feat: implement browser language detection and auto-redirect for homepage by Copilot · Pull Request #30 · objectstack-ai/objectstack

Copilot · 2026-01-19T14:29:24Z

The homepage now redirects users to their language-preferred interface based on browser Accept-Language headers. Chinese users are redirected to /cn, while English users remain on / (the default).

Changes

Custom Middleware (apps/docs/middleware.ts)

Replaced fumadocs default middleware with custom implementation
Maps Chinese language codes (zh, zh-CN, zh-TW, zh-HK) → cn
English (default): Internal rewrite to /en, URL stays /
Non-default languages: HTTP 307 redirect to localized path + cookie persistence
Cookie options: sameSite: 'lax', path: '/'

Dependencies (apps/docs/package.json)

Added negotiator for Accept-Language parsing
Added @types/negotiator

Implementation

functiongetPreferredLanguage(request: NextRequest): string{// Cookie first, then Accept-Language headerconstcookieLocale=request.cookies.get('FD_LOCALE')?.value;if(cookieLocale&&SUPPORTED_LANGUAGES.includes(cookieLocale)){returncookieLocale;}constnegotiator=newNegotiator({headers: Object.fromEntries(request.headers.entries())});constbrowserLanguages=negotiator.languages().map(normalizeLanguage);returnbrowserLanguages.find(lang=>SUPPORTED_LANGUAGES.includes(lang))||i18n.defaultLanguage;}

Behavior

Browser Language	URL Visited	Result
`en-US`	`/`	Stays on `/` (rewritten to `/en` internally)
`zh-CN`	`/`	Redirects to `/cn`
Any	`/en`	Redirects to `/` (strips default locale)

Screenshots

English Homepage (/)

Chinese Homepage (/cn)

Original prompt

首页应根据当前的语言自动跳转到对应的语言界面

✨ Let Copilot coding agent set things up for you — coding agent works faster and does higher quality work when set up for your repo.

vercel · 2026-01-19T14:30:19Z

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Review	Updated (UTC)
spec	Ready	Preview, Comment	Jan 19, 2026 3:21pm

- Add custom middleware for automatic language detection - Map Chinese language codes (zh, zh-CN, zh-TW, zh-HK) to 'cn' - Redirect non-default language users to localized paths (/cn/) - Keep default language (en) users on clean URLs (/) - Store language preference in cookies for consistency - Add negotiator and type definitions as dependencies Co-authored-by: huangyiirene <7665279+huangyiirene@users.noreply.github.com>

- Remove unused @formatjs/intl-localematcher dependency - Extract SUPPORTED_LANGUAGES constant to reduce type assertion duplication - Use Object.fromEntries for more concise header conversion - Improve code readability and efficiency Co-authored-by: huangyiirene <7665279+huangyiirene@users.noreply.github.com>

- Add setLocaleCookie helper function with consistent cookie options - Set sameSite=lax and path=/ for security and consistency - Update comment for SUPPORTED_LANGUAGES constant - Ensure all cookie operations use the same configuration Co-authored-by: huangyiirene <7665279+huangyiirene@users.noreply.github.com>

- Handle root path (/) specially to avoid double slashes - Use precise regex for locale prefix removal - Ensure clean URLs: /cn instead of /cn/ - Improve path normalization logic Co-authored-by: huangyiirene <7665279+huangyiirene@users.noreply.github.com>

Copilot

Pull request overview

This PR implements browser language detection and automatic redirection for the homepage, replacing the default fumadocs i18n middleware with a custom implementation that maps Chinese language codes to /cn while keeping English users on / through internal rewrites.

Changes:

Custom middleware with Accept-Language header parsing using the negotiator library
Cookie-based language preference persistence with FD_LOCALE cookie
Locale-specific redirection logic: Chinese variants (zh, zh-CN, zh-TW, zh-HK) redirect to /cn, English stays on / with internal rewrite to /en

Reviewed changes

Copilot reviewed 2 out of 3 changed files in this pull request and generated 10 comments.

File	Description
apps/docs/middleware.ts	Replaced fumadocs default middleware with custom implementation for language detection, normalization, and routing
apps/docs/package.json	Added `negotiator` and `@types/negotiator` dependencies for Accept-Language parsing
pnpm-lock.yaml	Updated lockfile with new negotiator package and its type definitions

Files not reviewed (1)

pnpm-lock.yaml: Language not supported

Copilot · 2026-01-20T03:06:51Z

+function getPreferredLanguage(request: NextRequest): string {
+ // Check cookie first
+ const cookieLocale = request.cookies.get(LOCALE_COOKIE)?.value;
+ if (cookieLocale && SUPPORTED_LANGUAGES.includes(cookieLocale)) {
+ return cookieLocale;
+ }
+
+ // Then check Accept-Language header
+ const negotiatorHeaders = Object.fromEntries(request.headers.entries());
+ const negotiator = new Negotiator({ headers: negotiatorHeaders });


The middleware creates a new Negotiator instance on every request even when a cookie is already set and valid. Consider skipping the Negotiator initialization if the cookie check at lines 56-59 returns early, by restructuring the code to only create the Negotiator instance after the cookie check fails.

