✨ feat: add support for NIP-09 deletion events and filtering deleted events

index.ts

@@ -31,6 +31,7 @@ import {
   isAddressableEvent,
   isArray,
   isCCNReplaceableEvent,
+  isDeleteEvent,
   isLocalhost,
   isReplaceableEvent,
   isValidJSON,
@@ -135,6 +136,11 @@ function addEventToDb(
 
   if (existingEvent) throw new EventAlreadyExistsException();
 
+  if (isDeleteEvent(decryptedEvent.kind)) {
+    handleDeletionEvent(decryptedEvent, encryptedEvent, ccnPubkey);
+    return;
+  }
+
   const isInvite =
     decryptedEvent.tags.findIndex(
       (tag: string[]) => tag[0] === 'type' && tag[1] === 'invite',
@@ -486,6 +492,8 @@ function filtersMatchingEvent(
   event: NostrEvent,
   connection: UserConnection,
 ): string[] {
+  if (isDeleteEvent(event.kind)) return [];
+
   const matching = [];
   for (const subscription of connection.subscriptions.keys()) {
     const filters = connection.subscriptions.get(subscription);
@@ -530,7 +538,7 @@ function handleRequest(connection: UserConnection, request: NostrClientREQ) {
     return log.warn('No active CCN found');
   }
 
-  let query = sqlPartial`SELECT * FROM events WHERE replaced = 0 AND ccn_pubkey = ${activeCCN.pubkey}`;
+  let query = sqlPartial`SELECT * FROM events WHERE replaced = 0 AND deleted = 0 AND ccn_pubkey = ${activeCCN.pubkey}`;
 
   const filtersAreNotEmpty = filters.some((filter) => {
     return Object.values(filter).some((value) => {
@@ -1041,6 +1049,122 @@ function handleCCNCommands(
   }
 }
 
+function handleDeletionEvent(
+  deletionEvent: nostrTools.VerifiedEvent,
+  encryptedEvent: nostrTools.VerifiedEvent,
+  ccnPubkey: string,
+) {
+  const eventIds: string[] = [];
+  const aTagRefs: { kind: number; pubkey: string; dTag?: string }[] = [];
+
+  for (const tag of deletionEvent.tags) {
+    if (tag[0] === 'e' && tag[1]) {
+      eventIds.push(tag[1]);
+    } else if (tag[0] === 'a' && tag[1]) {
+      const parsedATag = parseATagQuery(tag[1]);
+      if (parsedATag.kind && parsedATag.pubkey) {
+        aTagRefs.push(parsedATag);
+      }
+    }
+  }
+
+  if (eventIds.length === 0 && aTagRefs.length === 0) {
+    return;
+  }
+
+  try {
+    db.run('BEGIN TRANSACTION');
+
+    sql`
+      INSERT INTO events (id, original_id, pubkey, created_at, kind, content, sig, first_seen, ccn_pubkey) VALUES (
+        ${deletionEvent.id},
+        ${encryptedEvent.id},
+        ${deletionEvent.pubkey},
+        ${deletionEvent.created_at},
+        ${deletionEvent.kind},
+        ${deletionEvent.content},
+        ${deletionEvent.sig},
+        unixepoch(),
+        ${ccnPubkey}
+      )
+    `(db);
+
+    if (deletionEvent.tags) {
+      for (let i = 0; i < deletionEvent.tags.length; i++) {
+        const tag = sql`
+          INSERT INTO event_tags(event_id, tag_name, tag_index) VALUES (
+            ${deletionEvent.id},
+            ${deletionEvent.tags[i][0]},
+            ${i}
+          ) RETURNING tag_id
+        `(db)[0];
+
+        for (let j = 1; j < deletionEvent.tags[i].length; j++) {
+          sql`
+            INSERT INTO event_tags_values(tag_id, value_position, value) VALUES (
+              ${tag.tag_id},
+              ${j},
+              ${deletionEvent.tags[i][j]}
+            )
+          `(db);
+        }
+      }
+    }
+
+    if (eventIds.length > 0) {
+      sql`
+        UPDATE events
+        SET deleted = 1
+        WHERE id IN (${eventIds})
+        AND pubkey = ${deletionEvent.pubkey}
+        AND ccn_pubkey = ${ccnPubkey}
+      `(db);
+    }
+
+    if (aTagRefs.length > 0) {
+      const withDTag = aTagRefs.filter((ref) => ref.dTag);
+      const withoutDTag = aTagRefs.filter((ref) => !ref.dTag);
+
+      if (withoutDTag.length > 0) {
+        const kinds = withoutDTag.map((ref) => ref.kind);
+        sql`
+          UPDATE events
+          SET deleted = 1
+          WHERE kind IN (${kinds})
+          AND pubkey = ${deletionEvent.pubkey}
+          AND ccn_pubkey = ${ccnPubkey}
+          AND created_at <= ${deletionEvent.created_at}
+        `(db);
+      }
+
+      for (const aTagRef of withDTag) {
+        sql`
+          UPDATE events
+          SET deleted = 1
+          WHERE kind = ${aTagRef.kind}
+          AND pubkey = ${deletionEvent.pubkey}
+          AND ccn_pubkey = ${ccnPubkey}
+          AND created_at <= ${deletionEvent.created_at}
+          AND id IN (
+            SELECT event_id FROM event_tags
+            WHERE tag_name = 'd'
+            AND tag_id IN (
+              SELECT tag_id FROM event_tags_values
+              WHERE value_position = 1
+              AND value = ${aTagRef.dTag}
+            )
+          )
+        `(db);
+      }
+    }
+
+    db.run('COMMIT TRANSACTION');
+  } catch (e) {
+    db.run('ROLLBACK TRANSACTION');
+    throw e;
+  }
+}
+
 Deno.serve({
   port: 6942,
   handler: (request) => {

migrations/7-addDeletedStatus.sql

@@ -0,0 +1,2 @@
+ALTER TABLE events ADD COLUMN deleted INTEGER DEFAULT 0;
+CREATE INDEX idx_events_deleted ON events(deleted);

utils.ts

@@ -127,6 +127,10 @@ export function isRegularEvent(kind: number): boolean {
   );
 }
 
+export function isDeleteEvent(kind: number): boolean {
+  return kind === 5;
+}
+
 export function isCCNReplaceableEvent(kind: number): boolean {
   return kind >= 60000 && kind < 65536;
 }