fix(html)!: align html serving between dev and preview

docs/guide/migration.md

@@ -102,10 +102,29 @@ In Vite 4, `worker.plugins` accepted an array of plugins (`(Plugin | Plugin[])[]
 
 ### Allow path containing `.` to fallback to index.html
 
-In Vite 4, accessing a path containing `.` did not fallback to index.html even if `appType` is set to `'SPA'` (default).
-From Vite 5, it will fallback to index.html.
+In Vite 4, accessing a path in dev containing `.` did not fallback to index.html even if `appType` is set to `'spa'` (default). From Vite 5, it will fallback to index.html.
 
-Note that the browser will no longer show the 404 error message in the console if you point the image path to a non-existent file (e.g. `<img src="./file-does-not-exist.png">`).
+Note that the browser will no longer show a 404 error message in the console if you point the image path to a non-existent file (e.g. `<img src="./file-does-not-exist.png">`).
+
+### Align dev and preview HTML serving behaviour
+
+In Vite 4, the dev and preview servers serve HTML based on its directory structure and trailing slash differently. This causes inconsistencies when testing your built app. Vite 5 refactors into a single behaviour like below, given the following file structure:
+
+```
+├── index.html
+├── file.html
+└── dir
+    └── index.html
+```
+
+| Request           | Before (dev)                 | Before (preview)  | After (dev & preview)        |
+| ----------------- | ---------------------------- | ----------------- | ---------------------------- |
+| `/dir/index.html` | `/dir/index.html`            | `/dir/index.html` | `/dir/index.html`            |
+| `/dir`            | `/index.html` (SPA fallback) | `/dir/index.html` | `/dir.html` (SPA fallback)   |
+| `/dir/`           | `/dir/index.html`            | `/dir/index.html` | `/dir/index.html`            |
+| `/file.html`      | `/file.html`                 | `/file.html`      | `/file.html`                 |
+| `/file`           | `/index.html` (SPA fallback) | `/file.html`      | `/file.html`                 |
+| `/file/`          | `/index.html` (SPA fallback) | `/file.html`      | `/index.html` (SPA fallback) |
 
 ### Manifest files are now generated in `.vite` directory by default
 

packages/vite/LICENSE.md

@@ -911,35 +911,6 @@ Repository: senchalabs/connect
 
 ---------------------------------------
 
-## connect-history-api-fallback
-License: MIT
-By: Ben Ripkens, Craig Myles
-Repository: http://github.com/bripkens/connect-history-api-fallback.git
-
-> The MIT License
-> 
-> Copyright (c) 2022 Ben Blackmore and contributors
-> 
-> Permission is hereby granted, free of charge, to any person obtaining a copy
-> of this software and associated documentation files (the "Software"), to deal
-> in the Software without restriction, including without limitation the rights
-> to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-> copies of the Software, and to permit persons to whom the Software is
-> furnished to do so, subject to the following conditions:
-> 
-> The above copyright notice and this permission notice shall be included in
-> all copies or substantial portions of the Software.
-> 
-> THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-> IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-> FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-> AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-> LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-> OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-> THE SOFTWARE.
-
----------------------------------------
-
 ## convert-source-map
 License: MIT
 By: Thorsten Lorenz

packages/vite/package.json

@@ -98,7 +98,6 @@
     "cac": "^6.7.14",
     "chokidar": "^3.5.3",
     "connect": "^3.7.0",
-    "connect-history-api-fallback": "^2.0.0",
     "convert-source-map": "^2.0.0",
     "cors": "^2.8.5",
     "cross-spawn": "^7.0.3",

packages/vite/src/node/preview.ts

@@ -15,6 +15,9 @@ import {
 } from './http'
 import { openBrowser } from './server/openBrowser'
 import compression from './server/middlewares/compression'
+import { htmlFallbackMiddleware } from './server/middlewares/htmlFallback'
+import { indexHtmlMiddleware } from './server/middlewares/indexHtml'
+import { notFoundMiddleware } from './server/middlewares/notFound'
 import { proxyMiddleware } from './server/middlewares/proxy'
 import { resolveHostname, resolveServerUrls, shouldServeFile } from './utils'
 import { printServerUrls } from './logger'
@@ -170,7 +173,7 @@ export async function preview(
     sirv(distDir, {
       etag: true,
       dev: true,
-      single: config.appType === 'spa',
+      extensions: [],
       ignores: false,
       setHeaders(res) {
         if (headers) {
@@ -186,9 +189,29 @@ export async function preview(
 
   app.use(previewBase, viteAssetMiddleware)
 
