Minio Storage

Configuration (appsettings.json)

{
  "MinIO": {
    "Endpoint": "localhost:9000",
    "AccessKey": "minioadmin",
    "SecretKey": "minioadmin",
    "Secure": false
  }
}

Usage Patterns

Inject IMinioClient

public class FileService
{
    private readonly IMinioClient _minio;

    public FileService(IMinioClient minio) => _minio = minio;
}

Create Bucket

public async Task EnsureBucketExists(string bucketName)
{
    var exists = await _minio.BucketExistsAsync(
        new BucketExistsArgs().WithBucket(bucketName));
    
    if (!exists)
    {
        await _minio.MakeBucketAsync(
            new MakeBucketArgs().WithBucket(bucketName));
    }
}

Upload File

public async Task UploadFile(string bucket, string objectName, string filePath, string contentType)
{
    await _minio.PutObjectAsync(new PutObjectArgs()
        .WithBucket(bucket)
        .WithObject(objectName)
        .WithFileName(filePath)
        .WithContentType(contentType));
}

Upload from Stream

public async Task UploadStream(string bucket, string objectName, Stream data, long size, string contentType)
{
    await _minio.PutObjectAsync(new PutObjectArgs()
        .WithBucket(bucket)
        .WithObject(objectName)
        .WithStreamData(data)
        .WithObjectSize(size)
        .WithContentType(contentType));
}

Download File

public async Task<Stream> DownloadFile(string bucket, string objectName)
{
    var memoryStream = new MemoryStream();
    await _minio.GetObjectAsync(new GetObjectArgs()
        .WithBucket(bucket)
        .WithObject(objectName)
        .WithCallbackStream(stream => stream.CopyTo(memoryStream)));
    memoryStream.Position = 0;
    return memoryStream;
}

Generate Presigned URL

public async Task<string> GetPresignedUrl(string bucket, string objectName, int expirySeconds = 3600)
{
    return await _minio.PresignedGetObjectAsync(new PresignedGetObjectArgs()
        .WithBucket(bucket)
        .WithObject(objectName)
        .WithExpiry(expirySeconds));
}

Delete Object

public async Task DeleteObject(string bucket, string objectName)
{
    await _minio.RemoveObjectAsync(new RemoveObjectArgs()
        .WithBucket(bucket)
        .WithObject(objectName));
}

List Objects

public async Task<List<string>> ListObjects(string bucket, string prefix = "")
{
    var objects = new List<string>();
    await foreach (var item in _minio.ListObjectsEnumAsync(
        new ListObjectsArgs().WithBucket(bucket).WithPrefix(prefix)))
    {
        objects.Add(item.Key);
    }
    return objects;
}

API Controller Example

[ApiController]
[Route("api/[controller]")]
public class FilesController : ControllerBase
{
    private readonly IMinioClient _minio;
    private const string BucketName = "uploads";

    public FilesController(IMinioClient minio) => _minio = minio;

    [HttpPost("upload")]
    public async Task<IActionResult> Upload(IFormFile file)
    {
        await using var stream = file.OpenReadStream();
        var objectName = $"{Guid.NewGuid()}{Path.GetExtension(file.FileName)}";
        
        await _minio.PutObjectAsync(new PutObjectArgs()
            .WithBucket(BucketName)
            .WithObject(objectName)
            .WithStreamData(stream)
            .WithObjectSize(file.Length)
            .WithContentType(file.ContentType));

        return Ok(new { objectName });
    }

    [HttpGet("{objectName}/url")]
    public async Task<IActionResult> GetUrl(string objectName)
    {
        var url = await _minio.PresignedGetObjectAsync(
            new PresignedGetObjectArgs()
                .WithBucket(BucketName)
                .WithObject(objectName)
                .WithExpiry(3600));
        
        return Ok(new { url });
    }
}

Using IMinioClientFactory

For multiple configurations or per-request client creation:

public class MultiTenantStorageService
{
    private readonly IMinioClientFactory _factory;

    public MultiTenantStorageService(IMinioClientFactory factory) => _factory = factory;

    public async Task UploadToTenant(string tenantId, string objectName, Stream data)
    {
        var client = _factory.CreateClient(); // Optional: pass configure action
        // Use client...
    }
}

Common Args Classes