tencent cloud

Overview

This document provides an overview of APIs and SDK code samples related to object upload.

Simple operations

API	Operation	Description
PUT Object	Uploading an object	Uploads an object to a bucket.
POST Object	Uploading an object using an HTML form	Uploads an object using an HTML form.
APPEND Object	Appending parts	Uploads an object by appending the object by parts.

Multipart operations

API	Operation	Description
List Multipart Uploads	Querying multipart uploads	Queries in-progress multipart uploads.
Initiate Multipart Upload	Initializing a multipart upload operation	Initializes a multipart upload operation.
Upload Part	Uploading parts	Uploads an object in multiple parts.
List Parts	Querying uploaded parts	Queries the uploaded parts of a multipart upload.
Complete Multipart Upload	Completing a multipart upload	Completes the multipart upload of a file.
Abort Multipart Upload	Aborting a multipart upload	Aborts a multipart upload and deletes the uploaded parts.

SDK API References

For the parameters and method description of all the APIs in the SDK, see API Documentation.

Advanced APIs (Recommended)

Uploading an object

Description

The advanced APIs encapsulate the simple upload and multipart upload APIs and can intelligently select the upload method based on file size. They also support checkpoint restart for resuming interrupted operations.

Note：

• If the file size is less than the multipart upload threshold, simple upload is used. Otherwise, multiple upload is used. The multipart upload threshold is configurable and is 5 MB by default.
• The part size is configurable and is 1 MB by default.
• If your .NET Framework version is 4.0 or earlier, advanced APIs are not available. For more information, please see Backward Compatibility.

Sample code 1. Uploading a local object via advanced API

using COSXML.Model.Object;
using COSXML.Auth;
using COSXML.Transfer;
using System;
using COSXML;
using System.Threading.Tasks;
namespace COSSnippet
{
   public class TransferUploadObjectModel {
      private CosXml cosXml;
      TransferUploadObjectModel() {
       CosXmlConfig config = new CosXmlConfig.Builder()
         .SetRegion("COS_REGION") // Set the default region. For abbreviations of COS regions, visit https://intl.cloud.tencent.com/document/product/436/6224.
         .Build();

       string secretId = "SECRET_ID";   // SecretId of the TencentCloud API. For more information about how to obtain the API key, see https://console.intl.cloud.tencent.com/cam/capi.
       string secretKey = "SECRET_KEY"; // SecretKey of the TencentCloud API. For more information about how to obtain the API key, see https://console.intl.cloud.tencent.com/cam/capi.
       long durationSecond = 600;          // Validity period of the request signature in seconds
       QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
         secretKey, durationSecond);

       this.cosXml = new CosXmlServer(config, qCloudCredentialProvider);
     }
      /// Upload a file via advanced API
     public async Task TransferUploadFile()
     {
       // Initialize TransferConfig
       TransferConfig transferConfig = new TransferConfig();
       // Set the object size threshold for multipart upload to 10 MB. Default value: 5 MB
       transferConfig.DivisionForUpload = 10 * 1024 * 1024;
       // Set the size of each object part for multipart upload to 2 MB. Default value: 1 MB
       transferConfig.SliceSizeForUpload = 2 * 1024 * 1024;

       // Initialize TransferManager
       TransferManager transferManager = new TransferManager(cosXml, transferConfig);
       // Bucket name in the format of `BucketName-APPID`. You can get APPID by referring to https://console.intl.cloud.tencent.com/developer.
       String bucket = "examplebucket-1250000000"; 
       String cosPath = "exampleobject"; // Location identifier of the object in the bucket, i.e., the object key
       String srcPath = @"temp-source-file";// Absolute path to the local file

       // Upload an object
       COSXMLUploadTask uploadTask = new COSXMLUploadTask(bucket, cosPath);
       uploadTask.SetSrcPath(srcPath);

       uploadTask.progressCallback = delegate (long completed, long total)
       {
           Console.WriteLine(String.Format("progress = {0:##.##}%", completed * 100.0 / total));
       };
        try {
         COSXML.Transfer.COSXMLUploadTask.UploadTaskResult result = await 
           transferManager.UploadAsync(uploadTask);
         Console.WriteLine(result.GetResultInfo());
         string eTag = result.eTag;
       } catch (Exception e) {
           Console.WriteLine("CosException: " + e);
       }
      }
      static void Main(string[] args)
     {
       TransferUploadObjectModel m = new TransferUploadObjectModel();
       /// Upload an object via advanced API
       m.TransferUploadFile().Wait();
       // .cssg-methods-pragma
     }
   }
}

Note：

• For the complete sample, go to GitHub.
• After the upload, you can generate a download URL for the uploaded file with the same key. For detailed directions, please see Generating Pre-signed Links. Please note that for private-read files, the download URL is only valid for a limited period of time.

