Add relays to database and start tracking them

src/db.ts

@@ -8,6 +8,7 @@ interface DittoDB {
   events: EventRow;
   tags: TagRow;
   users: UserRow;
+  relays: RelayRow;
 }
 
 interface EventRow {
@@ -34,6 +35,10 @@ interface UserRow {
   inserted_at: Date;
 }
 
+interface RelayRow {
+  url: string;
+}
+
 const db = new Kysely<DittoDB>({
   dialect: new DenoSqliteDialect({
     database: new Sqlite(Conf.dbPath),

src/db/migrations/001_add_relays.ts

@@ -0,0 +1,12 @@
+import { Kysely } from '@/deps.ts';
+
+export async function up(db: Kysely<any>): Promise<void> {
+  await db.schema
+    .createTable('relays')
+    .addColumn('url', 'text', (col) => col.primaryKey())
+    .execute();
+}
+
+export async function down(db: Kysely<any>): Promise<void> {
+  await db.schema.dropTable('relays').execute();
+}

src/db/relays.ts

@@ -0,0 +1,19 @@
+import { db } from '@/db.ts';
+
+/** Inserts relays into the database, skipping duplicates. */
+function addRelays(relays: `wss://${string}`[]) {
+  const values = relays.map((url) => ({ url }));
+
+  return db.insertInto('relays')
+    .values(values)
+    .onConflict((oc) => oc.column('url').doNothing())
+    .execute();
+}
+
+/** Get a list of all known good relays. */
+async function getAllRelays(): Promise<string[]> {
+  const rows = await db.selectFrom('relays').select('relays.url').execute();
+  return rows.map((row) => row.url);
+}
+
+export { addRelays, getAllRelays };

src/firehose.ts

@@ -1,20 +1,21 @@
-import { Conf } from '@/config.ts';
 import { insertEvent, isLocallyFollowed } from '@/db/events.ts';
+import { addRelays, getAllRelays } from '@/db/relays.ts';
 import { findUser } from '@/db/users.ts';
 import { RelayPool } from '@/deps.ts';
 import { trends } from '@/trends.ts';
-import { nostrDate, nostrNow } from '@/utils.ts';
+import { isRelay, nostrDate, nostrNow } from '@/utils.ts';
 
 import type { SignedEvent } from '@/event.ts';
 
-const relay = new RelayPool([Conf.relay]);
+const relays = await getAllRelays();
+const pool = new RelayPool(relays);
 
 // This file watches all events on your Ditto relay and triggers
 // side-effects based on them. This can be used for things like
 // notifications, trending hashtag tracking, etc.
-relay.subscribe(
+pool.subscribe(
   [{ kinds: [1], since: nostrNow() }],
-  [Conf.relay],
+  relays,
   handleEvent,
   undefined,
   undefined,
@@ -25,6 +26,7 @@ async function handleEvent(event: SignedEvent): Promise<void> {
   console.info('firehose event:', event.id);
 
   trackHashtags(event);
+  trackRelays(event);
 
   if (await findUser({ pubkey: event.pubkey }) || await isLocallyFollowed(event.pubkey)) {
     insertEvent(event).catch(console.warn);
@@ -49,3 +51,19 @@ function trackHashtags(event: SignedEvent): void {
     // do nothing
   }
 }
+
+/** Tracks nown relays in the database. */
+function trackRelays(event: SignedEvent) {
+  const relays = new Set<`wss://${string}`>();
+
+  event.tags.forEach((tag) => {
+    if (['p', 'e', 'a'].includes(tag[0]) && isRelay(tag[2])) {
+      relays.add(tag[2]);
+    }
+    if (event.kind === 10002 && tag[0] === 'r' && isRelay(tag[1])) {
+      relays.add(tag[1]);
+    }
+  });
+
+  return addRelays([...relays]);
+}

src/schema.ts

@@ -20,24 +20,6 @@ const jsonSchema = z.string().transform((value, ctx) => {
   }
 });
 
-/** Alias for `safeParse`, but instead of returning a success object it returns the value (or undefined on fail). */
-function parseValue<T>(schema: z.ZodType<T>, value: unknown): T | undefined {
-  const result = schema.safeParse(value);
-  return result.success ? result.data : undefined;
-}
-
-const parseRelay = (relay: string | URL) => parseValue(relaySchema, relay);
-
-const relaySchema = z.custom<URL>((relay) => {
-  if (typeof relay !== 'string') return false;
-  try {
-    const { protocol } = new URL(relay);
-    return protocol === 'wss:' || protocol === 'ws:';
-  } catch (_e) {
-    return false;
-  }
-});
-
 const emojiTagSchema = z.tuple([z.literal('emoji'), z.string(), z.string().url()]);
 
 /** https://developer.mozilla.org/en-US/docs/Glossary/Base64#the_unicode_problem */
@@ -60,13 +42,4 @@ const hashtagSchema = z.string().regex(/^\w{1,30}$/);
  */
 const safeUrlSchema = z.string().max(2048).url();
 
-export {
-  decode64Schema,
-  emojiTagSchema,
-  filteredArray,
-  hashtagSchema,
-  jsonSchema,
-  parseRelay,
-  relaySchema,
-  safeUrlSchema,
-};
+export { decode64Schema, emojiTagSchema, filteredArray, hashtagSchema, jsonSchema, safeUrlSchema };

src/utils.ts

@@ -142,6 +142,12 @@ function activityJson<T, P extends string>(c: Context<any, P>, object: T) {
   return response;
 }
 
+/** Schema to parse a relay URL. */
+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;
+
 export {
   activityJson,
   bech32ToPubkey,
@@ -149,6 +155,7 @@ export {
   eventAge,
   eventDateComparator,
   findTag,
+  isRelay,
   lookupAccount,
   type Nip05,
   nostrDate,