Piik/docs/product/rooms-access.md

Rooms And Access

This file owns the current room, admission, invitation, and persistence contract. ADR-0002 explains the storage decision; implementation detail belongs in code and tests.

Room Authority

• A room has one Host and at most 20 authenticated Viewers.
• Room codes are random free four-digit values from 1000..9999. A code locates a room; it is not a secret or permanent identity.
• Every room has a 256-bit Host token. The server stores only its digest; the owning Browser keeps the raw token locally.
• Each Host tab retains its current room in session storage. The origin keeps one persistent resume hint and a separate preferred code; a new tab may resume that room only when no other tab claims it. Secure Browser origins use Web Locks, including protection against copied tab storage. Without Web Locks, fresh tabs create independent rooms and same-tab reload can retain authority, but duplicated-tab exclusion is not guaranteed. Closing the tab releases its claim; losing Host authority clears that tab without erasing another tab's resume hint.
• Dormant rooms have a configurable lease, default 24 hours. An authenticated online Host clears the lease deadline whether or not it is currently sharing; Host absence starts the dormant lease. The exact Host token resumes an unexpired room; Viewer activity never renews it.
• The Host may replace its room code. Replacement atomically creates a different room and invalidates the old ownership, invitations, password, sessions, routes, and media resources. It ends an active share and stops its capture tracks; it does not migrate or automatically restart capture.
• A locally remembered preferred code is only a request. The server remains the authority and allocates another code when that code is unavailable or expired.

Admission Paths

Three independent authorities exist:

1. Site access. Production requires an independent SITE_ACCESS_PASSWORD. Successful entry creates a stateless, HttpOnly, SameSite=Strict cookie with a 24-hour rolling idle lifetime. An already authorized page renews it through the site-access check while it remains active. It authorizes room creation, Host role, and code-only Viewer attempts; it is not a room credential, and Viewer-grant admission cannot create or renew it. Cookie transport attributes follow the configured destination: public HTTPS retains the Secure host-prefixed cookie, while a separately configured HTTP LAN origin can use its HTTP cookie. Login, renewal, room creation and WebSocket admission use that same selection.
2. Host ownership. The exact Host token authorizes that room's Host and access-management operations. It cannot authorize another room.
3. Viewer invitation. Every room creates a 128-bit, 22-character base64url Viewer grant. It authorizes only the Viewer role for that exact room incarnation and bypasses site access and code-entry policy.

The invitation grant is carried in the URL fragment, removed from the address bar on first read, and retained only in room-scoped sessionStorage. Refreshing the same tab preserves it. It is not intentionally persisted across independent tabs or Browser sessions; tab duplication and opener initialization remain Browser behavior. The grant has no independent TTL and ends with the room or when the Host rotates or revokes it.

Code-only admission is independent of invitations:

• open admits a site-authorized Viewer by room code;
• private without a password is invitation-only;
• private with a password additionally admits a site-authorized matching code-and-password attempt.

An unknown, reclaimed, or expired code returns ROOM_NOT_FOUND. A current room that refuses a code-only attempt returns the generic ROOM_ACCESS_DENIED result without exposing its exact policy. Invalid grants and Host ownership failures remain separate.

Rotating or revoking the Viewer grant is a strong authorization change. The new generation is committed before old Viewers, signaling grace, routes, and sender edges are closed. An affected SFU Viewer's exact embedded subscription is closed before its egress reservation is released. Room-authenticated signaling cannot recreate a revoked subscription; no separate media token survives revocation. Changing code-entry policy or password affects later code-only attempts and does not silently revoke invitations.

Persistence Modes

• Lightweight mode: without ROOM_DATABASE_PATH, room authority is process memory and all rooms disappear on restart.
• Stable mode: with an explicit SQLite path, one exact-schema owner persists room authority across application restart.
• Client Local mode: the packaged Client composes the same memory RoomStore and ends every room when its local authority exits. It persists only its Site choice and optional Local site-access password, not rooms or media state. A blank password leaves that local site open.

The Client opens its own localhost Host page with the configured password, when present, in a fragment. The page removes the fragment and uses the existing SiteAccess endpoint; this does not create a fourth admission authority. LAN and one-link Internet Viewers use the same room-scoped invitation grant; its fragment never enters the public tunnel request, and the Host's Local RoomStore remains the only authority. Selecting a Site moves room authority wholly to that Site rather than synchronizing two stores.

Stable mode does not persist participants, signaling sessions, sharing state, routes, codec decisions, quality evidence, or SFU state. After restart, clients reauthenticate and rebuild media; a room that was active becomes dormant with a fresh lease. Status owns the selected deployment mode and ADR-0002 owns storage validation.

The Host Browser may persist its creation preferences, including policy and an optional room password. Raw Viewer grants never enter localStorage, cookies, queries, server logs, or SQLite. Credentials, passwords, and invitation URLs are never committed to the repository.