lanspread

Peer-to-peer game library sharing for LAN parties. Peers discover each other on the local network via mDNS, exchange library metadata over QUIC, and let users browse and download games from each other. Ships as a Tauri desktop app.

Peer identity and protocol status

Each desktop installation creates and reuses one Ed25519 identity in its Tauri app-data directory. Its PeerId is lowercase unpadded RFC 4648 base32 of BLAKE3 over the certificate's complete canonical DER SubjectPublicKeyInfo; certificates and private keys are never distributed from the repository. Outbound QUIC connections authenticate the responder against the exact expected PeerId. Wire protocol 8 (lanspread/8) is the only supported protocol. Peers exchange responder-owned, revisioned snapshots over identity-pinned endpoints; file and streamed-install requests name the catalog's exact ContentId. There are no legacy wire fallbacks or repository-shared identity keys.

First-time setup

Install Rust, Deno, and just first, then bootstrap the project:

just setup

That installs the Tauri CLI and the locked frontend dependencies. All routine repository work should go through just; the recipes carry the catalog mode and Tauri resource configuration needed to keep fixture authority out of production builds.

Daily development

Run the desktop app with the already-generated production catalog:

just run

Plain just (or the j shell alias) does the same. It checks the existing catalog and starts the launcher; no source package directory or environment variables are needed. Select the folder containing your games in the launcher.

To test directly with a local game folder and a separate catalog:

just run-local /srv/lanspread/test-games

This selects that game folder and generates or reuses test authority under crates/lanspread-tauri-deno-ts/src-tauri/local-catalog/, with its own cache in .lanspread/catalog-cache/local.json. Missing catalog games and differing version.ini values are allowed; directory names must still match known game IDs. The console identifies this as local test mode. Its opt-in is checked at build time and cannot enable local authority in a production build. The local launcher uses separate test settings and a window title marked LOCAL TEST.

Build a launcher from the already-published production catalog without creating an installer:

just build

Generate the production catalog from a package tree when necessary, then build the same no-bundle launcher:

just build-production /srv/lanspread/packages

To regenerate or reuse production authority from a package tree and then run:

just run-production /srv/lanspread/packages

The fixture-only paths remain explicit:

just run-fixture
just build-fixture

Run the standard checks before committing:

just fmt
just clippy
just test
just frontend-test

just build always uses the production resource map and production profile; use just build-fixture when a fixture build is intended. Tauri's build script rejects fixture and local resources unless their explicit development opt-in is present, and the production profile rejects both modes. Before Tauri copies catalog resources, the build script clears the generated game.db and manifests/ in the active Cargo profile directory. This keeps fixture/production switches and reduced production catalogs free of stale manifests. Cargo also watches these generated copies, so deleting them causes the next build to recreate them even when the source catalog is unchanged.

Catalog checksums and production manifests

Lanspread does not trust file descriptions received from peers. The release catalog contains the expected bytes for each included game version. The catalog publisher derives that authority from the canonical game packages and writes:

• one <game_id>.json manifest containing every ordinary file's size, full-file BLAKE3, and BLAKE3 for each 128 MiB transfer chunk;
• BLAKE3 and size for every file obtained by extracting the root-level .eti archives, which authorizes Stream Install output; and
• catalog-content-index-v1.jsonl, which binds every catalog game/version to its complete manifest ContentId and Stream Install capability.

The ContentId is a digest of the canonical manifest transcript, not merely a hash of one archive. Never calculate or edit these values by hand.

Prepare the package tree

Place the canonical packages under one directory, with each direct child named exactly like the game_id in the production game.db:

/srv/lanspread/packages/
├── alienswarm/
│   ├── version.ini
│   ├── alienswarm.eti
│   └── ...
├── bf1942/
│   ├── version.ini
│   ├── bf1942.eti
│   └── ...
└── ...

Each version.ini must match that game's game_version in game.db. Package entries must be regular files/directories with canonical portable names; links, reparse points, special files, aliases, unsafe archive output, or changing bytes make generation fail closed.

The default publisher uses the checked-in Linux unrar sidecar. Select another trusted executable when generating on a different supported host:

LANSPREAD_UNRAR=/absolute/path/to/unrar \
  just catalog-generate-production /srv/lanspread/packages

Generate and verify checksums

Generate the complete production catalog:

just catalog-generate-production /srv/lanspread/packages

The default remains strict: every game in the checked-in source game.db must have a package directory. To build a reduced catalog from only the package directories currently available, pass the explicit optional mode:

just catalog-generate-production /srv/lanspread/packages allow-missing-games

allow-missing-games omits absent package directories and reports their count; it still rejects a package whose version.ini differs from the source catalog. Version mismatches have their own independent opt-in:

just catalog-generate-production /srv/lanspread/packages allow-version-mismatch

That mode reports mismatched game IDs and uses each package's actual version.ini value in the generated database copy, while still requiring every package directory. Combine both options for an older, incomplete package corpus:

just catalog-generate-production /srv/lanspread/packages \
  allow-missing-games allow-version-mismatch

Invalid directories and unreadable or non-UTF-8 version files always fail. The generator copies and filters game.db to exactly the included games, then generates and validates their complete manifest/index set. At least one matching source-catalog game must be present. The checked-in full database is never modified; the coherent generated output is installed under crates/lanspread-tauri-deno-ts/src-tauri/production-catalog/.

