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Object Storage Service:Multipart upload

Last Updated:Jan 29, 2024

When you upload a large object that is larger than 5 GB in size to Object Storage Service (OSS), you may fail to upload the object due to network interruptions or program crashes. If the object fails to be uploaded after multiple retries, you can upload the large object by performing multipart upload. Multipart upload allows you to split the large object that you want to upload into multiple parts and upload the parts in parallel based on the network bandwidth and server resources. This way, the time required to upload the object is shortened. After the parts are uploaded, you must call the CompleteMultipartUpload operation to combine the parts into a complete object.

Prerequisites

Scenarios

  • Accelerated upload of large objects

    If you want to upload an object that is larger than 5 GB in size, you can use multipart upload to split the object into multiple parts and upload the parts in parallel to accelerate the upload.

  • Unstable network connections

    We recommend that you use multipart upload when network connections are unstable. If specific parts fail to be uploaded, you need to re-upload only the failed parts.

  • Unknown object size

    If you do not know the sizes of the objects that you want to upload, you can use multipart upload. This case is common in industrial applications, such as video surveillance.

Process

image

The preceding process consists of the following steps:

Note

To complete a multipart upload task, the oss:PutObject permission is required. A multipart upload task consists of three steps: multipart upload initiation, part upload, and part combination. For more information, see Attach a custom policy to a RAM user.

  1. Split the object that you want to upload into parts based on a specific part size.

  2. Call the InitiateMultipartUpload operation to initiate a multipart upload task.

  3. Call the UploadPart operation to upload parts.

    After an object is split into parts, configure the partNumber parameter of each part to specify the sequence of the parts. This way, the parts are uploaded in parallel. More uploads in parallel do not necessarily result in a faster upload. We recommend that you specify the number of parallel uploads based on your network conditions and the workload of your devices.

    To cancel a multipart upload task, call the AbortMultipartUpload operation. After the multipart upload task is canceled, the parts that are uploaded are deleted.

  4. Call the CompleteMultipartUpload operation to combine the uploaded parts into an object.

Limits

Item

Limit

Object size

Multipart upload supports objects whose sizes are up to 48.8 TB.

Number of parts

You can set the number of parts to a value that ranges from 1 to 10,000.

Part size

The size of a part, except for the last one, must range from 100 KB to 5 GB. The size of the last part can be smaller than 100 KB.

Maximum number of parts that can be returned for a single ListParts request

Up to 1,000 parts can be returned for a single ListParts request.

Maximum number of multipart upload tasks that can be returned for a single ListMultipartUploads request

Up to 1,000 tasks can be returned for a single ListMultipartUploads request.

Usage notes

  • When you use multipart upload to upload objects, you can upload only one object at a time and you cannot upload directories.

  • Lower PUT request fees

    If you want to upload a large number of objects and set the storage classes of the objects to Deep Cold Archive, you are charged high PUT request fees. We recommend that you set the storage classes of the objects to Standard when you upload the objects, and configure lifecycle rules to convert the storage classes of the Standard objects to Deep Cold Archive. This reduces PUT request fees.

  • Optimize object upload performance

    If you upload a large number of objects whose names contain sequential prefixes, such as timestamps and letters, multiple object indexes may be stored in a single partition. If a large number of requests are sent to query these objects, the latency increases. We recommend that you do not upload a large number of objects whose names contain sequential prefixes. For more information, see OSS performance and scalability best practices.

  • Overwrite objects

    If you upload an object whose name is the same as an existing object in OSS, the existing object is overwritten by the uploaded object. You can use one of the following methods to prevent objects from being unexpectedly overwritten:

    • Enable versioning

      If versioning is enabled for a bucket, overwritten objects are saved as previous versions. You can restore the previous versions. For more information, see Overview.

    • Include the x-oss-forbid-overwrite header in the upload request

      Include the x-oss-forbid-overwrite header in the upload request and set the header to true. This way, if you upload an object that has the same name as an existing object, the upload fails and the FileAlreadyExists error is returned. For more information, see InitiateMultipartUpload.

Procedure

Use OSS SDKs

The following sample code provides examples on how to perform multipart upload by using OSS SDKs for common programming languages. For information about how to perform multipart upload by using OSS SDKs for other programming languages, see Overview.

import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.internal.Mimetypes;
import com.aliyun.oss.model.*;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

public class Demo {

    public static void main(String[] args) throws Exception {
        // In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. 
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
        EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();
        // Specify the name of the bucket. Example: examplebucket. 
        String bucketName = "examplebucket";
        // Specify the full path of the object. Example: exampledir/exampleobject.txt. Do not include the bucket name in the full path. 
        String objectName = "exampledir/exampleobject.txt";
        // Specify the path of the local file that you want to upload. 
        String filePath = "D:\\localpath\\examplefile.txt";

        // Create an OSSClient instance. 
        OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);
        try {
            // Create an InitiateMultipartUploadRequest object. 
            InitiateMultipartUploadRequest request = new InitiateMultipartUploadRequest(bucketName, objectName);

            // The following code provides an example on how to specify the request headers when you initiate a multipart upload task: 
             ObjectMetadata metadata = new ObjectMetadata();
            // metadata.setHeader(OSSHeaders.OSS_STORAGE_CLASS, StorageClass.Standard.toString());
            // Specify the caching behavior of the web page for the object. 
            // metadata.setCacheControl("no-cache");
            // Specify the name of the object when the object is downloaded. 
            // metadata.setContentDisposition("attachment;filename=oss_MultipartUpload.txt");
            // Specify the encoding format for the content of the object. 
            // metadata.setContentEncoding(OSSConstants.DEFAULT_CHARSET_NAME);
            // Specify whether existing objects are overwritten by objects that have the same names when the multipart upload task is initiated. In this example, this parameter is set to true, which indicates that an existing object with the same name as the object to upload is not overwritten. 
            // metadata.setHeader("x-oss-forbid-overwrite", "true");
            // Specify the server-side encryption method that you want to use to encrypt each part of the object that you want to upload. 
            // metadata.setHeader(OSSHeaders.OSS_SERVER_SIDE_ENCRYPTION, ObjectMetadata.KMS_SERVER_SIDE_ENCRYPTION);
            // Specify the algorithm that is used to encrypt the object. If you do not configure this parameter, the object is encrypted by using AES-256. 
            // metadata.setHeader(OSSHeaders.OSS_SERVER_SIDE_DATA_ENCRYPTION, ObjectMetadata.KMS_SERVER_SIDE_ENCRYPTION);
            // Specify the ID of the customer master key (CMK) that is managed by Key Management Service (KMS). 
            // metadata.setHeader(OSSHeaders.OSS_SERVER_SIDE_ENCRYPTION_KEY_ID, "9468da86-3509-4f8d-a61e-6eab1eac****");
            // Specify the storage class of the object. 
            // metadata.setHeader(OSSHeaders.OSS_STORAGE_CLASS, StorageClass.Standard);
            // Specify tags for the object. You can specify multiple tags for the object at a time. 
            // metadata.setHeader(OSSHeaders.OSS_TAGGING, "a:1");
            // request.setObjectMetadata(metadata);

