Make following work

src/app.ts

@@ -17,6 +17,7 @@ import {
   accountSearchController,
   accountStatusesController,
   createAccountController,
+  followController,
   relationshipsController,
   updateCredentialsController,
   verifyCredentialsController,
@@ -98,6 +99,7 @@ app.patch('/api/v1/accounts/update_credentials', requireAuth, updateCredentialsC
 app.get('/api/v1/accounts/search', accountSearchController);
 app.get('/api/v1/accounts/lookup', accountLookupController);
 app.get('/api/v1/accounts/relationships', relationshipsController);
+app.post('/api/v1/accounts/:pubkey{[0-9a-f]{64}}/follow', followController);
 app.get('/api/v1/accounts/:pubkey{[0-9a-f]{64}}/statuses', accountStatusesController);
 app.get('/api/v1/accounts/:pubkey{[0-9a-f]{64}}', accountController);
 

src/controllers/api/accounts.ts

@@ -3,10 +3,20 @@ import { type Filter, findReplyTag, z } from '@/deps.ts';
 import * as mixer from '@/mixer.ts';
 import * as pipeline from '@/pipeline.ts';
 import { getAuthor, getFollows } from '@/queries.ts';
+import { booleanParamSchema } from '@/schema.ts';
 import { jsonMetaContentSchema } from '@/schemas/nostr.ts';
 import { signEvent } from '@/sign.ts';
-import { toAccount, toStatus } from '@/transformers/nostr-to-mastoapi.ts';
-import { buildLinkHeader, eventDateComparator, lookupAccount, nostrNow, paginationSchema, parseBody } from '@/utils.ts';
+import { toAccount, toRelationship, toStatus } from '@/transformers/nostr-to-mastoapi.ts';
+import {
+  buildLinkHeader,
+  eventDateComparator,
+  isFollowing,
+  lookupAccount,
+  nostrNow,
+  paginationSchema,
+  parseBody,
+} from '@/utils.ts';
+import { createEvent } from '@/utils/web.ts';
 
 const createAccountController: AppController = (c) => {
   return c.json({ error: 'Please log in with Nostr.' }, 405);
@@ -72,29 +82,11 @@ const relationshipsController: AppController = async (c) => {
     return c.json({ error: 'Missing `id[]` query parameters.' }, 422);
   }
 
-  const follows = await getFollows(pubkey);
-
-  const result = ids.data.map((id) => ({
-    id,
-    following: !!follows?.tags.find((tag) => tag[0] === 'p' && ids.data.includes(tag[1])),
-    showing_reblogs: false,
-    notifying: false,
-    followed_by: false,
-    blocking: false,
-    blocked_by: false,
-    muting: false,
-    muting_notifications: false,
-    requested: false,
-    domain_blocking: false,
-    endorsed: false,
-  }));
+  const result = await Promise.all(ids.data.map((id) => toRelationship(pubkey, id)));
 
   return c.json(result);
 };
 
-/** https://github.com/colinhacks/zod/issues/1630#issuecomment-1365983831 */
-const booleanParamSchema = z.enum(['true', 'false']).transform((value) => value === 'true');
-
 const accountStatusesQuerySchema = z.object({
   pinned: booleanParamSchema.optional(),
   limit: z.coerce.number().positive().transform((v) => Math.min(v, 40)).catch(20),
@@ -179,12 +171,34 @@ const updateCredentialsController: AppController = async (c) => {
   return c.json(account);
 };
 
+const followController: AppController = async (c) => {
+  const sourcePubkey = c.get('pubkey')!;
+  const targetPubkey = c.req.param('pubkey');
+
+  const source = await getFollows(sourcePubkey);
+
+  if (!source || !isFollowing(source, targetPubkey)) {
+    await createEvent({
+      kind: 3,
+      content: '',
+      tags: [
+        ...(source?.tags ?? []),
+        ['p', targetPubkey],
+      ],
+    }, c);
+  }
+
+  const relationship = await toRelationship(sourcePubkey, targetPubkey);
+  return c.json(relationship);
+};
+
 export {
   accountController,
   accountLookupController,
   accountSearchController,
   accountStatusesController,
   createAccountController,
+  followController,
   relationshipsController,
   updateCredentialsController,
   verifyCredentialsController,

src/queries.ts

@@ -26,13 +26,13 @@ const getEvent = async <K extends number = number>(
 
 /** Get a Nostr `set_medatadata` event for a user's pubkey. */
 const getAuthor = async (pubkey: string, timeout = 1000): Promise<Event<0> | undefined> => {
-  const [event] = await mixer.getFilters([{ authors: [pubkey], kinds: [0] }], { timeout });
+  const [event] = await mixer.getFilters([{ authors: [pubkey], kinds: [0], limit: 1 }], { limit: 1, timeout });
   return event;
 };
 
