Add TrendsWorker for tracking/querying trending tags with a Web Worker

deno.json

@@ -5,7 +5,7 @@
     "start": "deno run -A --unstable src/server.ts",
     "dev": "deno run -A --unstable --watch src/server.ts",
     "debug": "deno run -A --unstable --inspect src/server.ts",
-    "test": "DB_PATH=\":memory:\" deno test -A --unstable src",
+    "test": "DB_PATH=\":memory:\" deno test -A --unstable",
     "check": "deno check src/server.ts",
     "relays:sync": "deno run -A --unstable scripts/relays.ts sync"
   },

src/controllers/api/trends.ts

@@ -1,13 +1,15 @@
 import { type AppController } from '@/app.ts';
 import { Conf } from '@/config.ts';
 import { z } from '@/deps.ts';
-import { trends } from '@/trends.ts';
 import { Time } from '@/utils.ts';
 import { stripTime } from '@/utils/time.ts';
+import { TrendsWorker } from '@/workers/trends.ts';
+
+await TrendsWorker.open('data/trends.sqlite3');
 
 const limitSchema = z.coerce.number().catch(10).transform((value) => Math.min(Math.max(value, 0), 20));
 
-const trendingTagsController: AppController = (c) => {
+const trendingTagsController: AppController = async (c) => {
   const limit = limitSchema.parse(c.req.query('limit'));
   if (limit < 1) return c.json([]);
 
@@ -16,37 +18,39 @@ const trendingTagsController: AppController = (c) => {
   const lastWeek = new Date(now.getTime() - Time.days(7));
 
   /** Most used hashtags within the past 24h. */
-  const tags = trends.getTrendingTags({
+  const tags = await TrendsWorker.getTrendingTags({
     since: yesterday,
     until: now,
     limit,
   });
 
-  return c.json(tags.map(({ name, uses, accounts }) => ({
-    name,
-    url: Conf.local(`/tags/${name}`),
-    history: [
-      // Use the full 24h query for the current day. Then use `offset: 1` to adjust for this below.
-      // This result is more accurate than what Mastodon returns.
-      {
-        day: String(Math.floor(stripTime(now).getTime() / 1000)),
-        accounts: String(accounts),
-        uses: String(uses),
-      },
-      ...trends.getTagHistory({
-        tag: name,
-        since: lastWeek,
-        until: now,
-        limit: 6,
-        offset: 1,
-      }).map((history) => ({
-        // For some reason, Mastodon wants these to be strings... oh well.
-        day: String(Math.floor(history.day.getTime() / 1000)),
-        accounts: String(history.accounts),
-        uses: String(history.uses),
-      })),
-    ],
-  })));
+  return c.json(
+    await Promise.all(tags.map(async ({ name, uses, accounts }) => ({
+      name,
+      url: Conf.local(`/tags/${name}`),
+      history: [
+        // Use the full 24h query for the current day. Then use `offset: 1` to adjust for this below.
+        // This result is more accurate than what Mastodon returns.
+        {
+          day: String(Math.floor(stripTime(now).getTime() / 1000)),
+          accounts: String(accounts),
+          uses: String(uses),
+        },
+        ...(await TrendsWorker.getTagHistory({
+          tag: name,
+          since: lastWeek,
+          until: now,
+          limit: 6,
+          offset: 1,
+        })).map((history) => ({
+          // For some reason, Mastodon wants these to be strings... oh well.
+          day: String(Math.floor(history.day.getTime() / 1000)),
+          accounts: String(history.accounts),
+          uses: String(history.uses),
+        })),
+      ],
+    }))),
+  );
 };
 
 export { trendingTagsController };

src/pipeline.ts

@@ -10,8 +10,8 @@ import { publish } from '@/pool.ts';
 import { isLocallyFollowed } from '@/queries.ts';
 import { Sub } from '@/subs.ts';
 import { getTagSet } from '@/tags.ts';
-import { trends } from '@/trends.ts';
 import { eventAge, isRelay, nostrDate, Time } from '@/utils.ts';
+import { TrendsWorker } from '@/workers/trends.ts';
 import { verifySignatureWorker } from '@/workers/verify.ts';
 
 import type { EventData } from '@/types.ts';
@@ -90,7 +90,7 @@ async function processDeletions(event: Event): Promise<void> {
 }
 