            // Specify ContentType based on the object type. If you do not specify this parameter, the default value of the ContentType field is application/oct-srream. 
            if (metadata.getContentType() == null) {
                metadata.setContentType(Mimetypes.getInstance().getMimetype(new File(filePath), objectName));
            }

            // Initiate a multipart upload task. 
            InitiateMultipartUploadResult upresult = ossClient.initiateMultipartUpload(request);
            // Obtain the upload ID. 
            String uploadId = upresult.getUploadId();
            // Cancel the multipart upload task or list uploaded parts based on the upload ID. 
            // If you want to cancel a multipart upload task based on the upload ID, obtain the upload ID after you call the InitiateMultipartUpload operation to initiate the multipart upload task.  
            // If you want to list the uploaded parts in a multipart upload task based on the upload ID, obtain the upload ID after you call the InitiateMultipartUpload operation to initiate the multipart upload task and before you call the CompleteMultipartUpload operation to complete the multipart upload task. 
            // System.out.println(uploadId);

            // partETags is a set of PartETags. A PartETag consists of the part number and ETag of an uploaded part. 
            List<PartETag> partETags =  new ArrayList<PartETag>();
            // Specify the size of each part. The part size is used to calculate the number of parts of the object. Unit: bytes. 
            final long partSize = 1 * 1024 * 1024L; // Set the part size to 1 MB. 

            // Calculate the number of parts based on the size of the uploaded data. In the following code, a local file is used as an example to show how to use the File.length() method to obtain the size of the uploaded data. 
            final File sampleFile = new File(filePath);
            long fileLength = sampleFile.length();
            int partCount = (int) (fileLength / partSize);
            if (fileLength % partSize != 0) {
                partCount++;
            }
            // Upload all parts. 
            for (int i = 0; i < partCount; i++) {
                long startPos = i * partSize;
                long curPartSize = (i + 1 == partCount) ? (fileLength - startPos) : partSize;
                UploadPartRequest uploadPartRequest = new UploadPartRequest();
                uploadPartRequest.setBucketName(bucketName);
                uploadPartRequest.setKey(objectName);
                uploadPartRequest.setUploadId(uploadId);
                // Specify the input stream of the multipart upload task. 
                // In the following code, a local file is used as an example to show how to create a FIleInputstream and use the InputStream.skip() method to skip the specified data. 
                InputStream instream = new FileInputStream(sampleFile);
                instream.skip(startPos);
                uploadPartRequest.setInputStream(instream);
                // Specify the part size. Each part except the last part must be equal to or greater than 100 KB in size. 
                uploadPartRequest.setPartSize(curPartSize);
                // Set part numbers. Each part has a part number that ranges from 1 to 10,000. If the number that you specify does not fall within the range, OSS returns the InvalidArgument error code. 
                uploadPartRequest.setPartNumber( i + 1);
                // Parts are not uploaded in sequence. Parts can be uploaded from different OSS clients. OSS sorts the parts based on the part number and then combines the parts to obtain a complete object. 
                UploadPartResult uploadPartResult = ossClient.uploadPart(uploadPartRequest);
                // When a part is uploaded, OSS returns a result that contains a PartETag. The PartETag is stored in partETags. 
                partETags.add(uploadPartResult.getPartETag());
            }


            // Create a CompleteMultipartUploadRequest object. 
            // When you call the CompleteMultipartUpload operation, you must provide all valid PartETags. After OSS receives the partETags, OSS verifies all parts one by one. After all parts are verified, OSS combines these parts into a complete object. 
            CompleteMultipartUploadRequest completeMultipartUploadRequest =
                    new CompleteMultipartUploadRequest(bucketName, objectName, uploadId, partETags);

            // The following code provides an example on how to configure the access control list (ACL) of the object when the multipart upload task is completed: 
            // completeMultipartUploadRequest.setObjectACL(CannedAccessControlList.Private);
            // Specify whether to list all parts that are uploaded by using the current upload ID. For OSS SDK for Java 3.14.0 and later, you can set partETags in CompleteMultipartUploadRequest to null only when you list all parts uploaded to the OSS server to combine the parts into a complete object. 
            // Map<String, String> headers = new HashMap<String, String>();
            // If you set x-oss-complete-all to yes in the request, OSS lists all parts that are uploaded by using the current upload ID, sorts the parts by part number, and then performs the CompleteMultipartUpload operation. 
            // If you set x-oss-complete-all to yes in the request, the request body cannot be specified. If you specify the request body, an error is reported. 
            // headers.put("x-oss-complete-all","yes");
            // completeMultipartUploadRequest.setHeaders(headers);

            // Complete the multipart upload task. 
            CompleteMultipartUploadResult completeMultipartUploadResult = ossClient.completeMultipartUpload(completeMultipartUploadRequest);
            System.out.println(completeMultipartUploadResult.getETag());
        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            System.out.println("Error Message:" + oe.getErrorMessage());
            System.out.println("Error Code:" + oe.getErrorCode());
            System.out.println("Request ID:" + oe.getRequestId());
            System.out.println("Host ID:" + oe.getHostId());
        } catch (ClientException ce) {
            System.out.println("Caught an ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        } finally {
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
    }
}
<?php
if (is_file(__DIR__ . '/../autoload.php')) {
    require_once __DIR__ . '/../autoload.php';
}
if (is_file(__DIR__ . '/../vendor/autoload.php')) {
    require_once __DIR__ . '/../vendor/autoload.php';
}

use OSS\OssClient;
use OSS\Core\OssException;
use OSS\Core\OssUtil;

// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured.  
$accessKeyId = getenv("OSS_ACCESS_KEY_ID"); 
$accessKeySecret = getenv("OSS_ACCESS_KEY_SECRET");
// In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. 
$endpoint = 'https://oss-cn-hangzhou.aliyuncs.com';
// Specify the name of the bucket. Example: examplebucket. 
$bucket= 'examplebucket';
// Specify the full path of the object. Do not include the bucket name in the full path. Example: exampledir/exampleobject.txt. 
$object = 'exampledir/exampleobject.txt';
// Specify the full path of the local file that you want to upload. 
$uploadFile = 'D:\\localpath\\examplefile.txt';
$initOptions = array(
    OssClient::OSS_HEADERS  => array(
        // Specify the caching behavior of the web page when the object is downloaded. 
        // 'Cache-Control' => 'no-cache',
        // Specify the name of the object when the object is downloaded. 
        // 'Content-Disposition' => 'attachment;filename=oss_download.jpg',
        // Specify the content encoding format of the object when the object is downloaded. 
        // 'Content-Encoding' => 'utf-8',
        // Specify the validity period of the request. Unit: milliseconds. 
        // 'Expires' => 150,
        // Specify whether the object that is uploaded by using multipart upload overwrites the existing object that has the same name when the multipart upload task is initiated. In this example, the x-oss-forbid-overwrite parameter is set to true. This value specifies that an existing object cannot be overwritten by the object that has the same name. 
        //'x-oss-forbid-overwrite' => 'true',
        // Specify the server-side encryption method that you want to use to encrypt each part of the object. 
        // 'x-oss-server-side-encryption'=> 'KMS',
        // Specify the algorithm that is used to encrypt the object. 
        // 'x-oss-server-side-data-encryption'=>'SM4',
        // Specify the ID of the CMK that is managed by KMS. 
        //'x-oss-server-side-encryption-key-id' => '9468da86-3509-4f8d-a61e-6eab1eac****',
        // Specify the storage class of the object. 
        // 'x-oss-storage-class' => 'Standard',
        // Specify tags for the object. You can specify multiple tags for the object at the same time. 
        // 'x-oss-tagging' => 'TagA=A&TagB=B',
    ),
);

