Object Storage Service:Copy an object (C++ SDK)

Usage notes

• In this topic, the public endpoint of the China (Hangzhou) region is used. If you want to access OSS from other Alibaba Cloud services in the same region as OSS, use an internal endpoint. For more information about OSS regions and endpoints, see Regions and endpoints.

• In this topic, an OSSClient instance is created by using an OSS endpoint. If you want to create an OSSClient by using custom domain names or Security Token Service (STS), see Create an OSSClient instance.

• To copy an object, you must have the oss:GetObject and oss:PutObject permissions. For more information, see Attach a custom policy to a RAM user.

Copy a small object

You can call CopyObject to copy an object that is up to 1 GB in size from a source bucket to a destination bucket within the same region.

• If you do not specify a version ID in the x-oss-copy-source header of the CopyObject request, the current version of the object is copied. If the current version of the object is a delete marker, OSS returns 404, which indicates that the object does not exist. You can add a version ID to the x-oss-copy-source header to copy a specific object version. Delete markers cannot be copied.

• You can copy a previous version of an object to the same bucket. The copied previous version becomes the new current version of the object. This way, the previous version of the object is restored.

• If versioning is enabled for the destination bucket, OSS generates a unique version ID for the destination object. The version ID is returned in the x-oss-version-id response header. If versioning is disabled or suspended for the destination bucket, OSS generates a version whose version ID is null for the destination object and overwrites the existing version whose version ID is null.

• Appendable objects cannot be copied to a destination bucket for which versioning is enabled or suspended.

The following code shows how to copy a small object:

#include <alibabacloud/oss/OssClient.h>
using namespace AlibabaCloud::OSS;

int main(void)
{
    /* Initialize OSS account information. */
            
    /* Set Endpoint to the endpoint of the region where the bucket is located. For example, if the bucket is in the China (Hangzhou) region, set Endpoint to https://oss-cn-hangzhou.aliyuncs.com. */
    std::string Endpoint = "yourEndpoint";
    /* Set Region to the region where the bucket is located. For example, if the bucket is in the China (Hangzhou) region, set Region to cn-hangzhou. */
    std::string Region = "yourRegion";
    /* Specify the name of the source bucket. Example: srcexamplebucket. */
    std::string SourceBucketName = "srcexamplebucket";
    /* Specify the name of the destination bucket, which must be in the same region as the source bucket. Example: destbucket. */
    std::string CopyBucketName = "destbucket";
    /* Specify the full path of the source object. The full path cannot contain the bucket name. Example: srcdir/scrobject.txt. */
    std::string SourceObjectName = "srcdir/scrobject.txt";
    /* Specify the full path of the destination object. The full path cannot contain the bucket name. Example: destdir/destobject.txt. */
    std::string CopyObjectName = "destdir/destobject.txt";


    /* Initialize network resources. */
    InitializeSdk();

    ClientConfiguration conf;
    conf.signatureVersion = SignatureVersionType::V4;
    /* Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. */
    auto credentialsProvider = std::make_shared<EnvironmentVariableCredentialsProvider>();
    OssClient client(Endpoint, credentialsProvider, conf);
    client.SetRegion(Region);

    CopyObjectRequest request(CopyBucketName, CopyObjectName);
    request.setCopySource(SourceBucketName, SourceObjectName);
    /* Specify the version ID of the source object. */
    request.setVersionId("yourSourceObjectVersionId");

    /* Copy the specified version of the object. */
    auto outcome = client.CopyObject(request);

    if (outcome.isSuccess()) {
        std::cout << "versionid:" << outcome.result().VersionId() << std::endl;
    }
    else {
        /* Handle exceptions. */
        std::cout << "CopyObject fail" <<
        ",code:" << outcome.error().Code() <<
        ",message:" << outcome.error().Message() <<
        ",requestId:" << outcome.error().RequestId() << std::endl;
        return -1;
    }

    /* Release network resources. */
    ShutdownSdk();
    return 0;
}

Copy a large object

To copy an object that is larger than 1 GB in size, you need to split the object into parts and copy the parts by using UploadPartCopy.

If a version ID is not specified in the request and the current version of the source object is a delete marker, OSS returns 404 Not Found. If a version ID is specified in the request and the specified version of the source object is a delete marker, OSS returns 400 Bad Request.

