Object Storage Service:Download progress bar (C++ SDK)

Observações

• Neste tópico, usamos o endpoint público da região China (Hangzhou). Para acessar o OSS a partir de outros service da Alibaba Cloud na mesma região do OSS, use um endpoint interno. Para mais informações sobre regiões e endpoints do OSS, consulte Regions and endpoints.

• Este tópico demonstra como crie uma instância do OSSClient com um endpoint do OSS. Para configurações alternativas, como usar um domínio personalizado ou se autenticar com credenciais do Security Token Service (STS), consulte Create an OssClient instance.

Código de exemplo

O código a seguir mostra como exibir o progresso do baixe.

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

void ProgressCallback(size_t increment, int64_t transfered, int64_t total, void* userData)
{
    // increment: the size of data received in this callback.
    // transfered: the size of data that has been received.
    // total: the total size of the file to download.
    std::cout << "ProgressCallback[" << userData << "] => " <<
                 increment <<" ," << transfered << "," << total << std::endl;
}

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. Example: examplebucket. */
    std::string BucketName = "examplebucket";
    /* Specify the full path of the object. The full path cannot contain the bucket name. Example: 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);
  
    /* Get the file. */
    GetObjectRequest request(BucketName, ObjectName);
    TransferProgress progressCallback = { ProgressCallback , nullptr };
    request.setTransferProgress(progressCallback);

    auto outcome = client.GetObject(request);

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

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

Referências

Para o código de exemplo completo que mostra como usar uma barra de progresso no baixe de arquivos, consulte o exemplo no GitHub.