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Technical Wiki

Backend (Rust)

The Tauri v2 command surface, internal plugin engine, metadata modules, and persistence architecture

Backend (Rust)

The Universal Game Launcher backend is a Rust codebase at src-tauri/ exposing a strongly typed command surface to the SvelteKit frontend via Tauri v2 IPC handlers and providing a headless CLI interface (--cli).

The core backend owns the application lifecycle, local SQLite persistence (database.sqlite), in-memory KV caching (mem_kv), storage footprint analytics, client launch delegation protocols, title normalization, and the automatic multi-source metadata cascade.

🧩 Backend Modules

Path Role
src-tauri/src/metadata/universal.rs Automatic multi-source metadata cascade querying Local Inspector, Libretro CDN, Steam Store, GOG Catalog v1, Wikipedia/Wikidata, and PCGamingWiki.
src-tauri/src/metadata/local.rs Local folder inspector parsing RPG Maker System.json ("gameTitle"), itch.io receipt manifests, rom.ini configurations, and binary headers.
src-tauri/src/metadata/steam_store.rs Steam Store API client parsing store details and modern Akamai CDN MP4 video trailers (movie_max.mp4).
src-tauri/src/plugins/title_normalizer.rs Dedicated Rust title normalization engine (normalize_game_title, normalize_rom_title, canonical_title_key) handling article inversion, unified subtitle separators, and slug separation.
src-tauri/src/plugins/engine.rs Platform discovery and launch specification engine.
src-tauri/src/cli.rs Headless CLI interface (--cli scan, scan-roms, scaffold-roms, normalize-title, inspect-local, launchers).
src-tauri/src/cache.rs Embedded SQLite persistence layer (database.sqlite) with WAL mode, prepared statements, and the high-speed in-memory KV tier (mem_kv).
src-tauri/src/settings.rs Application preferences, discovery roots, and plugin settings persistence.
src-tauri/src/commands.rs Tauri IPC commands, asynchronous scan triggers, and shared AppState.
src-tauri/src/lib.rs Tauri application builder, state mounting, and command registration.
src-tauri/src/platforms/ Platform detectors, launch protocol builders (steam://, com.epicgames.launcher://, goggalaxy://, native executables), and storage footprint discovery.
src-tauri/src/platforms/windows.rs Windows-specific APIs (registry inspection, known folders, shortcut resolution).
src-tauri/src/platforms/linux.rs Linux-specific APIs (XDG desktop entries, Flatpak manifests).
src-tauri/src/platforms/macos.rs macOS-specific APIs (Application Support discovery, NSWorkspace helpers).

🖥️ Primary Command Surface

Command Purpose
load_library Loads all games with collection memberships and artwork paths via the sub-millisecond in-memory KV tier.
get_cached_game_metadata Retrieves cached multi-source metadata (game_meta:<appId>) including developer, publisher, release date, genres, and modern video trailers.
fetch_external_json Native Rust HTTP proxy executing secure external GET requests with custom User-Agent headers, avoiding CORS blocks in the frontend.
load_collections Reads all custom and dynamic smart collections from local SQLite.
update_collection Add/remove games or rename a collection, persisting directly to local SQLite.
create_collection / delete_collection Creates or removes user collections safely.
launch_game Executes official client launch protocols (steam://, goggalaxy://, etc.) or spawns standalone binaries.
install_game / uninstall_game Delegates installation or uninstallation intent directly to official clients.
open_game_folder Opens the local installation directory in the host system file manager.
get_storage_report Calculates drive capacity and game disk footprints across all detected volumes via background workers.
get_cache_stats / clear_metadata_cache Inspects and resets cached artwork mappings and temporary keys.
detect_platforms Discovers games installed across official platform storefront clients.
get_installed_plugins Returns all discovered plugins with active states and capabilities.
toggle_plugin Enables or disables a plugin dynamically.

🔒 Non-Invasive Safety & Performance

  • Zero Client Modification: Never alters external client files (shortcuts.vdf, cloud-storage-namespace-1.json). Official clients can remain open and running freely.
  • Serverless In-Memory KV Tier (mem_kv): Library queries and collection filters complete in under 1 millisecond.
  • Zero Credentials: Launching and installation delegate entirely to the operating system protocol handlers or native binaries.

➡️ Next Steps