From 75ba27c22258cb3e9f5f7b9ffc54ca3e42c78e8b Mon Sep 17 00:00:00 2001
From: Tim Neutkens <tim@timneutkens.nl>
Date: Sun, 17 Sep 2023 12:25:19 +0200
Subject: [PATCH] Generate middlewareManifestPath only once (#55489)

Ensures the `join()` is skipped for each request. Did a load test and this increases throughput by about ~150RPS at minimum.
---
 packages/next/src/server/next-server.ts | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/packages/next/src/server/next-server.ts b/packages/next/src/server/next-server.ts
index f5d3d7feb62eb..0271395ba1d13 100644
--- a/packages/next/src/server/next-server.ts
+++ b/packages/next/src/server/next-server.ts
@@ -145,6 +145,7 @@ function getMiddlewareMatcher(
 }
 
 export default class NextNodeServer extends BaseServer {
+  protected middlewareManifestPath: string
   private _serverDistDir: string | undefined
   private imageResponseCache?: ResponseCache
   protected renderWorkersPromises?: Promise<void>
@@ -231,6 +232,8 @@ export default class NextNodeServer extends BaseServer {
       const { interceptTestApis } = require('../experimental/testmode/server')
       interceptTestApis()
     }
+
+    this.middlewareManifestPath = join(this.serverDistDir, MIDDLEWARE_MANIFEST)
   }
 
   protected async handleUpgrade(): Promise<void> {
@@ -1335,10 +1338,7 @@ export default class NextNodeServer extends BaseServer {
 
   protected getMiddlewareManifest(): MiddlewareManifest | null {
     if (this.minimalMode) return null
-    const manifest: MiddlewareManifest = require(join(
-      this.serverDistDir,
-      MIDDLEWARE_MANIFEST
-    ))
+    const manifest: MiddlewareManifest = require(this.middlewareManifestPath)
     return manifest
   }