+  // html fallback
+  if (config.appType === 'spa' || config.appType === 'mpa') {
+    app.use(
+      previewBase,
+      htmlFallbackMiddleware(
+        distDir,
+        config.appType === 'spa',
+        previewBase !== '/',
+      ),
+    )
+  }
+
   // 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))
+
+    // handle 404s
+    app.use(previewBase, notFoundMiddleware())
+  }
+
   const hostname = await resolveHostname(options.host)
   const port = options.port ?? DEFAULT_PREVIEW_PORT
   const protocol = options.https ? 'https' : 'http'

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

@@ -66,6 +66,7 @@ import {
 import { timeMiddleware } from './middlewares/time'
 import type { ModuleNode } from './moduleGraph'
 import { ModuleGraph } from './moduleGraph'
+import { notFoundMiddleware } from './middlewares/notFound'
 import { errorMiddleware, prepareError } from './middlewares/error'
 import type { HmrOptions } from './hmr'
 import {
@@ -692,14 +693,10 @@ export async function _createServer(
 
   if (config.appType === 'spa' || config.appType === 'mpa') {
     // transform index.html
-    middlewares.use(indexHtmlMiddleware(server))
+    middlewares.use(indexHtmlMiddleware(root, server))
 
     // handle 404s
-    // Keep the named function. The name is visible in debug logs via `DEBUG=connect:dispatcher ...`
-    middlewares.use(function vite404Middleware(_, res) {
-      res.statusCode = 404
-      res.end()
-    })
+    middlewares.use(notFoundMiddleware())
   }
 
   // error handler

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

@@ -1,48 +1,86 @@
 import fs from 'node:fs'
 import path from 'node:path'
-import history from 'connect-history-api-fallback'
 import type { Connect } from 'dep-types/connect'
-import { createDebugger } from '../../utils'
+import { cleanUrl, createDebugger } from '../../utils'
+
+const debug = createDebugger('vite:html-fallback')
 
 export function htmlFallbackMiddleware(
   root: string,
   spaFallback: boolean,
+  mounted = false,
 ): Connect.NextHandleFunction {
-  const historyHtmlFallbackMiddleware = history({
-    disableDotRule: true,
-    logger: createDebugger('vite:html-fallback'),
-    rewrites: [
-      // support /dir/ without explicit index.html
-      {
-        from: /\/$/,
-        to({ parsedUrl, request }: any) {
-          const rewritten =
-            decodeURIComponent(parsedUrl.pathname) + 'index.html'
-
-          if (fs.existsSync(path.join(root, rewritten))) {
-            return rewritten
-          }
-
-          return spaFallback ? `/index.html` : request.url
-        },
-      },
-      {
-        from: /\.html$/,
-        to({ parsedUrl, request }: any) {
-          // .html files are not handled by serveStaticMiddleware
-          // so we need to check if the file exists
-          const pathname = decodeURIComponent(parsedUrl.pathname)
-          if (fs.existsSync(path.join(root, pathname))) {
-            return request.url
-          }
-          return spaFallback ? `/index.html` : request.url
-        },
-      },
-    ],
-  })
+  // 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) {
-    return historyHtmlFallbackMiddleware(req, res, next)
+    if (
+      // Only accept GET or HEAD
+      (req.method !== 'GET' && req.method !== 'HEAD') ||
+      // Require Accept header
+      !req.headers ||
+      typeof req.headers.accept !== 'string' ||
+      // Ignore JSON requests
+      req.headers.accept.includes('application/json') ||
+      // Require Accept: text/html or */*
+      !(
+        req.headers.accept.includes('text/html') ||
+        req.headers.accept.includes('*/*')
+      )
+    ) {
+      return next()
+    }
+
+    const url = cleanUrl(req.url!)
+    const pathname = decodeURIComponent(url)
+
+    // .html files are not handled by serveStaticMiddleware
+    // so we need to check if the file exists
+    if (pathname.endsWith('.html')) {
+      const filePath = path.join(root, pathname)
+      if (fs.existsSync(filePath)) {
+        debug?.(`Rewriting ${req.method} ${req.url} to ${url}`)
+        req.url = prepend + url
+        return next()
+      }
+    }
+    // trailing slash should check for fallback index.html
+    else if (pathname[pathname.length - 1] === '/') {
+      const filePath = path.join(root, pathname, 'index.html')
+      if (fs.existsSync(filePath)) {
+        const newUrl = url + 'index.html'
+        debug?.(`Rewriting ${req.method} ${req.url} to ${newUrl}`)
+        req.url = prepend + newUrl
+        return next()
+      }
+    }
+    // non-trailing slash should check for fallback .html
+    else {
+      const filePath = path.join(root, pathname + '.html')
+      if (fs.existsSync(filePath)) {
+        const newUrl = url + '.html'
+        debug?.(`Rewriting ${req.method} ${req.url} to ${newUrl}`)
+        req.url = prepend + newUrl
+        return next()
+      }
+    }
+
+    if (spaFallback) {
+      debug?.(`Rewriting ${req.method} ${req.url} to /index.html`)
+      req.url = prepend + '/index.html'
+    }
+
+    next()
   }
 }

