fix: add verifyWithFallback() function in the web entrypoint (#312)

Author: wolfy1339

src/web.ts

@@ -79,3 +79,26 @@ export async function verify(
     enc.encode(eventPayload),
   );
 }
+export async function verifyWithFallback(
+  secret: string,
+  payload: string,
+  signature: string,
+  additionalSecrets: undefined | string[],
+): Promise<any> {
+  const firstPass = await verify(secret, payload, signature);
+
+  if (firstPass) {
+    return true;
+  }
+
+  if (additionalSecrets !== undefined) {
+    for (const s of additionalSecrets) {
+      const v: boolean = await verify(s, payload, signature);
+      if (v) {
+        return v;
+      }
+    }
+  }
+
+  return false;
+}

test/deno/web_test.ts

@@ -1,4 +1,4 @@
-import { sign, verify } from "../../pkg/dist-web/index.js";
+import { sign, verify, verifyWithFallback } from "../../pkg/dist-web/index.js";
 
 import { assertEquals } from "@std/assert";
 
@@ -16,3 +16,11 @@ Deno.test("verify", async () => {
   const expected = true;
   assertEquals(actual, expected);
 });
+
+Deno.test("verify with fallback", async () => {
+  const signature =
+    "sha256=1b2c16b75bd2a870c114153ccda5bcfca63314bc722fa160d690de133ccbb9db";
+  const actual = await verifyWithFallback("foo", "data", signature, ["secret"]);
+  const expected = true;
+  assertEquals(actual, expected);
+});