Assembling Parts

Function

This API is used to assemble the uploaded parts to complete the multipart upload. Before performing this operation, you cannot download the uploaded data. When assembling parts, you need to copy the additional message header information recorded during the multipart upload initiation to the object metadata. Such information is processed the same way the information in a common object upload is processed. In the case of assembling parts concurrently, the server follows the Last Write Wins policy, where the Last Write is determined by the time the multipart upload was initiated.

As long as the multipart upload is not aborted, all uploaded parts occupy the space. However, after you assemble the specified parts, the uploaded but unassembled parts will be deleted to free up space.

When assembling parts, OBS creates an object by putting part numbers in ascending order. If any object metadata is provided in the initiation of the multipart upload, OBS will associate the metadata with the object. After the multipart upload is complete, the parts will no longer exist. A part assembling request must contain the upload ID, part numbers, and a list of corresponding ETag values. An OBS response includes an ETag that uniquely identifies the object data. This ETag is not required to be the MD5 hash value of the object data.

Restrictions

• To assemble parts, you must be the bucket owner or have the required permission (obs:object:PutObject granted using IAM or PutObject granted using a bucket policy). For details, see Introduction to OBS Access Control, IAM Custom Policies, and Configuring an Object Policy.
• The mapping between OBS regions and endpoints must comply with what is listed in Regions and Endpoints.
• After a multipart upload is complete, the uploaded parts that are not assembled will be automatically deleted and cannot be recovered. Before assembling parts, use the API for listing uploaded parts to check all parts to ensure that no part is missed.

Method

ObsClient.completeMultipartUpload(params)

Request Parameters

Responses

Sample Code

You can call ObsClient.completeMultipartUpload to assemble parts.

// Create an ObsClient instance.
var obsClient = new ObsClient({
    // Hard-coded or plaintext AK and SK are risky. For security purposes, encrypt your AK and SK before storing them in the configuration file or environment variables. In this example, the AK and SK are stored in environment variables. Before running the code in this example, configure environment variables AccessKeyID and SecretAccessKey.
    // The front-end code does not have the process environment variable, so you need to use a module bundler like webpack to define the process variable.
    // Obtain an AK/SK pair on the management console. For details, see https://support.huaweicloud.com/intl/en-us/usermanual-ca/ca_01_0003.html.
    access_key_id: process.env.AccessKeyID,
    secret_access_key: process.env.SecretAccessKey,
    // CN-Hong Kong is used here in this example. Replace it with the one currently in use.
    server: 'https://obs.ap-southeast-1.myhuaweicloud.com'
});

obsClient.completeMultipartUpload({
       Bucket:'bucketname',
       Key:'objectname',
       // Set the upload ID.
       UploadId:'upload id from initiateMultipartUpload',
       Parts: [{'PartNumber':1,'ETag':'etag value from uploadPart'}]
}, function (err, result) {
       if(err){
              console.log('Error-->' + err);
       }else{
              console.log('Status-->' + result.CommonMsg.Status);
       }
});

• If the size of a part other than the last part is smaller than 100 KB, OBS returns 400 Bad Request.

• Use the UploadId parameter to specify the globally unique identifier for the multipart upload and the Parts parameter to specify the list of part numbers and ETags. Content in the list is displayed in the ascending order by part number.
• Part numbers can be inconsecutive.