3. 快速入门¶

使用S3 C# SDK前，您可以先参照 API 手册熟悉NOS的基本概念，如Bucket、Object、EndPoint、AccessKeyId和AccessKeySecret等。本节您将看到如何快速的使用S3 C# SDK，完成常用的操作，上传文件、下载文件等。

3.1. 常用类¶

常用类	备注
AmazonS3Client	NOS客户端类，用户通过AmazonS3Client调用服务
AmazonException	NOS异常，在调用过程中去捕获这个异常，查看失败原因

3.2. 基本操作¶

3.2.1. 上传文件¶

对象（Object）是NOS中最基本的数据单元，您可以把它简单的理解为文件，以下代码可以实现简单的对象上传:

 public void PutObjectByFilePath(string bucket, string key, string filePath)
{
    PutObjectRequest putObjectRequest = new PutObjectRequest()
    {
        BucketName = bucket,
        Key = key,
        FilePath = filePath,
    };

    try
    {
        PutObjectResponse resp = s3Client.PutObject(putObjectRequest);
    }
    catch (AmazonS3Exception ex)
    {
        Console.WriteLine("Failed with HTTPStatus: {0}; \nErrorCode: {1}; \nErrorMessage: {2}; \nRequestID:{3};",
        ex.StatusCode, ex.ErrorCode, ex.Message, ex.RequestId);
    }
    catch (Exception ex)
    {
        Console.WriteLine("Failed with error info: {0}", ex.Message);
    }

}

Attention

对象命名规则请参见 API 手册对象
更多的上传文件信息，请参见 S3-C#-SDK 上传文件

3.2.2. 下载文件¶

上传对象成功之后，您可以读取它的内容，以下代码可以实现文件的下载:

public void GetObject(string bucket,string key){
    GetObjectRequest request = new GetObjectRequest
    {
        BucketName = bucket,
        Key = key
    };
    try
    {
        using (GetObjectResponse response = s3Client.GetObject(request))
        {
            using (StreamReader reader = new StreamReader(response.ResponseStream))
            {
                string contents = reader.ReadToEnd();
                Console.WriteLine(" Object   - " + response.Key);
                Console.WriteLine(" Contents - " + contents);
            }
        }

    } catch(AmazonS3Exception ex){
        Console.WriteLine("Failed with HTTPStatus: {0}; \nErrorCode: {1}; \nErrorMessage: {2}; \nRequestID:{3};",
        ex.StatusCode, ex.ErrorCode, ex.Message, ex.RequestId);
    } catch(Exception ex){
        Console.WriteLine("Failed with error info: {0}", ex.Message);
    }

}

更多的下载文件信息，请参见 S3 C# SDK 下载文件

3.2.3. 列举文件¶

当上传文件成功之后，可以查看桶中包含的文件列表，以下代码展示如何列举桶内的文件:

public void ListObjects(string bucketName){
    try
    {
        var keys = new List<string>();
        ListObjectsResponse result = null;
        string nextMarker = string.Empty;
        do
        {
            var listObjectsRequest = new ListObjectsRequest()
            {
                BucketName = bucketName,
                Marker = nextMarker,
                MaxKeys = 5
            };
            result = s3Client.ListObjects(listObjectsRequest);

            foreach (var obj in result.S3Objects)
            {
                Console.WriteLine(obj.Key);
            }

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

        Console.WriteLine("List objects of bucket:{0} succeeded ", bucketName);
    }
    catch (AmazonS3Exception ex)
    {
        Console.WriteLine("Failed with HTTPStatus: {0}; \nErrorCode: {1}; \nErrorMessage: {2}; \nRequestID:{3};",
            ex.StatusCode, ex.ErrorCode, ex.Message, ex.RequestId);
    }
    catch (Exception ex)
    {
        Console.WriteLine("Failed with error info: {0}", ex.Message);
    }
}

Note

上面的代码默认列举100个object

更多的管理文件信息，请参见 S3 C# SDK 文件管理

3.2.4. 删除文件¶

文件上传成功后，可以指定删除桶中的文件，以下代码实现桶中文件的删除:

public void DeleteObject(string bucketNaame, string key)
{
    try
    {
        var resp = s3Client.DeleteObject(bucketNaame,key);
        Console.WriteLine("StatusCode : {0}", resp.HttpStatusCode);
    }
    catch (AmazonS3Exception ex)
    {
        Console.WriteLine("Failed with HTTPStatus: {0}; \nErrorCode: {1}; \nErrorMessage: {2}; \nRequestID:{3};",
            ex.StatusCode, ex.ErrorCode, ex.Message, ex.RequestId);
    }
    catch (Exception ex)
    {
        Console.WriteLine("Failed with error info: {0}", ex.Message);
    }
}

3.2.5. 返回结果处理¶

S3 提供的所有接口都是有返回值的，如果你关心，那么就接住返回值，然后取你想要的信息，如果不关注，那么就不用获取

例如:

try
{
    var request = new CopyObjectRequest(){
        SourceBucket = sourceBucket,
        SourceKey = sourceKey,
        DestinationBucket = targetBucket,
        DestinationKey = targetKey
    };
    s3Client.CopyObject(request);
    Console.WriteLine("Copy object succeeded");
}
catch (AmazonS3Exception ex)
{
    Console.WriteLine("Failed with HTTPStatus: {0}; \nErrorCode: {1}; \nErrorMessage: {2}; \nRequestID:{3};",
        ex.StatusCode, ex.ErrorCode, ex.Message, ex.RequestId);
}
catch (Exception ex)
{
    Console.WriteLine("Failed with error info: {0}", ex.Message);
}