Help Center/ Object Storage Service/ SDK Reference/ BrowserJS/ Object APIs/ Basic Operations/ Multipart Upload/ Performing a Multipart Copy
Updated on 2026-08-14 GMT+08:00
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Performing a Multipart Copy

Function

This API allows you to upload a part by copying an object or part of this object.

You can call ObsClient.copyPart to copy parts.

If you have any questions during development, post them on the Issues page of GitHub. For details about parameters and usage of each API, see the API Reference.

Restrictions

  • To copy an object, you must be the bucket owner or have the required permission (obs:object:PutObject granted using IAM or PutObject granted using a bucket policy). For details, see Introduction to OBS Access Control, IAM Custom Policies, and Configuring an Object Policy.
  • You must have the read permission for the source object.
  • The mapping between OBS regions and endpoints must comply with what is listed in Regions and Endpoints.
  • The object copy request contains the information about the source bucket and object to be copied in the header. The message body cannot be contained.
  • Cross-bucket replication in the same region is supported, but cross-region replication is not supported.
  • If the source object is in the Archive storage class, you must restore it first.

Method

ObsClient.copyPart(params)

Request Parameters

Table 1 List of request parameters

Parameter

Type

Mandatory (Yes/No)

Description

Bucket

String

Yes

Explanation:

Bucket name

Restrictions:

  • A bucket name must be unique across all accounts and regions.
  • A bucket name:
    • Must be 3 to 63 characters long and start with a digit or letter. Lowercase letters, digits, hyphens (-), and periods (.) are allowed.
    • Cannot be formatted as an IP address.
    • Cannot start or end with a hyphen (-) or period (.).
    • Cannot contain two consecutive periods (..), for example, my..bucket.
    • Cannot contain a period (.) and a hyphen (-) adjacent to each other, for example, my-.bucket or my.-bucket.
  • If you repeatedly create buckets with the same name in the same region, no error will be reported and the bucket properties comply with those set in the first creation request.

Default value:

None

Key

String

Yes

Explanation:

Object name. An object is uniquely identified by an object name in a bucket. An object name is a complete path of the object that does not contain the bucket name.

For example, if the address for accessing the object is examplebucket.obs.ap-southeast-1.myhuaweicloud.com/folder/test.txt, the object name is folder/test.txt.

Value range:

The value must contain 1 to 1,024 characters.

Default value:

None

NOTE:

The object URL is in the following format: https://Bucket name.Domain name/Folder directory level/Object name. If this object is stored in the root directory of the bucket, its URL does not contain the folder directory level.

RequestDate

String

or

Date

No

Explanation:

Request time

NOTE:

When the parameter type is String, the value must comply with the ISO8601 or RFC822 standard.

PartNumber

Number

Yes

Explanation:

Part number

Value range:

1 to 10000

Default value:

None

UploadId

String

Yes

Explanation:

Multipart upload ID, which can be obtained by initiating a multipart upload, for example, 000001648453845DBB78F2340DD460D8

Restrictions:

The value must contain 32 characters.

Default value:

None

CopySource

String

Yes

Explanation:

Specifies the source bucket, source object, and source object version ID (which can be left blank)

Restrictions:

Format: Source bucket name/Source object name?versionId=Source object version ID

Default value:

None

CopySourceRange

String

No

Explanation:

Copy source range

Value range:

0 to the source object length minus 1

Restrictions:

  • Format: bytes=x-y
  • If the ending byte position specified in CopySourceRange exceeds the source object length minus 1, the source object length minus 1 is used.

Default value:

By default, the entire object is copied.

SseC

String

No

Explanation:

Algorithm used for SSE-C

Value range:

AES256: SSE-C and the AES-256 algorithm are used.

Default value:

None

SseCKey

String

No

Explanation:

Custom key used in SSE-C encryption. The value is a Base64-encoded 256-bit key.

Default value:

None

CopySourceSseC

String

No

Explanation:

SSE-C is used for decrypting the source object.

Value range:

AES256: SSE-C and the AES-256 algorithm are used.

Default value:

None

CopySourceSseCKey

String

No

Explanation:

Key used to decrypt the source object in SSE-C mode

Default value:

None

Responses

Table 2 ICommonMsg

Parameter

Type

Description

Status

number

Explanation:

HTTP status code returned by the OBS server

Value range:

A status code is a group of digits indicating the status of a response. It ranges from 2xx (indicating successes) to 4xx or 5xx (indicating errors). For details, see Status Codes.

Code

string

Explanation:

Error code returned by the OBS server

Message

string

Explanation:

Error description returned by the OBS server

HostId

string

Explanation:

Request server ID returned by the OBS server

RequestId

string

Explanation:

Request ID returned by the OBS server

Id2

string

Explanation:

Request ID2 returned by the OBS server

Indicator

string

Explanation:

Error code details returned by the OBS server
Table 3 InterfaceResult

Parameter

Type

Description

ETag

String

Explanation:

Base64-encoded 128-bit MD5 digest of a part. ETag is the unique identifier of the part content. It can be used to determine whether the part content is changed.

Value range:

The value must contain 32 characters.

Default value:

None

LastModified

String

Explanation:

Last modification time of the destination part

Default value:

None

Sample Code

This example copies a part of object sourceobjectname in bucket sourcebucketname to a part of object destobjectname in bucket destbucketname.

// Create an ObsClient instance.
var obsClient = new ObsClient({
    // Hard-coded or plaintext AK and SK are risky. For security purposes, encrypt your AK and SK before storing them in the configuration file or environment variables. In this example, the AK and SK are stored in environment variables. Before running the code in this example, configure environment variables AccessKeyID and SecretAccessKey.
    // The front-end code does not have the process environment variable, so you need to use a module bundler like webpack to define the process variable.
    // Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
    access_key_id: process.env.AccessKeyID,
    secret_access_key: process.env.SecretAccessKey,
    // CN-Hong Kong is used here in this example. Replace it with the one currently in use.
    server: 'https://obs.ap-southeast-1.myhuaweicloud.com'
});

var destBucketName = 'destbucketname';
var destObjectKey = 'destobjectname';
var sourceBucketName = 'sourcebucketname';
var sourceObjectKey = 'sourceobjectname';

obsClient.CopyPart({
       Bucket : destBucketName,
       Key : destObjectKey,
       // Set the part number, which ranges from 1 to 10000.
       PartNumber : 1,
       // Set the upload ID.
       UploadId : 'upload id from initiateMultipartUpload',
       // Set the source object to be copied.
       CopySource : sourceBucketName + '/' + sourceObjectKey,
       // Set the to-be-copied range of the source object.
       CopySourceRange : 'bytes=0-100'
}, function(err, result) {
       if (err) {
              console.log('Error-->' + err);
       } else {
              console.log('Status-->' + result.CommonMsg.Status);
              if (result.CommonMsg.Status < 300 && result.InterfaceResult) {
                     console.log('RequestId-->' + result.InterfaceResult.RequestId);
                     console.log('LastModified-->' + result.InterfaceResult.LastModified);
                     console.log('ETag-->' + result.InterfaceResult.ETag);
              }
       }
});
  • Use the PartNumber parameter to specify the part number, the UploadId parameter to specify the globally unique ID for the multipart upload, the CopySource parameter to specify the information about the source object, and the CopySourceRange parameter to specify the byte range to copy.
Parent topic: Multipart Upload