/**
 * Step 1: Initiate a multipart upload task and obtain the upload ID. 
 */
try{
    $ossClient = new OssClient($accessKeyId, $accessKeySecret, $endpoint);
    // Obtain the upload ID. The upload ID is the unique identifier for a multipart upload task. You can perform related operations such as canceling or querying the multipart upload task based on the upload ID. 
    $uploadId = $ossClient->initiateMultipartUpload($bucket, $object, $initOptions);
    print("initiateMultipartUpload OK" . "\n");
    // Cancel the multipart upload task or list uploaded parts based on the upload ID. 
    // If you want to cancel a multipart upload task based on the upload ID, obtain the upload ID after you call the InitiateMultipartUpload operation to initiate the multipart upload task.  
    // If you want to list the uploaded parts in a multipart upload task based on the upload ID, obtain the upload ID after you call the InitiateMultipartUpload operation to initiate the multipart upload task but before you call the CompleteMultipartUpload operation to complete the multipart upload task. 
    //print("UploadId: " . $uploadId . "\n");
} catch(OssException $e) {
    printf($e->getMessage() . "\n");
    return;
}

/*
 * Step 2: Upload parts. 
 */
$partSize = 10 * 1024 * 1024;
$uploadFileSize = sprintf('%u',filesize($uploadFile));
$pieces = $ossClient->generateMultiuploadParts($uploadFileSize, $partSize);
$responseUploadPart = array();
$uploadPosition = 0;
$isCheckMd5 = true;
foreach ($pieces as $i => $piece) {
    $fromPos = $uploadPosition + (integer)$piece[$ossClient::OSS_SEEK_TO];
    $toPos = (integer)$piece[$ossClient::OSS_LENGTH] + $fromPos - 1;
    $upOptions = array(
        // Upload the local file. 
        $ossClient::OSS_FILE_UPLOAD => $uploadFile,
        // Specify part numbers. 
        $ossClient::OSS_PART_NUM => ($i + 1),
        // Specify the position from which the multipart upload task starts. 
        $ossClient::OSS_SEEK_TO => $fromPos,
        // Specify the object length. 
        $ossClient::OSS_LENGTH => $toPos - $fromPos + 1,
        // Specify whether to enable MD5 verification. A value of true indicates that MD5 verification is enabled. 
        $ossClient::OSS_CHECK_MD5 => $isCheckMd5,
    );
    // Enable MD5 verification. 
    if ($isCheckMd5) {
        $contentMd5 = OssUtil::getMd5SumForFile($uploadFile, $fromPos, $toPos);
        $upOptions[$ossClient::OSS_CONTENT_MD5] = $contentMd5;
    }
    try {
        // Upload the parts. 
        $responseUploadPart[] = $ossClient->uploadPart($bucket, $object, $uploadId, $upOptions);
        printf("initiateMultipartUpload, uploadPart - part#{$i} OK\n");
    } catch(OssException $e) {
        printf("initiateMultipartUpload, uploadPart - part#{$i} FAILED\n");
        printf($e->getMessage() . "\n");
        return;
    }

}
// The $uploadParts parameter is an array that consists of the ETag and PartNumber parameters of each part. 
$uploadParts = array();
foreach ($responseUploadPart as $i => $eTag) {
    $uploadParts[] = array(
        'PartNumber' => ($i + 1),
        'ETag' => $eTag,
    );
}
/**
 * Step 3: Complete the multipart upload task. 
 */
$comOptions['headers'] = array(
    // Specify whether the object that is uploaded by using multipart upload overwrites the existing object that has the same name when the multipart upload task is completed. In this example, the x-oss-forbid-overwrite parameter is set to true. This value specifies that an existing object cannot be overwritten by the object that has the same name. 
    // 'x-oss-forbid-overwrite' => 'true',
    // If you set the x-oss-complete-all parameter to yes, OSS lists all parts that are uploaded by using the current upload ID, sorts the parts by part number, and then performs the CompleteMultipartUpload operation. 
    // 'x-oss-complete-all'=> 'yes'
);

try {
    // All valid values of the $uploadParts parameter are required for the CompleteMultipartUpload operation. After OSS receives the values of the $uploadParts parameter, OSS verifies all parts one by one. After all parts are verified, OSS combines these parts into a complete object. 
    $ossClient->completeMultipartUpload($bucket, $object, $uploadId, $uploadParts,$comOptions);
    printf( "Complete Multipart Upload OK\n");
}  catch(OssException $e) {
    printf("Complete Multipart Upload FAILED\n");
    printf($e->getMessage() . "\n");
    return;
}
           
const OSS = require('ali-oss');
const path = require("path");

const client = new OSS({
  // Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to oss-cn-hangzhou. 
  region: 'yourregion',
  // Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
  accessKeyId: process.env.OSS_ACCESS_KEY_ID,
  accessKeySecret: process.env.OSS_ACCESS_KEY_SECRET,
  // Specify the name of the bucket. 
  bucket: 'yourbucketname'
});


const progress = (p, _checkpoint) => {
  // Record the upload progress of the object. 
  console.log(p); 
  // Record the checkpoint information about the multipart upload task. 
  console.log(_checkpoint); 
};

const headers = {  
  // Specify the storage class of the object. 
  'x-oss-storage-class': 'Standard', 
  // Specify tags for the object. You can specify multiple tags for the object. 
  'x-oss-tagging': 'Tag1=1&Tag2=2', 
  // Specify whether to overwite an existing object with the same name when the multipart upload task is initialized. In this example, this parameter is set to true, which indicates that an existing object with the same name as the object to upload is not overwritten. 
  'x-oss-forbid-overwrite': 'true'
}

// Start the multipart upload task. 
async function multipartUpload() {
  try {
    // Specify the full path of the object. Example: exampledir/exampleobject.txt. Then, specify the full path of the local file. Example: D:\\localpath\\examplefile.txt. Do not include the bucket name in the full path. 
    // By default, if you set this parameter to the name of a local file such as examplefile.txt without specifying the local path, the local file is uploaded from the local path of the project to which the sample program belongs. 
    const result = await client.multipartUpload('exampledir/exampleobject.txt', path.normalize('D:\\localpath\\examplefile.txt'), {
      progress,
      // headers,
      // Configure the meta parameter to specify metadata for the object. You can call the HeadObject operation to obtain the object metadata. 
      meta: {
        year: 2020,
        people: 'test',
      },
    });
    console.log(result);
    // Specify the full path of the object. Example: exampledir/exampleobject.txt. Do not include the bucket name in the full path. 
    const head = await client.head('exampledir/exampleobject.txt');
    console.log(head);
  } catch (e) {
    // Handle timeout exceptions. 
    if (e.code === 'ConnectionTimeoutError') {
      console.log('TimeoutError');
      // do ConnectionTimeoutError operation
    }
    console.log(e);
  }
}

multipartUpload();
# -*- coding: utf-8 -*-
import os
from oss2 import SizedFileAdapter, determine_part_size
from oss2.models import PartInfo
import oss2
from oss2.credentials import EnvironmentVariableCredentialsProvider

# Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
auth = oss2.ProviderAuth(EnvironmentVariableCredentialsProvider())
# In this example, the endpoint of the China (Hangzhou) region is used. Specify your actual endpoint. 
# Specify the name of the bucket. Example: examplebucket. 
bucket = oss2.Bucket(auth, 'https://oss-cn-hangzhou.aliyuncs.com', 'examplebucket')
# Specify the full path of the object. Do not include the bucket name in the full path. Example: exampledir/exampleobject.txt. 
key = 'exampledir/exampleobject.txt'
# Specify the full path of the local file that you want to upload. Example: D:\\localpath\\examplefile.txt. 
filename = 'D:\\localpath\\examplefile.txt'

total_size = os.path.getsize(filename)
# Use the determine_part_size method to determine the part size. 
part_size = determine_part_size(total_size, preferred_size=100 * 1024)

# Initiate a multipart upload task. 
# If you want to specify the storage class of the object when you initiate the multipart upload task, configure the related headers when you use the init_multipart_upload method. 
# headers = dict()
# Specify the caching behavior of the web page for the object. 
# headers['Cache-Control'] = 'no-cache'
# Specify the name of the object when it is downloaded. 
# headers['Content-Disposition'] = 'oss_MultipartUpload.txt'
# Specify the content encoding format of the object. 
# headers['Content-Encoding'] = 'utf-8'
# Specify the validity period. Unit: milliseconds. 
# headers['Expires'] = '1000'
# Specify whether the object that is uploaded by performing multipart upload overwrites the existing object that has the same name when the multipart upload task is initiated. In this example, this parameter is set to true, which indicates that the object with the same name cannot be overwritten. 
# headers['x-oss-forbid-overwrite'] = 'true'
# Specify the server-side encryption method that you want to use to encrypt each part. 
# headers[OSS_SERVER_SIDE_ENCRYPTION] = SERVER_SIDE_ENCRYPTION_KMS
# Specify the algorithm that you want to use to encrypt the object. If you do not configure this parameter, the object is encrypted by using AES-256. 
# headers[OSS_SERVER_SIDE_DATA_ENCRYPTION] = SERVER_SIDE_ENCRYPTION_KMS
# Specify the ID of the Customer Master Key (CMK) that is managed by Key Management Service (KMS). 
# headers[OSS_SERVER_SIDE_ENCRYPTION_KEY_ID] = '9468da86-3509-4f8d-a61e-6eab1eac****'
# Specify the storage class of the object. 
# headers['x-oss-storage-class'] = oss2.BUCKET_STORAGE_CLASS_STANDARD
# Specify tags for the object. You can specify multiple tags for the object at the same time. 
# headers[OSS_OBJECT_TAGGING] = 'k1=v1&k2=v2&k3=v3'
# upload_id = bucket.init_multipart_upload(key, headers=headers).upload_id
upload_id = bucket.init_multipart_upload(key).upload_id
# Cancel the multipart upload task or list uploaded parts based on the upload ID. 
# If you want to cancel a multipart upload task based on the upload ID, obtain the upload ID after you call the InitiateMultipartUpload operation to initiate the multipart upload task. 
# If you want to list the uploaded parts in a multipart upload task based on the upload ID, obtain the upload ID after you call the InitiateMultipartUpload operation to initiate the multipart upload task but before you call the CompleteMultipartUpload operation to complete the multipart upload task. 
# print("UploadID:", upload_id)
parts = []

# Upload the parts. 
with open(filename, 'rb') as fileobj:
    part_number = 1
    offset = 0
    while offset < total_size:
        num_to_upload = min(part_size, total_size - offset)
        # Use the SizedFileAdapter(fileobj, size) method to generate a new object and recalculate the position from which the append operation starts. 
        result = bucket.upload_part(key, upload_id, part_number,
                                    SizedFileAdapter(fileobj, num_to_upload))
        parts.append(PartInfo(part_number, result.etag))

        offset += num_to_upload
        part_number += 1

# Complete the multipart upload task. 
# Configure headers (if you want to) when you complete the multipart upload task. 
headers = dict()
# Specify the access control list (ACL) of the object. In this example, the ACL is set to OBJECT_ACL_PRIVATE, which indicates that the ACL of the object is private. 
# headers["x-oss-object-acl"] = oss2.OBJECT_ACL_PRIVATE
bucket.complete_multipart_upload(key, upload_id, parts, headers=headers)
# bucket.complete_multipart_upload(key, upload_id, parts)
<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>Document</title>
  </head>

  <body>
    <button id="submit">Upload</button>
    <input id="file" type="file" />
    <!-- Import the SDK file -->
    <script
      type="text/javascript"
      src="https://gosspublic.alicdn.com/aliyun-oss-sdk-6.18.0.min.js"
    ></script>
    <script type="text/javascript">
      const client = new OSS({
        // Specify the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the region to oss-cn-hangzhou. 
        region: "yourRegion",
        // Specify the temporary AccessKey pair obtained from STS. The AccessKey pair consists of an AccessKey ID and an AccessKey secret. 
        accessKeyId: "yourAccessKeyId",
        accessKeySecret: "yourAccessKeySecret",
        // Specify the security token obtained from STS. 
        stsToken: "yourSecurityToken",
        // Specify the name of the bucket. Example: examplebucket. 
        bucket: "examplebucket",
      });

      const headers = {
        // Specify the caching behavior of the web page when the object is downloaded. 
        "Cache-Control": "no-cache",
        // Specify the name of the object when the object is downloaded. 
        "Content-Disposition": "example.txt",
        // Specify the content encoding format of the object when the object is downloaded. 
        "Content-Encoding": "utf-8",
        // Specify the validity period of the request. Unit: milliseconds. 
        Expires: "1000",
        // Specify the storage class of the object. 
        "x-oss-storage-class": "Standard",
        // Specify one or more tags for the object. 
        "x-oss-tagging": "Tag1=1&Tag2=2",
        // Specify whether to overwrite an existing object with the same name when the multipart upload task is initialized. In this example, the x-oss-forbid-overwrite parameter is set to true. This value specifies that an existing object cannot be overwritten by the object that has the same name. 
        "x-oss-forbid-overwrite": "true",
      };

