| 1 | /** |
| 2 | * Opening the site's live sockets from the browser. A page signed in by a |
| 3 | * session opens them at once, its cookie going along as always. A page |
| 4 | * opened with an access token has no cookie, and a socket cannot carry the |
| 5 | * token's header, so it first asks for a socket ticket and adds it to the |
| 6 | * address (lib/socket-ticket.ts). Browser-only. |
| 7 | */ |
| 8 | |
| 9 | /** As lib/socket-ticket.ts's, kept apart so the page does not load its sealing code. */ |
| 10 | const TICKET_PARAM = "ticket"; |
| 11 | const TICKET_ROUTE = "/-/live/ticket"; |
| 12 | |
| 13 | let viaToken = false; |
| 14 | |
| 15 | /** Set by the root as it renders: whether this page was opened with an access token. */ |
| 16 | export function setLiveViaToken(on: boolean): void { |
| 17 | viaToken = on; |
| 18 | } |
| 19 | |
| 20 | /** A ticket a page's loader minted with the page, as routes/notify/ticket.ts would have. */ |
| 21 | export type OfferedTicket = { ticket: string; expires_at: string }; |
| 22 | |
| 23 | const offered = new Map<string, OfferedTicket>(); |
| 24 | |
| 25 | /** |
| 26 | * A ticket minted on the server with the page (the root loader's for the |
| 27 | * feed, an artifact's for its room), so the first socket opens without |
| 28 | * first asking `/-/live/ticket`: one round trip less before anything is |
| 29 | * live. Each is used once, and never past its minute. |
| 30 | */ |
| 31 | export function offerTicket(path: string, ticket: OfferedTicket | null | undefined): void { |
| 32 | if (ticket) offered.set(path, ticket); |
| 33 | } |
| 34 | |
| 35 | /** The offered ticket for `path`, if one is left and still good. */ |
| 36 | export function takeOfferedTicket(path: string, now = Date.now()): string | null { |
| 37 | const found = offered.get(path); |
| 38 | if (!found) return null; |
| 39 | offered.delete(path); |
| 40 | return Date.parse(found.expires_at) - now > 5_000 ? found.ticket : null; |
| 41 | } |
| 42 | |
| 43 | /** `wss://<this site><path>?<params>`, with a ticket when one was given. */ |
| 44 | export function liveAddress(path: string, params: Record<string, string | null | undefined>, ticket: string | null): string { |
| 45 | const url = new URL(path, location.href); |
| 46 | url.protocol = location.protocol === "https:" ? "wss:" : "ws:"; |
| 47 | for (const [name, value] of Object.entries(params)) if (value != null && value !== "") url.searchParams.set(name, value); |
| 48 | if (ticket) url.searchParams.set(TICKET_PARAM, ticket); |
| 49 | return url.toString(); |
| 50 | } |
| 51 | |
| 52 | async function ticketFor(path: string): Promise<string | null> { |
| 53 | try { |
| 54 | const answer = await fetch(`${TICKET_ROUTE}?path=${encodeURIComponent(path)}`, { |
| 55 | headers: { accept: "application/json" }, |
| 56 | cache: "no-store", |
| 57 | credentials: "same-origin", |
| 58 | }); |
| 59 | if (!answer.ok) return null; |
| 60 | const body = (await answer.json()) as { ticket?: unknown }; |
| 61 | return typeof body.ticket === "string" ? body.ticket : null; |
| 62 | } catch { |
| 63 | return null; |
| 64 | } |
| 65 | } |
| 66 | |
| 67 | /** |
| 68 | * Calls `open` with the address of the socket at `path`: at once for a |
| 69 | * session, after fetching a fresh ticket for a token's page (each attempt |
| 70 | * gets its own, as one lasts a minute). `params` is read when the address |
| 71 | * is made, so it sees any change meanwhile. Nothing is opened once |
| 72 | * `cancelled` says so. |
| 73 | */ |
| 74 | export function openLive( |
| 75 | path: string, |
| 76 | params: () => Record<string, string | null | undefined>, |
| 77 | open: (address: string) => void, |
| 78 | cancelled: () => boolean, |
| 79 | ): void { |
| 80 | if (!viaToken) { |
| 81 | open(liveAddress(path, params(), null)); |
| 82 | return; |
| 83 | } |
| 84 | const minted = takeOfferedTicket(path); |
| 85 | if (minted) { |
| 86 | open(liveAddress(path, params(), minted)); |
| 87 | return; |
| 88 | } |
| 89 | void ticketFor(path).then((ticket) => { |
| 90 | if (!cancelled()) open(liveAddress(path, params(), ticket)); |
| 91 | }); |
| 92 | } |