improved network url in (dev) cli

packages/next/src/lib/get-network-host.ts

@@ -0,0 +1,36 @@
+import os from 'os'
+
+function getNetworkHosts(family: 'IPv4' | 'IPv6'): string[] {
+  const interfaces = os.networkInterfaces()
+  const hosts: string[] = []
+
+  Object.keys(interfaces).forEach((key) => {
+    interfaces[key]
+      ?.filter((networkInterface) => {
+        switch (networkInterface.family) {
+          case 'IPv6':
+            return (
+              family === 'IPv6' &&
+              networkInterface.scopeid === 0 &&
+              networkInterface.address !== '::1'
+            )
+          case 'IPv4':
+            return family === 'IPv4' && networkInterface.address !== '127.0.0.1'
+          default:
+            return false
+        }
+      })
+      .forEach((networkInterface) => {
+        if (networkInterface.address) {
+          hosts.push(networkInterface.address)
+        }
+      })
+  })
+
+  return hosts
+}
+
+export function getNetworkHost(family: 'IPv4' | 'IPv6'): string | null {
+  const hosts = getNetworkHosts(family)
+  return hosts[0] ?? null
+}

packages/next/src/server/lib/app-info-log.ts

@@ -31,7 +31,7 @@ export function logStartInfo({
   if (networkUrl) {
     Log.bootstrap(`- Network:      ${networkUrl}`)
   }
-  if (envInfo?.length) Log.bootstrap(`- Environments: ${envInfo.join(', ')}`)
+  if (envInfo?.length) Log.bootstrap(` - Environments: ${envInfo.join(', ')}`)
 
   if (expFeatureInfo?.length) {
     Log.bootstrap(`- Experiments (use with caution):`)

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

@@ -1,3 +1,5 @@
+import { getNetworkHost } from '../../lib/get-network-host'
+
 if (performance.getEntriesByName('next-start').length === 0) {
   performance.mark('next-start')
 }
@@ -29,6 +31,7 @@ import { getStartServerInfo, logStartInfo } from './app-info-log'
 import { validateTurboNextConfig } from '../../lib/turbopack-warning'
 import { type Span, trace, flushAllTraces } from '../../trace'
 import { isPostpone } from './router-utils/is-postpone'
+import { isIPv6 } from './is-ipv6'
 
 const debug = setupDebug('next:start-server')
 let startServerSpan: Span | undefined
@@ -234,12 +237,16 @@ export async function startServer(
 
       port = typeof addr === 'object' ? addr?.port || port : port
 
-      const networkUrl = hostname
-        ? `${selfSignedCertificate ? 'https' : 'http'}://${actualHostname}:${port}`
+      const networkHostname =
+        hostname ?? getNetworkHost(isIPv6(actualHostname) ? 'IPv6' : 'IPv4')
+
+      const protocol = selfSignedCertificate ? 'https' : 'http'
+
+      const networkUrl = networkHostname
+        ? `${protocol}://${formatHostname(networkHostname)}:${port}`
         : null
-      const appUrl = `${
-        selfSignedCertificate ? 'https' : 'http'
-      }://${formattedHostname}:${port}`
+
+      const appUrl = `${protocol}://${formattedHostname}:${port}`
 
       if (nodeDebugType) {
         const formattedDebugAddress = getFormattedDebugAddress()

test/integration/cli/test/index.test.js

@@ -476,6 +476,10 @@ describe('CLI Usage', () => {
       )
       try {
         await check(() => output, new RegExp(`http://localhost:${port}`))
+        await check(
+          () => output,
+          /Network:\s*http:\/\/[\d]{1,}\.[\d]{1,}\.[\d]{1,}/
+        )
       } finally {
         await killApp(app)
       }
@@ -495,6 +499,10 @@ describe('CLI Usage', () => {
       )
       try {
         await check(() => output, new RegExp(`http://localhost:${port}`))
+        await check(
+          () => output,
+          /Network:\s*http:\/\/[\d]{1,}\.[\d]{1,}\.[\d]{1,}/
+        )
       } finally {
         await killApp(app)
       }