      // Specify the name of the object that is uploaded to the examplebucket bucket. Example: exampleobject.txt. 
      const name = "exampleobject.txt";
      // Obtain DOM. 
      const submit = document.getElementById("submit");
      const options = {
        // Query the progress, checkpoint, and return value of the multipart upload task. 
        progress: (p, cpt, res) => {
          console.log(p);
        },
        // Specify the number of parts that can be uploaded in parallel. 
        parallel: 4,
        // Specify the part size. Default value: 1 MB. Minimum value: 100 KB. 
        partSize: 1024 * 1024,
        // headers,
        // Specify the user metadata of the object. You can call the HeadObject operation to query the object metadata. 
        meta: { year: 2020, people: "test" },
        mime: "text/plain",
      };

      // Configure an event listener. 
      submit.addEventListener("click", async () => {
        try {
          const data = document.getElementById("file").files[0];
          // Start the multipart upload task. 
          const res = await client.multipartUpload(name, data, {
            ...options,
            // Configure an upload callback. 
            // If no callback server is required, delete the callback configurations. 
            callback: {
              // Specify the address of the server that receives the callback request. 
              url: "http://examplebucket.aliyuncs.com:23450",
              // Specify the Host header in the callback request. 
              host: "yourHost",
              /* eslint no-template-curly-in-string: [0] */
              // Specify the body content of the callback request. 
              body: "bucket=${bucket}&object=${object}&var1=${x:var1}",
              // Specify Content-Type in the callback request. 
              contentType: "application/x-www-form-urlencoded",
              customValue: {
                // Specify custom parameters for the callback request. 
                var1: "value1",
                var2: "value2",
              },
            },
          });
          console.log(res);
        } catch (err) {
          console.log(err);
        }
      });
    </script>
  </body>
</html>
using Aliyun.OSS;

// Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. 
var endpoint = "yourEndpoint";
// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
var accessKeyId = Environment.GetEnvironmentVariable("OSS_ACCESS_KEY_ID");
var accessKeySecret = Environment.GetEnvironmentVariable("OSS_ACCESS_KEY_SECRET");
// Specify the name of the bucket. 
var bucketName = "examplebucket";
// Specify the full path of the object. Do not include the bucket name in the full path. 
var objectName = "exampleobject.txt";
// Specify the full path of the local file that you want to upload. By default, if you do not specify the full path of a local file, the local file is uploaded from the path of the project to which the sample program belongs. 
var localFilename = "D:\\localpath\\examplefile.txt";
// Create an OSSClient instance. 
var client = new OssClient(endpoint, accessKeyId, accessKeySecret);

// Initiate the multipart upload task and obtain the upload ID in the response. 
var uploadId = "";
try
{
    // Specify the name of the uploaded object and the bucket for the object. You can configure object metadata in InitiateMultipartUploadRequest. However, you do not need to specify ContentLength. 
    var request = new InitiateMultipartUploadRequest(bucketName, objectName);
    var result = client.InitiateMultipartUpload(request);
    uploadId = result.UploadId;
    // Display the upload ID. 
    Console.WriteLine("Init multi part upload succeeded");
    // Cancel the multipart upload task or list uploaded parts based on the upload ID. 
    // If you want to cancel a multipart upload task based on the upload ID, obtain the upload ID after you call the InitiateMultipartUpload operation to initiate the multipart upload task.  
    // If you want to list the uploaded parts in a multipart upload task based on the upload ID, obtain the upload ID after you call the InitiateMultipartUpload operation to initiate the multipart upload task but before you call the CompleteMultipartUpload operation to complete the multipart upload task. 
    Console.WriteLine("Upload Id:{0}", result.UploadId);
}
catch (Exception ex)
{
    Console.WriteLine("Init multi part upload failed, {0}", ex.Message);
}
// Calculate the total number of parts. 
var partSize = 100 * 1024;
var fi = new FileInfo(localFilename);
var fileSize = fi.Length;
var partCount = fileSize / partSize;
if (fileSize % partSize != 0)
{
    partCount++;
}
// Start the multipart upload task. partETags is a list of PartETags. After OSS receives the partETags, OSS verifies all parts one by one. After all parts are verified, OSS combines these parts into a complete object. 
var partETags = new List<PartETag>();
try
{
    using (var fs = File.Open(localFilename, FileMode.Open))
    {
        for (var i = 0; i < partCount; i++)
        {
            var skipBytes = (long)partSize * i;
            // Find the start position of the current upload task. 
            fs.Seek(skipBytes, 0);
            // Calculate the part size in this upload. The size of the last part is the size of the remainder after the object is split by the calculated part size. 
            var size = (partSize < fileSize - skipBytes) ? partSize : (fileSize - skipBytes);
            var request = new UploadPartRequest(bucketName, objectName, uploadId)
            {
                InputStream = fs,
                PartSize = size,
                PartNumber = i + 1
            };
            // Call UploadPart to upload parts. The returned results contain the ETag values of parts. 
            var result = client.UploadPart(request);
            partETags.Add(result.PartETag);
            Console.WriteLine("finish {0}/{1}", partETags.Count, partCount);
        }
        Console.WriteLine("Put multi part upload succeeded");
    }
}
catch (Exception ex)
{
    Console.WriteLine("Put multi part upload failed, {0}", ex.Message);
}
// Complete the multipart upload task. 
try
{
    var completeMultipartUploadRequest = new CompleteMultipartUploadRequest(bucketName, objectName, uploadId);
    foreach (var partETag in partETags)
    {
        completeMultipartUploadRequest.PartETags.Add(partETag);
    }
    var result = client.CompleteMultipartUpload(completeMultipartUploadRequest);
    Console.WriteLine("complete multi part succeeded");
}
catch (Exception ex)
{
    Console.WriteLine("complete multi part failed, {0}", ex.Message);
}
// Specify the name of the bucket. Example: examplebucket. 
String bucketName = "examplebucket";
// Specify the full path of the object. Example: exampledir/exampleobject.txt. Do not include the bucket name in the full path. 
String objectName = "exampledir/exampleobject.txt";
// Specify the full path of the local file. Example: /storage/emulated/0/oss/examplefile.txt. 
String localFilepath = "/storage/emulated/0/oss/examplefile.txt";

// Initiate a multipart upload task. 
InitiateMultipartUploadRequest init = new InitiateMultipartUploadRequest(bucketName, objectName);
InitiateMultipartUploadResult initResult = oss.initMultipartUpload(init);
// Obtain the upload ID. 
String uploadId = initResult.getUploadId();
// Cancel the multipart upload task or list uploaded parts based on the upload ID. 
// If you want to cancel a multipart upload task based on the upload ID, obtain the upload ID after you call the InitiateMultipartUpload operation to initiate the multipart upload task.  
// If you want to list the uploaded parts in a multipart upload task based on the upload ID, obtain the upload ID after you call the InitiateMultipartUpload operation to initiate the multipart upload task and before you call the CompleteMultipartUpload operation to complete the multipart upload task. 
// Log.d("uploadId", uploadId);

// Specify the part size. Unit: bytes. Valid values: 100 KB to 5 GB. 
int partCount = 100 * 1024;
// Start the multipart upload task. 
List<PartETag> partETags = new ArrayList<>();
for (int i = 1; i < 5; i++) {
    byte[] data = new byte[partCount];

