Add fetchWorker for fetching off the main thread

.tool-versions

@@ -1 +1 @@
-deno 1.37.1
+deno 1.38.3

src/deps.ts

@@ -76,5 +76,6 @@ export { default as uuid62 } from 'npm:uuid62@^1.0.2';
 export { Machina } from 'https://gitlab.com/soapbox-pub/nostr-machina/-/raw/08a157d39f2741c9a3a4364cb97db36e71d8c03a/mod.ts';
 export * as Sentry from 'https://deno.land/x/sentry@7.78.0/index.js';
 export { sentry as sentryMiddleware } from 'npm:@hono/sentry@^1.0.0';
+export * as Comlink from 'npm:comlink@^4.4.1';
 
 export type * as TypeFest from 'npm:type-fest@^4.3.0';

src/utils/nip05.ts

@@ -1,5 +1,6 @@
 import { TTLCache, z } from '@/deps.ts';
 import { Time } from '@/utils/time.ts';
+import { fetchWorker } from '@/workers/fetch.ts';
 
 const nip05Cache = new TTLCache<string, Promise<string | null>>({ ttl: Time.hours(1), max: 5000 });
 
@@ -19,7 +20,7 @@ async function lookup(value: string, opts: LookupOpts = {}): Promise<string | nu
   const [_, name = '_', domain] = match;
 
   try {
-    const res = await fetch(`https://${domain}/.well-known/nostr.json?name=${name}`, {
+    const res = await fetchWorker(`https://${domain}/.well-known/nostr.json?name=${name}`, {
       signal: AbortSignal.timeout(timeout),
     });
 

src/utils/unfurl.ts

@@ -1,5 +1,6 @@
 import { TTLCache, unfurl } from '@/deps.ts';
 import { Time } from '@/utils/time.ts';
+import { fetchWorker } from '@/workers/fetch.ts';
 
 interface PreviewCard {
   url: string;
@@ -22,7 +23,7 @@ async function unfurlCard(url: string, signal: AbortSignal): Promise<PreviewCard
   console.log(`Unfurling ${url}...`);
   try {
     const result = await unfurl(url, {
-      fetch: (url) => fetch(url, { signal }),
+      fetch: (url) => fetchWorker(url, { signal }),
     });
 
     return {

src/workers/fetch.test.ts

@@ -0,0 +1,14 @@
+import { assert } from '@/deps-test.ts';
+
+import { fetchWorker } from './fetch.ts';
+
+Deno.test('fetchWorker', async () => {
+  await sleep(2000);
+  const response = await fetchWorker('https://example.com');
+  const text = await response.text();
+  assert(text.includes('Example Domain'));
+});
+
+function sleep(ms: number) {
+  return new Promise((resolve) => setTimeout(resolve, ms));
+}

src/workers/fetch.ts

@@ -0,0 +1,19 @@
+import { Comlink } from '@/deps.ts';
+
+import type { FetchWorker } from './fetch.worker.ts';
+
+const _worker = Comlink.wrap<typeof FetchWorker>(
+  new Worker(
+    new URL('./fetch.worker.ts', import.meta.url),
+    { type: 'module' },
+  ),
+);
+
+const fetchWorker: typeof fetch = async (input) => {
+  const url = input instanceof Request ? input.url : input.toString();
+
+  const args = await _worker.fetch(url);
+  return new Response(...args);
+};
+
+export { fetchWorker };

src/workers/fetch.worker.ts

@@ -0,0 +1,17 @@
+import { Comlink } from '@/deps.ts';
+
+export const FetchWorker = {
+  async fetch(url: string): Promise<[BodyInit, ResponseInit]> {
+    const response = await fetch(url);
+    return [
+      await response.text(),
+      {
+        status: response.status,
+        statusText: response.statusText,
+        headers: Array.from(response.headers.entries()),
+      },
+    ];
+  },
+};
+
+Comlink.expose(FetchWorker);