Help Center/ Object Storage Service/ API Reference (Ankara Region)/ APIs/ Operations on Multipart Upload/ Initiating a Multipart Upload
Updated on 2024-04-15 GMT+08:00
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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. This identifier can be used in subsequent requests including UploadPart, CompleteMultipartUpload, and ListParts. 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.

Request Syntax

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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

Description

Mandatory

uploads

Indicates a multipart upload.

Type: string

NOTE:
  • This parameter is an empty string.
  • If this parameter is not contained in a request, the request performs a common upload using POST.

Yes

Request Headers

The request can use additional headers, as shown in Table 2.

Table 2 Request headers

Header

Description

Mandatory

x-obs-acl

When initiating a multipart upload, you can add this message header to set the permission control policy for the object. The predefined common policies are as follows: private, public-read, and public-read-write.

Type: string

Note: This header is a predefined policy expressed in a character string.

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

No

x-obs-grant-read

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

Type: string

Example: x-obs-grant-read: ID=domainID. If multiple accounts are authorized, separate them with commas (,).

No

x-obs-grant-read-acp

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

Type: string

Example: x-obs-grant-read-acp: ID=domainID. If multiple accounts are authorized, separate them with commas (,).

No

x-obs-grant-write-acp

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

Type: string

Example: x-obs-grant-write-acp: ID=domainID. If multiple accounts are authorized, separate them with commas (,).

No

x-obs-grant-full-control

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

Type: string

Example: x-obs-grant-full-control: ID=domainID. If multiple accounts are authorized, separate them with commas (,).

No

x-obs-website-redirect-location

If a bucket is configured with the static website hosting function, it will redirect requests for this object to another object in the same bucket or to an external URL. OBS stores the value of this header in the object metadata.

Type: string

Default value: none

Constraint: The value must be prefixed by a slash (/), http://, or https://. The length of the value cannot exceed 2 KB.

No

x-obs-expires

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).

Type: integer

Example: x-obs-expires:3

No

x-obs-meta-*

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 user-defined metadata will be returned in the response when you retrieve the object or query the object metadata.

Type: string

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

No

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

Request Elements

This request involves no elements.

Response Syntax

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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.

Response Elements

This response contains elements to indicate the upload ID and the key (name) of the object (bucket) for which the multipart upload was initiated. The returned information is used in the subsequent operations. Table 3 describes the elements.

Table 3 Response elements

Element

Description

InitiateMultipartUploadResult

Container of a multipart upload task.

Type: XML

Bucket

Indicates the name of the bucket to which the multipart upload was initiated.

Type: string

Key

Indicates the object key in a multipart upload.

Type: string

UploadId

Indicates the ID for the initiated multipart upload. This ID is used for the subsequent operation.

Type: string

Error Responses

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

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

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

Other errors are included in Table 2.

Sample Request: Initiating a Multipart Upload

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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

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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)

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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)

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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>