MiDM — Modern Internet Download Manager

A fast, modern download manager for Windows built with:

• Python 3.13 — Async download engine with dynamic segmentation
• Tauri 2 — Native Windows app shell (Rust)
• React + Vite — Modern UI with real-time progress

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Architecture

MiDM/
├── backend/                  # Python async download engine
│   ├── core/
│   │   ├── downloader.py     # IDM-style dynamic segment engine
│   │   └── manager.py        # Queue, state persistence, scheduling
|   |   └── settings.py 
│   └── server.py             # WebSocket + HTTP bridge to UI
│
├── midm-ui/                  # Tauri + React frontend
│   ├── src/
│   │   ├── components/
│   │   │   ├── TitleBar.jsx
│   │   │   ├── Sidebar.jsx
│   │   │   ├── DownloadList.jsx
│   │   │   └── AddDownloadModal.jsx
|   |   |   └── SettingsModal.jsx
|   |   |   └── Statusbar.jsx
│   │   ├── store/
│   │   │   └── downloadStore.js   # Zustand + WebSocket state
│   │   ├── App.jsx
│   │   └── App.css
│   └── src-tauri/            # Tauri Rust shell
│
├── setup.bat                 # One-time setup
├── dev.bat                   # Development mode
├── build.bat                 # Build production .exe
└── requirements.txt

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Prerequisites

Tool	Version	Download
Python	3.11+	https://python.org
Node.js	18+	https://nodejs.org
NPM	11+	https://npmjs.com
Rust	latest	https://rustup.rs
VS Build Tools	2019+	https://visualstudio.microsoft.com/visual-cpp-build-tools/

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Getting Started

1. One-time Setup

setup.bat

2. Development Mode (2 terminals)

# Terminal 1 — Python backend
python backend/server.py

# Terminal 2 — Tauri UI
cd midm-ui
npm run tauri dev

Or use the helper script:

dev.bat

3. Build Production .exe

build.bat

Output → midm-ui/src-tauri/target/release/bundle/nsis/MiDM_1.0.0_x64-setup.exe

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How the Download Engine Works

MiDM implements IDM's core algorithm:

1. Probe: HEAD request to get file size and check Accept-Ranges: bytes
2. Segment: Split file into N equal parts (default: 8)
3. Parallel fetch: Each segment downloads on its own async connection
4. Dynamic stealing: When a thread finishes, it splits the largest remaining segment in half and takes over the second half — no thread ever idles
5. Merge: Segments assembled in order into the final file
6. Resume: .part files persist across restarts via state saved to ~/.midm/state.json

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WebSocket Protocol

The UI communicates with the Python backend over ws://localhost:7475/ws.

Commands (UI → Backend):

{ "cmd": "add_download", "data": { "url": "...", "connections": 8 }, "id": "1" }
{ "cmd": "pause",   "data": { "id": "abc123" }, "id": "2" }
{ "cmd": "resume",  "data": { "id": "abc123" }, "id": "3" }
{ "cmd": "cancel",  "data": { "id": "abc123" }, "id": "4" }
{ "cmd": "remove",  "data": { "id": "abc123", "delete_file": false }, "id": "5" }

Events (Backend → UI):

{ "type": "event", "event": "task_added",    "data": { ...task } }
{ "type": "event", "event": "task_progress", "data": { ...task } }
{ "type": "event", "event": "task_updated",  "data": { ...task } }
{ "type": "event", "event": "task_removed",  "data": { "id": "abc123" } }

HTTP API (for browser extension): http://localhost:7475

GET  /status      → health check
GET  /downloads   → all tasks
POST /add         → { "url": "..." }
GET  /stats       → aggregated stats

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Keyboard Shortcuts

Shortcut	Action
Ctrl+N	New download
Escape	Close modal

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Roadmap

• Phase 1: Dynamic segment engine
• Phase 2: WebSocket bridge
• Phase 3: Tauri + React UI
• Phase 4: Browser extensions (Chrome, Firefox, Edge)
• Phase 5: Scheduler (download at night, speed limits)
• Phase 6: System tray icon
• Phase 7: Auto-update

License

Copyright 2026 Mohaimenul Islam Mubin

Licensed under the Apache License, Version 2.0. See LICENSE for details.