c# - 使用 C# 从 S3 Bucket 下载对象

Question

我正尝试从面临以下问题的 S3 存储桶中下载对象 请求中包含的安全 token 无效。 请检查并更正错误的地方。

下面是我的代码 1. 获取临时凭证:

main()    
{
    string path = "http://XXX.XXX.XXX./latest/meta-data/iam/security-credentials/EC2_WLMA_Permissions";

                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(path);
                request.Method = "GET";
                request.ContentType = "application/json";
                HttpWebResponse response = request.GetResponse() as HttpWebResponse;
                string result = string.Empty;
                using (StreamReader reader = new StreamReader(response.GetResponseStream()))
                {
                    result = reader.ReadToEnd();
                    dynamic metaData = JsonConvert.DeserializeObject(result);
                    _awsAccessKeyId = metaData.AccessKeyId;
                    _awsSecretAccessKey = metaData.SecretAccessKey;
                }
}

1. 创建 SessionAWSCredentials 实例:

   SessionAWSCredentials tempCredentials =
                    GetTemporaryCredentials(_awsAccessKeyId, _awsSecretAccessKey);
   

   //GetTemporaryCredentials方法:

      private static SessionAWSCredentials GetTemporaryCredentials(
                       string accessKeyId, string secretAccessKeyId)
       {             
   
           AmazonSecurityTokenServiceClient stsClient =
           new AmazonSecurityTokenServiceClient(accessKeyId,
                                                    secretAccessKeyId);
           Console.WriteLine(stsClient.ToString());
           GetSessionTokenRequest getSessionTokenRequest =
                                            new GetSessionTokenRequest();
   
           getSessionTokenRequest.DurationSeconds = 7200; // seconds
           GetSessionTokenResponse sessionTokenResponse =
                         stsClient.GetSessionToken(getSessionTokenRequest);
   
           Console.WriteLine(sessionTokenResponse.ToString());
           Credentials credentials = sessionTokenResponse.Credentials;
           Console.WriteLine(credentials.ToString());
   
           SessionAWSCredentials sessionCredentials =
               new SessionAWSCredentials(credentials.AccessKeyId,
                                         credentials.SecretAccessKey,
                                         credentials.SessionToken);
   
   
           return sessionCredentials;
       }
   

2. 使用 AmazonS3Client 从 S3 获取文件:

   using (IAmazonS3 client = new AmazonS3Client(tempCredentials,RegionEndpoint.USEast1))                        
       {
                       GetObjectRequest request = new GetObjectRequest();
                       request.BucketName = "bucketName" + @"/" + "foldername";
                       request.Key = "Terms.docx";
                       GetObjectResponse response = client.GetObject(request);
                       response.WriteResponseStreamToFile("C:\\MyFile.docx");
       }
   

Answer 1

我们做了一些更简单的事情来连接 S3(下载和上传)

看起来您采用了更复杂的方法。您应该尝试使用 TransferUtility 代替:

TransferUtility fileTransferUtility =
    new TransferUtility(
        new AmazonS3Client("ACCESS-KEY-ID", "SECRET-ACCESS-KEY", Amazon.RegionEndpoint.CACentral1));

// Note the 'fileName' is the 'key' of the object in S3 (which is usually just the file name)
fileTransferUtility.Download(filePath, "my-bucket-name", fileName);

---

注意 TransferUtility.Download() 返回 void，因为它将文件下载到 filePath 参数中指定的路径。这可能与您的预期略有不同，但您仍然可以在之后打开指向该路径的 FileStream 并根据需要操作文件。例如:

using (FileStream fileDownloaded = new FileStream(filePath, FileMode.Open, FileAccess.Read))
{
    // Do stuff with our newly downloaded file
}