refactor(preview)!: use base middleware

docs/guide/migration.md

@@ -201,6 +201,9 @@ const packageJson = JSON.parse(fs.readFileSync(packageJsonPath, 'utf-8'))
 There are some changes which only affect plugin/tool creators.
 
 - [[#14119] refactor!: merge `PreviewServerForHook` into `PreviewServer` type](https://github.com/vitejs/vite/pull/14119)
+  - The `configurePreviewServer` hook now accepts the `PreviewServer` type instead of `PreviewServerForHook` type.
+- [[#14818] refactor(preview)!: use base middleware](https://github.com/vitejs/vite/pull/14818)
+  - Middlewares added from the returned function in `configurePreviewServer` now does not have access to the `base` when comparing the `req.url` value. This aligns the behaviour with the dev server. You can check the `base` from the `configResolved` hook if needed.
 
 Also there are other breaking changes which only affect few users.
 

packages/vite/src/node/preview.ts

@@ -15,6 +15,7 @@ import {
 } from './http'
 import { openBrowser } from './server/openBrowser'
 import compression from './server/middlewares/compression'
+import { baseMiddleware } from './server/middlewares/base'
 import { htmlFallbackMiddleware } from './server/middlewares/htmlFallback'
 import { indexHtmlMiddleware } from './server/middlewares/indexHtml'
 import { notFoundMiddleware } from './server/middlewares/notFound'
@@ -164,8 +165,10 @@ export async function preview(
 
   app.use(compression())
 
-  const previewBase =
-    config.base === './' || config.base === '' ? '/' : config.base
+  // base
+  if (config.base !== '/') {
+    app.use(baseMiddleware(config.rawBase, false))
+  }
 
   // static assets
   const headers = config.preview.headers
@@ -187,36 +190,28 @@ export async function preview(
       },
     })(...args)
 
-  app.use(previewBase, viteAssetMiddleware)
+  app.use(viteAssetMiddleware)
 
   // html fallback
   if (config.appType === 'spa' || config.appType === 'mpa') {
-    app.use(
-      previewBase,
-      htmlFallbackMiddleware(
-        distDir,
-        config.appType === 'spa',
-        previewBase !== '/',
-      ),
-    )
+    app.use(htmlFallbackMiddleware(distDir, config.appType === 'spa'))
   }
 
   // apply post server hooks from plugins
   postHooks.forEach((fn) => fn && fn())
 
   if (config.appType === 'spa' || config.appType === 'mpa') {
     // transform index.html
-    app.use(previewBase, indexHtmlMiddleware(distDir, server))
+    app.use(indexHtmlMiddleware(distDir, server))
 
     // handle 404s
-    app.use(previewBase, notFoundMiddleware())
+    app.use(notFoundMiddleware())
   }
 
   const hostname = await resolveHostname(options.host)
   const port = options.port ?? DEFAULT_PREVIEW_PORT
-  const protocol = options.https ? 'https' : 'http'
 
-  const serverPort = await httpServerStart(httpServer, {
+  await httpServerStart(httpServer, {
     port,
     strictPort: options.strictPort,
     host: hostname.host,
@@ -230,14 +225,12 @@ export async function preview(
   )
 
   if (options.open) {
-    const path = typeof options.open === 'string' ? options.open : previewBase
-    openBrowser(
-      path.startsWith('http')
-        ? path
-        : new URL(path, `${protocol}://${hostname.name}:${serverPort}`).href,
-      true,
-      logger,
-    )
+    const url = server.resolvedUrls?.local[0] ?? server.resolvedUrls?.network[0]
+    if (url) {
+      const path =
+        typeof options.open === 'string' ? new URL(options.open, url).href : url
+      openBrowser(path, true, logger)
+    }
   }
 
   return server as PreviewServer

packages/vite/src/node/server/index.ts

@@ -677,7 +677,7 @@ export async function _createServer(
 
   // base
   if (config.base !== '/') {
-    middlewares.use(baseMiddleware(server))
+    middlewares.use(baseMiddleware(config.rawBase, middlewareMode))
   }
 