    RandomAccessFile raf = new RandomAccessFile(localFilepath, "r");
    long skip = (i-1) * partCount;
    raf.seek(skip);
    raf.readFully(data, 0, partCount);

    UploadPartRequest uploadPart = new UploadPartRequest();
    uploadPart.setBucketName(bucketName);
    uploadPart.setObjectKey(objectName);
    uploadPart.setUploadId(uploadId);
    // Specify the part number of each part. The number starts from 1. Each part has a part number. Valid values: 1 to 10000. 
    uploadPart.setPartNumber(i); 
    uploadPart.setPartContent(data);
    try {
        UploadPartResult result = oss.uploadPart(uploadPart);
        PartETag partETag = new PartETag(uploadPart.getPartNumber(), result.getETag());
        partETags.add(partETag);
    } catch (ServiceException serviceException) {
        OSSLog.logError(serviceException.getErrorCode());
    }
}
Collections.sort(partETags, new Comparator<PartETag>() {
    @Override
    public int compare(PartETag lhs, PartETag rhs) {
        if (lhs.getPartNumber() < rhs.getPartNumber()) {
            return -1;
        } else if (lhs.getPartNumber() > rhs.getPartNumber()) {
            return 1;
        } else {
            return 0;
        }
    }
});

// Complete the multipart upload task. 
CompleteMultipartUploadRequest complete = new CompleteMultipartUploadRequest(bucketName, objectName, uploadId, partETags);

// Implement upload callback. You can configure the CALLBACK_SERVER parameter when you complete the multipart upload task. A callback request is sent to the specified server address after you complete the multipart upload task. You can view the servercallback result in completeResult.getServerCallbackReturnBody() of the response. 
complete.setCallbackParam(new HashMap<String, String>() {
    {
        put("callbackUrl", CALLBACK_SERVER); // Set the CALLBACK_SERVER parameter to your server address. 
        put("callbackBody", "test");
    }
});
CompleteMultipartUploadResult completeResult = oss.completeMultipartUpload(complete);
OSSLog.logError("-------------- serverCallback: " + completeResult.getServerCallbackReturnBody());
package main

import (
    "fmt"
    "os"
    "time"

    "github.com/aliyun/aliyun-oss-go-sdk/oss"
)

func main() {
	// Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. 
	provider, err := oss.NewEnvironmentVariableCredentialsProvider()
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}
	// Create an OSSClient instance. 
	// Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. Specify your actual endpoint. 
	client, err := oss.New("yourEndpoint", "", "", oss.SetCredentialsProvider(&provider))
	if err != nil {
		fmt.Println("Error:", err)
		os.Exit(-1)
	}
    // Specify the name of the bucket. 
    bucketName := "examplebucket"
    // Specify the full path of the object. Do not include the bucket name in the full path. 
    objectName := "exampleobject.txt"
    // Specify the full path of the local file that you want to upload. By default, if you do not specify the full path of the local file, the local file is uploaded from the path of the project to which the sample program belongs. 
    locaFilename := "D:\\localpath\\examplefile.txt"
   
    bucket, err := client.Bucket(bucketName)
    if err != nil {
        fmt.Println("Error:", err)
        os.Exit(-1)
    }
    // Split the local file into three parts. 
    chunks, err := oss.SplitFileByPartNum(locaFilename, 3)
    if err != nil {
        fmt.Println("Error:", err)
        os.Exit(-1)
    }
    fd, err := os.Open(locaFilename)
    if err != nil {
        fmt.Println("Error:", err)
        os.Exit(-1)
    }
    defer fd.Close()

    // Specify the validity period of the request. 
    expires := time.Date(2049, time.January, 10, 23, 0, 0, 0, time.UTC)
    // The following code provides an example on how to specify the request headers when you initiate a multipart upload task. 
    options := []oss.Option{
        oss.MetadataDirective(oss.MetaReplace),
        oss.Expires(expires),
        // Specify the caching behavior of the web page when the object is downloaded. 
        // oss.CacheControl("no-cache"),
        // Specify the name of the object when it is downloaded. 
        // oss.ContentDisposition("attachment;filename=FileName.txt"),
        // Specify the content encoding format of the object. 
        // oss.ContentEncoding("gzip"),
        // Specify the method that is used to encode the object name in the response. Only URL encoding is supported. 
        // oss.EncodingType("url"),
        // Specify the storage class of the object. 
        // oss.ObjectStorageClass(oss.StorageStandard),
    }

    // Step 1: Initiate a multipart upload task. 
    imur, err := bucket.InitiateMultipartUpload(objectName, options...)
    if err != nil {
        fmt.Println("Error:", err)
        os.Exit(-1)
    }
    // Step 2: Upload the parts. 
    var parts []oss.UploadPart
    for _, chunk := range chunks {
        fd.Seek(chunk.Offset, os.SEEK_SET)
        // Call the UploadPart method to upload each part. 
        part, err := bucket.UploadPart(imur, fd, chunk.Size, chunk.Number)
        if err != nil {
            fmt.Println("Error:", err)
            os.Exit(-1)
        }
        parts = append(parts, part)
    }

    // Set the access control list (ACL) of the object to private. By default, the object inherits the ACL of the bucket. 
    objectAcl := oss.ObjectACL(oss.ACLPrivate)

    // Step 3: Complete the multipart upload task. 
    cmur, err := bucket.CompleteMultipartUpload(imur, parts, objectAcl)
    if err != nil {
        fmt.Println("Error:", err)
        os.Exit(-1)
    }
    fmt.Println("cmur:", cmur)
}
__block NSString * uploadId = nil;
__block NSMutableArray * partInfos = [NSMutableArray new];
// Specify the name of the bucket. Example: examplebucket. 
NSString * uploadToBucket = @"examplebucket";
// Specify the full path of the object. Example: exampledir/exampleobject.txt. Do not include the bucket name in the full path. 
NSString * uploadObjectkey = @"exampledir/exampleobject.txt";
// You can use OSSInitMultipartUploadRequest to specify the name of the uploaded object and the name of the bucket in which the object is stored. 
OSSInitMultipartUploadRequest * init = [OSSInitMultipartUploadRequest new];
init.bucketName = uploadToBucket;
init.objectKey = uploadObjectkey;
// init.contentType = @"application/octet-stream";
// The response to multipartUploadInit contains the upload ID. The upload ID is the unique ID of the multipart upload task. 
OSSTask * initTask = [client multipartUploadInit:init];
[initTask waitUntilFinished];
if (!initTask.error) {
    OSSInitMultipartUploadResult * result = initTask.result;
    uploadId = result.uploadId;
    // Cancel the multipart upload task or list uploaded parts based on the upload ID. 
    // If you want to cancel a multipart upload task based on the upload ID, obtain the upload ID after you call the InitiateMultipartUpload operation to initiate the multipart upload task. 
    // If you want to list the uploaded parts in a multipart upload task based on the upload ID, obtain the upload ID after you call the InitiateMultipartUpload operation to initiate the multipart upload task but before you call the CompleteMultipartUpload operation to complete the multipart upload task. 
    //NSLog(@"UploadId": %@, uploadId);
} else {
    NSLog(@"multipart upload failed, error: %@", initTask.error);
    return;
}

