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    Object Storage Service:append-object

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    Object Storage Service:append-object

    Last Updated:Jul 03, 2025

    Uploads an object by appending the object to an existing object.

    Usage notes

    • The maximum size of an object that is generated by running the append-object command is 5 GB.

    • You cannot encrypt appendable objects by using SSE-KMS with a specific customer master key (CMK) ID.

    Permissions

    By default, an Alibaba Cloud account has full permissions. RAM users or RAM roles under an Alibaba Cloud account do not have any permissions by default. The Alibaba Cloud account or account administrator must grant operation permissions through RAM Policy or Bucket Policy.

    API

    Action

    Definition

    AppendObject

    oss:PutObject

    You can call this operation to upload an object by appending the object to an existing object.

    oss:PutObjectTagging

    When uploading an object by appending the object to an existing object, if you specify object tags through x-oss-tagging, this permission is required.

    Command syntax

    ossutil api append-object --bucket value --key value --position value [flags]

    Parameter

    Type

    Description

    --body

    string

    The request body.

    --bucket

    string

    The name of the bucket.

    --cache-control

    string

    The web page caching behavior of the object.

    --content-disposition

    string

    The name of the object when the object is downloaded.

    --content-encoding

    string

    The method that you want to use to encode the object.

    --content-md5

    string

    The MD5 hash calculated by using the MD5 algorithm. This parameter is used to check whether the content of the received message is the same as that of the sent message.

    --expires

    string

    The time when the request expires.

    --key

    string

    The full path of the object.

    --metadata

    stringArray

    The metadata of the object. To specify custom metadata, you must specify parameters prefixed with x-oss-meta-*.

    --object-acl

    string

    The access control list (ACL) of the object.

    --position

    string

    The position from which you want to append the object.

    --server-side-encryption

    string

    The method that is used to encrypt the object.

    --storage-class

    string

    The storage class of the object.

    --tagging

    string

    The tag that you want to specify for the object by using a key-value pair. You can specify multiple tags for an object. Example: TagA=A&TagB=B.

    Note

    • The append-object command corresponds to the AppendObject operation. For more information about the parameters in the AppendObject operation, see AppendObject.

    • For more information about supported global command-line options, see Global command-line options.

    Examples

    • Append an object to the exampleobject object by uploading a string. 

      ossutil api append-object --bucket examplebucket --key exampleobject --position 0 --body "hi oss"

    • Append an object to the exampleobject object by uploading a file. 

      ossutil api append-object --bucket examplebucket --key exampleobject --position 0 --body file://appendFile

    • Append an object to the exampleobject object by uploading a string and specify the object metadata. 

      ossutil api append-object --bucket examplebucket --key exampleobject --position 0 --body "hi oss" --metadata user=aliyun --metadata email=ali***@aliyuncs.com

    • Append an object to the exampleobject object by uploading a string and specify the object tags. 

      ossutil api append-object --bucket examplebucket --key exampleobject --position 0 --body "hi oss" --tagging "TagA=A&TagB=B"

    • Append an object to the exampleobject object by uploading a string and specify the object ACL and storage class. 

      ossutil api append-object --bucket examplebucket --key exampleobject --position 0 --body "hi oss" --object-acl private --storage-class IA

    • Append an object to the exampleobject object by uploading a string and specify the method that you want to use to encrypt the object. 

      ossutil api append-object --bucket examplebucket --key exampleobject --position 0 --body "hi oss" --body "hi oss" --server-side-encryption AES256

    • Append an object to the exampleobject object by uploading a string and specify the caching behavior of the web page when the object is downloaded. 

      ossutil api append-object --bucket examplebucket --key exampleobject --position 0 --body "hi oss" --cache-control no-cache

    • Append an object to the exampleobject object by uploading a string and specify the name of the object when the object is downloaded. 

      ossutil api append-object --bucket examplebucket --key exampleobject --position 0 --body "hi oss" --content-disposition "attachment;filename=oss_download.jpg"

    • Append an object to the exampleobject object by uploading a string and specify the MD5 hash of the object. 

      ossutil api append-object --bucket examplebucket --key exampleobject --position 0 --body "hi oss" --content-md5 ohhnqLBJFiKkPSBO1eNaUA==