Simple Download Manager

Simple Download Manager is a complete desktop application built with Python and CustomTkinter. It downloads files from direct URLs, accelerates transfers with segmented multi-threading, supports pause and resume, and keeps a persistent download history across application restarts.

Features

The project includes:

• a src-based package layout
• a runnable CustomTkinter desktop shell
• domain models for downloads and status tracking
• an HTTP probe service that inspects remote files before download
• a simple download manager with worker threads, pause, resume, cancel, partial resume, and file assembly
• SQLite-backed task history loaded automatically on startup
• SQLite-backed per-segment metadata for richer recovery and diagnostics
• configurable default save location, thread count, retry count, and max concurrent downloads
• queueing when the concurrent download limit is reached
• optional scheduled start times per download
• shared bandwidth limiting across active downloads
• queue actions for removing tasks and opening download folders
• direct open-file actions for completed downloads
• advanced progress with live speed and ETA
• a recent activity panel and in-app completion/failure notifications
• a live task details dialog for segment-level diagnostics
• unit and integration tests for speed tracking, persistence, segment resume, and end-to-end downloads

Functional Coverage

This implementation satisfies the project requirements for:

• file downloading from URLs
• multi-threaded segmented downloads
• HTTP Range request handling
• error handling with automatic retry
• pause and resume
• progress monitoring with percentage, speed, and ETA
• download history persistence
• download scheduling
• bandwidth limiting
• resume after application restart
• queue management

Architecture

graph TD
    UI[UI Layer] --> APP[Application Controller]
    APP --> DM[Download Manager]
    DM --> HTTP[HTTP Probe Service]
    DM --> CTRL[Thread Controller]
    CTRL --> WORKERS[Segment Workers]
    CTRL --> ASSEMBLER[File Assembler]
    DM --> CORE[Download Domain Model]
    DM --> PERSIST[SQLite History Store]

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The application follows a layered desktop architecture with a clear split between UI, orchestration, download execution, and persistence. Communication between components is handled through Python objects, threads, and HTTP requests.

Project Layout

Simple Download Manager/
├── main.py
├── pyproject.toml
├── requirements.txt
├── src/
│   └── sdm/
│       ├── app.py
│       ├── core/
│       ├── models/
│       └── ui/
└── tests/

Testing

Run the full automated suite:

python -m pytest

Current result: 19 passed.

Run

Create a virtual environment and install dependencies:

# Optional, but highly recommended
python3 -m venv venv

python -m pip install -r requirements.txt

If you are using Debian/Ubuntu:

sudo apt update
sudo apt install python3-tk

Finally, run the application:

python main.py

License

This project is licensed under the GNU General Public License v3.0. See the LICENSE file for the full text.