Sample code 2. Uploading binary data

using COSXML.Model.Object;
using COSXML.Auth;
using COSXML.Transfer;
using System;
using COSXML;
namespace COSSnippet
{
   public class TransferUploadObjectModel {
      private CosXml cosXml;
      TransferUploadObjectModel() {
       CosXmlConfig config = new CosXmlConfig.Builder()
         .SetRegion("COS_REGION") // Set the default region. For abbreviations of COS regions, visit https://intl.cloud.tencent.com/document/product/436/6224.
         .Build();

       string secretId = "SECRET_ID";   // SecretId of the TencentCloud API. For more information about how to obtain the API key, see https://console.intl.cloud.tencent.com/cam/capi.
       string secretKey = "SECRET_KEY"; // SecretKey of the TencentCloud API. For more information about how to obtain the API key, see https://console.intl.cloud.tencent.com/cam/capi.
       long durationSecond = 600;          // Validity period of the request signature in seconds
       QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
         secretKey, durationSecond);

       this.cosXml = new CosXmlServer(config, qCloudCredentialProvider);
     }
      /// Upload binary data
     public void TransferUploadBytes()
     {
       try
       {
         // Bucket name in the format of `BucketName-APPID`. You can get APPID by referring to https://console.intl.cloud.tencent.com/developer.
         string bucket = "examplebucket-1250000000";
         string cosPath = "exampleObject"; // Object key
         byte[] data = new byte[1024]; // Binary data
         PutObjectRequest putObjectRequest = new PutObjectRequest(bucket, cosPath, data);
         // Initiate an upload.
         PutObjectResult result = cosXml.PutObject(putObjectRequest);
         Console.WriteLine(result.GetResultInfo());
       }
       catch (COSXML.CosException.CosClientException clientEx)
       {
         // Request failed
         Console.WriteLine("CosClientException: " + clientEx);
       }
       catch (COSXML.CosException.CosServerException serverEx)
       {
         // Request failed
         Console.WriteLine("CosServerException: " + serverEx.GetInfo());
       }
     }
      static void Main(string[] args)
     {
       TransferUploadObjectModel m = new TransferUploadObjectModel();
        /// Upload binary data via an advanced API
       m.TransferUploadBytes();
     }
   }
}

Note：

• For the complete sample, go to GitHub.
• After the upload, you can generate a download URL for the uploaded file with the same key. For detailed directions, please see Generating Pre-signed Links. Please note that for private-read files, the download URL is only valid for a limited period of time.

Sample code 3. Uploading with a file stream

using COSXML.Model.Object;
using COSXML.Utils;
using COSXML.Auth;
using System;
using COSXML;
using System.IO;
namespace COSSnippet
{
   public class PutObjectModel {
      private CosXml cosXml;
      PutObjectModel() {
       CosXmlConfig config = new CosXmlConfig.Builder()
         .SetRegion("COS_REGION") // Set the default region. For abbreviations of COS regions, visit https://intl.cloud.tencent.com/document/product/436/6224. 
         .Build();

       string secretId = "SECRET_ID";   // SecretId of the TencentCloud API. For more information about how to obtain the API key, see https://console.intl.cloud.tencent.com/cam/capi.
       string secretKey = "SECRET_KEY"; // SecretKey of the TencentCloud API. For more information about how to obtain the API key, see https://console.intl.cloud.tencent.com/cam/capi.
       long durationSecond = 600;          // Validity period of the request signature in seconds
       QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
         secretKey, durationSecond);

