Initiating a Multipart Upload

Functions

Before using this operation, make an API operation call to create a multipart upload task. The system will return a globally unique upload ID as the multipart upload identifier. You can use this ID to upload, assemble, and list parts. Create a multipart upload task does not affect the object that has the same name as object to be uploaded in multiple parts. You can create more than one multipart upload tasks for an object. This operation request can contain headers x-obs-acl, x-obs-meta-*, Content-Type, and Content-Encoding. The headers are recorded in the multipart upload metadata.

This operation supports server-side encryption.

WORM

If a bucket has WORM enabled, you can configure object-level retention policies when initiating multipart uploads. You can specify the x-obs-object-lock-mode and x-obs-object-lock-retain-until-date headers when you initiate a multipart upload to protect the object assembled. If you do not specify these two headers but have configured a default bucket-level WORM policy, this default policy automatically applies to the object newly assembled. You can also configure or update a WORM retention policy after the object is assembled.

Different from uploads with PUT and POST, a multipart upload only requires that the date specified in the x-obs-object-lock-retain-until-date header be no later than the initiation time, but does not have to be later than the completion time of the multipart upload. When the default bucket-level WORM policy is applied, the protection starts when the object parts are assembled and ends once the default bucket-level protection period expires. Before assembling the object parts uploaded, the multipart upload can be canceled and will not be affected by the WORM configuration.

Request Syntax

POST /ObjectName?uploads  HTTP/1.1
Host: bucketname.obs.region.example.com
Date: date
Authorization: authorization

Request Parameters

This request uses parameters to specify a multipart upload. Table 1 describes the parameters.

Table 1 Request parameters

Parameter

Type

Mandatory (Yes/No)

Description

uploads

String

Yes

Explanation:

Indicates a multipart upload.

Restrictions:

  • This parameter is an empty string.

  • If this parameter is not included, the request is treated as an ordinary POST upload.

Value range:

An empty string.

Default value:

None

Request Headers

The request can use additional headers shown in Table 2.

Table 2 Request headers

Header

Type

Mandatory (Yes/No)

Description

x-obs-acl

String

No

Explanation:

When initiating a multipart upload, you can add this header to set an object ACL.

Example: x-obs-acl: public-read-write

Restrictions:

Use character strings.

Value range:

  • private

  • public-read

  • public-read-write

Default value:

private

x-obs-grant-read

String

No

Explanation:

When initiating a multipart upload, you can use this header to grant all users in a domain the permissions to read the object and obtain the object metadata.

Example: x-obs-grant-read: ID=domainID.

Restrictions:

If multiple accounts are authorized, separate them with commas (,).

Value range:

None

Default value:

None

x-obs-grant-read-acp

String

No

Explanation:

When initiating a multipart upload, you can use this header to grant all users in a domain the permissions to obtain the object ACL.

Example: x-obs-grant-read-acp: ID=domainID.

Restrictions:

If multiple accounts are authorized, separate them with commas (,).

Value range:

None

Default value:

None

x-obs-grant-write-acp

String

No

Explanation:

When initiating a multipart upload, you can use this header to grant all users in a domain the permissions to write the object ACL.

Example: x-obs-grant-write-acp: ID=domainID

Restrictions:

If multiple accounts are authorized, separate them with commas (,).

Value range:

None

Default value:

None

x-obs-grant-full-control

String

No

Explanation:

When initiating a multipart upload, you can use this header to grant all users in a domain the following permissions:

Permissions to read objects, obtain object metadata, obtain object ACLs, and write object ACLs.

Example: x-obs-grant-full-control: ID=domainID.

Restrictions:

If multiple accounts are authorized, separate them with commas (,).

Value range:

None

Default value:

None

x-obs-storage-class

String

No

Explanation:

When initiating a multipart upload, you can add this header to specify the storage class for the object.

Example: x-obs-storage-class: STANDARD

Restrictions:

  • If you do not use this header, the object storage class is the default storage class of the bucket.

  • The value is case-sensitive.

Value range:

  • STANDARD

  • WARM

  • COLD

Default value:

By default, the storage class of the bucket is inherited.

x-obs-website-redirect-location

String

No

Explanation:

If the bucket is configured with website hosting, the request for obtaining the object can be redirected to another object in the bucket or an external URL.

To another object in the same bucket:

x-obs-website-redirect-location:/anotherPage.html

To an external URL:

x-obs-website-redirect-location:http://www.example.com/

OBS obtains the specified value from the header and stores it in the object metadata WebsiteRedirectLocation.

Restrictions:

  • The value must start with a slash (/), http://, or https:// and cannot exceed 2 KB.

  • OBS supports redirection for objects in the root directory of a bucket, not for those in folders.

Default value:

None

x-obs-server-side-encryption

String

No. This header is required when SSE-KMS is used.

Explanation:

Indicates that SSE-KMS is used.

