open-standards/joule-code/joule-code-rs/crates/joule-moq-room/README.md

joule-moq-room

A room service for WAI live rooms (wai/extensions/live-rooms.md) over joule-moq-relay. It holds one room's authority and clock keys and:

• issues grants. A visitor's page makes an Ed25519 key and asks for a grant for it (POST /grant). The service signs a short-lived WRG1 grant: a publisher's (its own audio and video, one of the room's places) or a viewer's (the room to watch). A grant is public, so it is useless without its key: the relay, configured with the authority's key ([[auth.authorities]]), honours it only beside a proof of possession over the relay's own challenge (§10.5), which only the page that holds the key can make. Grants are bounded per client address and overall, and publishers per room. Every role, and so every grant, holds the seek power (live-rooms §3.3, bit 4): a visitor may fetch a track below its live edge (§10.6), from the relay's cache or its DVR window, as a late joiner does for the groups before it joined. A relay refuses such a fetch to a grant without it.

• authors the lifecycle (§7.2). The service's clock is a session on the relay. It watches each publisher's video track (a SUBSCRIBE that asks for no objects): when the track appears the clock signs join and publish for the publisher on its events track (live-events §8.1), and when the relay ends the track (the publisher's session closed) it signs leave. Pages author none of it.

• serves the room. GET /room gives the signed descriptor, the composition descriptor and the publishers' grants, which a page verifies the room with (live-rooms §9).

• keeps end-to-end encrypted rooms ([room] e2ee = true, WAI extensions/confidentiality.md). Each room then has a confidentiality record (WRE1) the authority signs, and one MLS group whose only external sender is the room's clock: the clock proposes the Add of each publisher it records joining and the Remove of each it records leaving, and follows the group from its public messages, holding no key. The service is the room's carrier of MLS messages (§5.1, §15.2): one log per room holding the clock's lifecycle records, its proposals, and every GroupInfo, commit and Welcome a member posts, in the order the clock took them; a post the clock refuses (§5.5) is not carried.

• admits by age ([age], WAI extensions/age-assurance.md §5.6), as the Privacy Pass origin of RFC 9577. Each room then has an age policy (§4) naming the configured issuers with one key per threshold, and a rating (§3), a room claim, both signed by the authority. A grant request without a token is answered 401 with a PrivateToken challenge for each key (WWW-Authenticate, RFC 9577 §2.1.2): its redemption context HMAC-SHA-256 over the room and a window of token_window_s under a key drawn at start (a restart turns outstanding challenges away), its origin_info the service's server name (origin, else the request's Host). A request with Authorization: PrivateToken token="…" has the token checked by wai-rs's §5.2 against the room's age, and its grant states the token's threshold in age (§5.4), from which the relay holds every track to the serving rule (§5.5). The nonces redeemed are kept for the current window and the one before, at most max_nonces a window (past it, 503 and nothing spent), and dropped as a window ages out. Each admission is counted by its window, issuer and threshold, and nothing else of it is kept: GET /age/receipt gives the room's wai-age-admissions receipt so far (§7), signed by the clock, every count under 50 suppressed, and with receipts_out each window's is appended there as it closes, and the rest of a room's when it ends. The room's rating rides the clock's events track and the grant answer's room, which a publisher's page carries on its tracks (§5.7). Operating an issuer, or the attester that establishes an age, is not the service's.

• keeps co-performance ([co], WAI extensions/co-performance.md). With audience_input above 0, every viewer's grant carries the audience-input power (the attribute audience_input, the most inputs it may send to one selection window) and may send meta events and reactions, and the viewers' grants are listed with the room (co.audience) so a page verifies their inputs; with latency_budget_ms above 0, every publisher's grant carries that budget. Either gives the room a co-performance policy (WPP1) the authority signs (co.policy), its publishers meta events (their intents), a lead role with the direct power for the first publisher (lead), and, with ai, a grant marked as an AI participant's for a page that asks ("ai": <model digest>). The clock then keeps what only it knows (src/co.rs, co-performance §8): it records each audience member joining when its events track appears, holds the room as a verifier does (every member's chain, by FETCH where it has a gap), logs each publisher's media objects with their arrival and their due instant (GET /co/objects, the objects a verifier is given), and signs a mark (WPM1) for each object out of turn under a schedule that marks or later than its budget, the commitment (WPK1) and selection (WPS1) of each window once it closes, and the periodic fidelity statement (WPF1). A page asks the clock for a turn schedule (WPT1), a handover (WPH1) or a window (WPW1) over HTTP (POST /co/...), with its grant and a proof of possession over a challenge the service issued (live-rooms §10.5.3); its powers decide what it may ask. The relay holds the floor and the audience's inputs (its [floor], which relay-lines prints commented out).

A room lasts while anyone publishes in it. When the last publisher has left, the next one starts a new room: a new descriptor at a new t0, under the same authority and clock, so each room's grants and chain hold one stretch of company.

