Add next configuration as an option for custom servers (#2058)

* Add a configuration parameter to custom server startup

* Adding related documentation

* Do not access filesystem if configuration is supplied

* Make the configuration log clearer

* Make the conf default value to `null`

readme.md

@@ -576,6 +576,7 @@ Supported options:
 - `dev` (`bool`) whether to launch Next.js in dev mode - default `false`
 - `dir` (`string`) where the Next project is located - default `'.'`
 - `quiet` (`bool`) Hide error messages containing server information - default `false`
+- `conf` (`object`) the same object you would use in `next.config.js` - default `{}`
 
 Then, change your `start` script to `NODE_ENV=production node server.js`.
 

server/build/webpack.js

@@ -308,7 +308,7 @@ export default async function createCompiler (dir, { dev = false, quiet = false,
   }
 
   if (config.webpack) {
-    console.log('> Using "webpack" config function defined in next.config.js.')
+    console.log(`> Using "webpack" config function defined in ${config.configOrigin}.`)
     webpackConfig = await config.webpack(webpackConfig, { dev })
   }
   return webpack(webpackConfig)

server/config.js

@@ -9,17 +9,22 @@ const defaultConfig = {
   poweredByHeader: true,
   distDir: '.next',
   assetPrefix: '',
+  configOrigin: 'default',
   useFileSystemPublicRoutes: true
 }
 
-export default function getConfig (dir) {
+export default function getConfig (dir, customConfig) {
   if (!cache.has(dir)) {
-    cache.set(dir, loadConfig(dir))
+    cache.set(dir, loadConfig(dir, customConfig))
   }
   return cache.get(dir)
 }
 
-function loadConfig (dir) {
+function loadConfig (dir, customConfig) {
+  if (customConfig && typeof customConfig === 'object') {
+    customConfig.configOrigin = 'server'
+    return withDefaults(customConfig)
+  }
   const path = join(dir, 'next.config.js')
 
   let userConfig = {}
@@ -28,7 +33,12 @@ function loadConfig (dir) {
   if (userHasConfig) {
     const userConfigModule = require(path)
     userConfig = userConfigModule.default || userConfigModule
+    userConfig.configOrigin = 'next.config.js'
   }
 
-  return Object.assign({}, defaultConfig, userConfig)
+  return withDefaults(userConfig)
+}
+
+function withDefaults (config) {
+  return Object.assign({}, defaultConfig, config)
 }

server/hot-reloader.js

@@ -8,7 +8,7 @@ import clean from './build/clean'
 import getConfig from './config'
 
 export default class HotReloader {
-  constructor (dir, { quiet } = {}) {
+  constructor (dir, { quiet, conf } = {}) {
     this.dir = dir
     this.quiet = quiet
     this.middlewares = []
@@ -22,7 +22,7 @@ export default class HotReloader {
     this.prevFailedChunkNames = null
     this.prevChunkHashes = null
 
-    this.config = getConfig(dir)
+    this.config = getConfig(dir, conf)
   }
 
   async run (req, res) {
@@ -148,7 +148,7 @@ export default class HotReloader {
     }
 
     if (this.config.webpackDevMiddleware) {
-      console.log('> Using "webpackDevMiddleware" config function defined in next.config.js.')
+      console.log(`> Using "webpackDevMiddleware" config function defined in ${this.config.configOrigin}.`)
       webpackDevMiddlewareConfig = this.config.webpackDevMiddleware(webpackDevMiddlewareConfig)
     }
 

server/index.js

@@ -24,14 +24,14 @@ const internalPrefixes = [
 ]
 
 export default class Server {
-  constructor ({ dir = '.', dev = false, staticMarkup = false, quiet = false } = {}) {
+  constructor ({ dir = '.', dev = false, staticMarkup = false, quiet = false, conf = null } = {}) {
     this.dir = resolve(dir)
     this.dev = dev
     this.quiet = quiet
     this.router = new Router()
-    this.hotReloader = dev ? new HotReloader(this.dir, { quiet }) : null
+    this.hotReloader = dev ? new HotReloader(this.dir, { quiet, conf }) : null
     this.http = null
-    this.config = getConfig(this.dir)
+    this.config = getConfig(this.dir, conf)
     this.dist = this.config.distDir
     this.buildStats = !dev ? require(join(this.dir, this.dist, 'build-stats.json')) : null
     this.buildId = !dev ? this.readBuildId() : '-'