Vali-Blob.ImageSharp 1.0.0

Vali-Blob.ImageSharp

Image processing middleware for Vali-Blob using SixLabors.ImageSharp.

Plugs into the Vali-Blob middleware pipeline and automatically resizes, converts, and optimizes images before they are stored via any Vali-Blob provider (AWS S3, Azure Blob, GCP, OCI, Supabase, Local). Optionally generates a thumbnail alongside the main upload — all in a single pipeline step.

Compatibility

Installation

dotnet add package ValiBlob.Core
dotnet add package ValiBlob.ImageSharp

Registration

using ValiBlob.Core.DependencyInjection;
using ValiBlob.AWS.Extensions;
using ValiBlob.ImageSharp.Extensions;

builder.Services
    .AddValiBlob(opts => opts.DefaultProvider = "AWS")
    .UseAWS()
    .WithImageProcessing(opts =>
    {
        opts.MaxWidth     = 1920;
        opts.MaxHeight    = 1080;
        opts.JpegQuality  = 85;
        opts.OutputFormat = ImageOutputFormat.Jpeg;
    });

With thumbnail generation

builder.Services
    .AddValiBlob(opts => opts.DefaultProvider = "AWS")
    .UseAWS()
    .WithImageProcessing(opts =>
    {
        opts.MaxWidth     = 2048;
        opts.MaxHeight    = 2048;
        opts.JpegQuality  = 80;
        opts.OutputFormat = ImageOutputFormat.WebP;

        opts.Thumbnail = new ThumbnailOptions
        {
            Width  = 300,
            Height = 300,
            Suffix = "_thumb"  // stored as "uploads/photo_thumb.webp"
        };
    });

Combined with validation

builder.Services
    .AddValiBlob(opts => opts.DefaultProvider = "Azure")
    .UseAzure()
    .WithPipeline(p => p
        .UseValidation(v =>
        {
            v.AllowedExtensions = new[] { ".jpg", ".jpeg", ".png", ".webp", ".gif" };
            v.MaxFileSizeBytes  = 20 * 1024 * 1024; // 20 MB before processing
        })
    )
    .WithImageProcessing(opts =>
    {
        opts.MaxWidth     = 1920;
        opts.MaxHeight    = 1080;
        opts.JpegQuality  = 82;
        opts.OutputFormat = ImageOutputFormat.Jpeg;

        opts.Thumbnail = new ThumbnailOptions
        {
            Width  = 200,
            Height = 200,
            Suffix = "_sm"
        };
    });

Usage

Once registered, image processing is fully transparent — just upload normally:

public class PhotoService(IStorageProvider storage)
{
    public async Task<PhotoResult> UploadPhotoAsync(IFormFile file, string userId)
    {
        await using var stream = file.OpenReadStream();

        var result = await storage.UploadAsync(new UploadRequest
        {
            Path        = StoragePath.From("photos", userId, file.FileName),
            Content     = stream,
            ContentType = file.ContentType
        });

        if (!result.IsSuccess)
            throw new Exception(result.ErrorMessage);

        // Image was automatically resized + converted + thumbnail generated
        return new PhotoResult
        {
            Url          = result.Value!.Url,
            ThumbnailUrl = result.Value!.ThumbnailUrl  // populated when opts.Thumbnail is set
        };
    }
}

How the pipeline works

Client upload (original JPEG, 8 MB, 4000×3000)
        │
        ▼
┌───────────────────────┐
│  ValidationMiddleware  │  ← reject if wrong extension / too large
└───────────┬───────────┘
            │
            ▼
┌───────────────────────┐
│  ImageSharpMiddleware  │  ← resize → 1920×1080, convert → WebP, quality 80
└───────────┬───────────┘        also generates 300×300 thumbnail
            │
            ▼
┌───────────────────────┐
│     Cloud Provider     │  ← store processed image + thumbnail
└───────────────────────┘

Non-image content types (e.g. PDF, ZIP) pass through unchanged.

Supported input formats

Output formats

Options reference

Aspect ratio: Images are resized with aspect-ratio preservation (fit inside MaxWidth × MaxHeight without cropping). Thumbnails are cropped to fill the exact Width × Height specified.

Features

Documentation

• Image processing docs
• Pipeline & Middleware
• Full documentation

Links

• GitHub Repository
• NuGet Package

Donations

If Vali-Blob is useful to you, consider supporting its development:

• Latin America — MercadoPago
• International — PayPal

License

MIT License

Contributions

Issues and pull requests are welcome on GitHub.