Download Objects from S3 Bucket using c#

Question

Im trying to download object from S3 bucket facing below issue The Security token included in the request is Invalid . Please check and correct where is the mistake.

Below is my code 1. Get Temporary credentails:

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;
                }
}

2. Create SessionAWSCredentials instance:

   SessionAWSCredentials tempCredentials =
                    GetTemporaryCredentials(_awsAccessKeyId, _awsSecretAccessKey);
   

   //GetTemporaryCredentials method:

      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;
       }
   

3. Get files from S3 using AmazonS3Client:

   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

We do something a little simpler for interfacing with S3 (downloads and uploads)

It looks like you went the more complex approach. You should try just using the TransferUtility instead:

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);

---

NOTE: TransferUtility.Download() returns void because it downloads the file to the path specified in the filePath argument. This may be a little different than what you were expecting but you can still open a FileStream to that path afterwards and manipulate the file all you want. For example:

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