SDK for .NET (v4) を使用した Amazon S3 の例

/// <summary>
/// Hello Amazon Simple Storage Service
// (Amazon S3) example.
/// </summary>
public class HelloS3
{
    /// <summary>
    /// Main method to run the Hello S3 example.
    /// </summary>
    /// <param name="args">Command line arguments.</param>
    /// <returns>A Task object.</returns>
    public static async Task Main(string[] args)
    {
        var s3Client = new AmazonS3Client();

        try
        {
            Console.WriteLine("Hello Amazon S3! Let's list your buckets:");
            Console.WriteLine(new string('-', 80));

            // Use the built-in paginator to list buckets
            var request = new ListBucketsRequest();
            var paginator = s3Client.Paginators.ListBuckets(request);

            var buckets = new List<S3Bucket>();

            await foreach (var response in paginator.Responses)
            {
                buckets.AddRange(response.Buckets);
            }

            if (buckets.Any())
            {
                Console.WriteLine($"Found {buckets.Count} S3 buckets:");
                Console.WriteLine();

                foreach (var bucket in buckets)
                {
                    Console.WriteLine($"- Bucket Name: {bucket.BucketName}");
                    Console.WriteLine($"  Creation Date: {bucket.CreationDate:yyyy-MM-dd HH:mm:ss UTC}");
                    Console.WriteLine();
                }
            }
            else
            {
                Console.WriteLine("No S3 buckets found in your account.");
            }

            Console.WriteLine("Hello S3 completed successfully.");
        }
        catch (AmazonS3Exception ex)
        {
            Console.WriteLine($"S3 service error occurred: {ex.Message}");
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Couldn't list S3 buckets. Here's why: {ex.Message}");
        }
    }
}

Amazon S3 機能を示すインタラクティブなシナリオを実行します。

public class S3_Basics
{
    public static bool IsInteractive = true;
    public static string BucketName = null!;
    public static string TempFilePath = null!;
    public static S3Wrapper _s3Wrapper = null!;
    public static ILogger<S3_Basics> _logger = null!;

    public static async Task Main(string[] args)
    {
        // Set up dependency injection for the Amazon service.
        using var host = Host.CreateDefaultBuilder(args)
            .ConfigureServices((_, services) =>
                services.AddAWSService<IAmazonS3>()
                    .AddTransient<S3Wrapper>()
                    .AddLogging(builder => builder.AddConsole()))
            .Build();

        _logger = LoggerFactory.Create(builder => builder.AddConsole())
            .CreateLogger<S3_Basics>();

        _s3Wrapper = host.Services.GetRequiredService<S3Wrapper>();

        var sepBar = new string('-', 45);

        Console.WriteLine(sepBar);
        Console.WriteLine("Amazon Simple Storage Service (Amazon S3) basic");
        Console.WriteLine("procedures. This application will:");
        Console.WriteLine("\n\t1. Create a bucket");
        Console.WriteLine("\n\t2. Upload an object to the new bucket");
        Console.WriteLine("\n\t3. Copy the uploaded object to a folder in the bucket");
        Console.WriteLine("\n\t4. List the items in the new bucket");
        Console.WriteLine("\n\t5. Delete all the items in the bucket");
        Console.WriteLine("\n\t6. Delete the bucket");
        Console.WriteLine(sepBar);

        await RunScenario(_s3Wrapper, _logger);

        Console.WriteLine(sepBar);
        Console.WriteLine("The Amazon S3 scenario has successfully completed.");
        Console.WriteLine(sepBar);
    }

    /// <summary>
    /// Run the S3 Basics scenario with injected dependencies.
    /// </summary>
    /// <param name="s3Wrapper">The S3 wrapper instance.</param>
    /// <param name="scenarioLogger">The logger instance.</param>
    /// <returns>A Task object.</returns>
    public static async Task RunScenario(S3Wrapper s3Wrapper, ILogger<S3_Basics> scenarioLogger)
    {
        string bucketName = BucketName;
        string filePath = TempFilePath;
        string keyName = string.Empty;

        var sepBar = new string('-', 45);

        try
        {
            // Create a bucket.
            Console.WriteLine($"\n{sepBar}");
            Console.WriteLine("\nCreate a new Amazon S3 bucket.\n");
            Console.WriteLine(sepBar);

            if (IsInteractive)
            {
                Console.Write("Please enter a name for the new bucket: ");
                bucketName = Console.ReadLine();
            }
            else
            {
                Console.WriteLine($"Using bucket name: {bucketName}");
            }

            var success = await s3Wrapper.CreateBucketAsync(bucketName);
            if (success)
            {
                Console.WriteLine($"Successfully created bucket: {bucketName}.\n");
            }
            else
            {
                Console.WriteLine($"Could not create bucket: {bucketName}.\n");
            }

