SmokeDetector is a headless chatbot that monitors Stack Exchange for spam and abusive content in real time. It connects to the Stack Exchange WebSocket to receive new and edited posts, then runs them through a multi-layered detection engine that checks against extensive blacklists (keywords, websites, usernames, phone numbers, IP ranges, nameservers, ASNs) and applies heuristic rules including DNS lookups, homoglyph detection, and similarity analysis. Detected spam is reported to designated chat rooms on Stack Exchange Chat, where moderators can provide feedback that feeds back into the system via the Metasmoke statistics service. The architecture is event-driven: the main loop in `ws.py` listens for WebSocket events, enqueues posts for scanning via `bodyfetcher.py`, and dispatches results to `spamhandling.py` for chat reporting. A command system in `chatcommands.py` allows operators to manage blacklists, inspect posts, and control the bot through chat messages. Persistent state is stored in pickle files, and the bot integrates with GitHub for automated blacklist pull requests. The detection logic in `findspam.py` is rule-based with over 100 rules registered via a decorator pattern, each with configurable filters for site, reputation, and score. Key reusable components include a generic TTL cache (`metasmoke_cache.py`), an extensible blacklist parser hierarchy (`blacklists.py`), a phone number matching module with homoglyph support (`phone_numbers.py`), and a command registration decorator. The codebase is well-tested with extensive parametrized tests and has CI/CD pipelines. While the core detection file is large and tightly coupled, many supporting modules are cleanly separated and could be extracted for other projects.
Mosparo is a self-hosted, open-source spam protection system that replaces CAPTCHA on web forms. It is built as a monolithic Symfony 6.4 application (PHP 8.1+) with Doctrine ORM supporting MySQL, PostgreSQL, and SQLite. The system provides a multi-tenant architecture where each project (website) can define custom spam detection rules (field rules for words, emails, domains, IPs, user agents, etc. and submission rules like random value detection) and security measures (honeypot, minimum time, proof-of-work, request delaying, IP lockout, equal submission blocking). Integration is done via a frontend JavaScript widget that communicates with a verification API. The codebase also includes an administration panel for system settings, user management, GeoIP2 integration, rule package imports, statistics, and self-update capabilities. The architecture follows standard Symfony patterns with controllers, services (helpers), repositories, and Twig templates. The rule engine is extensible via interfaces and is reasonably well-tested at the unit level. The project is actively maintained with a robust CI/CD pipeline and Docker support.