AvaDM

A modern, open-source download manager for Linux, Windows, and macOS.

AvaDM is a fast, reliable, and feature-rich alternative to XDM, IDM, and FDM. Built with C#/.NET on the cutting-edge Avalonia framework, it delivers concurrent multi-segment downloads, intelligent resumption, and a beautiful native desktop experience across all major platforms.

Features

• Multi-segment Downloads — Split files into multiple concurrent chunks for faster downloads (with fallback to single-stream for non-compliant servers), you can choose the amount of segments in the settings
• Intelligent Resumption — Pause and resume downloads at will; automatically recover from connection failures with exponential backoff
• Speed Control — Real-time speed limiting to cap bandwidth consumption
• Persistent Storage — SQLite index automatically saves progress and metadata, surviving application restarts
• Cross-Platform — Native support for Linux, Windows, and macOS with platform-specific UI integrations
• System Integration — Autostart on login, tray icon with live download status, desktop shortcuts, and system notifications
• Auto-Update — Built-in update checker with safe in-place replacement
• Crash Reporting — Automatic error logging and GitHub issue pre-fill for quick troubleshooting

Quick Start

Download & Install

Visit the Releases page for pre-built binaries:

• Windows: Portable ZIP or Inno Setup installer
• Linux: tar.gz, AppImage, or .deb package
• macOS: DMG (unsigned; right-click → Open to bypass Gatekeeper)

From Source

# Clone the repository
git clone https://github.com/AvaDM-org/AvaDM.git
cd AvaDM

# Build and run the desktop UI
dotnet run --project src/AvaDM.UI

# Or the lightweight console interface
dotnet run --project src/AvaDM.Console

Requirements:

• .NET 10.0 SDK or later
• On Linux: GTK 3 development libraries (for Avalonia)

Project Structure

• src/AvaDM.Core — Core download engine and SQLite persistence layer
• src/AvaDM.UI — Avalonia-based desktop application (primary user-facing interface)
• src/AvaDM.Console — Lightweight Terminal.Gui console harness for headless operation and testing
• test/AvaDM.Core.Tests — xUnit test suite for the download engine

Architecture Highlights

Download Engine

AvaDM's core (Downloader.cs) uses modern .NET patterns for efficient concurrent I/O:

1. Smart Headers — Sends HEAD requests to detect server capabilities and content length
2. Parallel Chunks — For range-capable servers, splits files into concurrent byte ranges with a shared speed limiter
3. Pre-Allocation — Writes directly to a .avadm working file using File.OpenHandle and RandomAccess.WriteAsync to avoid stream synchronization overhead
4. Graceful Fallback — Single-stream downloads for non-compliant servers
5. Resilience — Polly-based retry pipeline with exponential backoff for transient errors

Persistence

• SQLite stores one record per (URL, destination path) in the platform data directory
• A binary footer in the .avadm file tracks chunk ranges, statuses, and byte counts
• Checkpoints occur every 5 seconds and on shutdown for safety
• Resumption is conflict-aware: stale or mismatched data triggers a safe fresh start

Desktop UI (Avalonia)

• Downloads Page — Live progress per download and per chunk, with pause/resume/cancel controls
• Settings Page — Configure download directory, chunk count, retries, speed limits, and UI preferences
• Tray Integration — Quick access to active downloads and window control
• Auto-Update — Check and apply updates with automatic restart
• Dark/Light Themes — Seamless theme support

Configuration

Most settings are available in the UI:

• Download Directory — Where completed files are saved
• Chunk Count — Number of parallel segments (1–n; default 5)
• Retry Strategy — Max attempts and backoff delay (default: 5 attempts, 30s per-attempt timeout)
• Speed Limit — Bytes per second (adjustable while downloading)
• Repository Path — Location of the SQLite metadata database (defaults to platform app-data directory)

UI-only preferences (theme, close-to-tray, autostart) are stored alongside the metadata.

Console Interface

For headless or scriptable use, the Terminal.Gui console harness supports:

start <url> [destPath] [chunkCount] [--resume|--overwrite|--rename <path>]
pause <id>
resume <id>
cancel <id>
speed <id> <bytesPerSec|off>
status [id]
setpath <dir>
quit

Building Releases

Releases are built and published via GitHub Actions on version tags:

git tag vX.Y.Z
git push origin vX.Y.Z

The workflow builds Windows, Linux, and macOS artifacts in parallel:

• Windows — Self-contained zip and Inno Setup installer
• Linux — Portable tar.gz, AppImage, and .deb
• macOS — DMG with .app bundle for both x64 and ARM64

All artifacts are verified against SHA256SUMS.txt before in-place updates.

Roadmap

Planned features (not yet implemented):

• Automatic download rehydration on startup
• Dynamic chunk tuning and retry-with-resume
• ETag/Last-Modified revalidation
• Richer protocol support (FTP, magnet, torrent)
• Code signing (Windows executables and macOS notarization)
• End-to-end test coverage for network failures and disk errors

Development

Running Tests

dotnet test

Code Style

Follow standard C# conventions. The codebase uses:

• async/await for I/O-bound work
• MVVM (CommunityToolkit.Mvvm) for the UI layer
• Immutable event data and defensive copying

Key Entry Points

• UI: src/AvaDM.UI/App.axaml.cs — Object graph wiring
• Console: src/AvaDM.Console/Program.cs — Terminal.Gui setup
• Core: src/AvaDM.Core/DownloadManager.cs — Orchestration
• Transfer: src/AvaDM.Core/Downloader.cs — HTTP and chunk logic

For detailed architecture, see docs/AvaDM-project-description.md.

Contributing

Contributions are welcome! Please see CONTRIBUTING.md for guidelines on opening issues, submitting pull requests, and setting up your development environment.

License

AvaDM is open source and available under the MIT License.

Support

• Report Bugs — GitHub Issues
• Discuss Features — GitHub Discussions
• View Logs — Settings > Log Folder (captures full Serilog output)

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Built with Avalonia and .NET.