Get started with OSS SDK for C++ - Object Storage Service

This topic describes how to use Object Storage Service (OSS) SDK for C++ to perform routine operations, such as creating buckets, uploading objects, and downloading objects.

Note

In the following sample code, conf is an instance of ClientConfiguration, and ClientConfiguration is a configuration class of OssClient. You can use this configuration class to configure items such as the proxy, the connection timeout period, and the maximum number of connections. For more information, see Initialization.

Create a bucket

A bucket is a global namespace in OSS. A bucket is a container that is used to store objects.

Note

For more information about the naming conventions for buckets, see the "Bucket" section of the Terms topic. For more information about endpoints, see Regions and endpoints.

The following code provides an example on how to create 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 name of the bucket. Example: examplebucket. */
    std::string BucketName = "examplebucket";
    /* 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);

    /* Specify the name, storage class, and access control list (ACL) of the bucket. */
    CreateBucketRequest request(BucketName, StorageClass::IA, CannedAccessControlList::PublicReadWrite);

    /* Create the bucket. */
    auto outcome = client.CreateBucket(request);

    if (!outcome.isSuccess()) {
        /* Handle exceptions. */
        std::cout << "CreateBucket 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 an object

The following code provides an example on how to upload an object to OSS:

#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 name of the bucket. Example: examplebucket. */
    std::string BucketName = "examplebucket";
    /* Specify the full path of the object. Example: exampledir/exampleobject.txt. Do not include the bucket name in the full path. */
    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);

    /* Upload the object. */
    /* 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. */
    auto outcome = client.PutObject(BucketName, ObjectName,"D:\\localpath\\examplefile.txt");

    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;
}

Download an object

The following code provides an example on how to download a specific object to a local computer:

#include <alibabacloud/oss/OssClient.h>
#include <memory>
#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 = "https://oss-cn-hangzhou.aliyuncs.com";
    /* 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";
    /* Download the object as a local file named examplefile.txt and save the file to D:\\localpath. If a file that has the same name already exists in the specified path, the downloaded object overwrites the file. Otherwise, the downloaded object is saved in the path. */
    /* If you do not specify the path of the local file, the downloaded object is saved to the path of the project to which the sample program belongs. */
    std::string FileNametoSave = "D:\\localpath\\examplefile.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);

    /* Download the object as a local file. */
    GetObjectRequest request(BucketName, ObjectName);
    request.setResponseStreamFactory([=]() {return std::make_shared<std::fstream>(FileNametoSave, std::ios_base::out | std::ios_base::in | std::ios_base::trunc| std::ios_base::binary); });

    auto outcome = client.GetObject(request);

    if (outcome.isSuccess()) {    
        std::cout << "GetObjectToFile success" << outcome.result().Metadata().ContentLength() << std::endl;
    }
    else {
        /* Handle exceptions. */
        std::cout << "GetObjectToFile 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;
}

List objects

The following sample code provides an example on how to list objects in a bucket. By default, 100 objects are listed:

#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 name of the bucket. Example: examplebucket. */
    std::string BucketName = "examplebucket";
    /* 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);

    /* List objects. */
    ListObjectsRequest request(BucketName);
    auto outcome = client.ListObjects(request);

    if (!outcome.isSuccess()) {    
        /* Handle exceptions. */
        std::cout << "ListObjects fail" <<
        ",code:" << outcome.error().Code() <<
        ",message:" << outcome.error().Message() <<
        ",requestId:" << outcome.error().RequestId() << std::endl;
        return -1;  
    }
    else {
        for (const auto& object : outcome.result().ObjectSummarys()) {
            std::cout << "object"<<
            ",name:" << object.Key() <<
            ",size:" << object.Size() <<
            ",last modified time:" << object.LastModified() << std::endl;
        }      
    }

    /* Release resources, such as network resources. */
    ShutdownSdk();
    return 0;
}

Delete an object

The following sample code provides an example on how to delete an object:

#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 name of the bucket. Example: examplebucket. */
    std::string BucketName = "examplebucket";
    /* Specify the full path of the object. Example: exampledir/exampleobject.txt. Do not include the bucket name in the full path. */
    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);

    DeleteObjectRequest request(BucketName, ObjectName);

    /* Delete the object. */
    auto outcome = client.DeleteObject(request);

    if (!outcome.isSuccess()) {
        /* Handle exceptions. */
        std::cout << "DeleteObject 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 the operations described in this topic, visit GitHub.
For more information about the API operation that you can call to create a bucket, see PutBucket.
For more information about the API operation that you can call to upload an object, see PutObject.
For more information about the API operation that you can call to download an object, see GetObject.
For more information about the API operation that you can call to list objects, see GetBucket (ListObjects).
For more information about the API operation that you can call to delete an object, see DeleteObject.