Fix Next.js runtime discovery on Windows (#67)

Author: gaojude

.github/workflows/ci.yml

@@ -10,7 +10,10 @@ on:
 
 jobs:
   test:
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest]
     steps:
       - name: Checkout code
         uses: actions/checkout@v4

.gitignore

@@ -14,3 +14,8 @@ test/e2e/.env
 _*.md
 .mcpregistry*
 
+# Test fixtures
+test/fixtures/**/pnpm-lock.yaml
+test/fixtures/**/node_modules/
+test/fixtures/**/.next/
+

package.json

@@ -33,6 +33,7 @@
   },
   "dependencies": {
     "@modelcontextprotocol/sdk": "1.20.0",
+    "find-process": "^2.0.0",
     "xmcp": "^0.3.5",
     "zod": "^3.25.76"
   },

pnpm-lock.yaml

@@ -1,7 +1,4 @@
-import { exec } from "child_process"
-import { promisify } from "util"
-
-const execAsync = promisify(exec)
+import find from "find-process"
 
 interface NextJsServerInfo {
   port: number
@@ -30,52 +27,35 @@ interface NextJsMCPResponse {
 
 async function findNextJsServers(): Promise<NextJsServerInfo[]> {
   try {
-    const { stdout } = await execAsync("ps aux")
-    const lines = stdout.split("\n")
+    const nodeProcesses = await find("name", "node", true)
     const servers: NextJsServerInfo[] = []
     const seenPorts = new Set<number>()
 
-    for (const line of lines) {
-      // Enhanced detection patterns for Next.js servers
+    for (const proc of nodeProcesses) {
+      const command = proc.cmd || ""
+
       const isNextJsProcess =
-        line.includes("next dev") ||
-        line.includes("next-server") ||
-        line.includes("next/dist/bin/next") ||
-        (line.includes("node") && line.includes("next") && line.includes("dev"))
+        command.includes("next dev") ||
+        command.includes("next-server") ||
+        command.includes("next/dist/bin/next") ||
+        (command.includes("next") && command.includes("dev"))
 
       if (isNextJsProcess) {
-        const parts = line.trim().split(/\s+/)
-        const pid = parseInt(parts[1], 10)
-        const command = parts.slice(10).join(" ")
-
-        // Try multiple methods to detect port
         const portMatch =
           command.match(/--port[=\s]+(\d+)/) ||
           command.match(/-p[=\s]+(\d+)/) ||
+          command.match(/--port\s+["'](\d+)["']/) ||
+          command.match(/["']--port["']\s+["']?(\d+)["']?/) ||
+          command.match(/["'](\d+)["']\s*$/) ||
           command.match(/:(\d+)/)
 
-        let port = 3000 // Default Next.js port
-
         if (portMatch) {
-          port = parseInt(portMatch[1], 10)
-        } else {
-          // Fallback: use lsof to find the listening port
-          try {
-            const processInfo = await execAsync(`lsof -Pan -p ${pid} -i 2>/dev/null || true`)
-            const portFromLsof = processInfo.stdout.match(/:(\d+).*LISTEN/)
-            if (portFromLsof) {
-              port = parseInt(portFromLsof[1], 10)
-            }
-          } catch {
-            // If lsof fails, continue with default port
+          const port = parseInt(portMatch[1], 10)
+          if (!seenPorts.has(port)) {
+            seenPorts.add(port)
+            servers.push({ port, pid: proc.pid, command })
           }
         }
-
-        // Avoid duplicate ports (in case multiple processes are detected)
-        if (!seenPorts.has(port)) {
-          seenPorts.add(port)
-          servers.push({ port, pid, command })
-        }
       }
     }
 
@@ -159,22 +139,13 @@ async function makeNextJsMCPRequest(
   }
 }
 
-export async function discoverNextJsServer(
-  preferredPort?: number
-): Promise<NextJsServerInfo | null> {
+export async function discoverNextJsServer(): Promise<NextJsServerInfo | null> {
   const servers = await findNextJsServers()
 
   if (servers.length === 0) {
     return null
   }
 
-  if (preferredPort) {
-    const server = servers.find((s) => s.port === preferredPort)
-    if (server) {
-      return server
-    }
-  }
-
   if (servers.length === 1) {
     return servers[0]
   }

src/_internal/nextjs-runtime-manager.ts

@@ -0,0 +1,3 @@
+node_modules
+.next
+.env*.local

test/fixtures/nextjs16-minimal/.gitignore

@@ -0,0 +1,16 @@
+export const metadata = {
+  title: 'Next.js 16 Test Fixture',
+  description: 'Minimal Next.js 16 app for testing',
+}
+
+export default function RootLayout({
+  children,
+}: {
+  children: React.ReactNode
+}) {
+  return (
+    <html lang="en">
+      <body>{children}</body>
+    </html>
+  )
+}

test/fixtures/nextjs16-minimal/app/layout.tsx

@@ -0,0 +1,8 @@
+export default function Home() {
+  return (
+    <main>
+      <h1>Next.js 16 Minimal Test Fixture</h1>
+      <p>This is a minimal Next.js 16 app for testing.</p>
+    </main>
+  )
+}

test/fixtures/nextjs16-minimal/app/page.tsx

@@ -0,0 +1,6 @@
+/// <reference types="next" />
+/// <reference types="next/image-types/global" />
+import "./.next/dev/types/routes.d.ts";
+
+// NOTE: This file should not be edited
+// see https://nextjs.org/docs/app/api-reference/config/typescript for more information.

test/fixtures/nextjs16-minimal/next-env.d.ts

@@ -0,0 +1,5 @@
+import type { NextConfig } from 'next'
+
+const nextConfig: NextConfig = {}
+
+export default nextConfig