       this.cosXml = new CosXmlServer(config, qCloudCredentialProvider);
     }

     /// Uploading with a file stream, supported from v5.4.24
     public void PutObjectStream()
     {
       try
       {
         // Bucket name in the format of `BucketName-APPID`. You can get APPID by referring to https://console.intl.cloud.tencent.com/developer.
         string bucket = "examplebucket-1250000000";
         string key = "exampleobject"; // Object key
         string srcPath = @"temp-source-file";// Absolute path of the local file
         // Open the read-only file stream object
         FileStream fileStream = new FileStream(srcPath, FileMode.Open, FileAccess.Read);
         // Assemble the upload request, where offset sendLength is optional
         long offset = 0L;
         long sendLength = fileStream.Length;
         PutObjectRequest request = new PutObjectRequest(bucket, key, fileStream, offset, sendLength);
         // Set the progress callback
         request.SetCosProgressCallback(delegate (long completed, long total)
         {
           Console.WriteLine(String.Format("progress = {0:##.##}%", completed * 100.0 / total));
         });
         // Execute the request
         PutObjectResult result = cosXml.PutObject(request);
         // Close the file stream
         fileStream.Close();
         // Object ETag
         string eTag = result.eTag;
         // crc64ecma value of the object
         string crc64ecma = result.crc64ecma;
         // Print the request result.
         Console.WriteLine(result.GetResultInfo());
       }
       catch (COSXML.CosException.CosClientException clientEx)
       {
         // Request failed
         Console.WriteLine("CosClientException: " + clientEx);
       }
       catch (COSXML.CosException.CosServerException serverEx)
       {
         // Request failed
         Console.WriteLine("CosServerException: " + serverEx.GetInfo());
       }
     }
      static void Main(string[] args)
     {
       PutObjectModel m = new PutObjectModel();
       /// Upload the object with a file stream
       m.PutObjectStream();
     }
   }
}

Note：

• Uploading with a file stream is supported from v5.4.24. To download the latest version of SDK, go to Releases or refer to Getting Started.
• For the version changelog, see GitHub.
• For the complete sample, go to GitHub.
• After the upload, you can generate a download URL for the uploaded file with the same key. For detailed directions, please see Generating Pre-signed Links. Please note that for private-read files, the download URL is only valid for a limited period of time.

Sample code 4. Suspending, resuming, and canceling an upload

To suspend an upload, use the code below:

uploadTask.Pause();

To resume a suspended download, use the code below:

uploadTask.Resume();

To cancel an upload, use the code below:

uploadTask.Cancel();

Note：

For the complete sample, go to GitHub.

Sample code 5. Uploading multiple objects

TransferConfig transferConfig = new TransferConfig();
// Initialize TransferManager
TransferManager transferManager = new TransferManager(cosXml, transferConfig);
// Bucket name in the format of `BucketName-APPID`. You can get APPID by referring to https://console.intl.cloud.tencent.com/developer.
string bucket = "examplebucket-1250000000";
for (int i = 0; i < 5; i++) {
 // Upload an object
 string cosPath = "exampleobject" + i; // Location identifier of an object in the bucket, i.e. the object key
 string srcPath = @"temp-source-file";// Absolute path of the local file
 COSXMLUploadTask uploadTask = new COSXMLUploadTask(bucket, cosPath); 
 uploadTask.SetSrcPath(srcPath);
 await transferManager.UploadAsync(uploadTask);
}

Sample 6. Creating a directory

try
{
 // Bucket name in the format of `BucketName-APPID`. You can get APPID by referring to https://console.intl.cloud.tencent.com/developer.
 string bucket = "examplebucket-1250000000";
 string cosPath = "dir/"; // Object key
 PutObjectRequest putObjectRequest = new PutObjectRequest(bucket, cosPath, new byte[0]);

 cosXml.PutObject(putObjectRequest);
}
catch (COSXML.CosException.CosClientException clientEx)
{
 // Request failed
 Console.WriteLine("CosClientException: " + clientEx);
}
catch (COSXML.CosException.CosServerException serverEx)
{
 // Request failed
 Console.WriteLine("CosServerException: " + serverEx.GetInfo());
}

Note：

• For the complete sample, go to GitHub.
• After the upload, you can generate a download URL for the uploaded file with the same key. For detailed directions, please see Generating Pre-signed Links. Please note that for private-read files, the download URL is only valid for a limited period of time.

Simple Operations

Uploading an object using simple upload

Description

This API (PUT Object) is used to upload an object smaller than 5 GB to a specified bucket. To call this API, you need to have permission to write to the bucket. If the object size is larger than 5 GB, please use Multipart Upload or Advanced APIs for the upload.

