public InputStream downloadRange(long start, long end, String file) {
GetObjectRequest rangeObjectRequest = new GetObjectRequest(bucketName, file);
rangeObjectRequest.setRange(start, end); // retrieve 1st 10 bytes.
S3Object objectPortion = s3client.getObject(rangeObjectRequest);
InputStream objectData = objectPortion.getObjectContent();
return objectData;
}
/* (non-Javadoc)
* @see com.amazonaws.services.s3.AmazonS3#getObject(com.amazonaws.services.s3.model.GetObjectRequest)
*/
@Override
public S3Object getObject(GetObjectRequest getObjectRequest)
throws AmazonClientException, AmazonServiceException {
appendUserAgent(getObjectRequest, USER_AGENT);
// Adjust the crypto range to retrieve all of the cipher blocks needed to contain the user's
// desired
// range of bytes.
long[] desiredRange = getObjectRequest.getRange();
long[] adjustedCryptoRange = EncryptionUtils.getAdjustedCryptoRange(desiredRange);
if (adjustedCryptoRange != null) {
getObjectRequest.setRange(adjustedCryptoRange[0], adjustedCryptoRange[1]);
}
// Get the object from S3
S3Object retrievedObject = super.getObject(getObjectRequest);
// If the caller has specified constraints, it's possible that super.getObject(...)
// would return null, so we simply return null as well.
if (retrievedObject == null) return null;
S3Object objectToBeReturned;
try {
// Check if encryption info is in object metadata
if (EncryptionUtils.isEncryptionInfoInMetadata(retrievedObject)) {
objectToBeReturned = decryptObjectUsingMetadata(retrievedObject);
} else {
// Check if encrypted info is in an instruction file
S3Object instructionFile = null;
try {
instructionFile = getInstructionFile(getObjectRequest);
if (EncryptionUtils.isEncryptionInfoInInstructionFile(instructionFile)) {
objectToBeReturned =
decryptObjectUsingInstructionFile(retrievedObject, instructionFile);
} else {
// The object was not encrypted to begin with. Return the object without decrypting it.
log.warn(
String.format(
"Unable to detect encryption information for object '%s' in bucket '%s'. "
+ "Returning object without decryption.",
retrievedObject.getKey(), retrievedObject.getBucketName()));
objectToBeReturned = retrievedObject;
}
} finally {
if (instructionFile != null) {
try {
instructionFile.getObjectContent().close();
} catch (Exception e) {
}
}
}
}
} catch (AmazonClientException ace) {
// If we're unable to set up the decryption, make sure we close the HTTP connection
try {
retrievedObject.getObjectContent().close();
} catch (Exception e) {
}
throw ace;
}
// Adjust the output to the desired range of bytes.
return EncryptionUtils.adjustOutputToDesiredRange(objectToBeReturned, desiredRange);
}
/**
* Sets the optional inclusive byte range within the desired object that will be downloaded by
* this request. Returns this {@link GetObjectRequest}, enabling additional method calls to be
* chained together.
*
* <p>The first byte in an object has position 0; as an example, the first ten bytes of an object
* can be downloaded by specifying a range of 0 to 9.
*
* <p>If no byte range is specified, this request downloads the entire object from Amazon S3.
*
* @param start The start of the inclusive byte range to download.
* @param end The end of the inclusive byte range to download.
* @return This {@link GetObjectRequest}, enabling additional method calls to be chained together.
* @see GetObjectRequest#getRange()
* @see GetObjectRequest#setRange(long, long)
*/
public GetObjectRequest withRange(long start, long end) {
setRange(start, end);
return this;
}