The mode can also be used while running or building real data:

just run-production /srv/lanspread/packages \
  allow-missing-games allow-version-mismatch
just build-production /srv/lanspread/packages \
  allow-missing-games allow-version-mismatch

The recipe keeps a local metadata-only stamp in .lanspread/catalog-cache/production.json. It compares the package tree's paths, entry types, sizes, and nanosecond mtimes, plus the source and generated catalog databases, generation mode, and unrar metadata. If those values and the published output still match, the expensive package hashing and extraction step is skipped. This is only a performance cache: catalog-check-production and every production build still validate the catalog authority. Force a refresh when needed:

LANSPREAD_CATALOG_FORCE=1 just catalog-generate-production /srv/lanspread/packages

The publisher first checks every included package's version.ini against the generated game.db, then independently reads and hashes each package twice before publication. It creates the complete database, manifest, and index set in staging and validates it with the application loader before atomically replacing the previous production catalog directory.

Verify the published database/index/manifest set without rereading the package corpus:

just catalog-check-production

This is a packaging integrity check, not a substitute for retaining the canonical packages and the successful generation log as provenance. The output prints the game_id, game_version, and content_id for every checked game.

Regenerate one changed game

After a complete manifest set exists, update one game without rehashing every package:

just catalog-generate-production-game /srv/lanspread/packages alienswarm
just catalog-check-production

Incremental generation refuses to bootstrap a catalog. Under its durable publication marker it revalidates every unselected manifest/index identity, rebuilds the complete generated index, and then publishes the selected game. Use the main generation command for a new catalog or any intentionally broad catalog change.

Build a production bundle

Only after the production check succeeds, create the installer/bundle:

just bundle

just bundle repeats the production catalog gate before Tauri packaging. It never falls back to fixture manifests. This checkout does not include generated production authority, so the command intentionally fails until an external package corpus has been processed into crates/lanspread-tauri-deno-ts/src-tauri/production-catalog/.

Fixture catalogs and peer-CLI acceptance

The committed fixture profiles are test authority only:

just fixture-catalog-check       # explicit fixture GUI/CLI profile
just fixture-catalogs-check      # default + solid + multi + unknown profiles
just fixture-catalogs            # explicitly regenerate all committed profiles

The solid, multi-archive, and unknown-game profiles intentionally describe different package bytes, so the peer-CLI matrix checks all of them before building its Docker image. just run-fixture uses the default fixture profile.

Build or run the JSONL peer harness:

just peer-cli-build
just peer-cli-image
just peer-cli-tests S1 S2 S3
just peer-cli-run alpha

Run the entire S1-S49 acceptance matrix by omitting scenario arguments:

just peer-cli-tests

For an interactive three-peer session, start these in separate terminals:

just peer-cli-alpha
just peer-cli-bravo
just peer-cli-charlie

Important just commands

Command	Purpose
just setup	Install the Tauri CLI and frontend dependencies.
just / just run	Check the existing production catalog and run the GUI.
just run-local GAMES_DIR	Generate/reuse separate local test authority and run with that folder.
just run-production PACKAGES_DIR [MODE...]	Generate/reuse production authority and run the GUI.
just run-fixture	Check the default fixture catalog and run the GUI.
just build	Validate production authority and build without bundling.
just build-production PACKAGES_DIR [MODE]	Generate/reuse production authority and build without bundling.
just build-fixture	Check the default fixture catalog and build without bundling.
just bundle	Check production authority and build production bundles.
just catalog-generate-production DIR [MODE...]	Publish packages with explicit missing/version mismatch opt-ins.
just catalog-generate-production-game DIR GAME_ID	Safely regenerate one game in an already complete catalog.
just catalog-check-production	Validate all production database/index/manifest artifacts.
just fixture-catalog-check	Validate the default development fixture catalog.
just fixture-catalogs-check	Validate every peer-CLI fixture profile.
just fixture-catalogs	Regenerate all committed fixture profiles from their packages.
just fmt	Format Rust, TOML, Markdown, and the Justfile.
just clippy	Lint every Rust workspace target with warnings denied.
just test	Run every Rust workspace test target.
just frontend-test	Run the frontend reducer/lifecycle tests.
just peer-cli-build	Build the JSONL peer harness.
just peer-cli-image	Check fixture authority and build the harness Docker image.
just peer-cli-tests [SCENARIO ...]	Run selected scenarios, or the complete matrix when no IDs are supplied.
just peer-cli-run NAME	Start one persistent-state interactive harness peer.