Air2: High-Performance Download Engine
Air2 is a high-performance, multi-threaded download manager written in Python. It focuses on maximizing download speed through ultra-high concurrency, dynamic chunking strategies, and support for multiple protocols including HTTP/HTTPS, SFTP, and extensible architectures for BitTorrent. The tool provides both an interactive command-line interface (CLI) with modern visual feedback and a scriptable mode for automation.
Features
High Concurrency: Optimized thread pool supporting up to 200 concurrent workers to maximize bandwidth usage.
Dynamic Chunking: Automatically adjusts chunk sizes based on file size to optimize throughput and reduce overhead.
Multi-Protocol Support: Native support for HTTP/HTTPS and SFTP; architecture designed for easy addition of BitTorrent and other protocols.
Robust Resume Capability: Handles Range requests efficiently to ensure zero data loss during network interruptions.
Modern CLI Interface: Built with the rich library for real-time progress bars, speed meters, and ETA calculations without clutter.
Intelligent Input: Optional integration with prompt_toolkit for command auto-completion, history navigation, and syntax highlighting.
Task Management: Full lifecycle control including add, start, pause, resume, cancel, remove, and automatic ZIP extraction.
Speed Limiting: Configurable download speed limits to prevent network congestion.
Single File Deployment: Designed as a single executable script for easy distribution and deployment.
Installation
Ensure you have Python 3.8 or higher installed. Install the required dependencies:
bash
1
Note: prompt_toolkit is optional but recommended for enhanced command-line features like auto-completion.
Usage
Interactive Mode
Run the script directly to enter the interactive shell:
bash
1
Available Commands:
help: Display command list and help text.
add <URL> [options]: Add a new download task.
start <task_id>: Start a waiting task.
pause <task_id>: Pause a running task.
resume <task_id>: Resume a paused task.
cancel <task_id>: Cancel a task (keeps downloaded files).
remove <task_id> [--delete]: Remove a task and optionally delete the file.
unzip <task_id> [output_dir]: Extract completed ZIP files.
list / ls: Show all tasks and their status.
status: Display system statistics and overall progress.
exit / quit: Close the application.
Example:
text
1234
Command Line Mode (Scripting)
You can also run commands directly from the terminal without entering the interactive shell:
bash
1234567891011
Options for add Command
--threads=N: Number of concurrent threads (default: 8).
--output=DIR: Destination directory (default: current directory).
--chunk-size=S: Force specific chunk size (e.g., 10M, 1G). Defaults to dynamic calculation.
--speed-limit=N: Limit download speed in KB/s (0 for unlimited).
--timeout=N: Request timeout in seconds.
--retry=N: Number of retry attempts on failure.
Architecture
The codebase is structured into distinct modules for maintainability:
DownloadEngine: Manages the core logic, including task queues, thread pools, and state synchronization.
ChunkDownloader: Handles individual block retrieval, error recovery, and checksum verification.
ProtocolHandler: Abstract base class for different protocols (HTTP, SFTP, etc.), allowing easy extension.
ModernCLI: Provides the user interface layer using rich and prompt_toolkit.
Configuration
The engine automatically detects file sizes and adjusts chunk counts. For large files (>1GB), it increases chunk size to 16MB; for medium files (>100MB), it uses 4MB chunks. This dynamic approach minimizes connection overhead while maintaining high parallelism.
Users can override these defaults via command-line arguments if specific network conditions require manual tuning.
License
This project is licensed under the MIT License.
Requirements
Python 3.8+
requests
rich
urllib3
prompt_toolkit (optional)