Let caches be configurable

src/config.ts

@@ -247,6 +247,30 @@ class Conf {
   static get zapSplitsEnabled(): boolean {
     return optionalBooleanSchema.parse(Deno.env.get('ZAP_SPLITS_ENABLED')) ?? false;
   }
+  /** Cache settings. */
+  static caches = {
+    /** NIP-05 cache settings. */
+    get nip05(): { max: number; ttl: number } {
+      return {
+        max: Number(Deno.env.get('DITTO_CACHE_NIP05_MAX') || 3000),
+        ttl: Number(Deno.env.get('DITTO_CACHE_NIP05_TTL') || 1 * 60 * 60 * 1000),
+      };
+    },
+    /** Favicon cache settings. */
+    get favicon(): { max: number; ttl: number } {
+      return {
+        max: Number(Deno.env.get('DITTO_CACHE_FAVICON_MAX') || 500),
+        ttl: Number(Deno.env.get('DITTO_CACHE_FAVICON_TTL') || 1 * 60 * 60 * 1000),
+      };
+    },
+    /** Link preview cache settings. */
+    get linkPreview(): { max: number; ttl: number } {
+      return {
+        max: Number(Deno.env.get('DITTO_CACHE_LINK_PREVIEW_MAX') || 1000),
+        ttl: Number(Deno.env.get('DITTO_CACHE_LINK_PREVIEW_TTL') || 12 * 60 * 60 * 1000),
+      };
+    },
+  };
 }
 
 const optionalBooleanSchema = z

src/utils/favicon.ts

@@ -6,6 +6,7 @@ import { cachedFaviconsSizeGauge } from '@/metrics.ts';
 import { SimpleLRU } from '@/utils/SimpleLRU.ts';
 import { Time } from '@/utils/time.ts';
 import { fetchWorker } from '@/workers/fetch.ts';
+import { Conf } from '@/config.ts';
 
 const debug = Debug('ditto:favicon');
 
@@ -38,7 +39,7 @@ const faviconCache = new SimpleLRU<string, URL>(
 
     throw new Error(`Favicon not found: ${key}`);
   },
-  { max: 500, ttl: Time.hours(1), gauge: cachedFaviconsSizeGauge },
+  { ...Conf.caches.favicon, gauge: cachedFaviconsSizeGauge },
 );
 
 export { faviconCache };

src/utils/nip05.ts

@@ -44,7 +44,7 @@ const nip05Cache = new SimpleLRU<string, nip19.ProfilePointer>(
       throw e;
     }
   },
-  { max: 3000, ttl: Time.hours(1), gauge: cachedNip05sSizeGauge },
+  { ...Conf.caches.nip05, gauge: cachedNip05sSizeGauge },
 );
 
 async function localNip05Lookup(store: NStore, localpart: string): Promise<nip19.ProfilePointer | undefined> {

src/utils/unfurl.ts

@@ -6,7 +6,6 @@ import { unfurl } from 'unfurl.js';
 import { Conf } from '@/config.ts';
 import { PreviewCard } from '@/entities/PreviewCard.ts';
 import { cachedLinkPreviewSizeGauge } from '@/metrics.ts';
-import { Time } from '@/utils/time.ts';
 import { fetchWorker } from '@/workers/fetch.ts';
 
 const debug = Debug('ditto:unfurl');
@@ -55,10 +54,7 @@ async function unfurlCard(url: string, signal: AbortSignal): Promise<PreviewCard
 }
 
 /** TTL cache for preview cards. */
-const previewCardCache = new TTLCache<string, Promise<PreviewCard | null>>({
-  ttl: Time.hours(12),
-  max: 1000,
-});
+const previewCardCache = new TTLCache<string, Promise<PreviewCard | null>>(Conf.caches.linkPreview);
 
 /** Unfurl card from cache if available, otherwise fetch it. */
 function unfurlCardCached(url: string, signal = AbortSignal.timeout(1000)): Promise<PreviewCard | null> {