UploadPartCopy Amazon S3 API-CodePudding

As per the Amazon documentation there is a API called UploadPartCopy which copies an object from source bucket into a part of a destination object. But I cant find this API in S3Client for .Net interface. There is a UploadPart (for which I need to supply stream) but no UploadPartCopy. My usecase is that, I already have multiple objects in a source bucket and I want to form a destination bucket by combining all these objects into a single bucket. I want to do this without performing GetObject and then doing UploadPart as this involves a round trip.

I cant seem to find this API in SDK. What am I missing?

CodePudding user response：

My guess is that you are looking for the multipart functions: https://docs.aws.amazon.com/sdkfornet/v3/apidocs/items/S3/MS3InitiateMultipartUploadStringString.html

CodePudding user response：

The API that calls into the REST API UploadPartCopy is CopyPart and CopyPartRequest. You can find a fairly complete demo of using this API and the related APIs from Amazon, here's the salient portion that should demonstrate how to call the API:

// Create a list to store the upload part responses.
List<UploadPartResponse> uploadResponses = new List<UploadPartResponse>();
List<CopyPartResponse> copyResponses = new List<CopyPartResponse>();

// Setup information required to initiate the multipart upload.
InitiateMultipartUploadRequest initiateRequest =
    new InitiateMultipartUploadRequest
    {
        BucketName = targetBucket,
        Key = targetObjectKey
    };

// Initiate the upload.
InitiateMultipartUploadResponse initResponse = await s3Client.InitiateMultipartUploadAsync(initiateRequest);

// Save the upload ID.
String uploadId = initResponse.UploadId;

// Get the size of the object.
GetObjectMetadataRequest metadataRequest = new GetObjectMetadataRequest
{
    BucketName = sourceBucket,
    Key = sourceObjectKey
};

GetObjectMetadataResponse metadataResponse = await s3Client.GetObjectMetadataAsync(metadataRequest);
long objectSize = metadataResponse.ContentLength; // Length in bytes.

// Copy the parts.
long partSize = 5242880; // Part size is 5 MiB.
long bytePosition = 0;

for (int i = 1; bytePosition < objectSize; i  )
{
    CopyPartRequest copyRequest = new CopyPartRequest
    {
        DestinationBucket = targetBucket,
        DestinationKey = targetObjectKey,
        SourceBucket = sourceBucket,
        SourceKey = sourceObjectKey,
        UploadId = uploadId,
        FirstByte = bytePosition,
        LastByte = bytePosition   partSize - 1 >= objectSize ? objectSize - 1 : bytePosition   partSize - 1,
        PartNumber = i
    };

    copyResponses.Add(await s3Client.CopyPartAsync(copyRequest));

    bytePosition  = partSize;
}

// Set up to complete the copy.
CompleteMultipartUploadRequest completeRequest =
new CompleteMultipartUploadRequest
{
    BucketName = targetBucket,
    Key = targetObjectKey,
    UploadId = initResponse.UploadId
};
completeRequest.AddPartETags(copyResponses);

// Complete the copy.
CompleteMultipartUploadResponse completeUploadResponse = await s3Client.CompleteMultipartUploadAsync(completeRequest);