From 5355c3525cf1c9160da1c45eae475d9549e8cc1a Mon Sep 17 00:00:00 2001
From: uzlopak <aras.abbasi@googlemail.com>
Date: Sun, 21 Jul 2024 14:11:25 +0200
Subject: [PATCH] improve performance of headers check

---
 src/middleware/node/get-missing-headers.ts | 15 --------
 src/middleware/node/handler.ts             | 22 +++--------
 src/middleware/node/validate-headers.ts    | 45 ++++++++++++++++++++++
 test/integration/node-handler.test.ts      |  2 +-
 test/integration/node-middleware.test.ts   |  2 +-
 5 files changed, 52 insertions(+), 34 deletions(-)
 delete mode 100644 src/middleware/node/get-missing-headers.ts
 create mode 100644 src/middleware/node/validate-headers.ts

diff --git a/src/middleware/node/get-missing-headers.ts b/src/middleware/node/get-missing-headers.ts
deleted file mode 100644
index 8e4b0c32..00000000
--- a/src/middleware/node/get-missing-headers.ts
+++ /dev/null
@@ -1,15 +0,0 @@
-// remove type imports from http for Deno compatibility
-// see https://github.com/octokit/octokit.js/issues/24#issuecomment-817361886
-// import type { IncomingMessage } from "node:http";
-type IncomingMessage = any;
-
-const WEBHOOK_HEADERS = [
-  "x-github-event",
-  "x-hub-signature-256",
-  "x-github-delivery",
-];
-
-// https://docs.github.com/en/developers/webhooks-and-events/webhook-events-and-payloads#delivery-headers
-export function getMissingHeaders(request: IncomingMessage) {
-  return WEBHOOK_HEADERS.filter((header) => !(header in request.headers));
-}
diff --git a/src/middleware/node/handler.ts b/src/middleware/node/handler.ts
index 7fd5caf8..ecc58c52 100644
--- a/src/middleware/node/handler.ts
+++ b/src/middleware/node/handler.ts
@@ -9,7 +9,7 @@ import type { WebhookEventName } from "../../generated/webhook-identifiers.js";
 import type { Webhooks } from "../../index.js";
 import type { WebhookEventHandlerError } from "../../types.js";
 import type { MiddlewareOptions } from "./types.js";
-import { getMissingHeaders } from "./get-missing-headers.js";
+import { validateHeaders } from "./validate-headers.js";
 import { getPayload } from "./get-payload.js";
 
 type Handler = (
@@ -44,18 +44,7 @@ export function createNodeHandler(
       return true;
     }
 
-    const missingHeaders = getMissingHeaders(request).join(", ");
-
-    if (missingHeaders) {
-      response.writeHead(400, {
-        "content-type": "application/json",
-      });
-      response.end(
-        JSON.stringify({
-          error: `Required headers missing: ${missingHeaders}`,
-        }),
-      );
-
+    if (validateHeaders(request, response)) {
       return true;
     }
 
@@ -98,14 +87,13 @@ export function createNodeHandler(
       const errorMessage = err.message
         ? `${err.name}: ${err.message}`
         : "Error: An Unspecified error occurred";
-      
-      const statusCode =
-        typeof err.status !== "undefined" ? err.status : 500;
+
+      const statusCode = typeof err.status !== "undefined" ? err.status : 500;
 
       logger.error(error);
 
       response.writeHead(statusCode, {
-        "content-type": "application/json"
+        "content-type": "application/json",
       });
 
       response.end(
diff --git a/src/middleware/node/validate-headers.ts b/src/middleware/node/validate-headers.ts
new file mode 100644
index 00000000..819c016c
--- /dev/null
+++ b/src/middleware/node/validate-headers.ts
@@ -0,0 +1,45 @@
+// remove type imports from http for Deno compatibility
+// see https://github.com/octokit/octokit.js/issues/24#issuecomment-817361886
+// import type { IncomingMessage } from "node:http";
+type IncomingMessage = any;
+type OutgoingMessage = any;
+
+const webhookHeadersMissingMessage = {
+  "x-github-event": JSON.stringify({
+    error: `Required header missing: x-github-event`,
+  }),
+  "x-hub-signature-256": JSON.stringify({
+    error: `Required header missing: x-github-signature-256`,
+  }),
+  "x-github-delivery": JSON.stringify({
+    error: `Required header missing: x-github-delivery`,
+  }),
+};
+
+function sendMissindHeaderResponse(
+  response: OutgoingMessage,
+  missingHeader: keyof typeof webhookHeadersMissingMessage,
+) {
+  response.writeHead(400, {
+    "content-type": "application/json",
+  });
+  response.end(webhookHeadersMissingMessage[missingHeader]);
+}
+
+// https://docs.github.com/en/developers/webhooks-and-events/webhook-events-and-payloads#delivery-headers
+export function validateHeaders(
+  request: IncomingMessage,
+  response: OutgoingMessage,
+) {
+  if ("x-github-event" in request.headers === false) {
+    sendMissindHeaderResponse(response, "x-github-event");
+  } else if ("x-hub-signature-256" in request.headers === false) {
+    sendMissindHeaderResponse(response, "x-hub-signature-256");
+  } else if ("x-github-delivery" in request.headers === false) {
+    sendMissindHeaderResponse(response, "x-github-delivery");
+  } else {
+    return false;
+  }
+
+  return true;
+}
diff --git a/test/integration/node-handler.test.ts b/test/integration/node-handler.test.ts
index 8d36b333..020da548 100644
--- a/test/integration/node-handler.test.ts
+++ b/test/integration/node-handler.test.ts
@@ -250,7 +250,7 @@ describe("createNodeHandler(webhooks)", () => {
     expect(response.status).toEqual(400);
 
     await expect(response.text()).resolves.toMatch(
-      /Required headers missing: x-github-event/,
+      /Required header missing: x-github-event/,
     );
 
     server.close();
diff --git a/test/integration/node-middleware.test.ts b/test/integration/node-middleware.test.ts
index 3014241e..8c6eb369 100644
--- a/test/integration/node-middleware.test.ts
+++ b/test/integration/node-middleware.test.ts
@@ -287,7 +287,7 @@ describe("createNodeMiddleware(webhooks)", () => {
     expect(response.status).toEqual(400);
 
     await expect(response.text()).resolves.toMatch(
-      /Required headers missing: x-github-event/,
+      /Required header missing: x-github-event/,
     );
 
     server.close();