improve resolving files, cache files

package.json

@@ -35,6 +35,7 @@
     "path-match": "1.2.4",
     "react": "15.3.2",
     "react-dom": "15.3.2",
+    "resolve": "1.1.7",
     "send": "0.14.1",
     "url": "0.11.0",
     "webpack": "1.13.2"

server/index.js

@@ -61,7 +61,7 @@ export default class Server {
     try {
       html = await render(path, req, res, { dir, dev })
     } catch (err) {
-      if ('MODULE_NOT_FOUND' === err.code) {
+      if ('ENOENT' === err.code) {
         return this.render404(req, res)
       }
       throw err
@@ -77,7 +77,7 @@ export default class Server {
     try {
       json = await renderJSON(path, { dir })
     } catch (err) {
-      if ('MODULE_NOT_FOUND' === err.code) {
+      if ('ENOENT' === err.code) {
         return this.render404(req, res)
       }
       throw err

server/read.js

@@ -0,0 +1,22 @@
+import fs from 'mz/fs'
+import resolve from './resolve'
+
+const cache = {}
+
+/**
+ * resolve a file like `require.resolve`,
+ * and read and cache the file content
+ */
+
+async function read (path) {
+  const f = await resolve(path)
+  let promise = cache[f]
+  if (!promise) {
+    promise = cache[f] = fs.readFile(f, 'utf8')
+  }
+  return promise
+}
+
+module.exports = read
+
+exports.cache = cache

server/render.js

@@ -2,6 +2,8 @@ import { relative, resolve } from 'path'
 import { createElement } from 'react'
 import { renderToString, renderToStaticMarkup } from 'react-dom/server'
 import fs from 'mz/fs'
+import requireResolve from './resolve'
+import read from './read'
 import Router from '../lib/router'
 import Document from '../lib/document'
 import Head from '../lib/head'
@@ -9,7 +11,8 @@ import App from '../lib/app'
 import { StyleSheetServer } from '../lib/css'
 
 export async function render (path, req, res, { dir = process.cwd(), dev = false } = {}) {
-  const mod = require(resolve(dir, '.next', 'pages', path))
+  const p = await requireResolve(resolve(dir, '.next', 'pages', path))
+  const mod = require(p)
   const Component = mod.default || mod
 
   let props = {}
@@ -17,8 +20,7 @@ export async function render (path, req, res, { dir = process.cwd(), dev = false
     props = await Component.getInitialProps({ req, res })
   }
 
-  const bundlePath = resolve(dir, '.next', '_bundles', 'pages', (path || 'index') + '.js')
-  const component = await fs.readFile(bundlePath, 'utf8')
+  const component = await read(resolve(dir, '.next', '_bundles', 'pages', path))
 
   const { html, css } = StyleSheetServer.renderStatic(() => {
     const app = createElement(App, {
@@ -45,7 +47,6 @@ export async function render (path, req, res, { dir = process.cwd(), dev = false
 }
 
 export async function renderJSON (path, { dir = process.cwd() }) {
-  const bundlePath = resolve(dir, '.next', '_bundles', 'pages', (path || 'index') + '.js')
-  const component = await fs.readFile(bundlePath, 'utf8')
+  const component = await read(resolve(dir, '.next', '_bundles', 'pages', path))
   return { component }
 }

server/resolve.js

@@ -0,0 +1,15 @@
+import _resolve from 'resolve'
+
+export default function resolve (id, opts) {
+  return new Promise((resolve, reject) => {
+    _resolve(id, opts, (err, path) => {
+      if (err) {
+        const e = new Error(err)
+        e.code = 'ENOENT'
+        return reject(e)
+      }
+      resolve(path)
+    })
+  })
+}
+