remove catch-bad-accept-language middleware (#25231)

middleware/catch-bad-accept-language.js

@@ -1,15 +0,0 @@
-import accept from '@hapi/accept'
-
-// Next.JS uses the @hapi/accept package to parse and detect languages. If the accept-language header is malformed
-// it throws an error from within Next.JS, which results in a 500 response. This ends up being noisy because we
-// track 500s. To counteract this, we'll try to catch the error first and make sure it doesn't happen
-export default function catchBadAcceptLanguage(req, res, next) {
-  try {
-    accept.language(req.headers['accept-language'])
-  } catch (e) {
-    // if there's a problem with parsing 'accept-language', just clear it out.
-    req.headers['accept-language'] = ''
-  }
-
-  return next()
-}

middleware/index.js

@@ -17,7 +17,6 @@ import csrf from './csrf.js'
 import handleCsrfErrors from './handle-csrf-errors.js'
 import { setDefaultFastlySurrogateKey } from './set-fastly-surrogate-key.js'
 import setFastlyCacheHeaders from './set-fastly-cache-headers.js'
-import catchBadAcceptLanguage from './catch-bad-accept-language.js'
 import reqUtils from './req-utils.js'
 import recordRedirect from './record-redirect.js'
 import connectSlashes from 'connect-slashes'
@@ -207,7 +206,6 @@ export default function (app) {
 
   // *** Headers ***
   app.set('etag', false) // We will manage our own ETags if desired
-  app.use(catchBadAcceptLanguage)
 
   // *** Config and context for redirects ***
   app.use(reqUtils) // Must come before record-redirect and events

package-lock.json

@@ -8,7 +8,6 @@
       "license": "(MIT AND CC-BY-4.0)",
       "dependencies": {
         "@github/failbot": "0.8.0",
-        "@hapi/accept": "^5.0.2",
         "@primer/components": "^33.1.0",
         "@primer/css": "^19.1.1",
         "@primer/octicons": "^16.3.0",

package.json

@@ -10,7 +10,6 @@
   ],
   "dependencies": {
     "@github/failbot": "0.8.0",
-    "@hapi/accept": "^5.0.2",
     "@primer/components": "^33.1.0",
     "@primer/css": "^19.1.1",
     "@primer/octicons": "^16.3.0",

tests/rendering/server.js

@@ -664,6 +664,24 @@ describe('server', () => {
       )
     })
 
+    // This test exists because in a previous life, our NextJS used to
+    // 500 if the 'Accept-Language' header was malformed.
+    // We *used* have a custom middleware to cope with this and force a
+    // fallback redirect.
+    // See internal issue 19909
+    test('redirects /en if Accept-Language header is malformed', async () => {
+      const res = await get('/', {
+        headers: {
+          'accept-language': 'ldfir;',
+        },
+      })
+
+      expect(res.statusCode).toBe(302)
+      expect(res.headers.location).toBe('/en')
+      expect(res.headers['cache-control']).toBe('private, no-store')
+      expect(res.headers['set-cookie']).toBeUndefined()
+    })
+
     test('redirects / to /en when unsupported language preference is specified', async () => {
       const res = await get('/', {
         headers: {