Uploading Parts

Functions

After a multipart upload task is created, you can upload parts for this task using the obtained multipart upload ID. When parts are uploaded in a multipart upload of an object, the upload sequence does not affect part merging, namely, multiple parts can be uploaded concurrently.

Part sizes range from 100 KB to 5 GB. However, when parts are being merged, the size of the last uploaded part ranges from 0 to 5 GB. The upload part ID ranges from 1 to 10,000.

This operation supports server-side encryption.

Important

The value of partNumber in a multipart task is unique. If you upload a part of the same partNumber repeatedly, the last part uploaded will overwrite the previous one. When multiple concurrent uploading of the same partNumber part of the same object is performed, the Last Write Win policy is applied. The time of Last Write is defined as the time when the metadata of the part is created. To ensure data accuracy, the client must be locked to ensure concurrent upload of the same part of the same object. Concurrent upload of different parts of the same object does not need to be locked.

Request Syntax

PUT /ObjectName?partNumber=partNum&uploadId=uploadID  HTTP/1.1
Host: bucketname.obs.region.example.com
Date: date
Content-Length: length
Authorization: authorization
Content-MD5:md5
<object Content>

Request Parameters

This request uses parameters to specify the upload task ID and part number. Table 1 describes the parameters.

Table 1 Request parameters

Parameter

Type

Mandatory (Yes/No)

Description

partNumber

Integer

Yes

Explanation:

Indicates the ID of a part to be uploaded.

Restrictions:

None

Value range:

An integer ranging from 1 to 10000.

Default value:

None

uploadId

String

Yes

Explanation:

Indicates a multipart upload ID.

Restrictions:

None

Value range:

None

Default value:

None

Request Headers

This request uses common headers. For details, see Table 3.

Table 2 Server-side encryption request headers

Header

Type

Mandatory (Yes/No)

Description

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

String

No. This header is required when SSE-C is used. The encryption algorithm must be the same as that used to initiate multipart upload tasks.

Explanation:

The algorithm used for encryption.

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

Restrictions:

  • Indicates the encryption algorithm used 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. The key must be the same as that used to initiate multipart upload tasks.

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 for encryption.

  • 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. The MD5 value must be the same as that used to initiate multipart upload tasks.

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 for encryption.

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

Request Elements

This request involves no elements.

Response Syntax

HTTP/1.1 status_code
Date: date
ETag: etag
Content-Length: length

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 no elements.

Error Responses

  1. If a part number is not within the range from 1 to 10000, OBS returns 400 Bad Request.

  2. If a part size has exceeded 5 GB, the error code 400 Bad Request is returned.

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

  4. Check whether the bucket exists. If the bucket is not found, OBS returns 404 Not Found and the error code is NoSuchBucket.

  5. View the bucket ACL to check whether the user has the read permission for the requested bucket. If the user does not have the read permission, OBS returns 403 AccessDenied.

  6. Check whether the multipart upload task exists. If the task does not exist, OBS returns 404 Not Found and the error code is NoSuchUpload.

  7. Check whether the request user is the initiator of the multipart upload task. If not, OBS returns 403 Forbidden and the error code is AccessDenied.

Other errors are included in Table 2.

Sample Request

PUT /object02?partNumber=1&uploadId=00000163D40171ED8DF4050919BD02B8 HTTP/1.1
User-Agent: curl/7.29.0
Host: examplebucket.obs.region.example.com
Accept: */*
Date: WED, 01 Jul 2015 05:15:55 GMT
Authorization: OBS H4IPJX0TQTHTHEBQQCEC:ZB0hFwaHubi1aKHv7dSZjJts40g=
Content-Length: 102015348

[102015348 Byte part content]

Sample Response

HTTP/1.1 200 OK
Server: OBS
x-obs-request-id: 8DF400000163D40956A703289CA066F1
ETag: "b026324c6904b2a9cb4b88d6d61c81d1"
x-obs-id-2: 32AAAQAAEAABAAAQAAEAABAAAQAAEAABCUQu/EOEVSMa04GXVwy0z9WI+BsDKvfh
Date: WED, 01 Jul 2015 05:15:55 GMT
Content-Length: 0