Note：

• The key (filename) cannot end with /; otherwise, it will be identified as a folder.
• Each root account (APPID) can have up to 1,000 bucket ACLs and an unlimited number of object ACLs. Do not configure ACLs for an object during upload if you don’t need to control access to it. The object will inherit the permissions of its bucket by default.
• Due to the limitations of the underlying SDK dependent language components, the general upload API may encounter unexpected exceptions in some environments when it is used to upload objects over 2 GB at a time. Therefore, we recommend you use the advanced API or multipart upload to avoid potential problems.

Sample code

try
{
 // Bucket name in the format of `BucketName-APPID`. You can get APPID by referring to https://console.intl.cloud.tencent.com/developer.
 string bucket = "examplebucket-1250000000";
 string key = "exampleobject"; // Object key
 string srcPath = @"temp-source-file";// Absolute path of the local file
  PutObjectRequest request = new PutObjectRequest(bucket, key, srcPath);
 // Set the progress callback
 request.SetCosProgressCallback(delegate (long completed, long total)
 {
   Console.WriteLine(String.Format("progress = {0:##.##}%", completed * 100.0 / total));
 });
 // Execute the request
 PutObjectResult result = cosXml.PutObject(request);
 // Object ETag
 string eTag = result.eTag;
}
catch (COSXML.CosException.CosClientException clientEx)
{
 // Request failed
 Console.WriteLine("CosClientException: " + clientEx);
}
catch (COSXML.CosException.CosServerException serverEx)
{
 // Request failed
 Console.WriteLine("CosServerException: " + serverEx.GetInfo());
}

Note：

• For the complete sample, go to GitHub.
• After the upload, you can generate a download URL for the uploaded file with the same key. For detailed directions, please see Generating Pre-signed Links. Please note that for private-read files, the download URL is only valid for a limited period of time.

Uploading an object using an HTML form

Description

This API is used to upload an object using an HTML form.

Sample code

try
{
 // Bucket name in the format of `BucketName-APPID`. You can get APPID by referring to https://console.intl.cloud.tencent.com/developer.
 string bucket = "examplebucket-1250000000";
 string key = "exampleobject"; // Object key
 string srcPath = @"temp-source-file";// Absolute path of the local file
 PostObjectRequest request = new PostObjectRequest(bucket, key, srcPath);
 // Set the progress callback
 request.SetCosProgressCallback(delegate (long completed, long total)
 {
   Console.WriteLine(String.Format("progress = {0:##.##}%", completed * 100.0 / total));
 });
 // Execute the request
 PostObjectResult result = cosXml.PostObject(request);
 // Request succeeded
 Console.WriteLine(result.GetResultInfo());
}
catch (COSXML.CosException.CosClientException clientEx)
{
 // Request failed
 Console.WriteLine("CosClientException: " + clientEx);
}
catch (COSXML.CosException.CosServerException serverEx)
{
 // Request failed
 Console.WriteLine("CosServerException: " + serverEx.GetInfo());
}

Note：

For the complete sample, go to GitHub.

Appending parts

Description

This API is used to upload an object by appending parts of the object.

Note：

This feature is supported starting from v5.4.22. For the version changelog, see GitHub.

Sample code

try
{
   // Bucket name in the format of `BucketName-APPID`. You can get APPID by referring to https://console.intl.cloud.tencent.com/developer.
   string bucket = "examplebucket-1250000000";
   string key = "exampleobject"; // Object key
   string srcPath = @"temp-source-file";// Absolute path of the local file
    // Append the first part. 0 is passed in for the appending position, and an appendable object is created
   long next_append_position = 0;
   AppendObjectRequest request = new AppendObjectRequest(bucket, key, srcPath, next_append_position);
   // Set the progress callback
   request.SetCosProgressCallback(delegate (long completed, long total)
   {
       Console.WriteLine(String.Format("progress = {0:##.##}%", completed * 100.0 / total));
   });
   AppendObjectResult result = cosXml.AppendObject(request);
   // Get the next appending position
   next_append_position = result.nextAppendPosition;
   Console.WriteLine(result.GetResultInfo());
    // Execute appending and pass in the object end obtained last time
   request = new AppendObjectRequest(bucket, key, srcPath, next_append_position);
   request.SetCosProgressCallback(delegate (long completed, long total)
   {
       Console.WriteLine(String.Format("progress = {0:##.##}%", completed * 100.0 / total));
   });
   result = cosXml.AppendObject(request);
   Console.WriteLine(result.GetResultInfo());
}
catch (COSXML.CosException.CosClientException clientEx)
{
   // Request failed
   Console.WriteLine("CosClientException: " + clientEx);
}
catch (COSXML.CosException.CosServerException serverEx)
{
   // Request failed
   Console.WriteLine("CosServerException: " + serverEx.GetInfo());
}

Note：

For the complete sample, go to GitHub.

