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Object Storage Service:C++ simple upload

Last Updated:Jul 08, 2025

This topic describes how to upload objects from memory or local disks.

Usage notes

  • In this topic, the public endpoint of the China (Hangzhou) region is used. If you want to access OSS from other Alibaba Cloud services in the same region as OSS, use an internal endpoint. For more information about OSS regions and endpoints, see Regions and endpoints.

  • In this topic, an OSSClient instance is created by using an OSS endpoint. If you want to create an OSSClient by using custom domain names or Security Token Service (STS), see Create an OSSClient instance.

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

PutObject

oss:PutObject

Uploads an object.

oss:PutObjectTagging

When uploading an object, if you specify object tags through x-oss-tagging, this permission is required.

kms:GenerateDataKey

When uploading an object, if the object metadata contains X-Oss-Server-Side-Encryption: KMS, these two permissions are required.

kms:Decrypt

Upload an object from memory

The following code provides an example on how to upload data from memory to an object named exampleobject.txt in the exampledir directory of a bucket named examplebucket:

#include <alibabacloud/oss/OssClient.h>
using namespace AlibabaCloud::OSS;

int main(void)
{
    /* Initialize information about the account that is used to access 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. */
    std::string Endpoint = "yourEndpoint";
    /* 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 cn-hangzhou. */
    std::string Region = "yourRegion";
    /* 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. Example: exampledir/exampleobject.txt. */
    std::string ObjectName = "exampledir/exampleobject.txt";

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

    ClientConfiguration conf;
    conf.signatureVersion = SignatureVersionType::V4;
    /* 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);
    client.SetRegion(Region);
    std::shared_ptr<std::iostream> content = std::make_shared<std::stringstream>();
    *content << "Thank you for using Alibaba Cloud Object Storage Service!";
    PutObjectRequest request(BucketName, ObjectName, content);

    /* (Optional) Set the ACL to private and the storage class to Standard for the object. */
    //request.MetaData().addHeader("x-oss-object-acl", "private");
    //request.MetaData().addHeader("x-oss-storage-class", "Standard");

    /* Upload the object. */
    auto outcome = client.PutObject(request);

    if (!outcome.isSuccess()) {
        /* Handle exceptions. */
        std::cout << "PutObject 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;
}

Upload a local file

The following code provides an example on how to upload a file named examplefile.txt from a directory named D:\\localpath on the local disk to the exampledir directory of a bucket named examplebucket. The uploaded file is stored as an object named exampleobject.txt in OSS.

#include <alibabacloud/oss/OssClient.h>
#include <fstream>
using namespace AlibabaCloud::OSS;

int main(void)
{
    /* Initialize information about the account that is used to access 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. */
    std::string Endpoint = "yourEndpoint";
    /* 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 cn-hangzhou. */
    std::string Region = "yourRegion";
    /* 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. Example: exampledir/exampleobject.txt. */
    std::string ObjectName = "exampledir/exampleobject.txt";

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

    ClientConfiguration conf;
    conf.signatureVersion = SignatureVersionType::V4;
    /* 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);
    client.SetRegion(Region);
    /* Specify the full path of the local file. Example: D:\\localpath\\examplefile.txt. In this example, localpath indicates the local path in which the examplefile.txt file is stored. */
    std::shared_ptr<std::iostream> content = std::make_shared<std::fstream>("D:\\localpath\\examplefile.txt", std::ios::in | std::ios::binary);
    PutObjectRequest request(BucketName, ObjectName, content);

    /* (Optional) Set the ACL to private and the storage class to Standard for the object. */
    //request.MetaData().addHeader("x-oss-object-acl", "private");
    //request.MetaData().addHeader("x-oss-storage-class", "Standard");

    auto outcome = client.PutObject(request);

    if (!outcome.isSuccess()) {
        /* Handle exceptions. */
        std::cout << "PutObject 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;
}

References

  • For the complete sample code that is used to perform simple upload, see GitHub.

  • For more information about the API operation that you can call to perform simple upload, see PutObject.