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Uploading Objects - Appending

API Description

You can use this API to upload an object in appendable mode and append data to the object.

Method Definition

ObsClient.appendObject(bucketName, objectKey, content, metadata, headers, progressCallback, autoClose)

Request Parameters

Field

Type

Optional or Mandatory

Description

bucketName

str

Mandatory

Bucket name

objectKey

str

Mandatory

Object name or the name of the uploaded object

content

AppendObjectContent

Mandatory

Content to be appended

metadata

dict

Optional

Customized metadata for the appendable upload. This parameter is effective only during the first appendable object creation.

headers

AppendObjectHeader

Optional

Additional header of the request for an appendable upload. This parameter is effective only during the first appendable object creation.

progressCallback

callable

Optional

Callback function for obtaining the upload progress

NOTE:

This function contains the following parameters in sequence: number of uploaded bytes, total number of bytes, and used time (unit: second). For details about the sample code, see Uploading an Object – Obtaining the Upload Progress.

autoClose

bool

Optional

After the upload is complete, data flow is automatically closed. The default value is True.

Returned Results

Type

Description

GetResult

SDK common result object

GetResult.body Type

Description

AppendObjectResponse

Response result of the request for appending an object

Sample Code

try:
    from obs import AppendObjectContent
    content = AppendObjectContent()
    content.content = 'Hello OBS'
    content.position = 0
    resp = obsClient.appendObject('bucketname', 'objectkey', content=content)

    if resp.status < 300:    
        print('requestId:', resp.requestId)    
        print('nextPosition:', resp.body.nextPosition)
    else:    
        print('errorCode:', resp.errorCode)    
        print('errorMessage:', resp.errorMessage)
except:
    import traceback
    print(traceback.format_exc())
  • Objects uploaded using ObsClient.putObject, referred to as normal objects, can overwrite objects uploaded using ObsClient.appendObject, referred to as appendable objects. Data cannot be appended to an appendable object anymore once the object has been overwritten by a normal object.
  • When you upload an object for the first time in appendable mode, an exception will be thrown (status code 409) if a normal object with the same name exists.
  • The ETag returned for an appendable upload is the ETag for the uploaded content, rather than that of the whole object.
  • Data appended each time can be up to 5 GB, and 10,000 times of appendable uploads can be performed on a single object.
  • After an appendable upload is complete successfully, you can use body.nextPosition obtained from the returned result or call ObsClient.getObjectMetadata, to get the location for next appending.
Parent topic: Objects-Related APIs