            Console.WriteLine(sepBar);
            Console.WriteLine("Upload a file to the new bucket.");
            Console.WriteLine(sepBar);

            if (IsInteractive)
            {
                // Get the local path and filename for the file to upload.
                while (string.IsNullOrEmpty(filePath))
                {
                    Console.Write("Please enter the path and filename of the file to upload: ");
                    filePath = Console.ReadLine();

                    // Confirm that the file exists on the local computer.
                    if (!File.Exists(filePath))
                    {
                        Console.WriteLine($"Couldn't find {filePath}. Try again.\n");
                        filePath = string.Empty;
                    }
                }
            }
            else
            {
                // Use the public variable if set, otherwise create a temp file
                if (!string.IsNullOrEmpty(TempFilePath))
                {
                    filePath = TempFilePath;
                    Console.WriteLine($"Using provided test file: {filePath}");
                }
                else
                {
                    // Create a temporary test file for non-interactive mode
                    filePath = Path.GetTempFileName();
                    var testContent = "This is a test file for S3 basics scenario.\nGenerated on: " + DateTime.UtcNow.ToString("yyyy-MM-dd HH:mm:ss UTC");
                    await File.WriteAllTextAsync(filePath, testContent);
                    Console.WriteLine($"Created temporary test file: {filePath}");
                }
            }

            // Get the file name from the full path.
            keyName = Path.GetFileName(filePath);

            success = await s3Wrapper.UploadFileAsync(bucketName, keyName, filePath);

            if (success)
            {
                Console.WriteLine($"Successfully uploaded {keyName} from {filePath} to {bucketName}.\n");
            }
            else
            {
                Console.WriteLine($"Could not upload {keyName}.\n");
            }

            // Set up download path
            string downloadPath = string.Empty;

            if (IsInteractive)
            {
                // Now get a new location where we can save the file.
                while (string.IsNullOrEmpty(downloadPath))
                {
                    // First get the path to which the file will be downloaded.
                    Console.Write("Please enter the path where the file will be downloaded: ");
                    downloadPath = Console.ReadLine();

                    // Confirm that the file doesn't already exist on the local computer.
                    if (File.Exists($"{downloadPath}\\{keyName}"))
                    {
                        Console.WriteLine($"Sorry, the file already exists in that location.\n");
                        downloadPath = string.Empty;
                    }
                }
            }
            else
            {
                downloadPath = Path.GetTempPath();
                var downloadFile = Path.Combine(downloadPath, keyName);
                if (File.Exists(downloadFile))
                {
                    File.Delete(downloadFile);
                }

                Console.WriteLine($"Using download path: {downloadPath}");
            }

            // Download an object from a bucket.
            success = await s3Wrapper.DownloadObjectFromBucketAsync(bucketName, keyName, downloadPath);

            if (success)
            {
                Console.WriteLine($"Successfully downloaded {keyName}.\n");
            }
            else
            {
                Console.WriteLine($"Sorry, could not download {keyName}.\n");
            }

            // Copy the object to a different folder in the bucket.
            string folderName = string.Empty;

            if (IsInteractive)
            {
                while (string.IsNullOrEmpty(folderName))
                {
                    Console.Write("Please enter the name of the folder to copy your object to: ");
                    folderName = Console.ReadLine();
                }
            }
            else
            {
                folderName = "test-folder";
                Console.WriteLine($"Using folder name: {folderName}");
            }

            await s3Wrapper.CopyObjectInBucketAsync(bucketName, keyName, folderName);

            // List the objects in the bucket.
            await s3Wrapper.ListBucketContentsAsync(bucketName);

            // Delete the contents of the bucket.
            if (IsInteractive)
            {
                Console.WriteLine("Press <Enter> when you are ready to delete the bucket contents.");
                _ = Console.ReadLine();
            }

            var deleteContentsSuccess = await s3Wrapper.DeleteBucketContentsAsync(bucketName);
            if (deleteContentsSuccess)
            {
                Console.WriteLine($"Successfully deleted contents of {bucketName}.\n");
            }
            else
            {
                Console.WriteLine($"Sorry, could not delete contents of {bucketName}.\n");
            }

            if (IsInteractive)
            {
                // Deleting the bucket too quickly after separately deleting its contents can
                // cause an error that the bucket isn't empty. To delete contents and bucket in one
                // operation, use AmazonS3Util.DeleteS3BucketWithObjectsAsync
                Console.WriteLine("Press <Enter> when you are ready to delete the bucket.");
                _ = Console.ReadLine();
            }
            else
            {
                // Add a small delay for non-interactive mode to ensure objects are fully deleted.
                Console.WriteLine("Waiting a moment for objects to be fully deleted...");
                await Task.Delay(2000);
            }