 /** Track whenever a hashtag is used, for processing trending tags. */
-function trackHashtags(event: Event): void {
+async function trackHashtags(event: Event): Promise<void> {
   const date = nostrDate(event.created_at);
 
   const tags = event.tags
@@ -102,7 +102,7 @@ function trackHashtags(event: Event): void {
 
   try {
     console.info('tracking tags:', tags);
-    trends.addTagUsages(event.pubkey, tags, date);
+    await TrendsWorker.addTagUsages(event.pubkey, tags, date);
   } catch (_e) {
     // do nothing
   }

src/trends.test.ts

@@ -1,32 +0,0 @@
-import { assertEquals } from '@/deps-test.ts';
-import { Sqlite } from '@/deps.ts';
-
-import { TrendsDB } from './trends.ts';
-
-const db = new Sqlite(':memory:');
-const trends = new TrendsDB(db);
-
-const p8 = (pubkey8: string) => `${pubkey8}00000000000000000000000000000000000000000000000000000000`;
-
-Deno.test('getTrendingTags', () => {
-  trends.addTagUsages(p8('00000000'), ['ditto', 'hello', 'yolo']);
-  trends.addTagUsages(p8('00000000'), ['hello']);
-  trends.addTagUsages(p8('00000001'), ['Ditto', 'hello']);
-  trends.addTagUsages(p8('00000010'), ['DITTO']);
-
-  const result = trends.getTrendingTags({
-    since: new Date('1999-01-01T00:00:00'),
-    until: new Date('2999-01-01T00:00:00'),
-    threshold: 1,
-  });
-
-  const expected = [
-    { name: 'ditto', accounts: 3, uses: 3 },
-    { name: 'hello', accounts: 2, uses: 3 },
-    { name: 'yolo', accounts: 1, uses: 1 },
-  ];
-
-  assertEquals(result, expected);
-
-  trends.cleanupTagUsages(new Date('2999-01-01T00:00:00'));
-});

src/workers/trends.test.ts

@@ -0,0 +1,30 @@
+import { assertEquals } from '@/deps-test.ts';
+
+import { TrendsWorker } from './trends.ts';
+
+await TrendsWorker.open(':memory:');
+
+const p8 = (pubkey8: string) => `${pubkey8}00000000000000000000000000000000000000000000000000000000`;
+
+Deno.test('getTrendingTags', async () => {
+  await TrendsWorker.addTagUsages(p8('00000000'), ['ditto', 'hello', 'yolo']);
+  await TrendsWorker.addTagUsages(p8('00000000'), ['hello']);
+  await TrendsWorker.addTagUsages(p8('00000001'), ['Ditto', 'hello']);
+  await TrendsWorker.addTagUsages(p8('00000010'), ['DITTO']);
+
+  const result = await TrendsWorker.getTrendingTags({
+    since: new Date('1999-01-01T00:00:00'),
+    until: new Date('2999-01-01T00:00:00'),
+    threshold: 1,
+  });
+
+  const expected = [
+    { name: 'ditto', accounts: 3, uses: 3 },
+    { name: 'hello', accounts: 2, uses: 3 },
+    { name: 'yolo', accounts: 1, uses: 1 },
+  ];
+
+  assertEquals(result, expected);
+
+  await TrendsWorker.cleanupTagUsages(new Date('2999-01-01T00:00:00'));
+});

