Object Storage Service:Asynchronous processing (C# SDK V2)

Notes

The sample code in this topic uses the China (Hangzhou) region (cn-hangzhou) as an example. By default, the public endpoint is used. To access OSS from other Alibaba Cloud services in the same region, use an internal endpoint. For more information about the mappings between OSS regions and endpoints, see Regions and endpoints.

Sample code

The following code provides an example of how to use the C# SDK V2 to transform a document into the required format.

using System.Text;
using OSS = AlibabaCloud.OSS.V2;  // Create an alias for Alibaba Cloud OSS SDK to simplify subsequent use.

var region = "cn-hangzhou";  // Required. The region where the bucket is located. For example, if the bucket is in the China (Hangzhou) region, set the region to cn-hangzhou.
var endpoint = null as string;  // Optional. The endpoint used to access OSS. For example, if the bucket is in the China (Hangzhou) region, set the endpoint to https://oss-cn-hangzhou.aliyuncs.com.
var bucket = "your bucket name";  // Required. The name of the bucket.
var key = "your object key";  // Required. The name of the object that you want to transform.

// Load the default configurations of the OSS SDK. The configurations automatically read credential information (such as AccessKey) from environment variables.
var cfg = OSS.Configuration.LoadDefault();
// Explicitly set the use of environment variables to obtain credentials for identity verification (Format: OSS_ACCESS_KEY_ID, OSS_ACCESS_KEY_SECRET).
cfg.CredentialsProvider = new OSS.Credentials.EnvironmentVariableCredentialsProvider();
// Set the region of the bucket in the configuration.
cfg.Region = region;   
// If an endpoint is specified, it overwrites the default endpoint. 
if(endpoint != null) 
{
    cfg.Endpoint = endpoint;
} 

// Create an OSS client instance using the configuration information.
using var client = new OSS.Client(cfg); 

// Specify the destination bucket to store the transformed file.
var targetBucket = bucket!;
// Specify the key of the transformed file. Add the "process-" prefix for differentiation.
var targetKey = $"process-{key}";
// Construct a document processing style string to define the document transformation parameters.
// This configuration specifies the rule for transforming a source Docx document into a PNG image.
// Format description: doc/convert,target_{target_format},source_{source_format}
var style = "doc/convert,target_png,source_docx";

// Base64-encode the name of the destination bucket.
var targetNameBase64 = Convert.ToBase64String(Encoding.UTF8.GetBytes(targetBucket));
// Base64-encode the key of the destination object.
var targetKeyBase64 = Convert.ToBase64String(Encoding.UTF8.GetBytes(targetKey));

// Construct the complete processing instruction:
// 1. Apply the document transformation style (doc/convert).
// 2. Use the sys/saveas operation to save the result.
//    - b_{Base64-encoded_bucket_name} specifies the destination bucket.
//    - o_{Base64-encoded_key} specifies the destination key.
//    - /notify enables the asynchronous processing mode.
var process = $"{style}|sys/saveas,b_{targetNameBase64},o_{targetKeyBase64}/notify";

// Call the AsyncProcessObjectAsync method to perform the document transformation.
var result = await client.AsyncProcessObjectAsync(new OSS.Models.AsyncProcessObjectRequest()
{
    Bucket = bucket,
    Key = key,
    Process = process
});

// Print the result information.
Console.WriteLine("AsyncProcessObject done");  // Indicates that the operation is complete.
Console.WriteLine($"StatusCode: {result.StatusCode}");  // HTTP status code
Console.WriteLine($"RequestId: {result.RequestId}");  // The request ID, which is used for troubleshooting in Alibaba Cloud.
Console.WriteLine("Response Headers:");  // Response header information.
result.Headers.ToList().ForEach(x => Console.WriteLine(x.Key + " : " + x.Value));  // Traverse and print all response headers.
Console.WriteLine($"ProcessResult: {result.ProcessResult}");  // Output the processing result.

References

• For more information about the asynchronous processing feature, see Asynchronous Processing.

• For the complete sample code for asynchronous processing, see AsyncProcessObject.cs.