Copilot · 2026-01-20T03:06:51Z

+
+ if (pathnameHasLocale) {
+ // Extract the locale from the pathname
+ const locale = pathname.split('/')[1];


The middleware doesn't handle the case where pathname.split('/')[1] could be an empty string. If a pathname like //something is provided, locale would be an empty string, which could cause unexpected behavior. Consider adding validation to ensure the extracted locale is a non-empty string before using it.
Suggested change
constlocale=pathname.split('/')[1];
constlocale=pathname.split('/')[1]||'';
// If the extracted locale segment is empty or invalid, skip locale-specific handling
if(!locale){
returnNextResponse.next();
}

Copilot · 2026-01-20T03:06:51Z

 * - Detects the user's preferred language from browser settings or cookies
 * - Redirects users to the appropriate localized version
+ * - For default language (en): keeps URL as "/" (with internal rewrite)
+ * - For other languages (cn): redirects to "/cn/"


The comment says "redirects to '/cn/'" (with trailing slash) but the actual implementation redirects to '/cn' (without trailing slash). The documentation should be corrected to accurately reflect the implementation.
Suggested change
*-Forotherlanguages(cn): redirectsto"/cn/"
*-Forotherlanguages(cn): redirectsto"/cn"

Copilot · 2026-01-20T03:06:51Z

+function setLocaleCookie(response: NextResponse, locale: string): void {
+ response.cookies.set(LOCALE_COOKIE, locale, {
+ sameSite: 'lax',
+ path: '/',


The cookie is being set without an expiration time. This means it will be a session cookie that gets deleted when the browser closes. For a language preference, it would be better to set an explicit expiration (e.g., 1 year) so the preference persists across browser sessions.
Suggested change
path: '/',
path: '/',
// Persist language preference across browser sessions (1 year)
maxAge: 60*60*24*365,

Copilot · 2026-01-20T03:06:52Z

+ return response;
+ }
+
+ return NextResponse.next();


When the pathname has a locale and it's not the default locale, the cookie is not being set. This means if a user manually navigates to a non-default locale URL (e.g., /cn), their preference won't be stored in the cookie. Consider adding a response with the cookie set in the else branch at line 111.
Suggested change
returnNextResponse.next();
constresponse=NextResponse.next();
setLocaleCookie(response,locale);
returnresponse;

Copilot · 2026-01-20T03:06:52Z

+ // Remove locale prefix more precisely to avoid issues with partial matches
+ url.pathname = pathname.replace(new RegExp(`^/${i18n.defaultLanguage}(/|$)`), '$1') || '/';


The regular expression ^/${i18n.defaultLanguage}(/|$) could be vulnerable to ReDoS (Regular Expression Denial of Service) if i18n.defaultLanguage contains special regex characters. While the current value 'en' is safe, it would be safer to escape the language code using a helper function or use a simpler string-based approach. Consider using pathname.slice(i18n.defaultLanguage.length + 1) or escaping the language code.
Suggested change
// Remove locale prefix more precisely to avoid issues with partial matches
url.pathname=pathname.replace(newRegExp(`^/${i18n.defaultLanguage}(/|$)`),'$1')||'/';
// Remove default locale prefix using string operations to avoid regex issues
constdefaultPrefix=`/${i18n.defaultLanguage}`;
if(pathname===defaultPrefix){
url.pathname='/';
}elseif(pathname.startsWith(`${defaultPrefix}/`)){
url.pathname=pathname.slice(defaultPrefix.length)||'/';
}else{
// Fallback: if for some reason the pathname doesn't match the expected pattern, keep it as is
url.pathname=pathname||'/';
}

Copilot · 2026-01-20T03:06:52Z

+ const url = new URL(request.url);
+ // Handle root path specially to avoid double slashes
+ url.pathname = pathname === '/' ? `/${i18n.defaultLanguage}` : `/${i18n.defaultLanguage}${pathname}`;
+ return NextResponse.rewrite(url);


The cookie is not being set when the user's preferred language matches the default language. This means if an English-speaking user visits the site, their preference won't be stored, and the language detection will run on every subsequent request instead of using the cached cookie value. Consider setting the cookie even for the default language to improve performance on subsequent requests.
Suggested change
returnNextResponse.rewrite(url);
constresponse=NextResponse.rewrite(url);
setLocaleCookie(response,preferredLanguage);
returnresponse;

Copilot · 2026-01-20T03:06:52Z

 "@types/react": "^19.2.8",
 "@types/react-dom": "^19.2.3",
 "autoprefixer": "^10.4.23",
+ "negotiator": "^1.0.0",


The negotiator package is listed as a devDependency but it's imported and used in the middleware which runs at runtime. This package should be moved to the dependencies section instead of devDependencies to ensure it's available in production builds.

