.NET SDK 手册

文件管理

在 NOS 中，用户可以通过一系列的接口管理桶 (Bucket) 中的文件 (Object)，比如 ListObjects，DeleteObject，CopyObject，DoesObjectExist 等。

列出桶中的文件

您可以使用 NosClient.ListObjects 列出存储中间中的文件:

// 初始化 NosClient
var nosClient = new NosClient(endpoint, accessKeyId, accessKeySecret);

/// <summary>
/// 列出指定存储空间下的文件的摘要信息
/// </summary>
/// <param name="bucket">桶名</param>
public void ListObjects(string bucket)
{
  try
  {
    var keys = new List<string>();
    ObjectListing result = null;
    string nextMarker = string.Empty;
  do
  {
    var listObjectsRequest = new ListObjectsRequest(bucket)
    {
      Marker = nextMarker,
      MaxKeys = 100
    };
  result = nosClient.ListObjects(listObjectsRequest);

  foreach (var summary in result.ObjectSummarise)
  {
    Console.WriteLine(summary.Key);
    keys.Add(summary.Key);
  }

  nextMarker = result.NextMarker;
  } while (result.IsTruncated);

  Console.WriteLine("List objects of bucket:{0} succeeded ", bucket);
  }
  catch (NosException ex)
  {
    Console.WriteLine("Failed with HTTPStatus: {0}; \nErrorCode: {1}; \nErrorMessage: {2}; \nRequestID:{3}; \nResource:{4}",
    ex.StatusCode, ex.ErrorCode, ex.Message, ex.RequestId, ex.Resource);
  }
  catch (Exception ex)
  {
    Console.WriteLine("Failed with error info: {0}", ex.Message);
  }
}

上述代码中的 ListObjectsRequest 中的可选参数如下所示:

参数说明
Delimiter用于对 Object 名字进行分组的字符。所有名字包含指定的前缀且第一次出现 delimiter 字符之间的 object 作为一组元素。限制长度为 10。
Prefix限定返回的 object key 必须以 prefix 作为前缀。注意使用 prefix 查询时，返回的 key 中仍会包含 prefix
MaxKeys限定此次返回 object 的最大数，如果不设定，默认为 100
Marker设定结果从 marker 之后按字母排序的第一个开始返回

Note

  1. 上述表中的参数都是可选参数。
  2. 会列出文件、目录以及目录中的文件。

判断文件是否存在

您可以使用 NosClient.DoesObjectExist 判断文件是否存在:

// 初始化 NosClient
var nosClient = new NosClient(endpoint, accessKeyId, accessKeySecret);

/// <summary>
/// 判断指定桶内是否存在指定文件
/// </summary>
/// <param name="bucket">桶名</param>
/// <param name="key">对象名</param>
public void DoesObjectExist(string bucket, string key)
{
  try
  {
    var exist = nosClient.DoesObjectExist(bucket, key);
    Console.WriteLine("exist ? " + exist);
  }
  catch (NosException ex)
  {
    Console.WriteLine("Failed with HTTPStatus: {0}; \nErrorCode: {1}; \nErrorMessage: {2}; \nRequestID:{3}; \nResource:{4}",
    ex.StatusCode, ex.ErrorCode, ex.Message, ex.RequestId, ex.Resource);
  }
  catch (Exception ex)
  {
    Console.WriteLine("Failed with error info: {0}", ex.Message);
  }
}

Attention

  1. 默认不能对目录进行判断。
  2. 判断目录内文件是否存在时参数 key 格式为 "dir1/file1"。

删除单个文件

您可以使用 NosClient.DeleteObject 删除单个需要删除的文件，删除目录时目录内不能有文件:

// 初始化 NosClient
var nosClient = new NosClient(endpoint, accessKeyId, accessKeySecret);

/// <summary>
/// 删除单个文件
/// </summary>
/// <param name="bucket">桶名</param>
/// <param name="key">对象名</param>
public void DeleteObject(string bucket, string key)
{
  try
  {
    nosClient.DeleteObject(bucket, key);
    Console.WriteLine("Delete object succeeded");
  }
  catch (NosException ex)
  {
    Console.WriteLine("Failed with HTTPStatus: {0}; \nErrorCode: {1}; \nErrorMessage: {2}; \nRequestID:{3}; \nResource:{4}",
    ex.StatusCode, ex.ErrorCode, ex.Message, ex.RequestId, ex.Resource);
  }
  catch (Exception ex)
  {
    Console.WriteLine("Failed with error info: {0}", ex.Message);
  }
}

Note

参数 key 书写格式：

  1. key 为空目录时格式为 "dir1/"。
  2. key 为目录内文件时格式为 "dir1/file1"。

删除多个文件

您可以使用 NosClient.DeleteObjects 批量删除文件，默认会删除当前桶内所有文件、目录以及目录内文件:

// 初始化 NosClient
var nosClient = new NosClient(endpoint, accessKeyId, accessKeySecret);