Multipart Operations

The multipart upload process is outlined below.

Performing a multipart upload

1. Initialize the multipart upload with Initiate Multipart Upload and get the UploadId.
2. Use the UploadId to upload the parts with Upload Part - Copy.
3. Complete the multipart upload with Complete Multipart Upload.

Resuming a multipart upload

1. If you did not record the UploadId of the multipart upload, you can query the multipart upload job with List Multipart Uploads to get the UploadId of the corresponding file.
2. Use the UploadId to list the uploaded parts with List Parts.
3. Use the UploadId to upload the remaining parts with Upload Part.
4. Complete the multipart upload with Complete Multipart Upload.

Aborting a multipart upload

1. If you did not record the UploadId of the multipart upload, you can query the multipart upload job with List Multipart Uploads to get the UploadId of the corresponding file.
2. Abort the multipart upload and delete the uploaded parts with Abort Multipart Upload.

Querying multipart uploads

Description

This API (List Multipart Uploads) is used to query in-progress multipart uploads in a specified bucket.

Sample code

try
{
 // Bucket name in the format of `BucketName-APPID`. You can get APPID by referring to https://console.intl.cloud.tencent.com/developer.
 string bucket = "examplebucket-1250000000";
 ListMultiUploadsRequest request = new ListMultiUploadsRequest(bucket);
 // Execute the request
 ListMultiUploadsResult result = cosXml.ListMultiUploads(request);
 // Request succeeded
 Console.WriteLine(result.GetResultInfo());
}
catch (COSXML.CosException.CosClientException clientEx)
{
 // Request failed
 Console.WriteLine("CosClientException: " + clientEx);
}
catch (COSXML.CosException.CosServerException serverEx)
{
 // Request failed
 Console.WriteLine("CosServerException: " + serverEx.GetInfo());
}

Note：

For the complete sample, go to GitHub.

Initializing a multipart upload

Description

This API is used to initialize a multipart upload operation and get its uploadId.

Sample code

try
{
 // Bucket name in the format of `BucketName-APPID`. You can get APPID by referring to https://console.intl.cloud.tencent.com/developer.
 string bucket = "examplebucket-1250000000";
 string key = "exampleobject"; // Object key
 InitMultipartUploadRequest request = new InitMultipartUploadRequest(bucket, key);
 // Execute the request
 InitMultipartUploadResult result = cosXml.InitMultipartUpload(request);
 // Request succeeded
 this.uploadId = result.initMultipartUpload.uploadId; // The uploadId to use for subsequent multipart uploads
 Console.WriteLine(result.GetResultInfo());
}
catch (COSXML.CosException.CosClientException clientEx)
{
 // Request failed
 Console.WriteLine("CosClientException: " + clientEx);
}
catch (COSXML.CosException.CosServerException serverEx)
{
 // Request failed
 Console.WriteLine("CosServerException: " + serverEx.GetInfo());
}

Note：

For the complete sample, go to GitHub.

Uploading parts

Description

This API (Upload Part) is used to upload an object in parts.