            // Delete the bucket.
            var deleteSuccess = await s3Wrapper.DeleteBucketAsync(bucketName);
            if (deleteSuccess)
            {
                Console.WriteLine($"Successfully deleted {bucketName}.\n");
            }
            else
            {
                Console.WriteLine($"Sorry, could not delete {bucketName}.\n");
            }

            // Clean up temporary files in non-interactive mode
            if (!IsInteractive)
            {
                try
                {
                    if (File.Exists(filePath))
                    {
                        File.Delete(filePath);
                        Console.WriteLine("Cleaned up temporary test file.");
                    }

                    var downloadFile = Path.Combine(downloadPath, keyName);
                    if (File.Exists(downloadFile))
                    {
                        File.Delete(downloadFile);
                        Console.WriteLine("Cleaned up downloaded test file.");
                    }
                }
                catch (Exception ex)
                {
                    scenarioLogger.LogWarning(ex, "Failed to clean up temporary files.");
                }
            }
        }
        catch (Exception ex)
        {
            scenarioLogger.LogError(ex, "An error occurred during the S3 scenario execution.");

            // Clean up on error - delete bucket if it exists
            try
            {
                if (!string.IsNullOrEmpty(bucketName))
                {
                    await s3Wrapper.DeleteBucketContentsAsync(bucketName);
                    await s3Wrapper.DeleteBucketAsync(bucketName);
                }
            }
            catch (Exception cleanupEx)
            {
                scenarioLogger.LogError(cleanupEx, "Error during cleanup.");
            }

            // Clean up temporary files in non-interactive mode
            if (!IsInteractive)
            {
                try
                {
                    if (!string.IsNullOrEmpty(filePath) && File.Exists(filePath))
                    {
                        File.Delete(filePath);
                    }
                }
                catch (Exception fileCleanupEx)
                {
                    scenarioLogger.LogWarning(fileCleanupEx, "Failed to clean up temporary files during error handling.");
                }
            }

            throw;
        }
    }
}

Amazon S3 SDK メソッドのラッパークラス。

using Amazon.S3;
using Amazon.S3.Model;

namespace S3_Actions;

/// <summary>
/// This class contains all of the methods for working with Amazon Simple
/// Storage Service (Amazon S3) buckets.
/// </summary>
public class S3Wrapper
{
    private readonly IAmazonS3 _amazonS3;

    /// <summary>
    /// Initializes a new instance of the <see cref="S3Wrapper"/> class.
    /// </summary>
    /// <param name="amazonS3">An initialized Amazon S3 client object.</param>
    public S3Wrapper(IAmazonS3 amazonS3)
    {
        _amazonS3 = amazonS3;
    }


    /// <summary>
    /// Shows how to create a new Amazon S3 bucket.
    /// </summary>
    /// <param name="bucketName">The name of the bucket to create.</param>
    /// <returns>A boolean value representing the success or failure of
    /// the bucket creation process.</returns>
    public async Task<bool> CreateBucketAsync(string bucketName)
    {
        try
        {
            var request = new PutBucketRequest
            {
                BucketName = bucketName,
                UseClientRegion = true,
            };

            var response = await _amazonS3.PutBucketAsync(request);
            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }
        catch (AmazonS3Exception ex)
        {
            Console.WriteLine($"Error creating bucket: '{ex.Message}'");
            return false;
        }
    }



    /// <summary>
    /// Shows how to upload a file from the local computer to an Amazon S3
    /// bucket.
    /// </summary>
    /// <param name="bucketName">The Amazon S3 bucket to which the object
    /// will be uploaded.</param>
    /// <param name="objectName">The object to upload.</param>
    /// <param name="filePath">The path, including file name, of the object
    /// on the local computer to upload.</param>
    /// <returns>A boolean value indicating the success or failure of the
    /// upload procedure.</returns>
    public async Task<bool> UploadFileAsync(
        string bucketName,
        string objectName,
        string filePath)
    {
        try
        {
            var request = new PutObjectRequest
            {
                BucketName = bucketName,
                Key = objectName,
                FilePath = filePath,
            };

            var response = await _amazonS3.PutObjectAsync(request);
            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }
        catch (AmazonS3Exception ex)
        {
            Console.WriteLine($"Error uploading {objectName}: {ex.Message}");
            return false;
        }
    }