   // open in editor support

packages/vite/src/node/server/middlewares/base.ts

@@ -1,35 +1,39 @@
 import type { Connect } from 'dep-types/connect'
-import type { ViteDevServer } from '..'
-import { joinUrlSegments, stripBase, withTrailingSlash } from '../../utils'
+import {
+  cleanUrl,
+  joinUrlSegments,
+  stripBase,
+  withTrailingSlash,
+} from '../../utils'
 
 // this middleware is only active when (base !== '/')
 
-export function baseMiddleware({
-  config,
-}: ViteDevServer): Connect.NextHandleFunction {
+export function baseMiddleware(
+  rawBase: string,
+  middlewareMode: boolean,
+): Connect.NextHandleFunction {
   // Keep the named function. The name is visible in debug logs via `DEBUG=connect:dispatcher ...`
   return function viteBaseMiddleware(req, res, next) {
     const url = req.url!
-    const parsed = new URL(url, 'http://vitejs.dev')
-    const path = parsed.pathname || '/'
-    const base = config.rawBase
+    const pathname = cleanUrl(url)
+    const base = rawBase
 
-    if (path.startsWith(base)) {
+    if (pathname.startsWith(base)) {
       // rewrite url to remove base. this ensures that other middleware does
       // not need to consider base being prepended or not
       req.url = stripBase(url, base)
       return next()
     }
 
     // skip redirect and error fallback on middleware mode, #4057
-    if (config.server.middlewareMode) {
+    if (middlewareMode) {
       return next()
     }
 
-    if (path === '/' || path === '/index.html') {
+    if (pathname === '/' || pathname === '/index.html') {
       // redirect root visit to based url with search and hash
       res.writeHead(302, {
-        Location: base + (parsed.search || '') + (parsed.hash || ''),
+        Location: base + url.slice(pathname.length),
       })
       res.end()
       return

packages/vite/src/node/server/middlewares/htmlFallback.ts

@@ -8,21 +8,7 @@ const debug = createDebugger('vite:html-fallback')
 export function htmlFallbackMiddleware(
   root: string,
   spaFallback: boolean,
-  mounted = false,
 ): Connect.NextHandleFunction {
-  // When this middleware is mounted on a route, we need to re-assign `req.url` with a
-  // leading `.` to signal a relative rewrite. Returning with a leading `/` returns a
-  // buggy `req.url`. e.g.:
-  //
-  // mount /foo/bar:
-  //  req.url = /index.html
-  //  final   = /foo/barindex.html
-  //
-  // mount /foo/bar:
-  //  req.url = ./index.html
-  //  final   = /foo/bar/index.html
-  const prepend = mounted ? '.' : ''
-
   // Keep the named function. The name is visible in debug logs via `DEBUG=connect:dispatcher ...`
   return function viteHtmlFallbackMiddleware(req, res, next) {
     if (
@@ -51,7 +37,7 @@ export function htmlFallbackMiddleware(
       const filePath = path.join(root, pathname)
       if (fs.existsSync(filePath)) {
         debug?.(`Rewriting ${req.method} ${req.url} to ${url}`)
-        req.url = prepend + url
+        req.url = url
         return next()
       }
     }
@@ -61,7 +47,7 @@ export function htmlFallbackMiddleware(
       if (fs.existsSync(filePath)) {
         const newUrl = url + 'index.html'
         debug?.(`Rewriting ${req.method} ${req.url} to ${newUrl}`)
-        req.url = prepend + newUrl
+        req.url = newUrl
         return next()
       }
     }
@@ -71,14 +57,14 @@ export function htmlFallbackMiddleware(
       if (fs.existsSync(filePath)) {
         const newUrl = url + '.html'
         debug?.(`Rewriting ${req.method} ${req.url} to ${newUrl}`)
-        req.url = prepend + newUrl
+        req.url = newUrl
         return next()
       }
     }
 
     if (spaFallback) {
       debug?.(`Rewriting ${req.method} ${req.url} to /index.html`)
-      req.url = prepend + '/index.html'
+      req.url = '/index.html'
     }
 
     next()