// Specify the object that you want to upload. 
NSString * filePath = @"<filepath>";
// Query the size of the object. 
uint64_t fileSize = [[[NSFileManager defaultManager] attributesOfItemAtPath:filePath error:nil] fileSize];
// Specify the number of parts. 
int chuckCount = 10;
// Specify the size of each part. 
uint64_t offset = fileSize/chuckCount;
for (int i = 1; i <= chuckCount; i++) {
    OSSUploadPartRequest * uploadPart = [OSSUploadPartRequest new];
    uploadPart.bucketName = uploadToBucket;
    uploadPart.objectkey = uploadObjectkey;
    uploadPart.uploadId = uploadId;
    uploadPart.partNumber = i; // part number start from 1

    NSFileHandle* readHandle = [NSFileHandle fileHandleForReadingAtPath:filePath];
    [readHandle seekToFileOffset:offset * (i -1)];

    NSData* data = [readHandle readDataOfLength:offset];
    uploadPart.uploadPartData = data;

    OSSTask * uploadPartTask = [client uploadPart:uploadPart];

    [uploadPartTask waitUntilFinished];

    if (!uploadPartTask.error) {
        OSSUploadPartResult * result = uploadPartTask.result;
        uint64_t fileSize = [[[NSFileManager defaultManager] attributesOfItemAtPath:uploadPart.uploadPartFileURL.absoluteString error:nil] fileSize];
        [partInfos addObject:[OSSPartInfo partInfoWithPartNum:i eTag:result.eTag size:fileSize]];
    } else {
        NSLog(@"upload part error: %@", uploadPartTask.error);
        return;
    }
}
OSSCompleteMultipartUploadRequest * complete = [OSSCompleteMultipartUploadRequest new];
complete.bucketName = uploadToBucket;
complete.objectKey = uploadObjectkey;
complete.uploadId = uploadId;
complete.partInfos = partInfos;

OSSTask * completeTask = [client completeMultipartUpload:complete];

[[completeTask continueWithBlock:^id(OSSTask *task) {
    if (!task.error) {
        OSSCompleteMultipartUploadResult * result = task.result;
        // ...
    } else {
        // ...
    }
    return nil;
}] waitUntilFinished];
#include <alibabacloud/oss/OssClient.h>
#include <fstream>

int64_t getFileSize(const std::string& file)
{
    std::fstream f(file, std::ios::in | std::ios::binary);
    f.seekg(0, f.end);
    int64_t size = f.tellg();
    f.close();
    return size;
}

using namespace AlibabaCloud::OSS;

int main(void)
{
    /* Initialize information about the account that is used to access OSS. */
    
    std::string Endpoint = "yourEndpoint";
    /* Specify the name of the bucket. Example: examplebucket. */
    std::string BucketName = "examplebucket";
    /* Specify the full path of the object. Do not include the bucket name in the full path of the object. Example: exampledir/exampleobject.txt.  */
    std::string ObjectName = "exampledir/exampleobject.txt";

    /* Initialize resources such as network resources. */
    InitializeSdk();

    ClientConfiguration conf;
    /* Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. */
    auto credentialsProvider = std::make_shared<EnvironmentVariableCredentialsProvider>();
    OssClient client(Endpoint, credentialsProvider, conf);
  
    InitiateMultipartUploadRequest initUploadRequest(BucketName, ObjectName);
    /* (Optional) Specify the storage class. */
    //initUploadRequest.MetaData().addHeader("x-oss-storage-class", "Standard");

    /* Initiate the multipart upload task. */
    auto uploadIdResult = client.InitiateMultipartUpload(initUploadRequest);
    /* Cancel the multipart upload task or list uploaded parts based on the upload ID. */
    /* If you want to cancel a multipart upload task based on the upload ID, obtain the upload ID after you call the InitiateMultipartUpload operation to initiate the multipart upload task. */
    /* If you want to list the uploaded parts in a multipart upload task based on the upload ID, obtain the upload ID after you call the InitiateMultipartUpload operation to initiate the multipart upload task but before you call the CompleteMultipartUpload operation to complete the multipart upload task. */ 
    auto uploadId = uploadIdResult.result().UploadId();
    std::string fileToUpload = "yourLocalFilename";
    int64_t partSize = 100 * 1024;
    PartList partETagList;
    auto fileSize = getFileSize(fileToUpload);
    int partCount = static_cast<int>(fileSize / partSize);
    /* Calculate the number of parts. */
    if (fileSize % partSize != 0) {
        partCount++;
    }

    /* Upload each part. */
    for (int i = 1; i <= partCount; i++) {
        auto skipBytes = partSize * (i - 1);
        auto size = (partSize < fileSize - skipBytes) ? partSize : (fileSize - skipBytes);
        std::shared_ptr<std::iostream> content = std::make_shared<std::fstream>(fileToUpload, std::ios::in|std::ios::binary);
        content->seekg(skipBytes, std::ios::beg);

        UploadPartRequest uploadPartRequest(BucketName, ObjectName, content);
        uploadPartRequest.setContentLength(size);
        uploadPartRequest.setUploadId(uploadId);
        uploadPartRequest.setPartNumber(i);
        auto uploadPartOutcome = client.UploadPart(uploadPartRequest);
        if (uploadPartOutcome.isSuccess()) {
            Part part(i, uploadPartOutcome.result().ETag());
            partETagList.push_back(part);
        }
        else {
            std::cout << "uploadPart fail" <<
            ",code:" << uploadPartOutcome.error().Code() <<
            ",message:" << uploadPartOutcome.error().Message() <<
            ",requestId:" << uploadPartOutcome.error().RequestId() << std::endl;
        }

    }

    /* Complete the multipart upload task. */
    /* When the multipart upload task is completed, you need to provide all valid PartETags. After OSS receives the PartETags, OSS verifies all parts one by one. After part verification is successful, OSS combines these parts into a complete object. */
    CompleteMultipartUploadRequest request(BucketName, ObjectName);
    request.setUploadId(uploadId);
    request.setPartList(partETagList);
    /* (Optional) Specify the ACL of the object. */
    //request.setAcl(CannedAccessControlList::Private);

    auto outcome = client.CompleteMultipartUpload(request);

    if (!outcome.isSuccess()) {
        /* Handle exceptions. */
        std::cout << "CompleteMultipartUpload fail" <<
        ",code:" << outcome.error().Code() <<
        ",message:" << outcome.error().Message() <<
        ",requestId:" << outcome.error().RequestId() << std::endl;
        return -1;
    }

    /* Release resources such as network resources. */
    ShutdownSdk();
    return 0;
}
#include "oss_api.h"
#include "aos_http_io.h"
#include <sys/stat.h>
/* Specify the endpoint of the region in which the bucket is located. For example, if the bucket is located in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com. */
const char *endpoint = "yourEndpoint";

