Request logging for web server

packages/next/src/bin/next.ts

@@ -339,6 +339,10 @@ program
     '-H, --hostname <hostname>',
     'Specify a hostname on which to start the application (default: 0.0.0.0).'
   )
+  .option(
+    '--access-log <path>',
+    'Specify the path to where to write the access log.'
+  )
   .addOption(
     new Option(
       '--keepAliveTimeout <keepAliveTimeout>',

packages/next/src/cli/next-start.ts

@@ -13,6 +13,7 @@ export type NextStartOptions = {
   port: number
   hostname?: string
   keepAliveTimeout?: number
+  accessLog?: string
 }
 
 /**
@@ -25,6 +26,7 @@ const nextStart = async (options: NextStartOptions, directory?: string) => {
   const dir = getProjectDir(directory)
   const hostname = options.hostname
   const port = options.port
+  const accessLog = options.accessLog
   const keepAliveTimeout = options.keepAliveTimeout
 
   if (isPortIsReserved(port)) {
@@ -37,6 +39,7 @@ const nextStart = async (options: NextStartOptions, directory?: string) => {
     hostname,
     port,
     keepAliveTimeout,
+    accessLog,
   })
 }
 

packages/next/src/server/lib/start-server.ts

@@ -46,6 +46,7 @@ export interface StartServerOptions {
   allowRetry?: boolean
   customServer?: boolean
   minimalMode?: boolean
+  accessLog?: string
   keepAliveTimeout?: number
   // this is dev-server only
   selfSignedCertificate?: SelfSignedCertificate
@@ -100,6 +101,7 @@ export async function startServer(
     allowRetry,
     keepAliveTimeout,
     selfSignedCertificate,
+    accessLog,
   } = serverOptions
   let { port } = serverOptions
 
@@ -145,6 +147,26 @@ export async function startServer(
   }
 
   async function requestListener(req: IncomingMessage, res: ServerResponse) {
+    if (accessLog) {
+      try {
+        let remoteAddress
+
+        if (req.headers['x-forwarded-for']) {
+          remoteAddress = req.headers['x-forwarded-for'].split(',')[0]
+        } else {
+          remoteAddress = req.socket.remoteAddress
+        }
+        res.on('finish', () => {
+          fs.appendFileSync(
+            accessLog,
+            `${remoteAddress} ${new Date().toISOString()} ${req.method} ${res.statusCode} ${req.url} ${req.headers['user-agent']}\n`
+          )
+        })
+      } catch (err) {
+        Log.error(`Failed to write to access log: ${accessLog}`)
+        console.error(err)
+      }
+    }
     try {
       if (handlersPromise) {
         await handlersPromise