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Object Storage Service:Upload callbacks

Last Updated:Sep 25, 2023

After an object is uploaded, Object Storage Service (OSS) can start a callback process for the application server. To configure upload callbacks, you must add the required callback parameters to the upload request that is sent to OSS.

Usage notes

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

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

Sample code

The following code provides an example on how to configure upload callbacks:

#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 = "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 of the object. Example: exampledir/exampleobject.txt. */
    std::string ObjectName = "exampledir/exampleobject.txt";
    /* Specify the URL of the callback server. */
    std::string ServerName = "https://example.aliyundoc.com:23450";

     /* 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);
    std::shared_ptr<std::iostream> content = std::make_shared<std::stringstream>();
    *content << "Thank you for using Aliyun Object Storage Service!";

    /* Configure the upload callback parameters. */
    std::string callbackBody = "bucket=${bucket}&object=${object}&etag=${etag}&size=${size}&mimeType=${mimeType}&my_var1=${x:var1}";
    ObjectCallbackBuilder builder(ServerName, callbackBody, "", ObjectCallbackBuilder::Type::URL);
    std::string value = builder.build();
    ObjectCallbackVariableBuilder varBuilder;
    varBuilder.addCallbackVariable("x:var1", "value1");
    std::string varValue = varBuilder.build();
    PutObjectRequest request(BucketName, ObjectName, content);
    request.MetaData().addHeader("x-oss-callback", value);
    request.MetaData().addHeader("x-oss-callback-var", varValue);
    auto outcome = client.PutObject(request);

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

References

For more information about the API operation that you can call to configure upload callbacks, see Callback.