/* Specify the name of the bucket. Example: examplebucket. */
const char *bucket_name = "examplebucket";
/* Specify the full path of the object. Do not include the bucket name in the full path. Example: exampledir/exampleobject.txt. */
const char *object_name = "exampledir/exampleobject.txt";
/* Specify the full path of the local file. */
const char *local_filename = "yourLocalFilename";
void init_options(oss_request_options_t *options)
{
    options->config = oss_config_create(options->pool);
    /* Use a char* string to initialize data of the aos_string_t type. */
    aos_str_set(&options->config->endpoint, endpoint);
    /* Obtain access credentials from environment variables. Before you run the sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are configured. */    
    aos_str_set(&options->config->access_key_id, getenv("OSS_ACCESS_KEY_ID"));
    aos_str_set(&options->config->access_key_secret, getenv("OSS_ACCESS_KEY_SECRET"));
    /* Specify whether to use CNAME to access OSS. The value 0 indicates that CNAME is not used. */
    options->config->is_cname = 0;
    /* Configure network parameters, such as the timeout period. */
    options->ctl = aos_http_controller_create(options->pool, 0);
}
int64_t get_file_size(const char *file_path)
{
    int64_t filesize = -1;
    struct stat statbuff;
    if(stat(file_path, &statbuff) < 0){
        return filesize;
    } else {
        filesize = statbuff.st_size;
    }
    return filesize;
}
int main(int argc, char *argv[])
{
    /* Call the aos_http_io_initialize method in main() to initialize global resources, such as network resources and memory resources. */
    if (aos_http_io_initialize(NULL, 0) != AOSE_OK) {
        exit(1);
    }
    /* Create a memory pool to manage memory. aos_pool_t is equivalent to apr_pool_t. The code used to create a memory pool is included in the APR library. */
    aos_pool_t *pool;
    /* Create a memory pool. The value of the second parameter is NULL. This value indicates that the pool does not inherit other memory pools. */
    aos_pool_create(&pool, NULL);
    /* Create and initialize options. This parameter includes global configuration information, such as endpoint, access_key_id, access_key_secret, is_cname, and curl. */
    oss_request_options_t *oss_client_options;
    /* Allocate the memory resources in the memory pool to the options. */
    oss_client_options = oss_request_options_create(pool);
    /* Initialize oss_client_options. */
    init_options(oss_client_options);
    /* Initialize the parameters. */
    aos_string_t bucket;
    aos_string_t object;
    oss_upload_file_t *upload_file = NULL;
    aos_string_t upload_id;   
    aos_table_t *headers = NULL;
    aos_table_t *complete_headers = NULL;
    aos_table_t *resp_headers = NULL;
    aos_status_t *resp_status = NULL; 
    aos_str_set(&bucket, bucket_name);
    aos_str_set(&object, object_name);
    aos_str_null(&upload_id);
    headers = aos_table_make(pool, 1);
    complete_headers = aos_table_make(pool, 1);
    int part_num = 1;
    /* Initiate a multipart upload task and obtain an upload ID. */
    resp_status = oss_init_multipart_upload(oss_client_options, &bucket, &object, &upload_id, headers, &resp_headers);
    /* Check whether the multipart upload task is initialized. */
    if (aos_status_is_ok(resp_status)) {
        printf("Init multipart upload succeeded, upload_id:%.*s\n", 
               upload_id.len, upload_id.data);
    } else {
        printf("Init multipart upload failed, upload_id:%.*s\n", 
               upload_id.len, upload_id.data);
    }
    /* Upload the parts. */
    int64_t file_length = 0;
    int64_t pos = 0;
    aos_list_t complete_part_list;
       oss_complete_part_content_t* complete_content = NULL;
    char* part_num_str = NULL;
    char* etag = NULL;
    aos_list_init(&complete_part_list);
    file_length = get_file_size(local_filename);
    while(pos < file_length) {
        upload_file = oss_create_upload_file(pool);
        aos_str_set(&upload_file->filename, local_filename);
        upload_file->file_pos = pos;
        pos += 100 * 1024;
        upload_file->file_last = pos < file_length ? pos : file_length;
        resp_status = oss_upload_part_from_file(oss_client_options, &bucket, &object, &upload_id, part_num++, upload_file, &resp_headers);

        /* Save the part numbers and ETags. */
        complete_content = oss_create_complete_part_content(pool);
        part_num_str = apr_psprintf(pool, "%d", part_num-1);
        aos_str_set(&complete_content->part_number, part_num_str);
        etag = apr_pstrdup(pool,
        (char*)apr_table_get(resp_headers, "ETag"));
        aos_str_set(&complete_content->etag, etag);
        aos_list_add_tail(&complete_content->node, &complete_part_list);

        if (aos_status_is_ok(resp_status)) {
            printf("Multipart upload part from file succeeded\n");
        } else {
            printf("Multipart upload part from file failed\n");
        }
    }

    /* Complete the multipart upload task. */
    resp_status = oss_complete_multipart_upload(oss_client_options, &bucket, &object, &upload_id,
            &complete_part_list, complete_headers, &resp_headers);
    /* Check whether the multipart upload task is complete. */
    if (aos_status_is_ok(resp_status)) {
        printf("Complete multipart upload from file succeeded, upload_id:%.*s\n", 
               upload_id.len, upload_id.data);
    } else {
        printf("Complete multipart upload from file failed\n");
    }
    /* Release the memory pool. This operation releases the memory resources allocated for the request. */
    aos_pool_destroy(pool);
    /* Release the allocated global resources. */
    aos_http_io_deinitialize();
    return 0;
}

Use ossutil

You can perform multipart upload by using ossutil. For more information, see Upload objects.

Use the OSS API

If your business requires a high level of customization, you can directly call RESTful APIs. To directly call an API, you must include the signature calculation in your code. For more information, see InitiateMultipartUpload.

FAQ

How do I delete parts?

If a multipart upload task is interrupted, the uploaded parts are stored in the bucket. If you no longer need the parts, you can use one of the following methods to delete the parts to prevent unnecessary storage costs:

How do I list parts?

  • If you want to list parts that are uploaded by using a specific upload ID, you can call the ListParts operation. For more information, see ListParts.

  • If you want to list multipart upload tasks that have been initiated but are not completed or canceled, you can call the ListMultipartUploads operation. For more information, see ListMultipartUploads.

Can I use multipart upload to upload a local file that is encrypted and compressed to OSS?

Yes, you can use multipart upload to upload a local file that is encrypted and compressed to OSS.

Are uploaded parts overwritten when I re-upload the parts after a multipart upload task is interrupted?

After a multipart upload task is interrupted, if you use the original upload ID to re-upload all parts, the uploaded parts that have the same name are overwritten. If you use a new upload ID to re-upload all parts, the uploaded parts that have the original upload ID are retained.

What is an upload ID in multipart upload?

An upload ID uniquely identifies a multipart upload task. Part numbers identify the relative positions of parts that share the same upload ID.

How long is the upload ID valid during a multipart upload task?

The upload ID remains valid throughout the multipart upload process. If the upload task is canceled or completed, the upload ID becomes invalid. If you want to perform another multipart upload task, you must reinitiate a multipart upload task to generate a new upload ID.

Does OSS support automatic combination of parts?

No, OSS does not support automatic combination of parts. You must manually combine parts into an object by calling the CompleteMultipartUpload operation.