src/workers/trends.ts

@@ -0,0 +1,19 @@
+import { Comlink } from '@/deps.ts';
+
+import type { TrendsWorker as _TrendsWorker } from '@/workers/trends.worker.ts';
+
+const worker = new Worker(new URL('./trends.worker.ts', import.meta.url), { type: 'module' });
+
+const TrendsWorker = Comlink.wrap<typeof _TrendsWorker>(worker);
+
+await new Promise<void>((resolve) => {
+  const handleEvent = ({ data }: MessageEvent) => {
+    if (data === 'ready') {
+      worker.removeEventListener('message', handleEvent);
+      resolve();
+    }
+  };
+  worker.addEventListener('message', handleEvent);
+});
+
+export { TrendsWorker };

src/workers/trends.worker.ts

@@ -1,8 +1,7 @@
-import { Sqlite } from '@/deps.ts';
+import { Comlink, Sqlite } from '@/deps.ts';
 import { hashtagSchema } from '@/schema.ts';
 import { nostrIdSchema } from '@/schemas/nostr.ts';
-import { Time } from '@/utils.ts';
-import { generateDateRange } from '@/utils/time.ts';
+import { generateDateRange, Time } from '@/utils/time.ts';
 
 interface GetTrendingTagsOpts {
   since: Date;
@@ -19,13 +18,13 @@ interface GetTagHistoryOpts {
   offset?: number;
 }
 
-class TrendsDB {
-  #db: Sqlite;
+let db: Sqlite;
 
-  constructor(db: Sqlite) {
-    this.#db = db;
+export const TrendsWorker = {
+  open(path: string) {
+    db = new Sqlite(path);
 
-    this.#db.execute(`
+    db.execute(`
       CREATE TABLE IF NOT EXISTS tag_usages (
         tag TEXT NOT NULL COLLATE NOCASE,
         pubkey8 TEXT NOT NULL,
@@ -43,11 +42,11 @@ class TrendsDB {
 
     setInterval(cleanup, Time.hours(1));
     cleanup();
-  }
+  },
 
   /** Gets the most used hashtags between the date range. */
   getTrendingTags({ since, until, limit = 10, threshold = 3 }: GetTrendingTagsOpts) {
-    return this.#db.query<string[]>(
+    return db.query<string[]>(
       `
       SELECT tag, COUNT(DISTINCT pubkey8), COUNT(*)
         FROM tag_usages
@@ -63,14 +62,14 @@ class TrendsDB {
       accounts: Number(row[1]),
       uses: Number(row[2]),
     }));
-  }
+  },
 
   /**
    * Gets the tag usage count for a specific tag.
    * It returns an array with counts for each date between the range.
    */
   getTagHistory({ tag, since, until, limit = 7, offset = 0 }: GetTagHistoryOpts) {
-    const result = this.#db.query<string[]>(
+    const result = db.query<string[]>(
       `
       SELECT date(inserted_at), COUNT(DISTINCT pubkey8), COUNT(*)
         FROM tag_usages
@@ -98,28 +97,26 @@ class TrendsDB {
       const data = result.find((item) => item.day.getTime() === day.getTime());
       return data || { day, accounts: 0, uses: 0 };
     });
-  }
+  },
 
   addTagUsages(pubkey: string, hashtags: string[], date = new Date()): void {
     const pubkey8 = nostrIdSchema.parse(pubkey).substring(0, 8);
     const tags = hashtagSchema.array().min(1).parse(hashtags);
 
-    this.#db.query(
+    db.query(
       'INSERT INTO tag_usages (tag, pubkey8, inserted_at) VALUES ' + tags.map(() => '(?, ?, ?)').join(', '),
       tags.map((tag) => [tag, pubkey8, date]).flat(),
     );
-  }
+  },
 
   cleanupTagUsages(until: Date): void {
-    this.#db.query(
+    db.query(
       'DELETE FROM tag_usages WHERE inserted_at < ?',
       [until],
     );
-  }
-}
+  },
+};
 
-const trends = new TrendsDB(
-  new Sqlite('data/trends.sqlite3'),
-);
+Comlink.expose(TrendsWorker);
 
-export { trends, TrendsDB };
+self.postMessage('ready');