shacraft-launcher/docs/launcher-architecture.md

ShaCraft Launcher architecture

Current capability

The launcher persists local settings, synchronises Aeronautics mod/config files from the signed ShaCraft v2 manifest, installs the exact Minecraft + NeoForge version the manifest specifies, and launches the game. A player signs in with the same local ShaCraft account used on the website. The game identity is derived only from that account's verified Aeronautics nickname; the legacy editable nickname setting is not trusted at launch.

The interface also shows a live Aeronautics player count from the fixed, read-only https://shacraft.ru/api/online/aoc endpoint. It is display-only: the result never controls files, versions, URLs, or the launch command.

Not yet implemented: a user-selectable profile directory, a "reset managed files only" recovery action, and signed cross-platform release builds of the launcher itself. Do not represent these as completed in UI or release notes.

Data flow

Two independent pipelines feed one launch:

ShaCraft manifest (mods/config + which MC/loader/Java version to use)
  signed-manifest endpoint -> Ed25519 verification (remote.rs)
  -> manifest schema + URL/path validation (manifest.rs)
  -> temporary download, SHA-256 verification, atomic replacement (profile.rs)

Game itself (never controlled by the manifest above)
  Mojang version manifest -> SHA-1-verified version JSON (mojang.rs)
  -> Java 21 via Adoptium if none installed (runtime.rs)
  -> NeoForge's own installer, run headlessly (neoforge.rs)
  -> generic inheritsFrom merge of the two version JSONs (mojang.rs)
  -> SHA-1-verified merged libraries + platform natives (mojang.rs)
  -> verified ShaCraft account link (shacraft_account.rs)
  -> deterministic offline UUID for the linked nickname (session.rs)
  -> java process spawned with the merged classpath/args (launch.rs)

Profiles (ShaCraft-managed mods/config, and the player's own worlds/ screenshots/resourcepacks) live below Tauri's app_data_dir()/profiles/ <profile-id> — this becomes --gameDir. The shared vanilla+NeoForge install (versions/libraries/assets/runtime, reused across profiles that target the same Minecraft version) lives at app_data_dir()/game. Settings live at app_data_dir()/settings.json, and the revocable ShaCraft session at app_data_dir()/shacraft-session (mode 600 on Unix). Passwords are never written to disk. None of these should be assumed to be the system .minecraft directory.

Aeronautics contract

• Profile ID: aeronautics
• Manifest endpoint: https://shacraft.ru/api/launcher/v2/profiles/aeronautics/signed-manifest
• Payload: manifest schema v1; also carries minecraft.{version, loader, javaMajor} (currently 1.21.1, NeoForge 21.1.248, Java 21) — the launcher reads this rather than hardcoding it, so a server-side version bump needs no launcher release.
• ShaCraft download files: HTTPS only, exact hosts shacraft.ru and cdn.shacraft.ru.
• Account API origin: fixed https://shacraft.ru; redirects are rejected.
• Launch identity: the most recently verified aoc nickname returned by the authenticated account API. Local nickname edits cannot select an identity.

Planned but not implemented

1. User-selectable profile directory and structured launcher logs.
2. "Reset managed files only" recovery action that doesn't touch player worlds/screenshots/resourcepacks.
3. Signed, cross-platform release builds of the launcher itself.
4. Real per-stage byte progress for the Java/NeoForge install steps (currently start/done only — the dominant, user-visible wait, asset downloading, already reports real bytes).

Do not represent these as completed features in UI or release notes.