Copper Download Manager

A high-performance, cross-platform download manager written in C++17 with Qt6.

Features

Multi-chunk HTTP downloads — Split files into multiple chunks for maximum speed
Torrent & Magnet support — Via aria2c integration
YouTube/video downloads — Via yt-dlp integration with format selection
Browser extension — Chrome & Firefox extensions to intercept downloads automatically
Playlist support — Download entire playlists with track numbering
Speed limiter — Set download/upload speed limits
Resume & pause — Pause and resume downloads at any time
Single instance — Multiple launches forward URLs to the running instance
System tray — Minimize to tray with download progress

Supported Platforms

Platform	Status
Windows	Supported
macOS	Supported
Linux	Supported

Requirements

Qt 6.5+ (validated on Qt 6.11.2 MinGW 64-bit) — LGPLv3
CMake 3.16+ (validated on 3.30.5)
Ninja build system
C++17 compiler — MinGW/GCC (validated on GCC 13.1.0, x86_64-posix-seh); also MSVC 2019+ / Clang 10+
Optional: libtorrent-rasterbar (torrent support; otherwise aria2c is used)

Note: Because the executable is linked as a GUI (Win32) application, it no longer opens a terminal/console log window on launch. Logs go only to copper.log in the app-data folder.

Building (Windows, MinGW)

Install Qt + MinGW toolchain (e.g. C:\Qt\6.11.2\mingw_64 with C:\Qt\Tools\mingw1310_64).
Ensure gcc, ninja, and cmake are on PATH.
Configure and build (use a space-free build directory):

cmake -S . -B C:\Qt\Builds\CopperDownloadManager\rel -G Ninja ^
  -DCMAKE_BUILD_TYPE=Release ^
  -DCMAKE_PREFIX_PATH=C:/Qt/6.11.2/mingw_64
cmake --build C:\Qt\Builds\CopperDownloadManager\rel

Windows version/icon resource: app.rc is compiled from a copy inside the build tree by windres (invoked directly, with no include flags, so the source path may contain spaces). The resulting .rsrc object is then normalized by tools/fix_version_resource.py to fix a binutils 2.39 windres quirk that otherwise makes the version invisible to Windows; the exe reliably reports FileVersion/ProductVersion in Explorer and via GetFileVersionInfo.

The release build is automatically deployed to installer/release/<version>/ (windeployqt) and the final package (Setup.exe + portable zip) is placed in Release/.

CI

A GitHub Actions workflow (.github/workflows/ci.yml) builds the project in Debug and Release on Windows (Qt 6.6.3), smoke-checks that the produced executable is a GUI (non-console) application, and uploads a portable zip artifact. (CI uses the Qt version whose MinGW binaries link against the runner's preinstalled GCC; the local dev machine additionally uses Qt 6.11.2.)

External Tools (Downloaded on Demand)

Copper downloads these tools when the user requests them from Settings → Tools:

Tool	Version	License	Purpose
aria2c	1.37.0	GPLv2	Torrent/magnet downloads
FFmpeg	Latest	GPL v2+	Audio/video processing
yt-dlp	2026.07.01	Unlicense	Video/audio downloading

Project Structure

Copper Download Manager/
├── CMakeLists.txt          # Build configuration
├── main.cpp                # Entry point, single-instance logic
├── app.rc                  # Windows resource file (icon, version)
├── THIRD-PARTY-NOTICES.txt # License notices for all dependencies
├── Assets/                 # Application icons
├── extensions/             # Browser extensions (Chrome & Firefox)
│   ├── Copper Download Manager Chrome/
│   └── Copper Download Manager Firefox/
├── include/
│   ├── core/               # Core download engine headers
│   ├── db/                 # Database manager header
│   ├── ui/                 # UI headers
│   └── utils/              # Utility headers (aria2c, ffmpeg, yt-dlp)
└── src/
    ├── core/               # Download engine implementation
    ├── db/                 # SQLite database
    ├── ui/                 # Qt UI (MainWindow, Settings, dialogs)
    └── utils/              # External tool managers