Asar 1.0.0

Asar

Asar is a high-performance, full-featured C# library designed for the modern .NET ecosystem. It provides a robust and intuitive API for reading, writing, and manipulating ASAR (Atom Shell Archive) files—the standard packaging format for Electron applications.

Built with a focus on performance and developer productivity, Asar offers first-class support for random-access streaming, asynchronous I/O, and thread-safe operations, making it suitable for everything from simple extraction tools to complex build pipelines.

Key Features

• 🚀 High Performance: Memory-efficient streaming and O(1) path resolution.
• 🧵 Thread-Safe: Concurrent random-access reads powered by shared stream locking.
• 🔄 Full Lifecycle Support: Create, Read, Update, and Delete (CRUD) operations on archives.
• ⚡ Async-First: Comprehensive Task-based APIs for responsive applications.
• 📦 Advanced Packing: Intelligent directory packing with glob filtering and native module (.unpacked) support.
• 🛡️ Data Integrity: Preservation of Electron integrity blocks and POSIX executable bits.
• 💎 Multi-Target: Optimized for .NET 8, 9, and 10.

Getting Started

Installation

Add the Asar package to your project via the NuGet CLI:

dotnet add package Asar

Quick Start

Read an existing archive

using Asar.Core;

// Open an archive for reading
using var archive = AsarArchive.Open("app.asar");

// Read file content directly
string config = archive.ReadAllText("config.json");

// Or use high-performance streaming for large files
using var stream = archive.OpenEntryStream("assets/video.mp4");

Modify and save

using var archive = AsarArchive.Open("app.asar");

// Update or add new files
archive.AddFile("main.js", "console.log('Patched!');");
archive.RemoveFile("old-asset.png");

// Save the changes
archive.Save("app-updated.asar");

Pack a directory

// Pack an entire folder with default Electron conventions
AsarPacker.Pack("./src", "app.asar");

Core Components

Why Asar?

Random-Access Guarantee

Unlike many archive libraries that require sequential scanning, Asar parses the archive header into an in-memory tree. This enables true random access: you can Seek to any byte in any file without reading the preceding data.

Optimized for Large Data

Whether you are working with a few kilobytes or several gigabytes, Asar maintains a constant memory footprint by leveraging modern .NET Stream and Span<byte> APIs.

Electron Compatibility

Asar is designed to be fully compatible with the official Electron asar tool. It correctly handles the companion .unpacked directories required for native .node modules and preserves file metadata across platforms.

Documentation

For more information, technical documentation, and usage examples, please visit the Github wiki page.

Feedback & Contribution

This project is maintained by Koray USTUNDAG. If you encounter any issues or have feature requests, please open an issue on the GitHub repository.

License

The Asar library is licensed under the MIT License.

Copyright © 2026 Koray USTUNDAG