feat: create fetchDittoDomain function

refactor: return NodeInfo object with default values in case of errors

src/utils/domains.ts

@@ -1,6 +1,8 @@
 import { fetchWorker } from '@/workers/fetch.ts';
 import { SimpleLRU } from '@/utils/SimpleLRU.ts';
 import { Time } from '@/utils/time.ts';
+import { DittoTables } from '@/db/DittoTables.ts';
+import { unfurlCardCached } from '@/utils/unfurl.ts';
 
 type NodeInfoV1 = {
   usage: {
@@ -33,9 +35,35 @@ export const nodeInfoCache = new SimpleLRU<Domain, NodeInfoV1>(
       return {
         usage,
       };
-    } catch (e) {
-      throw e;
+    } catch {
+      return {
+        usage: {
+          users: {
+            total: 0,
+            activeMonth: 0,
+            activeHalfyear: 0,
+          },
+        },
+      };
     }
   },
   { max: 500, ttl: Time.hours(1) },
 );
+
+/** Fetches a Ditto Domain by making one network request to
+ *  '/.well-known/nodeinfo' and another to root URL (to get OpenGraph data)
+ *  'domain' is just a domain, without the HTTPS protocol as prefix */
+export async function fetchDittoDomain(domain: string): Promise<DittoTables['ditto_domains'] | undefined> {
+  const total_users = (await nodeInfoCache.fetch(domain)).usage.users.total;
+
+  const { title, description, image } = (await unfurlCardCached(`https://${domain}`)) ?? { title: '', description: '' };
+
+  return {
+    domain,
+    title,
+    description,
+    categories: new Set(''),
+    image: image ?? '',
+    total_users,
+  };
+}