The following code shows how to perform a multipart copy:

#include <alibabacloud/oss/OssClient.h>
#include <sstream>
using namespace AlibabaCloud::OSS;

int main(void)
{
    /* Initialize OSS account information. */
            
    /* Set Endpoint to the endpoint of the region where the bucket is located. For example, if the bucket is in the China (Hangzhou) region, set Endpoint to https://oss-cn-hangzhou.aliyuncs.com. */
    std::string Endpoint = "yourEndpoint";
    /* Set Region to the region where the bucket is located. For example, if the bucket is in the China (Hangzhou) region, set Region to cn-hangzhou. */
    std::string Region = "yourRegion";
    /* Specify the name of the source bucket. Example: srcexamplebucket. */
    std::string SourceBucketName = "srcexamplebucket";
    /* Specify the name of the destination bucket, which must be in the same region as the source bucket. Example: destbucket. */
    std::string CopyBucketName = "destbucket";
    /* Specify the full path of the source object. The full path cannot contain the bucket name. Example: srcdir/scrobject.txt. */
    std::string SourceObjectName = "srcdir/scrobject.txt";
    /* Specify the full path of the destination object. The full path cannot contain the bucket name. Example: destdir/destobject.txt. */
    std::string CopyObjectName = "destdir/destobject.txt";


    /* Initialize network resources. */
    InitializeSdk();

    ClientConfiguration conf;
    conf.signatureVersion = SignatureVersionType::V4;
    /* Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. */
    auto credentialsProvider = std::make_shared<EnvironmentVariableCredentialsProvider>();
    OssClient client(Endpoint, credentialsProvider, conf);
    client.SetRegion(Region);

    auto getObjectMetaReq = GetObjectMetaRequest(SourceBucketName, SourceObjectName);
    /* Specify the version ID of the source object. */
    getObjectMetaReq.setVersionId("yourSourceObjectVersionId");
    auto getObjectMetaResult = client.GetObjectMeta(getObjectMetaReq);
    if (!getObjectMetaResult.isSuccess()) {
        std::cout << "GetObjectMeta fail" <<
        ",code:" << getObjectMetaResult.error().Code() <<
        ",message:" << getObjectMetaResult.error().Message() <<
        ",requestId:" << getObjectMetaResult.error().RequestId() << std::endl;
        return -1;
    }
    /* Obtain the size of the object to be copied. */
    auto objectSize = getObjectMetaResult.result().ContentLength();

    /* Copy the large object. */
    InitiateMultipartUploadRequest initUploadRequest(CopyBucketName, CopyObjectName);

    /* Initialize the multipart copy event. */
    auto uploadIdResult = client.InitiateMultipartUpload(initUploadRequest);
    auto uploadId = uploadIdResult.result().UploadId();
    int64_t partSize = 100 * 1024;
    PartList partETagList;
    int partCount = static_cast<int>(objectSize / partSize);
    /* Calculate the number of parts. */
    if (objectSize % partSize != 0) {
        partCount++;
    }

    /* Copy each part. */
    for (int i = 1; i <= partCount; i++) {
        auto skipBytes = partSize * (i - 1);
        auto size = (partSize < objectSize - skipBytes) ? partSize : (objectSize - skipBytes);
        auto uploadPartCopyReq = UploadPartCopyRequest(CopyBucketName, CopyObjectName, SourceBucketName, SourceObjectName,uploadId, i);
        uploadPartCopyReq.setCopySourceRange(skipBytes, skipBytes + size -1);
        /* Specify the version ID of the source object. */
        uploadPartCopyReq.setVersionId("yourSourceObjectVersionId");
        auto uploadPartOutcome = client.UploadPartCopy(uploadPartCopyReq);
        if (uploadPartOutcome.isSuccess()) {
            Part part(i, uploadPartOutcome.result().ETag());
            partETagList.push_back(part);
        }
        else {
            std::cout << "UploadPartCopy fail" <<
            ",code:" << uploadPartOutcome.error().Code() <<
            ",message:" << uploadPartOutcome.error().Message() <<
            ",requestId:" << uploadPartOutcome.error().RequestId() << std::endl;
        }
    }

    /* Complete the multipart copy. */
    CompleteMultipartUploadRequest request(CopyBucketName, CopyObjectName, partETagList, uploadId);
    auto outcome = client.CompleteMultipartUpload(request);

    if (outcome.isSuccess()) {
        std::cout << "versionid:" << outcome.result().VersionId() << std::endl;
    }
    else {
        /* Handle exceptions. */
        std::cout << "CompleteMultipartUpload fail" <<
        ",code:" << outcome.error().Code() <<
        ",message:" << outcome.error().Message() <<
        ",requestId:" << outcome.error().RequestId() << std::endl;
        return -1;
    }

    /* Release network resources. */
    ShutdownSdk();
    return 0;
}

References

• For more information about the CopyObject API operation, see CopyObject.

• For more information about the UploadPartCopy API operation, see UploadPartCopy.