    /// <summary>
    /// Shows how to download an object from an Amazon S3 bucket to the
    /// local computer.
    /// </summary>
    /// <param name="bucketName">The name of the bucket where the object is
    /// currently stored.</param>
    /// <param name="objectName">The name of the object to download.</param>
    /// <param name="filePath">The path, including filename, where the
    /// downloaded object will be stored.</param>
    /// <returns>A boolean value indicating the success or failure of the
    /// download process.</returns>
    public async Task<bool> DownloadObjectFromBucketAsync(
        string bucketName,
        string objectName,
        string filePath)
    {
        var request = new GetObjectRequest
        {
            BucketName = bucketName,
            Key = objectName,
        };

        using GetObjectResponse response = await _amazonS3.GetObjectAsync(request);

        try
        {
            // Save object to local file
            await response.WriteResponseStreamToFileAsync($"{filePath}\\{objectName}", true, CancellationToken.None);
            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }
        catch (AmazonS3Exception ex)
        {
            Console.WriteLine($"Error saving {objectName}: {ex.Message}");
            return false;
        }
    }



    /// <summary>
    /// Copies an object in an Amazon S3 bucket to a folder within the
    /// same bucket.
    /// </summary>
    /// <param name="bucketName">The name of the Amazon S3 bucket where the
    /// object to copy is located.</param>
    /// <param name="objectName">The object to be copied.</param>
    /// <param name="folderName">The folder to which the object will
    /// be copied.</param>
    /// <returns>A boolean value that indicates the success or failure of
    /// the copy operation.</returns>
    public async Task<bool> CopyObjectInBucketAsync(
        string bucketName,
        string objectName,
        string folderName)
    {
        try
        {
            var request = new CopyObjectRequest
            {
                SourceBucket = bucketName,
                SourceKey = objectName,
                DestinationBucket = bucketName,
                DestinationKey = $"{folderName}\\{objectName}",
            };
            var response = await _amazonS3.CopyObjectAsync(request);
            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }
        catch (AmazonS3Exception ex)
        {
            Console.WriteLine($"Error copying object: '{ex.Message}'");
            return false;
        }
    }



    /// <summary>
    /// Shows how to list the objects in an Amazon S3 bucket.
    /// </summary>
    /// <param name="bucketName">The name of the bucket for which to list.
    /// <param name="printList">True to print out the list.
    /// <returns>The collection of objects.</returns>
    public async Task<List<S3Object>?> ListBucketContentsAsync(string bucketName, bool printList = true)
    {
        try
        {
            var request = new ListObjectsV2Request
            {
                BucketName = bucketName,
                MaxKeys = 5,
            };

            if (printList)
            {
                Console.WriteLine("--------------------------------------");
                Console.WriteLine($"Listing the contents of {bucketName}:");
                Console.WriteLine("--------------------------------------");
            }

            var listObjectsV2Paginator = _amazonS3.Paginators.ListObjectsV2(new ListObjectsV2Request
            {
                BucketName = bucketName,
            });
            var s3Objects = new List<S3Object>();
            await foreach (var response in listObjectsV2Paginator.Responses)
            {
                if (response.S3Objects != null)
                {
                    s3Objects.AddRange(response.S3Objects);
                }
            }

            if (printList)
            {
                Console.WriteLine($"Number of Objects: {s3Objects.Count}");
                foreach (var entry in s3Objects)
                {
                    Console.WriteLine($"Key = {entry.Key} Size = {entry.Size}");
                }
            }

            return s3Objects;
        }
        catch (AmazonS3Exception ex)
        {
            Console.WriteLine($"Error encountered on server. Message:'{ex.Message}' getting list of objects.");
            return null;
        }
    }



    /// <summary>
    /// Delete all of the objects stored in an existing Amazon S3 bucket.
    /// </summary>
    /// <param name="bucketName">The name of the bucket from which the
    /// contents will be deleted.</param>
    /// <returns>A boolean value that represents the success or failure of
    /// deleting all of the objects in the bucket.</returns>
    public async Task<bool> DeleteBucketContentsAsync(string bucketName)
    {
        // Iterate over the contents of the bucket and delete all objects.
        try
        {
            // Delete all objects in the bucket.
            var deleteList = await ListBucketContentsAsync(bucketName, false);
            if (deleteList != null && deleteList.Any())
            {
                await _amazonS3.DeleteObjectsAsync(new DeleteObjectsRequest()
                {
                    BucketName = bucketName,
                    Objects = deleteList.Select(o => new KeyVersion { Key = o.Key }).ToList(),
                });
            }

            return true;
        }
        catch (AmazonS3Exception ex)
        {
            Console.WriteLine($"Error deleting objects: {ex.Message}");
            return false;
        }
    }



