Object Storage Service:Download a file (C++ SDK)

Ao chamar a operação GetObject em um bucket, uma das seguintes situações se aplica:

• Se a versão atual do objeto for um marcador de exclusão, o OSS retorna 404 Not Found.

• Caso você especifique o versionId de um objeto no parâmetro de consulta, a versão especificada será retornada. Se definir o versionId como "null", o sistema retorna a versão do objeto que possui um versionId nulo.

• Ao tentar recuperar um marcador de exclusão especificando seu versionId, o OSS retorna 405 Method Not Allowed.

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

int main(void)
{
    /* Initialize the OSS account information. */
            
    /* Set yourEndpoint to the Endpoint of the region where the bucket is located. For example, if the bucket is in the China (Hangzhou) region, set the Endpoint to https://oss-cn-hangzhou.aliyuncs.com. */
    std::string Endpoint = "yourEndpoint";
    /* Set yourRegion to the region where the bucket is located. For example, if the bucket is in the China (Hangzhou) region, set the Region to cn-hangzhou. */
    std::string Region = "yourRegion";
    /* Specify the bucket name, such as examplebucket. */
    std::string BucketName = "examplebucket";
    /* Specify the full path of the object. The full path cannot contain the bucket name, such as exampledir/exampleobject.txt. */
    std::string ObjectName = "exampledir/exampleobject.txt";

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

    ClientConfiguration conf;
    conf.signatureVersion = SignatureVersionType::V4;
    /* Obtain access credentials from environment variables. Before you run this sample code, make sure that the OSS_ACCESS_KEY_ID and OSS_ACCESS_KEY_SECRET environment variables are set. */
    auto credentialsProvider = std::make_shared<EnvironmentVariableCredentialsProvider>();
    OssClient client(Endpoint, credentialsProvider, conf);
    client.SetRegion(Region);

    /* Download the file to the local memory. */
    GetObjectRequest request(BucketName, ObjectName);
    request.setVersionId("yourObjectVersionId");
    auto outcome = client.GetObject(request);
    if (outcome.isSuccess()) {
        std::cout << "getObjectToBuffer" << " success, Content-Length:" << outcome.result().Metadata().ContentLength() << std::endl;
        /* Read the content of the downloaded object. */
        std::string content;
        *(outcome.result().Content()) >> content;
        std::cout << "getObjectToBuffer" << "content:" << content << std::endl;
        /* View the version ID of the downloaded object. */
        std::cout << "versionid:" << outcome.result().VersionId() << std::endl;
    }
    else {
            /* Handle the exception. */
            std::cout << "getObjectToBuffer fail" <<
        ",code:" << outcome.error().Code() <<
        ",message:" << outcome.error().Message() <<
        ",requestId:" << outcome.error().RequestId() << std::endl;
        return -1;
    }

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