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

@@ -23,7 +23,7 @@ import {
   resolveHtmlTransforms,
   traverseHtml,
 } from '../../plugins/html'
-import type { ResolvedConfig, ViteDevServer } from '../..'
+import type { PreviewServer, ResolvedConfig, ViteDevServer } from '../..'
 import { send } from '../send'
 import { CLIENT_PUBLIC_PATH, FS_PREFIX } from '../../constants'
 import {
@@ -32,6 +32,7 @@ import {
   fsPathFromId,
   getHash,
   injectQuery,
+  isDevServer,
   isJSRequest,
   joinUrlSegments,
   normalizePath,
@@ -378,8 +379,14 @@ const devHtmlHook: IndexHtmlTransformHook = async (
 }
 
 export function indexHtmlMiddleware(
-  server: ViteDevServer,
+  root: string,
+  server: ViteDevServer | PreviewServer,
 ): Connect.NextHandleFunction {
+  const isDev = isDevServer(server)
+  const headers = isDev
+    ? server.config.server.headers
+    : server.config.preview.headers
+
   // Keep the named function. The name is visible in debug logs via `DEBUG=connect:dispatcher ...`
   return async function viteIndexHtmlMiddleware(req, res, next) {
     if (res.writableEnded) {
@@ -389,14 +396,20 @@ export function indexHtmlMiddleware(
     const url = req.url && cleanUrl(req.url)
     // htmlFallbackMiddleware appends '.html' to URLs
     if (url?.endsWith('.html') && req.headers['sec-fetch-dest'] !== 'script') {
-      const filename = getHtmlFilename(url, server)
-      if (fs.existsSync(filename)) {
+      let filePath: string
+      if (isDev && url.startsWith(FS_PREFIX)) {
+        filePath = decodeURIComponent(fsPathFromId(url))
+      } else {
+        filePath = path.join(root, decodeURIComponent(url))
+      }
+
+      if (fs.existsSync(filePath)) {
         try {
-          let html = await fsp.readFile(filename, 'utf-8')
-          html = await server.transformIndexHtml(url, html, req.originalUrl)
-          return send(req, res, html, 'html', {
-            headers: server.config.server.headers,
-          })
+          let html = await fsp.readFile(filePath, 'utf-8')
+          if (isDev) {
+            html = await server.transformIndexHtml(url, html, req.originalUrl)
+          }
+          return send(req, res, html, 'html', { headers })
         } catch (e) {
           return next(e)
         }

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

@@ -0,0 +1,9 @@
+import type { Connect } from 'dep-types/connect'
+
+export function notFoundMiddleware(): Connect.NextHandleFunction {
+  // Keep the named function. The name is visible in debug logs via `DEBUG=connect:dispatcher ...`
+  return function vite404Middleware(_, res) {
+    res.statusCode = 404
+    res.end()
+  }
+}

packages/vite/src/node/shortcuts.ts

@@ -2,6 +2,7 @@ import readline from 'node:readline'
 import colors from 'picocolors'
 import { restartServerWithUrls } from './server'
 import type { ViteDevServer } from './server'
+import { isDevServer } from './utils'
 import type { PreviewServer } from './preview'
 import { openBrowser } from './server/openBrowser'
 
@@ -86,12 +87,6 @@ export function bindCLIShortcuts<Server extends ViteDevServer | PreviewServer>(
   server.httpServer.on('close', () => rl.close())
 }
 
-function isDevServer(
-  server: ViteDevServer | PreviewServer,
-): server is ViteDevServer {
-  return 'pluginContainer' in server
-}
-
 const BASE_DEV_SHORTCUTS: CLIShortcut<ViteDevServer>[] = [
   {
     key: 'r',

packages/vite/src/node/utils.ts

@@ -32,6 +32,7 @@ import {
 import type { DepOptimizationConfig } from './optimizer'
 import type { ResolvedConfig } from './config'
 import type { ResolvedServerUrls, ViteDevServer } from './server'
+import type { PreviewServer } from './preview'
 import {
   type PackageCache,
   findNearestPackageData,
@@ -1322,3 +1323,9 @@ export function getPackageManagerCommand(
       throw new TypeError(`Unknown command type: ${type}`)
   }
 }
+
+export function isDevServer(
+  server: ViteDevServer | PreviewServer,
+): server is ViteDevServer {
+  return 'pluginContainer' in server
+}

packages/vite/src/types/shims.d.ts

@@ -13,11 +13,6 @@ declare module 'http-proxy' {
   export = proxy
 }
 
-declare module 'connect-history-api-fallback' {
-  const plugin: any
-  export = plugin
-}
-
 declare module 'launch-editor-middleware' {
   const plugin: any
   export = plugin