/// <summary>
/// 删除多个文件
/// </summary>
/// <param name="bucket">桶名</param>
public void DeleteObjects(string bucket)
{
  try
  {
    var keys = new List<string>();
    var listObjectsResult = nosClient.ListObjects(bucket);
    foreach (var summary in listObjectsResult.ObjectSummarise)
    {
      keys.Add(summary.Key);
    }
    var result = nosClient.DeleteObjects(bucket, keys, false);

    Console.WriteLine("Delete objects succeeded");

    if (result.Keys != null)
    {
      foreach (var deletedObject in result.Keys)
      {
        Console.Write("\n[Deleted]: " + deletedObject.Key);
      }
    }
    if (result.Error != null)
    {
      foreach (var deleteError in result.Error)
      {
        Console.Write("\n[Error]: " + deleteError.Key + "\t" + deleteError.Code + "\t" + deleteError.Message);
      }
    }
  }
  catch (NosException ex)
  {
    Console.WriteLine("Failed with HTTPStatus: {0}; \nErrorCode: {1}; \nErrorMessage: {2}; \nRequestID:{3}; \nResource:{4}",
    ex.StatusCode, ex.ErrorCode, ex.Message, ex.RequestId, ex.Resource);
  }
  catch (Exception ex)
  {
    Console.WriteLine("Failed with error info: {0}", ex.Message);
  }
}

Note

可以结合列出桶内文件的接口进行使用。

拷贝文件

您可以使用 NosClient.CopyObject 拷贝文件:

// 初始化 NosClient
var nosClient = new NosClient(endpoint, accessKeyId, accessKeySecret);

/// <summary>
/// 拷贝文件
/// </summary>
/// <param name="sourceBucket">源桶名</param>
/// <param name="sourceKey">源对象名</param>
/// <param name="targetBucket">目标桶名</param>
/// <param name="targetKey">目标对象名</param>
public void CopyObject(string sourceBucket, string sourceKey, string targetBucket, string targetKey)
{
  try
  {
    var request = new CopyObjectRequest(sourceBucket, sourceKey, targetBucket, targetKey);
    nosClient.CopyObject(request);
    Console.WriteLine("Copy object succeeded");
  }
  catch (NosException ex)
  {
    Console.WriteLine("Failed with HTTPStatus: {0}; \nErrorCode: {1}; \nErrorMessage: {2}; \nRequestID:{3}; \nResource:{4}",
    ex.StatusCode, ex.ErrorCode, ex.Message, ex.RequestId, ex.Resource);
  }
  catch (Exception ex)
  {
    Console.WriteLine("Failed with error info: {0}", ex.Message);
  }
}

Attention

支持跨桶的文件 copy

移动文件

您可以使用 NosClient.MoveObject 移动文件:

// 初始化 NosClient
var nosClient = new NosClient(endpoint, accessKeyId, accessKeySecret);

/// <summary>
/// 移动文件
/// </summary>
/// <param name="sourceBucket">源桶名</param>
/// <param name="sourceKey">源对象名</param>
/// <param name="targetBucket">目标桶名</param>
/// <param name="targetKey">目标对象名</param>
public void MoveObject(string sourceBucket, string sourceKey, string targetBucket, string targetKey)
{
  try
  {
    var request = new MoveObjectRequest(sourceBucket, sourceKey, targetBucket, targetKey);
    nosClient.MoveObject(request);
    Console.WriteLine("Move object succeeded");
  }
  catch (NosException ex)
  {
    Console.WriteLine("Failed with HTTPStatus: {0}; \nErrorCode: {1}; \nErrorMessage: {2}; \nRequestID:{3}; \nResource:{4}",
    ex.StatusCode, ex.ErrorCode, ex.Message, ex.RequestId, ex.Resource);
  }
  catch (Exception ex)
  {
    Console.WriteLine("Failed with error info: {0}", ex.Message);
  }
}

Attention

暂时不支持跨桶的文件 move

修改文件元信息

暂时不提供此类方法

获取文件的文件元信息

您可以使用 NosClient.GetObjectMetadata 获取对象的元数据信息:

// 初始化 NosClient
var nosClient = new NosClient(endpoint, accessKeyId, accessKeySecret);

/// <summary>
/// 获取文件的文件元信息
/// </summary>
/// <param name="bucket">桶名</param>
/// <param name="key">对象名</param>
public void GetObjectMetadata(string bucket, string key)
{
  try
  {
    var objectMetadata = nosClient.GetObjectMetadata(bucket, key);
    Console.WriteLine("Get Object Metadata succeeded");
  }
  catch (NosException ex)
  {
    Console.WriteLine("Failed with HTTPStatus: {0}; \nErrorCode: {1}; \nErrorMessage: {2}; \nRequestID:{3}; \nResource:{4}",
    ex.StatusCode, ex.ErrorCode, ex.Message, ex.RequestId, ex.Resource);
  }
  catch (Exception ex)
  {
  Console.WriteLine("Failed with error info: {0}", ex.Message);
  }
}