Tracker

Tracker records which relays have sent or accepted each event, as a two-way map between event ids and relay urls. request uses one to detect events that arrive from more than one relay. Every repository owns one as repository.tracker, which an App reaches as app.repository.tracker.

Tracker

Properties:

• relaysById - Map<string, Set<string>> from event id to relay urls
• idsByRelay - Map<string, Set<string>> from relay url to event ids

Events:

• "add" - Emitted with (eventId, relay) when a new pair is recorded
• "remove" - Emitted with (eventId, relay) when a pair is removed
• "load" - Emitted by load()
• "clear" - Emitted by clear()

Methods:

• track(eventId, relay) - Records the pair and returns whether the event was already recorded for any relay
• addRelay(eventId, relay) / removeRelay(eventId, relay) - Records or removes one pair. Removing an event's last relay forgets the event, so a later track returns false
• hasRelay(eventId, relay) - Whether the pair is recorded
• getRelays(eventId) - The relays recorded for an event
• getIds(relay) - The events recorded for a relay
• copy(eventId1, eventId2) - Records every relay of the first event for the second, as WrapManager does from a gift wrap to its rumor
• hydrate(eventId, relays) - Records relays an event was seen on before, as when a repository reads its provenance back from storage
• load(relaysById) - Adds a Map<string, Set<string>> of pairs to those already recorded. Call clear() first to replace them
• clear() - Removes every pair

load emits only "load", not an "add" per pair, and hydrate emits nothing.

Example

import {Tracker} from "@welshman/store"
import {load} from "@welshman/net"

const tracker = new Tracker()

await load({
  relays: ["wss://relay1.com", "wss://relay2.com"],
  filters: [{kinds: [1], limit: 10}],
  tracker,
  context,
})

for (const id of tracker.getIds("wss://relay1.com")) {
  console.log(id, "also on", Array.from(tracker.getRelays(id)))
}