Falcon Downloader

Falcon is a cross-platform C++ downloader built as a monorepo. Its transfer foundation relies on open-source components such as libcurl, OpenSSL, libtorrent, and libssh2, all orchestrated around a unified engine that carries multi-protocol downloading.

Why Falcon?

• Concurrent downloads: a C++17 event-driven engine with multi-threaded chunking and resumable transfers
• Multi-protocol: HTTP/HTTPS, FTP, SFTP, WebDAV, BitTorrent, and Metalink enabled by default, plus a variety of optional protocol plugins
• Ease of use: provides both a CLI tool and a C++ API
• Extensible: a plugin-based architecture that makes adding protocols or capabilities easy
• Cross-platform: targets Windows, Linux, and macOS

Core Features

1. Multi-Protocol Downloads

Falcon currently focuses on composable protocol capabilities:

• Core protocols: HTTP/HTTPS, FTP/FTPS
• P2P / extended protocols: BitTorrent, ED2K
• Proprietary-protocol plugins: Thunder, QQ Whirlwind, FlashGet
• Streaming-protocol plugins: HLS, DASH

2. Concurrent Downloads and Resume

• Multi-threaded chunked downloads: splits files into chunks that are downloaded in parallel
• Resume: recovers interrupted tasks wherever range requests are supported
• Speed control: per-task speed limiting
• Connection reuse: reduces the overhead of repeated connection setup

3. Multiple Deployment Entry Points

• CLI tool: great for scripts and automation
• Daemon service: great for background jobs and remote management
• Core libraries: embeddable in other C++ projects
• Desktop app / browser extension: the code is already in the repository

Project Architecture

falcon/
├── packages/
│   ├── libfalcon-core/      # Core download engine, task model, event system
│   ├── libfalcon-protocols/ # Standard download protocols
│   ├── libfalcon-storage/   # Object storage and remote resource browsing
│   ├── libfalcon-drives/    # Cloud drive and share-link capabilities
│   ├── falcon-cli/          # Command-line tool
│   └── falcon-daemon/       # Background daemon
├── apps/
│   ├── desktop/             # Desktop application
│   └── browser_extension/   # Browser extension
└── docs/                    # Project documentation

Quick Start

Install

git clone https://github.com/cuihairu/falcon.git
cd falcon
cmake -B build -S . -DCMAKE_BUILD_TYPE=Release
cmake --build build --config Release

Basic Usage

# Download a single file
falcon-cli https://example.com/file.zip

# Multi-threaded download
falcon-cli https://example.com/large.zip -c 5

# Download a Thunder link
falcon-cli "thunder://QUFodHRwOi8vZXhhbXBsZS5jb20vZmlsZS56aXAuWg=="

# Read URLs from a file for batch downloading
falcon-cli -i urls.txt -j 3

Using the C++ API

#include <falcon/falcon.hpp>

int main() {
    falcon::DownloadEngine engine;

    falcon::DownloadOptions options;
    options.max_connections = 5;

    auto task = engine.add_task(
        "https://example.com/file.zip",
        options
    );

    if (task) {
        engine.start_task(task->id());
        task->wait();
    }
    return 0;
}

Documentation Navigation

• Getting Started - Get to know Falcon quickly
• Installation Guide - Detailed build steps
• Usage Guide - CLI and API usage
• Protocol Support - An overview of all supported protocols
• Developer Guide - Contributing and plugin development
• FAQ - Answers to common questions

Community

• GitHub: https://github.com/cuihairu/falcon
• Issues: https://github.com/cuihairu/falcon/issues
• Discussions: https://github.com/cuihairu/falcon/discussions

License

Apache License 2.0

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Getting Help

If you run into problems, check the FAQ first, or ask in GitHub Issues.