Running it

joule-moq-room keygen <keys.toml>       new keys (mode 0600, never over a file); prints the
                                        relay configuration lines that trust them
joule-moq-room relay-lines <keys.toml>  those lines again
joule-moq-room --config <room.toml>     serve (room.example.toml shows every field)

The keys file must be readable by its owner alone; the service refuses it otherwise. Keys has no Debug, so that no log prints a seed.

The relay needs, beside its listener and limits, the lines relay-lines prints:

[[auth.authorities]]
key = "<authority>"

[[auth.grants]]                  # the clock's events track, in any room
prefix = ["*", "<clock>", "events"]
token_sha256 = "<SHA-256 of the clock's token>"
publish = true
unlimited = true                 # no session or ingress limit for the clock's session

[[auth.grants]]                  # the clock watches the publishers
prefix = []
token_sha256 = "<SHA-256 of the clock's token>"
subscribe = true

and a door that holds each publisher's media to its own key:

[[receipts.door]]
prefix = ["*", "*", "video"]
trust_field = 1

HTTP

Request	Answer
GET /, GET /health	{"ok", "relay": the clock's session is open, "room"}
GET /room	the room: room, t0_us, descriptor, compose, grants (hex), present, publishers, max_publishers, e2ee ({"record": <hex>, "log"}, or null), and co ({"policy": <hex>, "audience": [<hex>]}, or null)
POST /grant {"principal": <64 hex>, "role": "publisher" | "viewer"}	{"grant", "digest", "exp", "role", "room": <as GET /room>}; 409 full or busy; 429 rate with retry_after_s; 503 relay while the clock has no session
GET /mls?room=<id>&from=<n>[&wait_ms=<ms>]	an end-to-end encrypted room's log from entry n: {"room", "entries": [{"seq", "event" or "mls": <hex>}], "next", "end"}, held up to 8 s while nothing is past n; 410 for a room since replaced, 404 for a room that is not end-to-end encrypted
POST /mls/key-package {"room", "key_package": <hex>}	kept for the principal's Add: {"ok", "principal"}; 403 for a principal the room has not granted
POST /mls/post {"room", "frames": [<hex>]}	a GroupInfo, or a commit and its Welcome, checked by the clock as a member checks it, then carried: {"ok", "seq"}; 409 {"error": <reason>} when the clock refuses it
POST /grant in a room that admits by age	without a token: 401 {"error": "token_required", "age"} and a WWW-Authenticate: PrivateToken challenge=…, token-key=…, max-age=… for each key; with Authorization: PrivateToken token="…": the grant, its age the token's threshold, or 403 {"error": <age-assurance §11's reason>} and the challenges again; 503 busy when the window's nonces are at their bound. GET /room's age is {"policy", "ratings", "age", "token_window_s"}
GET /age/receipt	{"receipt", "policy"}: the room's admission receipt so far, signed by its clock

Every answer is JSON with Cache-Control: no-store. The client's address is CF-Connecting-IP, else the first X-Forwarded-For, else the connection's: the service listens on loopback behind the front that sets them.

Tests

cargo test (this crate is a workspace of its own, with its own lock file, since it builds on wai-rs): the keys file, the grants checked against the descriptor and read by the relay's reader, the places, the limiter, and tests/room_service.rs, the service against a relay on loopback: a grant and its proof open a session and the clock announces the publisher, the grant alone opens none, the room verifies, a third publisher is refused, clients are bounded, and a new room starts when the last publisher has left; and an end-to-end encrypted room on a relay, two members keying through the service as pages do (a GroupInfo, the clock's Add, a commit and its Welcome), the posts the clock refuses not carried, each opening what the other seals, and a member that leaves removed by the next commit. Admission by age: unit tests of src/age.rs over published RSA test keys (tests/common/rfc_test_keys.rs: RFC 7517 A.2's, RFC 9500's testRSA2048 and RFC 9578 A.2's), whose tokens they sign directly, as the blind protocol's output is the same signature: the challenges by window, a token admitted once and at the room's age, the window before accepted and the one before that, another origin's and another service's challenge refused, the nonces bounded and dropped by window, and the receipt's cells the reference's and its signature the clock's; and tests/age_admission.rs, the service with [age] and a relay: the 401 and its challenges, tokens at 16 and 18 admitted and their grants' age read by the relay, one of 13 refused below_threshold, one spent twice token_replayed, one for another origin token_wrong_challenge, one that does not read token_malformed, a publisher challenged too, the relay serving the viewer at 16 the audio and refusing it the video the publisher rates 18, and the receipt read and checked by wai-rs. A room with co-performance: its policy, the audience-input power and the budgets on its grants, and two viewers' votes in a window the clock opens, commits and selects, verified as co-performance §9 verifies a room.

Licence

Apache-2.0.