClientSideValidationPerGetResponse(metadata)) {
clientSideHash = Md5Utils.computeMD5Hash(dstfile);
serverSideHash = BinaryUtils.fromHex(metadata.getETag());
}
} catch (Exception e) {
log.warn("Unable to calculate MD5 hash to validate download: " + e.getMessage(), e);
}
if (clientSideHash != null && serverSideHash != null && !Arrays.equals(clientSideHash, serverSideHash)) {
throw new CosClientException("Unable to verify integrity of data download. " +
"Client calculated content hash didn't match hash calculated by Qcloud COS. " +
"The data stored in '" + dstfile.getAbsolutePath() + "' may be corrupt.");
}
}
}
/**
* Downloads an COSObject, as returned from
* {@link COSClient#getObject(com.qcloud.cos.model.GetObjectRequest)},
* to the specified file.
*
* @param cosObject
* The COSObject containing a reference to an InputStream
* containing the object's data.
* @param destinationFile
* The file to store the object's data in.
* @param performIntegrityCheck
* Boolean valuable to indicate whether to perform integrity check
* @param appendData
* appends the data to end of the file.
*/
public static void downloadObjectToFile(COSObject cosObject,
final File destinationFile, boolean performIntegrityCheck,
boolean appendData) {
downloadToFile(cosObject, destinationFile, performIntegrityCheck, appendData, -1);
}
/**
* Interface for the task of downloading object from COS to a specific file,
* enabling one-time retry mechanism after integrity check failure
* on the downloaded file.
*/
public interface RetryableCOSDownloadTask {
/**
* User defines how to get the COSObject from COS for this RetryableCOSDownloadTask.
*
* @return
* The COSObject containing a reference to an InputStream
* containing the object's data.
*/
public COSObject getCOSObjectStream ();
/**
* User defines whether integrity check is needed for this RetryableCOSDownloadTask.
*
* @return
* Boolean value indicating whether this task requires integrity check
* after downloading the COS object to file.
*/
public boolean needIntegrityCheck ();
}
/**
* Gets an object stored in COS and downloads it into the specified file.
* This method includes the one-time retry mechanism after integrity check failure
* on the downloaded file. It will also return immediately after getting null valued
* COSObject (when getObject request does not meet the specified constraints).
*
* @param file
* The file to store the object's data in.
* @param retryableCOSDownloadTask
* The implementation of SafeCOSDownloadTask interface which allows user to
* get access to all the visible variables at the calling site of this method.
*/
public static COSObject retryableDownloadCOSObjectToFile(File file,
RetryableCOSDownloadTask retryableCOSDownloadTask, boolean appendData) {
boolean hasRetried = false;
boolean needRetry;
COSObject cosObject;
do {
needRetry = false;
cosObject = retryableCOSDownloadTask.getCOSObjectStream();
if ( cosObject == null )
return null;
try {
ServiceUtils.downloadObjectToFile(cosObject, file,
retryableCOSDownloadTask.needIntegrityCheck(),
appendData);
} catch (CosClientException cse) {
if (!cse.isRetryable()) {
cosObject.getObjectContent().abort();
throw cse;
}
// Determine whether an immediate retry is needed according to the captured CosClientException.
// (There are three cases when downloadObjectToFile() throws CosClientException:
// 1) SocketException or SSLProtocolException when writing to disk (e.g. when user aborts the download)
// 2) Other IOException when writing to disk
// 3) MD5 hashes don't match
// The current code will retry the download only when case 2) or 3) happens.
if (cse.getCause() instanceof SocketException || cse.getCause() instanceof SSLProtocolException) {
throw cse;
} else {
needRetry = true;
if ( hasRetried ) {
cosObject.getObjectContent().abort();
throw cse;
} else {
log.info("Retry the download of object " + cosObject.getKey() + " (bucket " + cosObject.getBucketName() + ")", cse);
hasRetried = true;
}
}
}
} while ( needRetry );
return cosObject;
}
}