    /// <summary>
    /// Shows how to delete an Amazon S3 bucket.
    /// </summary>
    /// <param name="bucketName">The name of the Amazon S3 bucket to delete.</param>
    /// <returns>A boolean value that represents the success or failure of
    /// the delete operation.</returns>
    public async Task<bool> DeleteBucketAsync(string bucketName)
    {
        try
        {
            var request = new DeleteBucketRequest { BucketName = bucketName, };

            await _amazonS3.DeleteBucketAsync(request);
            return true;
        }
        catch (AmazonS3Exception ex)
        {
            Console.WriteLine($"Error deleting bucket: {ex.Message}");
            return false;
        }
    }

}

    /// <summary>
    /// Copies an object in an Amazon S3 bucket to a folder within the
    /// same bucket.
    /// </summary>
    /// <param name="bucketName">The name of the Amazon S3 bucket where the
    /// object to copy is located.</param>
    /// <param name="objectName">The object to be copied.</param>
    /// <param name="folderName">The folder to which the object will
    /// be copied.</param>
    /// <returns>A boolean value that indicates the success or failure of
    /// the copy operation.</returns>
    public async Task<bool> CopyObjectInBucketAsync(
        string bucketName,
        string objectName,
        string folderName)
    {
        try
        {
            var request = new CopyObjectRequest
            {
                SourceBucket = bucketName,
                SourceKey = objectName,
                DestinationBucket = bucketName,
                DestinationKey = $"{folderName}\\{objectName}",
            };
            var response = await _amazonS3.CopyObjectAsync(request);
            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }
        catch (AmazonS3Exception ex)
        {
            Console.WriteLine($"Error copying object: '{ex.Message}'");
            return false;
        }
    }

    /// <summary>
    /// Shows how to create a new Amazon S3 bucket.
    /// </summary>
    /// <param name="bucketName">The name of the bucket to create.</param>
    /// <returns>A boolean value representing the success or failure of
    /// the bucket creation process.</returns>
    public async Task<bool> CreateBucketAsync(string bucketName)
    {
        try
        {
            var request = new PutBucketRequest
            {
                BucketName = bucketName,
                UseClientRegion = true,
            };

            var response = await _amazonS3.PutBucketAsync(request);
            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }
        catch (AmazonS3Exception ex)
        {
            Console.WriteLine($"Error creating bucket: '{ex.Message}'");
            return false;
        }
    }

署名付き POST URL を作成します。

    /// <summary>
    /// Create a presigned POST URL with conditions.
    /// </summary>
    /// <param name="s3Client">The Amazon S3 client.</param>
    /// <param name="bucketName">The name of the bucket.</param>
    /// <param name="objectKey">The object key (path) where the uploaded file will be stored.</param>
    /// <param name="expires">When the presigned URL expires.</param>
    /// <param name="fields">Dictionary of fields to add to the form.</param>
    /// <param name="conditions">List of conditions to apply.</param>
    /// <returns>A CreatePresignedPostResponse object with URL and form fields.</returns>
    public async Task<CreatePresignedPostResponse> CreatePresignedPostAsync(
        IAmazonS3 s3Client,
        string bucketName,
        string objectKey,
        DateTime expires,
        Dictionary<string, string>? fields = null,
        List<S3PostCondition>? conditions = null)
    {
        var request = new CreatePresignedPostRequest
        {
            BucketName = bucketName,
            Key = objectKey,
            Expires = expires
        };

        // Add custom fields if provided
        if (fields != null)
        {
            foreach (var field in fields)
            {
                request.Fields.Add(field.Key, field.Value);
            }
        }

        // Add conditions if provided
        if (conditions != null)
        {
            foreach (var condition in conditions)
            {
                request.Conditions.Add(condition);
            }
        }

        return await s3Client.CreatePresignedPostAsync(request);
    }

    /// <summary>
    /// Shows how to delete an Amazon S3 bucket.
    /// </summary>
    /// <param name="bucketName">The name of the Amazon S3 bucket to delete.</param>
    /// <returns>A boolean value that represents the success or failure of
    /// the delete operation.</returns>
    public async Task<bool> DeleteBucketAsync(string bucketName)
    {
        try
        {
            var request = new DeleteBucketRequest { BucketName = bucketName, };

            await _amazonS3.DeleteBucketAsync(request);
            return true;
        }
        catch (AmazonS3Exception ex)
        {
            Console.WriteLine($"Error deleting bucket: {ex.Message}");
            return false;
        }
    }

    /// <summary>
    /// Delete all of the objects stored in an existing Amazon S3 bucket.
    /// </summary>
    /// <param name="bucketName">The name of the bucket from which the
    /// contents will be deleted.</param>
    /// <returns>A boolean value that represents the success or failure of
    /// deleting all of the objects in the bucket.</returns>
    public async Task<bool> DeleteBucketContentsAsync(string bucketName)
    {
        // Iterate over the contents of the bucket and delete all objects.
        try
        {
            // Delete all objects in the bucket.
            var deleteList = await ListBucketContentsAsync(bucketName, false);
            if (deleteList != null && deleteList.Any())
            {
                await _amazonS3.DeleteObjectsAsync(new DeleteObjectsRequest()
                {
                    BucketName = bucketName,
                    Objects = deleteList.Select(o => new KeyVersion { Key = o.Key }).ToList(),
                });
            }

            return true;
        }
        catch (AmazonS3Exception ex)
        {
            Console.WriteLine($"Error deleting objects: {ex.Message}");
            return false;
        }
    }