Example: x-obs-server-side-encryption: kms

Restrictions:

None

Value range:

  • kms

  • AES256

Default value:

None

x-obs-server-side-encryption-kms-key-id

String

No

Explanation:

ID of a specified key used for SSE-KMS encryption.

Restrictions:

This header can only be used when you specify kms for the x-obs-server-side-encryption header.

Default value:

If you specify kms for encryption but do not specify a key ID, the default master key will be used. If there is not a default master key, OBS will create one and use it.

x-obs-server-side-encryption-customer-algorithm

String

No. This header is required when SSE-C is used.

Explanation:

The algorithm used for encryption.

Example: x-obs-server-side-encryption-customer-algorithm: AES256

Restrictions:

  • This header is used only when SSE-C is used.

  • This header must be used together with x-obs-server-side-encryption-customer-key and x-obs-server-side-encryption-customer-key-MD5.

Value range:

AES256

Default value:

None

x-obs-server-side-encryption-customer-key

String

No. This header is required when SSE-C is used.

Explanation:

The key used for encrypting an object.

Example: x-obs-server-side-encryption-customer-key:K7QkYpBkM5+hca27fsNkUnNVaobncnLht/rCB2o/9Cw=

Restrictions:

  • This header is used only when SSE-C is used.

  • This header is a Base64-encoded 256-bit key and must be used together with x-obs-server-side-encryption-customer-algorithm and x-obs-server-side-encryption-customer-key-MD5.

Value range:

None

Default value:

None

x-obs-server-side-encryption-customer-key-MD5

String

No. This header is required when SSE-C is used.

Explanation:

The MD5 value of the encryption key. The MD5 value is used to check whether any error occurs during the transmission of the key.

Example: x-obs-server-side-encryption-customer-key-MD5:4XvB3tbNTN+tIEVa0/fGaQ==

Restrictions:

  • This header is used only when SSE-C is used.

  • This header is a Base64-encoded 128-bit MD5 value and must be used together with x-obs-server-side-encryption-customer-algorithm and x-obs-server-side-encryption-customer-key.

Value range:

Base64-encoded MD5 value of the key ID.

Default value:

None

x-obs-expires

Integer

No

Explanation:

Specifies when an object expires. It is measured in days. Once the object expires, it is automatically deleted. (The calculation starts from when the object was last modified).

Example: x-obs-expires:3

Restrictions:

This parameter can be configured only when uploading the object. It cannot be modified by calling a metadata modification API.

Value range:

An integer greater than or equal to 0, in days

Default value:

None

x-obs-tagging

String

No

Explanation:

An object's tag information in key-value pairs. Multiple tags can be added at the same time.

Example: x-obs-tagging:TagA=A&TagB&TagC

Restrictions:

  • If a tag key or value contains special characters, equal signs (=), or full-width characters, it must be URL-encoded.

  • If there is no equal sign (=) in a configuration, the tag value is considered left blank.

Value range:

None

Default value:

None

x-obs-object-lock-mode

String

No, but required when x-obs-object-lock-retain-until-date is present.

Explanation:

WORM mode to be applied to an object.

Example: x-obs-object-lock-mode:COMPLIANCE

Restrictions:

This parameter must be used together with x-obs-object-lock-retain-until-date.

Value range:

Only COMPLIANCE (compliance mode) is supported.

Default value:

None

x-obs-object-lock-retain-until-date

String

No, but required when x-obs-object-lock-mode is present.

Explanation:

When the WORM policy of the object expires.

Example: x-obs-object-lock-retain-until-date:2015-07-01T04:11:15Z

Restrictions:

  • The value must be a UTC time that complies with the ISO 8601 standard. Example: 2015-07-01T04:11:15Z

  • This parameter must be used together with x-obs-object-lock-mode.

Value range:

The time must be later than the current time.

Default value:

None

x-obs-meta-*

String

No

Explanation:

When initiating a multipart upload, you can use a header starting with x-obs-meta- in the HTTP request to define object metadata for easy management. The custom metadata will be returned in the response when you retrieve the object or query the object metadata.

Example: x-obs-meta-test: test metadata

Restrictions:

This parameter can only be passed in HTTP request headers and cannot exceed 8 KB.

Value range:

None

Default value:

None

For details about other common message headers, see Table 3.

Request Elements

This request involves no elements.

Response Syntax

HTTP/1.1 status_code
Date: date
Content-Length: length
Connection: status

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<InitiateMultipartUploadResult xmlns="http://obs.region.example.com/doc/2015-06-30/">
    <Bucket>BucketName</Bucket>
    <Key>ObjectName</Key>
    <UploadId>uploadID</UploadId>
</InitiateMultipartUploadResult>

Response Headers

The response to the request uses common headers. For details, see Table 1.

Table 3 Additional response headers

Header

Type

Description

x-obs-server-side-encryption

String

Explanation:

The encryption method used by the server.

Example: x-obs-server-side-encryption: kms

Restrictions:

This header is included in a response if SSE-KMS is used.

