Add filterPolicy to block events that don't match the filter

deno.lock

@@ -54,5 +54,58 @@
     "https://deno.land/x/sqlite@v2.3.2/src/row_objects.ts": "cf7ad165bb14c0fd346c46a7f3ea08043ace747d1abae3787bbe4b36be11b09c",
     "https://deno.land/x/sqlite@v2.3.2/src/rows.ts": "1b05730096f8df626bfc9d1597a776cc5ac7d989910a20711fa28c7a8daebb0e",
     "https://deno.land/x/sqlite@v2.3.2/src/wasm.ts": "9747b8c4de5542f2359a35461317f08a244fe8a0933c7e279caad27a0190e6bf"
+  },
+  "npm": {
+    "specifiers": {
+      "nostr-tools@^1.7.4": "nostr-tools@1.7.4"
+    },
+    "packages": {
+      "@noble/hashes@1.0.0": {
+        "integrity": "sha512-DZVbtY62kc3kkBtMHqwCOfXrT/hnoORy5BJ4+HU1IR59X0KWAOqsfzQPcUl/lQLlG7qXbe/fZ3r/emxtAl+sqg==",
+        "dependencies": {}
+      },
+      "@noble/hashes@1.2.0": {
+        "integrity": "sha512-FZfhjEDbT5GRswV3C6uvLPHMiVD6lQBmpoX5+eSiPaMTXte/IKqI5dykDxzZB/WBeK/CDuQRBWarPdi3FNY2zQ==",
+        "dependencies": {}
+      },
+      "@noble/secp256k1@1.7.1": {
+        "integrity": "sha512-hOUk6AyBFmqVrv7k5WAw/LpszxVbj9gGN4JRkIX52fdFAj1UA61KXmZDvqVEm+pOyec3+fIeZB02LYa/pWOArw==",
+        "dependencies": {}
+      },
+      "@scure/base@1.1.1": {
+        "integrity": "sha512-ZxOhsSyxYwLJj3pLZCefNitxsj093tb2vq90mp2txoYeBqbcjDjqFhyM8eUjq/uFm6zJ+mUuqxlS2FkuSY1MTA==",
+        "dependencies": {}
+      },
+      "@scure/bip32@1.1.5": {
+        "integrity": "sha512-XyNh1rB0SkEqd3tXcXMi+Xe1fvg+kUIcoRIEujP1Jgv7DqW2r9lg3Ah0NkFaCs9sTkQAQA8kw7xiRXzENi9Rtw==",
+        "dependencies": {
+          "@noble/hashes": "@noble/hashes@1.2.0",
+          "@noble/secp256k1": "@noble/secp256k1@1.7.1",
+          "@scure/base": "@scure/base@1.1.1"
+        }
+      },
+      "@scure/bip39@1.1.1": {
+        "integrity": "sha512-t+wDck2rVkh65Hmv280fYdVdY25J9YeEUIgn2LG1WM6gxFkGzcksoDiUkWVpVp3Oex9xGC68JU2dSbUfwZ2jPg==",
+        "dependencies": {
+          "@noble/hashes": "@noble/hashes@1.2.0",
+          "@scure/base": "@scure/base@1.1.1"
+        }
+      },
+      "nostr-tools@1.7.4": {
+        "integrity": "sha512-YowDJ+S3UW9KCYPDZfZXXMITrJSMjiCmFOK5HohyKkg+w6EipFUTkFRBPRA2BTLXO/qw8gukKXfL0B7Dv3jtcQ==",
+        "dependencies": {
+          "@noble/hashes": "@noble/hashes@1.0.0",
+          "@noble/secp256k1": "@noble/secp256k1@1.7.1",
+          "@scure/base": "@scure/base@1.1.1",
+          "@scure/bip32": "@scure/bip32@1.1.5",
+          "@scure/bip39": "@scure/bip39@1.1.1",
+          "prettier": "prettier@2.8.4"
+        }
+      },
+      "prettier@2.8.4": {
+        "integrity": "sha512-vIS4Rlc2FNh0BySk3Wkd6xmwxB0FpOndW5fisM5H8hsZSxU2VWVB5CWIkIjWvrHjIhxk2g3bfMKM87zNTrZddw==",
+        "dependencies": {}
+      }
+    }
   }
 }

entrypoint.example.ts

@@ -2,6 +2,7 @@
 //bin/true; exec deno run -A "$0" "$@"
 import {
   antiDuplicationPolicy,
+  filterPolicy,
   hellthreadPolicy,
   keywordPolicy,
   noopPolicy,
@@ -16,6 +17,7 @@ import {
 for await (const msg of readStdin()) {
   const result = await pipeline(msg, [
     noopPolicy,
+    [filterPolicy, { kinds: [0, 1, 3, 5, 7, 1984, 9734, 9735, 10002] }],
     [keywordPolicy, ['https://t.me/']],
     [regexPolicy, /(🟠|🔥|😳)ChtaGPT/i],
     [pubkeyBanPolicy, ['e810fafa1e89cdf80cced8e013938e87e21b699b24c8570537be92aec4b12c18']],

mod.ts

@@ -1,4 +1,5 @@
 export { default as antiDuplicationPolicy } from './src/policies/anti-duplication-policy.ts';
+export { default as filterPolicy } from './src/policies/filter-policy.ts';
 export { default as hellthreadPolicy } from './src/policies/hellthread-policy.ts';
 export { default as keywordPolicy } from './src/policies/keyword-policy.ts';
 export { default as noopPolicy } from './src/policies/noop-policy.ts';

src/policies/filter-policy.test.ts

@@ -0,0 +1,13 @@
+import { assertEquals } from '../deps.ts';
+import { buildEvent, buildInputMessage } from '../test.ts';
+
+import filterPolicy from './filter-policy.ts';
+
+Deno.test('only allows events that match the filter', async () => {
+  const msg0 = buildInputMessage({ event: buildEvent({ kind: 0 }) });
+  const msg1 = buildInputMessage({ event: buildEvent({ kind: 1 }) });
+
+  assertEquals((await filterPolicy(msg0, { kinds: [1] })).action, 'reject');
+  assertEquals((await filterPolicy(msg1, { kinds: [1] })).action, 'accept');
+  assertEquals((await filterPolicy(msg1, { kinds: [1], authors: [] })).action, 'reject');
+});

src/policies/filter-policy.ts

@@ -0,0 +1,24 @@
+import { Policy } from '../types.ts';
+
+import { Filter, matchFilter } from 'npm:nostr-tools@^1.7.4';
+
+/** Reject all events which don't match the filter. */
+const filterPolicy: Policy<Filter> = ({ event }, filter = {}) => {
+  if (matchFilter(filter, event)) {
+    return {
+      id: event.id,
+      action: 'accept',
+      msg: '',
+    };
+  }
+
+  return {
+    id: event.id,
+    action: 'reject',
+    msg: 'blocked: the event doesn\'t match the allowed filters',
+  };
+};
+
+export default filterPolicy;
+
+export type { Filter };