From 658dd397f56da4684678c93738064f5c4d21e16a Mon Sep 17 00:00:00 2001
From: Alex Gleason <alex@alexgleason.me>
Date: Thu, 24 Aug 2023 15:28:13 -0500
Subject: [PATCH] relay: respect "local: true" filter

---
 src/filter.ts   | 27 +++++++++++++++++++++++++++
 src/pipeline.ts |  4 ++--
 src/subs.ts     | 14 +++++++++-----
 src/utils.ts    |  8 ++++++++
 4 files changed, 46 insertions(+), 7 deletions(-)
 create mode 100644 src/filter.ts

diff --git a/src/filter.ts b/src/filter.ts
new file mode 100644
index 0000000..d813c62
--- /dev/null
+++ b/src/filter.ts
@@ -0,0 +1,27 @@
+import { type Event, matchFilters } from '@/deps.ts';
+
+import type { DittoFilter } from '@/types.ts';
+
+interface EventData {
+  isLocal: boolean;
+}
+
+function matchDittoFilter(filter: DittoFilter, event: Event, data: EventData): boolean {
+  if (filter.local && !data.isLocal) {
+    return false;
+  }
+
+  return matchFilters([filter], event);
+}
+
+function matchDittoFilters(filters: DittoFilter[], event: Event, data: EventData): boolean {
+  for (const filter of filters) {
+    if (matchDittoFilter(filter, event, data)) {
+      return true;
+    }
+  }
+
+  return false;
+}
+
+export { matchDittoFilters };
diff --git a/src/pipeline.ts b/src/pipeline.ts
index 7632464..0507e75 100644
--- a/src/pipeline.ts
+++ b/src/pipeline.ts
@@ -66,8 +66,8 @@ function trackRelays(event: Event) {
 }
 
 /** Distribute the event through active subscriptions. */
-function streamOut(event: Event) {
-  for (const sub of Sub.matches(event)) {
+async function streamOut(event: Event) {
+  for await (const sub of Sub.matches(event)) {
     sub.socket.send(JSON.stringify(['EVENT', event]));
   }
 }
diff --git a/src/subs.ts b/src/subs.ts
index 2a63214..afe265a 100644
--- a/src/subs.ts
+++ b/src/subs.ts
@@ -1,4 +1,6 @@
-import { type Event, matchFilters } from '@/deps.ts';
+import { type Event } from '@/deps.ts';
+import { matchDittoFilters } from './filter.ts';
+import { isEventLocal } from '@/utils.ts';
 
 import type { DittoFilter } from '@/types.ts';
 
@@ -18,7 +20,7 @@ interface Subscription {
  * Subscriptions can be added, removed, and matched against events.
  *
  * ```ts
- * for (const sub of Sub.matches(event)) {
+ * for await (const sub of Sub.matches(event)) {
  *   // Send event to sub.socket
  *   sub.socket.send(JSON.stringify(event));
  * }
@@ -53,16 +55,18 @@ class SubscriptionStore {
    * Loop through matching subscriptions to stream out.
    *
    * ```ts
-   * for (const sub of Sub.matches(event)) {
+   * for await (const sub of Sub.matches(event)) {
    *   // Send event to sub.socket
    *   sub.socket.send(JSON.stringify(event));
    * }
    * ```
    */
-  *matches(event: Event): Iterable<Subscription> {
+  async *matches(event: Event) {
+    const isLocal = await isEventLocal(event);
+
     for (const subs of this.#store.values()) {
       for (const sub of subs.values()) {
-        if (matchFilters(sub.filters, event)) {
+        if (matchDittoFilters(sub.filters, event, { isLocal })) {
           yield sub;
         }
       }
diff --git a/src/utils.ts b/src/utils.ts
index 653c824..6cd6dd4 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -1,3 +1,4 @@
+import { findUser } from '@/db/users.ts';
 import { type Event, nip19, z } from '@/deps.ts';
 import { lookupNip05Cached } from '@/nip05.ts';
 import { getAuthor } from '@/queries.ts';
@@ -101,11 +102,18 @@ function isFollowing(source: Event<3>, targetPubkey: string): boolean {
   );
 }
 
+/** Check whether the event belongs to a local user. */
+async function isEventLocal(event: Event) {
+  const user = await findUser({ pubkey: event.pubkey });
+  return !!user;
+}
+
 export {
   bech32ToPubkey,
   eventAge,
   eventDateComparator,
   findTag,
+  isEventLocal,
   isFollowing,
   isRelay,
   lookupAccount,