    /// <summary>
    /// Shows how to download an object from an Amazon S3 bucket to the
    /// local computer.
    /// </summary>
    /// <param name="bucketName">The name of the bucket where the object is
    /// currently stored.</param>
    /// <param name="objectName">The name of the object to download.</param>
    /// <param name="filePath">The path, including filename, where the
    /// downloaded object will be stored.</param>
    /// <returns>A boolean value indicating the success or failure of the
    /// download process.</returns>
    public async Task<bool> DownloadObjectFromBucketAsync(
        string bucketName,
        string objectName,
        string filePath)
    {
        var request = new GetObjectRequest
        {
            BucketName = bucketName,
            Key = objectName,
        };

        using GetObjectResponse response = await _amazonS3.GetObjectAsync(request);

        try
        {
            // Save object to local file
            await response.WriteResponseStreamToFileAsync($"{filePath}\\{objectName}", true, CancellationToken.None);
            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }
        catch (AmazonS3Exception ex)
        {
            Console.WriteLine($"Error saving {objectName}: {ex.Message}");
            return false;
        }
    }

    /// <summary>
    /// Shows how to list the objects in an Amazon S3 bucket.
    /// </summary>
    /// <param name="bucketName">The name of the bucket for which to list.
    /// <param name="printList">True to print out the list.
    /// <returns>The collection of objects.</returns>
    public async Task<List<S3Object>?> ListBucketContentsAsync(string bucketName, bool printList = true)
    {
        try
        {
            var request = new ListObjectsV2Request
            {
                BucketName = bucketName,
                MaxKeys = 5,
            };

            if (printList)
            {
                Console.WriteLine("--------------------------------------");
                Console.WriteLine($"Listing the contents of {bucketName}:");
                Console.WriteLine("--------------------------------------");
            }

            var listObjectsV2Paginator = _amazonS3.Paginators.ListObjectsV2(new ListObjectsV2Request
            {
                BucketName = bucketName,
            });
            var s3Objects = new List<S3Object>();
            await foreach (var response in listObjectsV2Paginator.Responses)
            {
                if (response.S3Objects != null)
                {
                    s3Objects.AddRange(response.S3Objects);
                }
            }

            if (printList)
            {
                Console.WriteLine($"Number of Objects: {s3Objects.Count}");
                foreach (var entry in s3Objects)
                {
                    Console.WriteLine($"Key = {entry.Key} Size = {entry.Size}");
                }
            }

            return s3Objects;
        }
        catch (AmazonS3Exception ex)
        {
            Console.WriteLine($"Error encountered on server. Message:'{ex.Message}' getting list of objects.");
            return null;
        }
    }

    /// <summary>
    /// Shows how to upload a file from the local computer to an Amazon S3
    /// bucket.
    /// </summary>
    /// <param name="bucketName">The Amazon S3 bucket to which the object
    /// will be uploaded.</param>
    /// <param name="objectName">The object to upload.</param>
    /// <param name="filePath">The path, including file name, of the object
    /// on the local computer to upload.</param>
    /// <returns>A boolean value indicating the success or failure of the
    /// upload procedure.</returns>
    public async Task<bool> UploadFileAsync(
        string bucketName,
        string objectName,
        string filePath)
    {
        try
        {
            var request = new PutObjectRequest
            {
                BucketName = bucketName,
                Key = objectName,
                FilePath = filePath,
            };

            var response = await _amazonS3.PutObjectAsync(request);
            return response.HttpStatusCode == System.Net.HttpStatusCode.OK;
        }
        catch (AmazonS3Exception ex)
        {
            Console.WriteLine($"Error uploading {objectName}: {ex.Message}");
            return false;
        }
    }

署名付き POST URL を作成してブラウザからの直接アップロードに使用します。

/// <summary>
/// Scenario demonstrating the complete workflow for presigned POST URLs:
/// 1. Create an S3 bucket
/// 2. Create a presigned POST URL
/// 3. Upload a file using the presigned POST URL
/// 4. Clean up resources
/// </summary>
public class CreatePresignedPostBasics
{
    public static ILogger<CreatePresignedPostBasics> _logger = null!;
    public static S3Wrapper _s3Wrapper = null!;
    public static UiMethods _uiMethods = null!;
    public static IHttpClientFactory _httpClientFactory = null!;
    public static bool _isInteractive = true;
    public static string? _bucketName;
    public static string? _objectKey;

