From 254b0f1f11a3e4835ae5d02e7fdf0359f6f73b56 Mon Sep 17 00:00:00 2001
From: Alex Gleason <alex@alexgleason.me>
Date: Sun, 26 Mar 2023 15:58:37 -0500
Subject: [PATCH] Add whitelistPolicy

---
 src/policies/whitelist-policy.test.ts | 15 +++++++++++++
 src/policies/whitelist-policy.ts      | 32 +++++++++++++++++++++++++++
 2 files changed, 47 insertions(+)
 create mode 100644 src/policies/whitelist-policy.test.ts
 create mode 100644 src/policies/whitelist-policy.ts

diff --git a/src/policies/whitelist-policy.test.ts b/src/policies/whitelist-policy.test.ts
new file mode 100644
index 0000000..e6afe32
--- /dev/null
+++ b/src/policies/whitelist-policy.test.ts
@@ -0,0 +1,15 @@
+import { assert } from '../deps.ts';
+import { buildEvent, buildInputMessage } from '../test.ts';
+
+import whitelistPolicy from './whitelist-policy.ts';
+
+Deno.test('allows only whitelisted pubkeys', async () => {
+  const msgA = buildInputMessage({ event: buildEvent({ pubkey: 'A' }) });
+  const msgB = buildInputMessage({ event: buildEvent({ pubkey: 'B' }) });
+  const msgC = buildInputMessage({ event: buildEvent({ pubkey: 'C' }) });
+
+  assert((await whitelistPolicy(msgA, [])).action === 'reject');
+  assert((await whitelistPolicy(msgA, ['A'])).action === 'accept');
+  assert((await whitelistPolicy(msgC, ['B', 'A'])).action === 'reject');
+  assert((await whitelistPolicy(msgB, ['B', 'A'])).action === 'accept');
+});
diff --git a/src/policies/whitelist-policy.ts b/src/policies/whitelist-policy.ts
new file mode 100644
index 0000000..da9f2f4
--- /dev/null
+++ b/src/policies/whitelist-policy.ts
@@ -0,0 +1,32 @@
+import type { Policy } from '../types.ts';
+
+/**
+ * Allows only the listed pubkeys to post to the relay. All other events are rejected.
+ * Pass an array of pubkeys or an iterable, making it efficient to load pubkeys from a large file.
+ */
+const whitelistPolicy: Policy<Iterable<string>> = ({ event: { id, pubkey } }, pubkeys = []) => {
+  let isMatch = false;
+
+  for (const p of pubkeys) {
+    if (p === pubkey) {
+      isMatch = true;
+      break;
+    }
+  }
+
+  if (isMatch) {
+    return {
+      id,
+      action: 'accept',
+      msg: '',
+    };
+  }
+
+  return {
+    id,
+    action: 'reject',
+    msg: 'Only certain pubkeys are allowed.',
+  };
+};
+
+export default whitelistPolicy;