Value range:

  • kms

  • AES256

Default value:

None

x-obs-server-side-encryption-kms-key-id

String

Explanation:

ID of a specified key used for SSE-KMS encryption.

Restrictions:

This header can only be used when you specify kms for the x-obs-server-side-encryption header.

Default value:

If you specify kms for encryption but do not specify a key ID, the default master key will be used. If there is not a default master key, OBS will create one and use it.

x-obs-server-side-encryption-customer-algorithm

String

Explanation:

The algorithm used for encryption.

Example: x-obs-server-side-encryption-customer-algorithm: AES256

Restrictions:

This header is included in a response if SSE-C is used for server-side encryption.

Value range:

AES256

Default value:

None

x-obs-server-side-encryption-customer-key-MD5

String

Explanation:

The MD5 value of the encryption key.

Example: x-obs-server-side-encryption-customer-key-MD5:4XvB3tbNTN+tIEVa0/fGaQ==

Restrictions:

This header is included in a response if SSE-C is used for server-side encryption.

Value range:

Base64-encoded MD5 value of the key ID.

Default value:

None

Response Elements

This response contains elements that indicate the multipart upload ID and the bucket and object names, which are used for uploading and assembling parts. Table 4 describes the elements.

Table 4 Response elements

Element

Type

Description

InitiateMultipartUploadResult

XML

Explanation:

Container of a multipart upload task.

Restrictions:

None

Value range:

None

Default value:

None

Bucket

String

Explanation:

Indicates the bucket name in the multipart upload.

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 of the same name in the same region, no error will be reported and the bucket attributes comply with those set in the first creation request.

Value range:

None

Default value:

None

Key

String

Explanation:

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

Restrictions:

None

Value range:

The value must contain 1 to 1,024 characters.

Default value:

None

UploadId

String

Explanation:

ID of the multipart upload, which is used to specify a multipart upload in uploading parts

Restrictions:

None

Value range:

The value must contain 1 to 32 characters.

Default value:

None

Error Responses

  1. If the AK or signature was invalid, OBS returns 403 Forbidden and the error code is AccessDenied.

  2. If the bucket was not found, OBS returns 404 Not Found and the error code is NoSuchBucket.

  3. If the user did not have the write permission for the specified bucket, OBS returns 403 Forbidden and the error code is AccessDenied.

Other errors are included in Table 2.

Sample Request: Initiating a Multipart Upload

POST /objectkey?uploads  HTTP/1.1
Host: examplebucket.obs.region.example.com
Date: WED, 01 Jul 2015 05:14:52 GMT
Authorization: OBS AKIAIOSFODNN7EXAMPLE:VGhpcyBtZXNzYWdlIHNpZ25lZGGieSRlbHZpbmc=

Sample Response: Initiating a Multipart Upload

HTTP/1.1 200 OK
Server: OBS
x-obs-id-2: Weag1LuByRx9e6j5Onimru9pO4ZVKnJ2Qz7/C1NPcfTWAtRPfTaOFg==
x-obs-request-id: 996c76696e6727732072657175657374
Date: WED, 01 Jul 2015 05:14:52 GMT
Content-Length: 303

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<InitiateMultipartUploadResult xmlns="http://obs.region.example.com/doc/2015-06-30/">
  <Bucket>bucketname</Bucket>
  <Key>objectkey</Key>
  <UploadId>DCD2FC98B4F70000013DF578ACA318E7</UploadId>
</InitiateMultipartUploadResult>

Sample Request: Initiating a Multipart Upload (with the ACL Configured)

POST /objectkey?uploads  HTTP/1.1
Host: examplebucket.obs.region.example.com
Date: WED, 01 Jul 2015 05:15:43 GMT
x-obs-grant-write-acp:ID=52f24s3593as5730ea4f722483579ai7,ID=a93fcas852f24s3596ea8366794f7224
Authorization: OBS AKIAIOSFODNN7EXAMPLE:VGhpcyBtZXNzYWdlIHNpZ25lZGGieSRlbHZpbmc=

Sample Response: Initiating a Multipart Upload (with the ACL Configured)

HTTP/1.1 200 OK
Server: OBS
x-obs-id-2: 32AAAQAAEAABAAAQAAEAABAAAQAAEAABCTnv+daB51p+IVhAvWN7s5rSKhcWqDFs
x-obs-request-id: BB78000001648457112DF37FDFADD7AD
Date: WED, 01 Jul 2015 05:15:43 GMT
Content-Length: 303

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<InitiateMultipartUploadResult xmlns="http://obs.region.example.com/doc/2015-06-30/">
  <Bucket>bucketname</Bucket>
  <Key>objectkey</Key>
  <UploadId>000001648453845DBB78F2340DD460D8</UploadId>
</InitiateMultipartUploadResult>
last updated: 2024-12-11 10:27 UTC - commit: 1084b97f9d241d7af788bdfaa536dba9679533f7