    /// <summary>
    /// Set up the services and logging.
    /// </summary>
    /// <param name="host">The IHost instance.</param>
    public static void SetUpServices(IHost host)
    {
        var loggerFactory = LoggerFactory.Create(builder =>
        {
            builder.AddConsole();
        });
        _logger = new Logger<CreatePresignedPostBasics>(loggerFactory);

        _s3Wrapper = host.Services.GetRequiredService<S3Wrapper>();
        _httpClientFactory = host.Services.GetRequiredService<IHttpClientFactory>();
        _uiMethods = new UiMethods();
    }

    /// <summary>
    /// Perform the actions defined for the Amazon S3 Presigned POST scenario.
    /// </summary>
    /// <param name="args">Command line arguments.</param>
    /// <returns>A Task object.</returns>
    public static async Task Main(string[] args)
    {
        _isInteractive = !args.Contains("--non-interactive");

        // Set up dependency injection for Amazon S3
        using var host = Microsoft.Extensions.Hosting.Host.CreateDefaultBuilder(args)
            .ConfigureServices((_, services) =>
                services.AddAWSService<IAmazonS3>()
                    .AddTransient<S3Wrapper>()
                    .AddHttpClient()
            )
            .Build();

        SetUpServices(host);

        try
        {
            // Display overview
            _uiMethods.DisplayOverview();
            _uiMethods.PressEnter(_isInteractive);

            // Step 1: Create bucket
            await CreateBucketAsync();
            _uiMethods.PressEnter(_isInteractive);

            // Step 2: Create presigned URL
            _uiMethods.DisplayTitle("Step 2: Create presigned POST URL");
            var response = await CreatePresignedPostAsync();
            _uiMethods.PressEnter(_isInteractive);

            // Step 3: Display URL and fields
            _uiMethods.DisplayTitle("Step 3: Presigned POST URL details");
            DisplayPresignedPostFields(response);
            _uiMethods.PressEnter(_isInteractive);

            // Step 4: Upload file
            _uiMethods.DisplayTitle("Step 4: Upload test file using presigned POST URL");
            await UploadFileAsync(response);
            _uiMethods.PressEnter(_isInteractive);

            // Step 5: Verify file exists
            await VerifyFileExistsAsync();
            _uiMethods.PressEnter(_isInteractive);

            // Step 6: Cleanup
            _uiMethods.DisplayTitle("Step 6: Clean up resources");
            await CleanupAsync();

            _uiMethods.DisplayTitle("S3 Presigned POST Scenario completed successfully!");
            _uiMethods.PressEnter(_isInteractive);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error in scenario");
            Console.WriteLine($"Error: {ex.Message}");

            // Attempt cleanup if there was an error
            if (!string.IsNullOrEmpty(_bucketName))
            {
                _uiMethods.DisplayTitle("Cleaning up resources after error");
                await _s3Wrapper.DeleteBucketAsync(_bucketName);
                Console.WriteLine($"Cleaned up bucket: {_bucketName}");
            }
        }
    }

    /// <summary>
    /// Create an S3 bucket for the scenario.
    /// </summary>
    private static async Task CreateBucketAsync()
    {
        _uiMethods.DisplayTitle("Step 1: Create an S3 bucket");

        // Generate a default bucket name for the scenario
        var defaultBucketName = $"presigned-post-demo-{DateTime.Now:yyyyMMddHHmmss}".ToLower();

        // Prompt user for bucket name or use default in non-interactive mode
        _bucketName = _uiMethods.GetUserInput(
            $"Enter S3 bucket name (or press Enter for '{defaultBucketName}'): ",
            defaultBucketName,
            _isInteractive);

        // Basic validation to ensure bucket name is not empty
        if (string.IsNullOrWhiteSpace(_bucketName))
        {
            _bucketName = defaultBucketName;
        }

        Console.WriteLine($"Creating bucket: {_bucketName}");

        await _s3Wrapper.CreateBucketAsync(_bucketName);

        Console.WriteLine($"Successfully created bucket: {_bucketName}");
    }


    /// <summary>
    /// Create a presigned POST URL.
    /// </summary>
    private static async Task<CreatePresignedPostResponse> CreatePresignedPostAsync()
    {
        _objectKey = "example-upload.txt";
        var expiration = DateTime.UtcNow.AddMinutes(10); // Short expiration for the demo

        Console.WriteLine($"Creating presigned POST URL for {_bucketName}/{_objectKey}");
        Console.WriteLine($"Expiration: {expiration} UTC");

        var s3Client = _s3Wrapper.GetS3Client();

        var response = await _s3Wrapper.CreatePresignedPostAsync(
            s3Client, _bucketName!, _objectKey, expiration);

