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Copy an Object Using the AWS SDK for .NET Multipart Upload API
The following task guides you through using the .NET SDK to copy an Amazon S3 object from one source location to another, such as from one bucket to another. You can use the code demonstrated here to copy objects that are greater than 5 GB. For objects less than 5 GB, use the single operation copy described in Copy an Object Using the AWS SDK for .NET.
Copying Objects
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1 |
Create an instance of the |
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2 |
Initiate a multipart copy by executing the
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3 |
Save the upload ID from the response object that the
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4 |
Copy all the parts. For each part copy, create a new instance of the
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5 |
Save the response of the
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6 |
Repeat tasks 4 and 5 for each part. |
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7 | Execute the AmazonS3Client.CompleteMultipartUpload method to
complete the copy. |
The following C# code sample demonstrates the preceding tasks.
// Step 1. Create instance and provide credentials.
AmazonS3Config config = new AmazonS3Config();
AmazonS3 s3Client = new AmazonS3Client(AccessKeyID, SecretAccessKey, config);
// List to store upload part responses.
List<UploadPartResponse> uploadResponses =
new List<UploadPartResponse>();
List<CopyPartResponse> copyResponses =
new List<CopyPartResponse>();
InitiateMultipartUploadRequest initiateRequest =
new InitiateMultipartUploadRequest()
.WithBucketName(targetBucket)
.WithKey(targetObjectKey);
// Step 2. Initialize.
InitiateMultipartUploadResponse initResponse =
s3Client.InitiateMultipartUpload(initiateRequest);
// Step 3. Save Upload Id.
String uploadId = initResponse.UploadId;
try
{
// Get object size.
GetObjectMetadataRequest metadataRequest = new GetObjectMetadataRequest();
metadataRequest.BucketName = sourceBucket;
metadataRequest.Key = sourceObjectKey;
GetObjectMetadataResponse metadataResponse = s3Client.GetObjectMetadata(metadataRequest);
long objectSize = metadataResponse.ContentLength; // in bytes
// Step 4. Copy parts.
long partSize = 5 * (long)Math.Pow(2, 20); // 5 MB
long bytePosition = 0;
for (int i = 1; bytePosition < objectSize; i++)
{
// Step 5. Save copy response.
CopyPartRequest copyRequest = new CopyPartRequest()
.WithDestinationBucket(targetBucket)
.WithDestinationKey(targetObjectKey)
.WithSourceBucket(sourceBucket)
.WithSourceKey(sourceObjectKey)
.WithUploadID(uploadId)
.WithFirstByte(bytePosition)
.WithLastByte(bytePosition + partSize -1 >= objectSize ? objectSize - 1 : bytePosition + partSize - 1)
.WithPartNumber(i);
copyResponses.Add(s3Client.CopyPart(copyRequest));
bytePosition += partSize;
}
// Step 7. Complete copy operation.
CompleteMultipartUploadRequest completeRequest =
new CompleteMultipartUploadRequest()
.WithBucketName(targetBucket)
.WithKey(targetObjectKey)
.WithUploadId(initResponse.UploadId)
.WithPartETags(GetETags(copyResponses));
CompleteMultipartUploadResponse completeUploadResponse =
s3Client.CompleteMultipartUpload(completeRequest);
}
catch (Exception e) {
Console.WriteLine(e.Message);
}
Example
The following C# code example copies an object from one Amazon S3 bucket to another. For instructions on how to create and test a working sample, see Testing the .NET Code Examples.
using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Configuration;
using System.IO;
using Amazon.S3;
using Amazon.S3.Model;
namespace s3.amazon.com.docsamples.LowLevel_LargeObjectCopy
{
class MPUcopyObject
{
static string sourceBucket = "*** Source bucket name ***";
static string targetBucket = "*** Target bucket name ***";
static string sourceObjectKey = "*** Source object key ***";
static string targetObjectKey = "*** Target object key ***";
static void Main(string[] args)
{
NameValueCollection appConfig = ConfigurationManager.AppSettings;
string accessKeyID = appConfig["AWSAccessKey"];
string secretAccessKey = appConfig["AWSSecretKey"];
AmazonS3Config config = new AmazonS3Config();
AmazonS3 s3Client = new AmazonS3Client(accessKeyID, secretAccessKey, config);
// List to store upload part responses.
List<UploadPartResponse> uploadResponses =
new List<UploadPartResponse>();
List<CopyPartResponse> copyResponses =
new List<CopyPartResponse>();
InitiateMultipartUploadRequest initiateRequest =
new InitiateMultipartUploadRequest()
.WithBucketName(targetBucket)
.WithKey(targetObjectKey);
InitiateMultipartUploadResponse initResponse =
s3Client.InitiateMultipartUpload(initiateRequest);
String uploadId = initResponse.UploadId;
try
{
// Get object size.
GetObjectMetadataRequest metadataRequest = new GetObjectMetadataRequest();
metadataRequest.BucketName = sourceBucket;
metadataRequest.Key = sourceObjectKey;
GetObjectMetadataResponse metadataResponse = s3Client.GetObjectMetadata(metadataRequest);
long objectSize = metadataResponse.ContentLength; // in bytes
// Copy parts.
long partSize = 5 * (long)Math.Pow(2, 20); // 5 MB
long bytePosition = 0;
for (int i = 1; bytePosition < objectSize; i++)
{
CopyPartRequest copyRequest = new CopyPartRequest()
.WithDestinationBucket(targetBucket)
.WithDestinationKey(targetObjectKey)
.WithSourceBucket(sourceBucket)
.WithSourceKey(sourceObjectKey)
.WithUploadID(uploadId)
.WithFirstByte(bytePosition)
.WithLastByte(bytePosition + partSize - 1 >= objectSize ? objectSize - 1 : bytePosition + partSize - 1)
.WithPartNumber(i);
copyResponses.Add(s3Client.CopyPart(copyRequest));
bytePosition += partSize;
}
CompleteMultipartUploadRequest completeRequest =
new CompleteMultipartUploadRequest()
.WithBucketName(targetBucket)
.WithKey(targetObjectKey)
.WithUploadId(initResponse.UploadId)
.WithPartETags(GetETags(copyResponses));
CompleteMultipartUploadResponse completeUploadResponse =
s3Client.CompleteMultipartUpload(completeRequest);
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
}
// Helper function that constructs ETags.
static List<PartETag> GetETags(List<CopyPartResponse> responses)
{
List<PartETag> etags = new List<PartETag>();
foreach (CopyPartResponse response in responses)
{
etags.Add(new PartETag(response.PartNumber, response.ETag));
}
return etags;
}
}
}
