Restore an archived copy of an object back into an Amazon S3 bucket using an Amazon SDK

    using System;
    using System.Threading.Tasks;
    using Amazon;
    using Amazon.S3;
    using Amazon.S3.Model;

    public class RestoreArchivedObject
    {
        public static void Main()
        {
            string bucketName = "doc-example-bucket";
            string objectKey = "archived-object.txt";

            // Specify your bucket region (an example region is shown).
            RegionEndpoint bucketRegion = RegionEndpoint.USWest2;

            IAmazonS3 client = new AmazonS3Client(bucketRegion);
            RestoreObjectAsync(client, bucketName, objectKey).Wait();
        }

        /// <summary>
        /// This method restores an archived object from an Amazon S3 bucket.
        /// </summary>
        /// <param name="client">The initialized Amazon S3 client object used to call
        /// RestoreObjectAsync.</param>
        /// <param name="bucketName">A string representing the name of the
        /// bucket where the object was located before it was archived.</param>
        /// <param name="objectKey">A string representing the name of the
        /// archived object to restore.</param>
        public static async Task RestoreObjectAsync(IAmazonS3 client, string bucketName, string objectKey)
        {
            try
            {
                var restoreRequest = new RestoreObjectRequest
                {
                    BucketName = bucketName,
                    Key = objectKey,
                    Days = 2,
                };
                RestoreObjectResponse response = await client.RestoreObjectAsync(restoreRequest);

                // Check the status of the restoration.
                await CheckRestorationStatusAsync(client, bucketName, objectKey);
            }
            catch (AmazonS3Exception amazonS3Exception)
            {
                Console.WriteLine($"Error: {amazonS3Exception.Message}");
            }
        }

        /// <summary>
        /// This method retrieves the status of the object's restoration.
        /// </summary>
        /// <param name="client">The initialized Amazon S3 client object used to call
        /// GetObjectMetadataAsync.</param>
        /// <param name="bucketName">A string representing the name of the Amazon
        /// S3 bucket which contains the archived object.</param>
        /// <param name="objectKey">A string representing the name of the
        /// archived object you want to restore.</param>
        public static async Task CheckRestorationStatusAsync(IAmazonS3 client, string bucketName, string objectKey)
        {
            GetObjectMetadataRequest metadataRequest = new()
            {
                BucketName = bucketName,
                Key = objectKey,
            };

            GetObjectMetadataResponse response = await client.GetObjectMetadataAsync(metadataRequest);

            var restStatus = response.RestoreInProgress ? "in-progress" : "finished or failed";
            Console.WriteLine($"Restoration status: {restStatus}");
        }
    }

    public static void restoreS3Object(S3Client s3, String bucketName, String keyName, String expectedBucketOwner) {

        try {
            RestoreRequest restoreRequest = RestoreRequest.builder()
                .days(10)
                .glacierJobParameters(GlacierJobParameters.builder().tier(Tier.STANDARD).build())
                .build();

            RestoreObjectRequest objectRequest = RestoreObjectRequest.builder()
                .expectedBucketOwner(expectedBucketOwner)
                .bucket(bucketName)
                .key(keyName)
                .restoreRequest(restoreRequest)
                .build();

            s3.restoreObject(objectRequest);

        } catch (S3Exception e) {
            System.err.println(e.awsErrorDetails().errorMessage());
            System.exit(1);
        }
    }