This is probably enough to log in?

src/api/accounts.ts

@@ -1,7 +1,47 @@
+import { getPublicKey } from '@/deps.ts';
+
+import { LOCAL_DOMAIN } from '../config.ts';
+import { fetchUser } from '../client.ts';
+import { MetaContent, metaContentSchema } from '../schema.ts';
+
 import type { Context } from '@/deps.ts';
 
-function credentialsController(c: Context) {
+async function credentialsController(c: Context) {
-  return c.json({});
+  const authHeader = c.req.headers.get('Authorization') || '';
+
+  if (authHeader.startsWith('Bearer ')) {
+    const token = authHeader.split('Bearer ')[1];
+    const pubkey = getPublicKey(token);
+    const event = await fetchUser(pubkey);
+    const parsed = metaContentSchema.safeParse(JSON.parse(event?.content || ''));
+    const content: MetaContent = parsed.success ? parsed.data : {};
+    const { host, origin } = new URL(LOCAL_DOMAIN);
+
+    return c.json({
+      id: pubkey,
+      acct: pubkey,
+      avatar: content.picture,
+      avatar_static: content.picture,
+      bot: false,
+      created_at: event ? new Date(event.created_at * 1000).toISOString() : new Date().toISOString(),
+      display_name: content.name,
+      emojis: [],
+      fields: [],
+      follow_requests_count: 0,
+      followers_count: 0,
+      following_count: 0,
+      statuses_count: 0,
+      header: content.banner,
+      header_static: content.banner,
+      locked: false,
+      note: content.about,
+      fqn: `${pubkey}@${host}`,
+      url: `${origin}/users/${pubkey}`,
+      username: pubkey,
+    });
+  }
+
+  return c.json({ error: 'Invalid token' }, 400);
 }
 
 export { credentialsController };

src/client.ts

@@ -0,0 +1,37 @@
+import { Author, RelayPool } from '@/deps.ts';
+
+import { poolRelays } from './config.ts';
+
+import type { Event } from './event.ts';
+
+const pool = new RelayPool(poolRelays);
+
+/** Fetch a Nostr event by its ID. */
+const fetchEvent = async (id: string): Promise<Event | null> => {
+  const event = await (pool.getEventById(id, poolRelays, 0) as Promise<Event>);
+  return event?.id === id ? event : null;
+};
+
+/** Fetch a Nostr `set_medatadata` event for a user's pubkey. */
+const fetchUser = async (pubkey: string): Promise<Event<0> | null> => {
+  const author = new Author(pool, poolRelays, pubkey);
+  const event: Event<0> | null = await new Promise((resolve) => author.metaData(resolve, 0));
+  return event?.pubkey === pubkey ? event : null;
+};
+
+/** Fetch users the given pubkey follows. */
+const fetchFollows = (pubkey: string): Promise<Event<3> | null> => {
+  return new Promise((resolve) => {
+    pool.subscribe(
+      [{ authors: [pubkey], kinds: [3] }],
+      poolRelays,
+      (event: Event<3> | null) => {
+        resolve(event?.pubkey === pubkey ? event : null);
+      },
+      undefined,
+      undefined,
+    );
+  });
+};
+
+export { fetchEvent, fetchFollows, fetchUser };

src/config.ts

@@ -1,2 +1,4 @@
 export const LOCAL_DOMAIN = Deno.env.get('LOCAL_DOMAIN') || 'http://localhost:8000';
 export const POST_CHAR_LIMIT = Number(Deno.env.get('POST_CHAR_LIMIT') || 5000);
+
+export const poolRelays = (Deno.env.get('RELAY_POOL') || '').split(',').filter(Boolean);

src/deps.ts

@@ -1,4 +1,6 @@
 import { Context, Hono, validator } from 'https://deno.land/x/hono@v3.0.2/mod.ts';
 export { Hono, validator };
 export { z } from 'https://deno.land/x/zod@v3.20.5/mod.ts';
+export { Author, RelayPool } from 'https://dev.jspm.io/nostr-relaypool@0.5.3';
+export { getPublicKey } from 'https://dev.jspm.io/nostr-tools@1.6.0';
 export type { Context };

src/event.ts

@@ -0,0 +1,27 @@
+enum Kind {
+  Metadata = 0,
+  Text = 1,
+  RecommendRelay = 2,
+  Contacts = 3,
+  EncryptedDirectMessage = 4,
+  EventDeletion = 5,
+  DeprecatedRepost = 6,
+  Reaction = 7,
+  ChannelCreation = 40,
+  ChannelMetadata = 41,
+  ChannelMessage = 42,
+  ChannelHideMessage = 43,
+  ChannelMuteUser = 44,
+}
+
+interface Event<K = Kind> {
+  id?: string;
+  sig?: string;
+  kind: K;
+  tags: string[][];
+  pubkey: string;
+  content: string;
+  created_at: number;
+}
+
+export type { Event, Kind };

src/schema.ts

@@ -0,0 +1,17 @@
+import { z } from '@/deps.ts';
+
+const optionalString = z.string().optional().catch(undefined);
+
+const metaContentSchema = z.object({
+  name: optionalString,
+  about: optionalString,
+  picture: optionalString,
+  banner: optionalString,
+  nip05: optionalString,
+  lud16: optionalString,
+});
+
+type MetaContent = z.infer<typeof metaContentSchema>;
+
+export { metaContentSchema };
+export type { MetaContent };