Object Storage Service:Initialize an OSSClient instance for using OSS SDK for C++

Create an OSSClient instance

#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";
    
    /* Initialize resources, such as network resources. */
    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);

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

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

int main(void)
{
    /* Initialize the 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";
    
    /* 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);   

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

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

int main(void)
{
    /* Initialize the information about the account that is used to access OSS. */
            
    /* Set yourEndpoint to the custom domain name that you want to use. */
    std::string Endpoint = "yourEndpoint";
    
    /* Initialize resources, such as network resources. */
    InitializeSdk();

    ClientConfiguration conf;
    conf.isCname = true;
    /* 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);   

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

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

int main(void)
{
    /* 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";
        
    /* 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 temporary AccessKey pair and security token are configured by using the environment variables. */
    auto credentialsProvider = std::make_shared<EnvironmentVariableCredentialsProvider>();
    OssClient client(Endpoint, credentialsProvider, conf); 

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

Configure the OSSClient instance

ClientConfiguration is a configuration class of OSSClient. You can use ClientConfiguration to configure parameters, such as userAgent, connectTimeoutMs, and maxConnections.

You can configure parameters by using OSSClient. The following table describes the parameters.

Configure a timeout period

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

int main(void)
{
    /* Initialize the 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";
    
    /* Initialize resources, such as network resources. */
    InitializeSdk();
    ClientConfiguration conf;

    /* Specify the maximum number of connections. Default value: 16. */
    conf.maxConnections = 20;

    /* Specify the request timeout period. The connection is closed if no data is received during the timeout period. Unit: milliseconds. Default value: 10000. */
    conf.requestTimeoutMs = 8000;

    /* Specify the timeout period to establish a connection. Unit: milliseconds. Default value: 5000. */
    conf.connectTimeoutMs = 8000;

    /* 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);  

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

Configure SSL-based authentication

By default, SSL-based authentication is enabled in OSS SDK for C++ V1.8.2 and later. If SSL-based authentication fails, check whether the path of the SSL certificate is correct or disable SSL-based authentication.

The following sample code provides an example on how to configure SSL-based authentication:

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

int main(void)
{
    /* Initialize the 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";
    
    /* Initialize resources, such as network resources. */
    InitializeSdk();
    ClientConfiguration conf;

    /* Configure SSL-based authentication. Default value: true. The value true specifies that SSL-based authentication is enabled. */
    conf.verifySSL = true;

    /* Specify the root path of the CA certificate. This parameter is valid if verifySSL is set to true. By default, this parameter is left empty. */
    conf.caPath = "/etc/ssl/certs/";

    /* Specify the path of the CA certificate. This parameter is valid if verifySSL is set to true. By default, this parameter is left empty. */
    conf.caFile = "/etc/ssl/certs/ca-certificates.crt";;

    /* 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);  

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

Configure bandwidth throttling

#include <alibabacloud/oss/OssClient.h>
#include <alibabacloud/oss/client/RateLimiter.h>

using namespace AlibabaCloud::OSS;

class UserRateLimiter : public RateLimiter
{
public:
    UserRateLimiter() : rate_(0) {};
    ~UserRateLimiter() {};
    virtual void setRate(int rate) { rate_ = rate; };
    virtual int Rate() const { return rate_; };
private:
    int rate_;
};

int main(void)
{
    /* Initialize the 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. 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;

    auto sendrateLimiter = std::make_shared<UserRateLimiter>();
    auto recvrateLimiter = std::make_shared<UserRateLimiter>();
    conf.sendRateLimiter = sendrateLimiter;
    conf.recvRateLimiter = recvrateLimiter;

    /* 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);

    /* Configure bandwidth throttling for the download. Unit: KB/s. */
    recvrateLimiter->setRate(256);

    /* Configure bandwidth throttling for the upload. Unit: KB/s. */
    sendrateLimiter->setRate(256);

    /* Upload the object. Specify the full path of the local file. */
    auto outcome = client.PutObject(BucketName, ObjectName, "yourLocalFilename");  

    /* Update the speed limit during the upload. Unit: KB/s. */
    sendrateLimiter->setRate(300);

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

Configure a retry policy

The following sample code provides an example on how to configure a retry policy:

#include <alibabacloud/oss/OssClient.h>
#include <alibabacloud/oss/client/RetryStrategy.h>

using namespace AlibabaCloud::OSS;

class UserRetryStrategy : public RetryStrategy
{
public:

    /* maxRetries indicates the maximum number of allowed retry attempts. scaleFactor indicates the factor that is used to calculate the waiting time before a retry is attempted. */
    UserRetryStrategy(long maxRetries = 3, long scaleFactor = 300) :
        m_scaleFactor(scaleFactor), m_maxRetries(maxRetries)  
    {}

    /* You can specify the shouldRetry function to determine whether to retry a request. */
    bool shouldRetry(const Error & error, long attemptedRetries) const;

    /* You can specify the calcDelayTimeMs function to calculate the waiting time before a retry is attempted. */
    long calcDelayTimeMs(const Error & error, long attemptedRetries) const;

private:
    long m_scaleFactor;
    long m_maxRetries;
};

bool UserRetryStrategy::shouldRetry(const Error & error, long attemptedRetries) const
{    
    if (attemptedRetries >= m_maxRetries)
        return false;

    long responseCode = error.Status();

    //http code
    if ((responseCode == 403 && error.Message().find("RequestTimeTooSkewed") != std::string::npos) ||
        (responseCode > 499 && responseCode < 599)) {
        return true;
    }
    else {
        switch (responseCode)
        {
        //curl error code
        case (ERROR_CURL_BASE + 7):  //CURLE_COULDNT_CONNECT
        case (ERROR_CURL_BASE + 18): //CURLE_PARTIAL_FILE
        case (ERROR_CURL_BASE + 23): //CURLE_WRITE_ERROR
        case (ERROR_CURL_BASE + 28): //CURLE_OPERATION_TIMEDOUT
        case (ERROR_CURL_BASE + 52): //CURLE_GOT_NOTHING
        case (ERROR_CURL_BASE + 55): //CURLE_SEND_ERROR
        case (ERROR_CURL_BASE + 56): //CURLE_RECV_ERROR
            return true;
        default:
            break;
        };
    }

    return false;
}

long UserRetryStrategy::calcDelayTimeMs(const Error & error, long attemptedRetries) const
{
    return (1 << attemptedRetries) * m_scaleFactor;
}

int main(void)
{
    /* Initialize the 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";
    
    /* Initialize resources, such as network resources. */
    InitializeSdk();
    ClientConfiguration conf;

    /* Specify the maximum number of allowed retry attempts if a request fails. Default value: 3. */
    auto defaultRetryStrategy = std::make_shared<UserRetryStrategy>(5);
    conf.retryStrategy = defaultRetryStrategy;

    /* 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);  

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

Configure a proxy server

The following sample code provides an example on how to configure a proxy server:

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

int main(void)
{
    /* Initialize the 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";
    
    /* Initialize resources, such as network resources. */
    InitializeSdk();
    ClientConfiguration conf;

    /* Specify the address of the proxy server. */
    conf.proxyHost = "yourProxyHost";

    /* Set the port for the proxy server. */
    conf.proxyPort = 1234;

    /* Optional. Specify the username for proxy server authentication. */
    conf.proxyUserName = "yourProxyUserName";

    /* Optional. Specify the password for proxy server authentication. */
    conf.proxyPassword = "yourProxyPassword";

    /* 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);  

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