        Console.WriteLine("Successfully created presigned POST URL");
        return response;
    }

    /// <summary>
    /// Upload a file using the presigned POST URL.
    /// </summary>
    private static async Task UploadFileAsync(CreatePresignedPostResponse response)
    {

        // Create a temporary test file to upload
        string testFilePath = Path.GetTempFileName();
        string testContent = "This is a test file for the S3 presigned POST scenario.";

        await File.WriteAllTextAsync(testFilePath, testContent);
        Console.WriteLine($"Created test file at: {testFilePath}");

        // Upload the file using the presigned POST URL
        Console.WriteLine("\nUploading file using the presigned POST URL...");
        var uploadResult = await UploadFileWithPresignedPostAsync(response, testFilePath);

        // Display the upload result
        if (uploadResult.Success)
        {
            Console.WriteLine($"Upload successful! Status code: {uploadResult.StatusCode}");
        }
        else
        {
            Console.WriteLine($"Upload failed with status code: {uploadResult.StatusCode}");
            Console.WriteLine($"Error: {uploadResult.Response}");
            throw new Exception("File upload failed");
        }

        // Clean up the temporary file
        File.Delete(testFilePath);
        Console.WriteLine("Temporary file deleted");
    }

    /// <summary>
    /// Helper method to upload a file using a presigned POST URL.
    /// </summary>
    private static async Task<(bool Success, HttpStatusCode StatusCode, string Response)> UploadFileWithPresignedPostAsync(
        CreatePresignedPostResponse response,
        string filePath)
    {
        try
        {
            _logger.LogInformation("Uploading file {filePath} using presigned POST URL", filePath);

            using var httpClient = _httpClientFactory.CreateClient();
            using var formContent = new MultipartFormDataContent();

            // Add all the fields from the presigned POST response
            foreach (var field in response.Fields)
            {
                formContent.Add(new StringContent(field.Value), field.Key);
            }

            // Add the file content
            var fileStream = File.OpenRead(filePath);
            var fileName = Path.GetFileName(filePath);
            var fileContent = new StreamContent(fileStream);
            fileContent.Headers.ContentType = new MediaTypeHeaderValue("text/plain");
            formContent.Add(fileContent, "file", fileName);

            // Send the POST request
            var httpResponse = await httpClient.PostAsync(response.Url, formContent);
            var responseContent = await httpResponse.Content.ReadAsStringAsync();

            // Log and return the result
            _logger.LogInformation("Upload completed with status code {statusCode}", httpResponse.StatusCode);

            return (httpResponse.IsSuccessStatusCode, httpResponse.StatusCode, responseContent);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error uploading file");
            return (false, HttpStatusCode.InternalServerError, ex.Message);
        }
    }

    /// <summary>
    /// Verify that the uploaded file exists in the S3 bucket.
    /// </summary>
    private static async Task VerifyFileExistsAsync()
    {
        _uiMethods.DisplayTitle("Step 5: Verify uploaded file exists");

        Console.WriteLine($"Checking if file exists at {_bucketName}/{_objectKey}...");

        try
        {
            var metadata = await _s3Wrapper.GetObjectMetadataAsync(_bucketName!, _objectKey!);

            Console.WriteLine($"File verification successful! File exists in the bucket.");
            Console.WriteLine($"File size: {metadata.ContentLength} bytes");
            Console.WriteLine($"File type: {metadata.Headers.ContentType}");
            Console.WriteLine($"Last modified: {metadata.LastModified}");
        }
        catch (AmazonS3Exception ex) when (ex.StatusCode == System.Net.HttpStatusCode.NotFound)
        {
            Console.WriteLine($"Error: File was not found in the bucket.");
            throw;
        }
    }

    private static void DisplayPresignedPostFields(CreatePresignedPostResponse response)
    {
        Console.WriteLine($"Presigned POST URL: {response.Url}");
        Console.WriteLine("Form fields to include:");

        foreach (var field in response.Fields)
        {
            Console.WriteLine($"  {field.Key}: {field.Value}");
        }
    }

    /// <summary>
    /// Clean up resources created by the scenario.
    /// </summary>
    private static async Task CleanupAsync()
    {
        if (!string.IsNullOrEmpty(_bucketName))
        {
            Console.WriteLine($"Deleting bucket {_bucketName} and its contents...");
            bool result = await _s3Wrapper.DeleteBucketAsync(_bucketName);

            if (result)
            {
                Console.WriteLine("Bucket deleted successfully");
            }
            else
            {
                Console.WriteLine("Failed to delete bucket - it may have been already deleted");
            }
        }
    }
}