feat: add internal server for serverMiddleware (#375)

Co-authored-by: Daniel Roe <[email protected]>

README.md

@@ -102,6 +102,15 @@ Example:
 }
 ```
 
+### internalServer
+
+- Type: `Boolean`
+- Default: `false`
+
+If you have defined `serverMiddleware` in your `nuxt.config`, this builder will automatically enable an internal server within the lambda so you can access your own endpoints via `http://localhost:3000`. (This does not affect how you call your endpoints from client-side.)
+
+If you need to enable or disable the internal server manually (for example, if you are adding server middleware via a module), just set `internalServer` within the builder options.
+
 ### `generateStaticRoutes`
 
 - Type: `Boolean`

src/build.ts

@@ -24,6 +24,7 @@ interface NuxtBuilderConfig {
   generateStaticRoutes?: boolean
   includeFiles?: string[] | string
   serverFiles?: string[]
+  internalServer?: boolean
 }
 
 export async function build (opts: BuildOptions & { config: NuxtBuilderConfig }): Promise<BuilderOutput> {
@@ -137,6 +138,7 @@ export async function build (opts: BuildOptions & { config: NuxtBuilderConfig })
   const buildDir = nuxtConfigFile.buildDir ? path.relative(entrypointPath, nuxtConfigFile.buildDir) : '.nuxt'
   const srcDir = nuxtConfigFile.srcDir ? path.relative(entrypointPath, nuxtConfigFile.srcDir) : '.'
   const lambdaName = nuxtConfigFile.lambdaName ? nuxtConfigFile.lambdaName : 'index'
+  const usesServerMiddleware = config.internalServer !== undefined ? config.internalServer : !!nuxtConfigFile.serverMiddleware
 
   await exec('nuxt', [
     'build',
@@ -222,6 +224,7 @@ export async function build (opts: BuildOptions & { config: NuxtBuilderConfig })
   const launcherSrc = (await fs.readFile(launcherPath, 'utf8'))
     .replace(/__NUXT_SUFFIX__/g, nuxtDep.suffix)
     .replace(/__NUXT_CONFIG__/g, './' + nuxtConfigName)
+    .replace(/\/\* __ENABLE_INTERNAL_SERVER__ \*\/ *true/g, String(usesServerMiddleware))
 
   const launcherFiles = {
     'vercel__launcher.js': new FileBlob({ data: launcherSrc }),

src/launcher.ts

@@ -1,4 +1,4 @@
-import http from 'http'
+import type { RequestListener } from 'http'
 import esmCompiler from 'esm'
 
 const startTime = process.hrtime()
@@ -33,19 +33,26 @@ const readyPromise = nuxt.ready().then(() => {
 })
 
 // Create bridge and start listening
-const { Server } = require('http') as typeof http // eslint-disable-line import/order
+const { Server } = require('http') as typeof import('http') // eslint-disable-line import/order
 const { Bridge } = require('./vercel__bridge.js') as typeof import('@vercel/node-bridge/bridge')
 
-const server = new Server(
-  async (req, res) => {
-    if (!isReady) {
-      await readyPromise
-    }
-    nuxt.server.app(req, res)
+const requestListener: RequestListener = async (req, res) => {
+  if (!isReady) {
+    await readyPromise
   }
-)
-const bridge = new Bridge(server)
+  nuxt.server.app(req, res)
+}
 
+// This is used by Vercel
+const server = new Server(requestListener)
+const bridge = new Bridge(server)
 bridge.listen()
 
+// eslint-disable-next-line
+if (/* __ENABLE_INTERNAL_SERVER__ */true) {
+  // Allow internal calls from Nuxt to endpoints registered as serverMiddleware
+  const internalServer = new Server(requestListener)
+  internalServer.listen(3000, '127.0.0.1')
+}
+
 export const launcher: typeof bridge.launcher = bridge.launcher