From 6fcceebe34863c4fcde809885976b12cf5398fe1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=BF=A0=20/=20green?= <green@sapphi.red>
Date: Tue, 21 Nov 2023 22:27:41 +0900
Subject: [PATCH] fix: make htmlFallback more permissive (#15059)

---
 .../src/node/server/middlewares/htmlFallback.ts  |  3 +--
 playground/html/__tests__/html.spec.ts           | 16 ++++++++++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/packages/vite/src/node/server/middlewares/htmlFallback.ts b/packages/vite/src/node/server/middlewares/htmlFallback.ts
index d5f053fd34211c..5af9a34b2df2dd 100644
--- a/packages/vite/src/node/server/middlewares/htmlFallback.ts
+++ b/packages/vite/src/node/server/middlewares/htmlFallback.ts
@@ -14,11 +14,10 @@ export function htmlFallbackMiddleware(
     if (
       // Only accept GET or HEAD
       (req.method !== 'GET' && req.method !== 'HEAD') ||
-      // Ignore JSON requests
-      req.headers.accept?.includes('application/json') ||
       // Require Accept: text/html or */*
       !(
         req.headers.accept === undefined || // equivalent to `Accept: */*`
+        req.headers.accept === '' || // equivalent to `Accept: */*`
         req.headers.accept.includes('text/html') ||
         req.headers.accept.includes('*/*')
       )
diff --git a/playground/html/__tests__/html.spec.ts b/playground/html/__tests__/html.spec.ts
index 01f0eca2e7e445..a026ce71cf2a3d 100644
--- a/playground/html/__tests__/html.spec.ts
+++ b/playground/html/__tests__/html.spec.ts
@@ -414,3 +414,19 @@ test('html serve behavior', async () => {
   expect(bothSlashIndexHtml.status).toBe(200)
   expect(await bothSlashIndexHtml.text()).toContain('both/index.html')
 })
+
+test('html fallback works non browser accept header', async () => {
+  expect((await fetch(viteTestUrl, { headers: { Accept: '' } })).status).toBe(
+    200,
+  )
+  // defaults to "Accept: */*"
+  expect((await fetch(viteTestUrl)).status).toBe(200)
+  // wait-on uses axios and axios sends this accept header
+  expect(
+    (
+      await fetch(viteTestUrl, {
+        headers: { Accept: 'application/json, text/plain, */*' },
+      })
+    ).status,
+  ).toBe(200)
+})