pipeline: optimize database calls

src/filter.ts

@@ -1,19 +1,19 @@
 import { type Event, matchFilters } from '@/deps.ts';
 
-import type { DittoFilter } from '@/types.ts';
-
-interface EventData {
-  isLocal: boolean;
-}
+import type { DittoFilter, EventData } from '@/types.ts';
 
 function matchDittoFilter(filter: DittoFilter, event: Event, data: EventData): boolean {
-  if (filter.local && !data.isLocal) {
+  if (filter.local && !data.user) {
     return false;
   }
 
   return matchFilters([filter], event);
 }
 
+/**
+ * Similar to nostr-tools `matchFilters`, but supports Ditto's custom keys.
+ * Database calls are needed to look up the extra data, so it's passed in as an argument.
+ */
 function matchDittoFilters(filters: DittoFilter[], event: Event, data: EventData): boolean {
   for (const filter of filters) {
     if (matchDittoFilter(filter, event, data)) {

src/pipeline.ts

@@ -7,22 +7,32 @@ import { Sub } from '@/subs.ts';
 import { trends } from '@/trends.ts';
 import { isRelay, nostrDate } from '@/utils.ts';
 
+import type { EventData } from '@/types.ts';
+
 /**
  * Common pipeline function to process (and maybe store) events.
  * It is idempotent, so it can be called multiple times for the same event.
  */
 async function handleEvent(event: Event): Promise<void> {
+  const data = await getEventData(event);
+
   await Promise.all([
-    storeEvent(event),
+    storeEvent(event, data),
     trackRelays(event),
     trackHashtags(event),
-    streamOut(event),
+    streamOut(event, data),
   ]);
 }
 
+/** Preload data that will be useful to several tasks. */
+async function getEventData({ pubkey }: Event): Promise<EventData> {
+  const user = await findUser({ pubkey });
+  return { user };
+}
+
 /** Maybe store the event, if eligible. */
-async function storeEvent(event: Event): Promise<void> {
-  if (await findUser({ pubkey: event.pubkey }) || await isLocallyFollowed(event.pubkey)) {
+async function storeEvent(event: Event, data: EventData): Promise<void> {
+  if (data.user || await isLocallyFollowed(event.pubkey)) {
     await eventsDB.insertEvent(event).catch(console.warn);
   } else {
     return Promise.reject(new RelayError('blocked', 'only registered users can post'));
@@ -66,9 +76,9 @@ function trackRelays(event: Event) {
 }
 
 /** Distribute the event through active subscriptions. */
-async function streamOut(event: Event) {
-  for await (const sub of Sub.matches(event)) {
-    sub.socket.send(JSON.stringify(['EVENT', event]));
+function streamOut(event: Event, data: EventData) {
+  for (const { socket, id } of Sub.matches(event, data)) {
+    socket.send(JSON.stringify(['EVENT', id, event]));
   }
 }
 

src/subs.ts

@@ -1,8 +1,7 @@
 import { type Event } from '@/deps.ts';
 import { matchDittoFilters } from './filter.ts';
-import { isEventLocal } from '@/utils.ts';
 
-import type { DittoFilter } from '@/types.ts';
+import type { DittoFilter, EventData } from '@/types.ts';
 
 /** Nostr subscription to receive realtime events. */
 interface Subscription {
@@ -20,7 +19,7 @@ interface Subscription {
  * Subscriptions can be added, removed, and matched against events.
  *
  * ```ts
- * for await (const sub of Sub.matches(event)) {
+ * for (const sub of Sub.matches(event)) {
  *   // Send event to sub.socket
  *   sub.socket.send(JSON.stringify(event));
  * }
@@ -55,18 +54,16 @@ class SubscriptionStore {
    * Loop through matching subscriptions to stream out.
    *
    * ```ts
-   * for await (const sub of Sub.matches(event)) {
+   * for (const sub of Sub.matches(event)) {
    *   // Send event to sub.socket
    *   sub.socket.send(JSON.stringify(event));
    * }
    * ```
    */
-  async *matches(event: Event) {
-    const isLocal = await isEventLocal(event);
-
+  *matches(event: Event, data: EventData): Iterable<Subscription> {
     for (const subs of this.#store.values()) {
       for (const sub of subs.values()) {
-        if (matchDittoFilters(sub.filters, event, { isLocal })) {
+        if (matchDittoFilters(sub.filters, event, data)) {
           yield sub;
         }
       }

src/types.ts

@@ -1,3 +1,4 @@
+import { UserRow } from '@/db.ts';
 import { type Filter } from '@/deps.ts';
 
 /** Custom filter interface that extends Nostr filters with extra options for Ditto. */
@@ -13,4 +14,8 @@ interface GetFiltersOpts {
   limit?: number;
 }
 
-export type { DittoFilter, GetFiltersOpts };
+interface EventData {
+  user: UserRow | undefined;
+}
+
+export type { DittoFilter, EventData, GetFiltersOpts };

src/utils.ts

@@ -102,18 +102,11 @@ function isFollowing(source: Event<3>, targetPubkey: string): boolean {
   );
 }
 
-/** Check whether the event belongs to a local user. */
-async function isEventLocal(event: Event) {
-  const user = await findUser({ pubkey: event.pubkey });
-  return !!user;
-}
-
 export {
   bech32ToPubkey,
   eventAge,
   eventDateComparator,
   findTag,
-  isEventLocal,
   isFollowing,
   isRelay,
   lookupAccount,