Sample code

try
{
 // Bucket name in the format of `BucketName-APPID`. You can get APPID by referring to https://console.intl.cloud.tencent.com/developer.
 string bucket = "examplebucket-1250000000";
 string key = "exampleobject"; // Object key
 string uploadId = "exampleUploadId"; // uploadId returned when the multipart upload is initialized
 int partNumber = 1; // Part number, increases incrementally starting from 1
 string srcPath = @"temp-source-file";// Absolute path of the local file
 UploadPartRequest request = new UploadPartRequest(bucket, key, partNumber, 
   uploadId, srcPath, 0, -1);
 // Set the progress callback
 request.SetCosProgressCallback(delegate (long completed, long total)
 {
   Console.WriteLine(String.Format("progress = {0:##.##}%", completed * 100.0 / total));
 });
 // Execute the request
 UploadPartResult result = cosXml.UploadPart(request);
 // Request succeeded
 // Get the ETag of the returned part for subsequent CompleteMultiUploads.
 this.eTag = result.eTag;
 Console.WriteLine(result.GetResultInfo());
}
catch (COSXML.CosException.CosClientException clientEx)
{
 // Request failed
 Console.WriteLine("CosClientException: " + clientEx);
}
catch (COSXML.CosException.CosServerException serverEx)
{
 // Request failed
 Console.WriteLine("CosServerException: " + serverEx.GetInfo());
}

Note：

For the complete sample, go to GitHub.

Querying uploaded parts

Description

This API (List Parts) is used to query the uploaded parts of a multipart upload.

Sample code

try
{
 // Bucket name in the format of `BucketName-APPID`. You can get APPID by referring to https://console.intl.cloud.tencent.com/developer.
 string bucket = "examplebucket-1250000000";
 string key = "exampleobject"; // Object key
 string uploadId = "exampleUploadId"; // uploadId returned when the multipart upload is initialized
 ListPartsRequest request = new ListPartsRequest(bucket, key, uploadId);
 // Execute the request
 ListPartsResult result = cosXml.ListParts(request);
 // Request succeeded
 // List the parts that have been uploaded
 List<COSXML.Model.Tag.ListParts.Part> alreadyUploadParts = result.listParts.parts;
 Console.WriteLine(result.GetResultInfo());
}
catch (COSXML.CosException.CosClientException clientEx)
{
 // Request failed
 Console.WriteLine("CosClientException: " + clientEx);
}
catch (COSXML.CosException.CosServerException serverEx)
{
 // Request failed
 Console.WriteLine("CosServerException: " + serverEx.GetInfo());
}

Note：

For the complete sample, go to GitHub.

Completing a multipart upload

Description

This API (Complete Multipart Upload) is used to complete the multipart upload of a file.

Sample code

try
{
 // Bucket name in the format of `BucketName-APPID`. You can get APPID by referring to https://console.intl.cloud.tencent.com/developer.
 string bucket = "examplebucket-1250000000";
 string key = "exampleobject"; // Object key
 string uploadId = "exampleUploadId"; // uploadId returned when the multipart upload is initialized
 CompleteMultipartUploadRequest request = new CompleteMultipartUploadRequest(bucket, 
   key, uploadId);
 // Concatenate uploaded parts in ascending order by partNumber.
 request.SetPartNumberAndETag(1, this.eTag);
 // Execute the request
 CompleteMultipartUploadResult result = cosXml.CompleteMultiUpload(request);
 // Request succeeded
 Console.WriteLine(result.GetResultInfo());
}
catch (COSXML.CosException.CosClientException clientEx)
{
 // Request failed
 Console.WriteLine("CosClientException: " + clientEx);
}
catch (COSXML.CosException.CosServerException serverEx)
{
 // Request failed
 Console.WriteLine("CosServerException: " + serverEx.GetInfo());
}

Note：

For the complete sample, go to GitHub.

Aborting a multipart upload

Description

This API (Abort Multipart Upload) is used to abort a multipart upload and delete the uploaded parts.

Sample code

try
{
 // Bucket name in the format of `BucketName-APPID`. You can get APPID by referring to https://console.intl.cloud.tencent.com/developer.
 string bucket = "examplebucket-1250000000";
 string key = "exampleobject"; // Object key
 string uploadId = "exampleUploadId"; // uploadId returned when the multipart upload is initialized
 AbortMultipartUploadRequest request = new AbortMultipartUploadRequest(bucket, key, uploadId);
 // Execute the request
 AbortMultipartUploadResult result = cosXml.AbortMultiUpload(request);
 // Request succeeded
 Console.WriteLine(result.GetResultInfo());
}
catch (COSXML.CosException.CosClientException clientEx)
{
 // Request failed
 Console.WriteLine("CosClientException: " + clientEx);
}
catch (COSXML.CosException.CosServerException serverEx)
{
 // Request failed
 Console.WriteLine("CosServerException: " + serverEx.GetInfo());
}

Note：

For the complete sample, go to GitHub.