6. 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。

6.1. 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

6.2. 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);
    }
}

6.3. 删除单个文件

您可以使用NosClient.DeleteObject删除单个需要删除的文件:

// 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);
    }
}

6.4. 删除多个文件

您可以使用NosClient.DeleteObjects批量删除文件:

// 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);
            break;
        }
        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);
    }
}

6.5. 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

1. 支持跨桶的文件copy

6.6. 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

1. 暂时不支持跨桶的文件move

6.7. 修改文件元信息

暂时不提供此类方法

6.8. 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);
    }
}