 /** Get users the given pubkey follows. */
 const getFollows = async (pubkey: string, timeout = 1000): Promise<Event<3> | undefined> => {
-  const [event] = await mixer.getFilters([{ authors: [pubkey], kinds: [3] }], { timeout });
+  const [event] = await mixer.getFilters([{ authors: [pubkey], kinds: [3], limit: 1 }], { limit: 1, timeout });
   return event;
 };
 
@@ -85,7 +85,7 @@ function getDescendants(eventId: string): Promise<Event<1>[]> {
 
 /** Returns whether the pubkey is followed by a local user. */
 async function isLocallyFollowed(pubkey: string): Promise<boolean> {
-  const [event] = await eventsDB.getFilters([{ kinds: [3], '#p': [pubkey], local: true }], { limit: 1 });
+  const [event] = await eventsDB.getFilters([{ kinds: [3], '#p': [pubkey], local: true, limit: 1 }], { limit: 1 });
   return Boolean(event);
 }
 

src/transformers/nostr-to-mastoapi.ts

@@ -4,10 +4,10 @@ import { Conf } from '@/config.ts';
 import { type Event, findReplyTag, lodash, nip19, sanitizeHtml, TTLCache, unfurl, z } from '@/deps.ts';
 import { verifyNip05Cached } from '@/nip05.ts';
 import { getMediaLinks, type MediaLink, parseNoteContent } from '@/note.ts';
-import { getAuthor } from '@/queries.ts';
+import { getAuthor, getFollows } from '@/queries.ts';
 import { emojiTagSchema, filteredArray } from '@/schema.ts';
 import { jsonMetaContentSchema } from '@/schemas/nostr.ts';
-import { type Nip05, nostrDate, parseNip05, Time } from '@/utils.ts';
+import { isFollowing, type Nip05, nostrDate, parseNip05, Time } from '@/utils.ts';
 
 const DEFAULT_AVATAR = 'https://gleasonator.com/images/avi.png';
 const DEFAULT_BANNER = 'https://gleasonator.com/images/banner.png';
@@ -254,4 +254,26 @@ function toEmojis(event: Event) {
     }));
 }
 
-export { toAccount, toStatus };
+async function toRelationship(sourcePubkey: string, targetPubkey: string) {
+  const [source, target] = await Promise.all([
+    getFollows(sourcePubkey),
+    getFollows(targetPubkey),
+  ]);
+
+  return {
+    id: targetPubkey,
+    following: source ? isFollowing(source, targetPubkey) : false,
+    showing_reblogs: true,
+    notifying: false,
+    followed_by: target ? isFollowing(target, sourcePubkey) : false,
+    blocking: false,
+    blocked_by: false,
+    muting: false,
+    muting_notifications: false,
+    requested: false,
+    domain_blocking: false,
+    endorsed: false,
+  };
+}
+
+export { toAccount, toRelationship, toStatus };

src/utils.ts

@@ -147,6 +147,13 @@ const relaySchema = z.string().max(255).startsWith('wss://').url();
 /** Check whether the value is a valid relay URL. */
 const isRelay = (relay: string): relay is `wss://${string}` => relaySchema.safeParse(relay).success;
 
+/** Check whether source is following target. */
+function isFollowing(source: Event<3>, targetPubkey: string): boolean {
+  return Boolean(
+    source.tags.find(([tagName, tagValue]) => tagName === 'p' && tagValue === targetPubkey),
+  );
+}
+
 export {
   activityJson,
   bech32ToPubkey,
@@ -154,6 +161,7 @@ export {
   eventAge,
   eventDateComparator,
   findTag,
+  isFollowing,
   isRelay,
   lookupAccount,
   type Nip05,

src/utils/web.ts

@@ -0,0 +1,34 @@
+import { EventTemplate, HTTPException } from '@/deps.ts';
+import * as pipeline from '@/pipeline.ts';
+import { signEvent } from '@/sign.ts';
+import { nostrNow } from '@/utils.ts';
+
+import type { AppContext } from '@/app.ts';
+
+/** Publish an event through the API, throwing a Hono exception on failure. */
+async function createEvent<K extends number>(t: Omit<EventTemplate<K>, 'created_at'>, c: AppContext) {
+  const pubkey = c.get('pubkey');
+
+  if (!pubkey) {
+    throw new HTTPException(401);
+  }
+
+  const event = await signEvent({
+    created_at: nostrNow(),
+    ...t,
+  }, c);
+
+  try {
+    await pipeline.handleEvent(event);
+  } catch (e) {
+    if (e instanceof pipeline.RelayError) {
+      throw new HTTPException(422, {
+        res: c.json({ error: e.message }, 422),
+      });
+    }
+  }
+
+  return event;
+}
+
+export { createEvent };