components/LiteCharms.Features/S3/Abstractions/S3ServiceBase.cs

using static LiteCharms.Features.Extensions.Hash;

namespace LiteCharms.Features.S3.Abstractions;

public abstract class S3ServiceBase(IAmazonS3 amazonS3)
{
    protected readonly IAmazonS3 Client = amazonS3;

    protected abstract string BucketName { get; }
    protected abstract string CdnBaseUrl { get; }

    public virtual async Task<Result<string>> UploadFileAsync(string fileName, Stream fileStream, string contentType, CancellationToken cancellationToken = default)
    {
        try
        {
            if (string.IsNullOrWhiteSpace(BucketName))
                return Result.Fail<string>("Bucket name is not configured.");

            if (string.IsNullOrWhiteSpace(CdnBaseUrl))
                return Result.Fail<string>("CDN base URL is not configured.");

            using var stream = new MemoryStream();

            await fileStream.CopyToAsync(stream, cancellationToken);
            await fileStream.DisposeAsync();

            stream.Seek(0, SeekOrigin.Begin);

            var fileHash = StreamToSha256Hash(stream);

            if(string.IsNullOrWhiteSpace(fileHash))
                return Result.Fail<string>("Failed to compute file hash.");

            var fileKey = $"{fileHash.ToLower()}{Path.GetExtension(fileName)}";

            var putRequest = new PutObjectRequest
            {
                BucketName = BucketName,
                Key = fileKey,
                InputStream = stream,
                ContentType = contentType,
                UseChunkEncoding = false
            };

            stream.Seek(0, SeekOrigin.Begin);

            var response = await Client.PutObjectAsync(putRequest, cancellationToken);

            return response.HttpStatusCode != System.Net.HttpStatusCode.OK
                ? Result.Fail<string>($"Failed to upload {fileName} to S3.")
                : Result.Ok($"{CdnBaseUrl}/{fileKey}");
        }
        catch (Exception ex)
        {
            return Result.Fail<string>(new Error($"Error uploading {fileName} to S3: {ex.Message}").CausedBy(ex));
        }
    }

    public virtual async Task<Result> DeleteFileAsync(string fileKey, CancellationToken cancellationToken = default)
    {
        try
        {
            if (string.IsNullOrWhiteSpace(BucketName))
                return Result.Fail("Bucket name is not configured.");

            var deleteRequest = new DeleteObjectRequest
            {
                BucketName = BucketName,
                Key = fileKey
            };

            var response = await Client.DeleteObjectAsync(deleteRequest, cancellationToken);

            return response.HttpStatusCode != System.Net.HttpStatusCode.NoContent
                ? Result.Fail($"Failed to delete {fileKey} from S3.")
                : Result.Ok();
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error($"Error deleting {fileKey} from S3: {ex.Message}").CausedBy(ex));
        }
    }
}