Files
snort/packages/system/src/gossip-model.ts
2023-06-21 16:48:35 +01:00

119 lines
3.1 KiB
TypeScript

import { ReqFilter, UsersRelays } from ".";
import { unwrap } from "@snort/shared";
import debug from "debug";
const PickNRelays = 2;
export interface RelayTaggedFilter {
relay: string;
filter: ReqFilter;
}
export interface RelayTaggedFilters {
relay: string;
filters: Array<ReqFilter>;
}
export interface RelayCache {
getFromCache(pubkey?: string): UsersRelays | undefined;
}
export function splitAllByWriteRelays(cache: RelayCache, filters: Array<ReqFilter>) {
const allSplit = filters
.map(a => splitByWriteRelays(cache, a))
.reduce((acc, v) => {
for (const vn of v) {
const existing = acc.get(vn.relay);
if (existing) {
existing.push(vn.filter);
} else {
acc.set(vn.relay, [vn.filter]);
}
}
return acc;
}, new Map<string, Array<ReqFilter>>());
return [...allSplit.entries()].map(([k, v]) => {
return {
relay: k,
filters: v,
} as RelayTaggedFilters;
});
}
/**
* Split filters by authors
* @param filter
* @returns
*/
export function splitByWriteRelays(cache: RelayCache, filter: ReqFilter): Array<RelayTaggedFilter> {
if ((filter.authors?.length ?? 0) === 0) {
return [
{
relay: "",
filter,
},
];
}
const allRelays = unwrap(filter.authors).map(a => {
return {
key: a,
relays: cache.getFromCache(a)?.relays?.filter(a => a.settings.write).sort(() => Math.random() < 0.5 ? 1 : -1),
};
});
const missing = allRelays.filter(a => a.relays === undefined || a.relays.length === 0);
const hasRelays = allRelays.filter(a => a.relays !== undefined && a.relays.length > 0);
const relayUserMap = hasRelays.reduce((acc, v) => {
for (const r of unwrap(v.relays)) {
if (!acc.has(r.url)) {
acc.set(r.url, new Set([v.key]));
} else {
unwrap(acc.get(r.url)).add(v.key);
}
}
return acc;
}, new Map<string, Set<string>>());
// selection algo will just pick relays with the most users
const topRelays = [...relayUserMap.entries()].sort(([, v], [, v1]) => v1.size - v.size);
// <relay, key[]> - count keys per relay
// <key, relay[]> - pick n top relays
// <relay, key[]> - map keys per relay (for subscription filter)
const userPickedRelays = unwrap(filter.authors).map(k => {
// pick top 3 relays for this key
const relaysForKey = topRelays
.filter(([, v]) => v.has(k))
.slice(0, PickNRelays)
.map(([k]) => k);
return { k, relaysForKey };
});
const pickedRelays = new Set(userPickedRelays.map(a => a.relaysForKey).flat());
const picked = [...pickedRelays].map(a => {
const keysOnPickedRelay = new Set(userPickedRelays.filter(b => b.relaysForKey.includes(a)).map(b => b.k));
return {
relay: a,
filter: {
...filter,
authors: [...keysOnPickedRelay],
},
} as RelayTaggedFilter;
});
if (missing.length > 0) {
picked.push({
relay: "",
filter: {
...filter,
authors: missing.map(a => a.key),
},
});
}
debug("GOSSIP")("Picked %o", picked);
return picked;
}