Copilot · 2026-01-20T03:06:53Z

+ const negotiatorHeaders = Object.fromEntries(request.headers.entries());
+ const negotiator = new Negotiator({ headers: negotiatorHeaders });


Converting headers to a plain object using Object.fromEntries(request.headers.entries()) could potentially cause issues if there are duplicate header names (though unlikely with Accept-Language). Additionally, this creates a new object on every call. Consider passing the headers directly if the Negotiator API supports it, or at least document why this conversion is necessary.
Suggested change
constnegotiatorHeaders=Object.fromEntries(request.headers.entries());
constnegotiator=newNegotiator({headers: negotiatorHeaders});
constacceptLanguage=request.headers.get('accept-language');
if(!acceptLanguage){
returni18n.defaultLanguage;
}
constnegotiator=newNegotiator({
headers: {'accept-language': acceptLanguage},
});

Copilot · 2026-01-20T03:06:53Z

+function setLocaleCookie(response: NextResponse, locale: string): void {
+ response.cookies.set(LOCALE_COOKIE, locale, {
+ sameSite: 'lax',
+ path: '/',


The cookie should also set the secure flag in production environments to ensure it's only transmitted over HTTPS. Consider adding secure: process.env.NODE_ENV === 'production' to the cookie options.
Suggested change
path: '/',
path: '/',
secure: process.env.NODE_ENV==='production',

Adds entries 26-40 covering the gaps that make the helpdesk template 'pretty but not daily-usable' from an end-user perspective: P0 additions: - #26 No inline message composer on detail pages - #27 No external-user portal mechanism - #28 Attachment/file-list field UI not E2E P1 additions: - #29 No 'changed since last visit' indicator - #30 Bulk operations UI unverified (escalates #17) - #31 Rich-text editor scoped to comments only - #32 No first-class canned response / macro - #33 No collaboration presence indicators - #34 No keyboard-shortcut API - #35 No conditional SLA timer (pause on waiting_customer) - #36 Formula fields can't reference foreign object fields P2 additions: - #37 No chart drill-down - #38 No period-over-period analytics primitive - #39 No inbound-channel abstraction (email-to-ticket etc.) - #40 i18n translation namespace validation weak Includes 'user-pain → platform-gap' mapping table tracing each end-user complaint to a specific issue number. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Initial plan
c74ab5a

CopilotAI assigned Copilot and huangyiirene Jan 19, 2026

vercelBotdeployed to Preview January 19, 2026 14:30 View deployment

Copilotstarted work on behalf of huangyiirene January 19, 2026 14:30 View session

vercelBotdeployed to Preview January 19, 2026 15:02 View deployment

vercelBotdeployed to Preview January 19, 2026 15:07 View deployment

vercelBotdeployed to Preview January 19, 2026 15:14 View deployment

vercelBotdeployed to Preview January 19, 2026 15:21 View deployment

CopilotAI changed the title ~~[WIP] Add automatic language redirection for homepage~~feat: implement browser language detection and auto-redirect for homepageJan 19, 2026

CopilotAI requested a review from huangyiirene January 19, 2026 15:23

Copilotfinished work on behalf of huangyiirene January 19, 2026 15:23

github-actionsBot added documentation Improvements or additions to documentation dependencies Pull requests that update a dependency file size/m labels Jan 20, 2026

hotlong marked this pull request as ready for review January 20, 2026 03:02

CopilotAI review requested due to automatic review settings January 20, 2026 03:02

hotlong merged commit 2298e72 into mainJan 20, 2026
13 checks passed

Copilotstarted reviewing on behalf of hotlong January 20, 2026 03:03 View session

CopilotAI reviewed Jan 20, 2026
View reviewed changes

xuyushun441-sys mentioned this pull request May 25, 2026
[P1] list: bulk operations UI not E2E — multi-select → assignee/status change is the daily ops workflow #1305
Closed
4 tasks

Navigation Menu

Uh oh!

feat: implement browser language detection and auto-redirect for homepage - #30

feat: implement browser language detection and auto-redirect for homepage#30
hotlong merged 5 commits into
mainfrom
copilot/add-language-auto-redirect

CopilotAI commented Jan 19, 2026•
edited
Loading

Uh oh!

vercelBot commented Jan 19, 2026•
edited
Loading

Uh oh!

Uh oh!

CopilotAI left a comment

Uh oh!

CopilotAIJan 20, 2026

Uh oh!

CopilotAIJan 20, 2026

Uh oh!

CopilotAIJan 20, 2026

Uh oh!

CopilotAIJan 20, 2026

Uh oh!

CopilotAIJan 20, 2026

Uh oh!

CopilotAIJan 20, 2026

Uh oh!

CopilotAIJan 20, 2026

Uh oh!

CopilotAIJan 20, 2026

Uh oh!

CopilotAIJan 20, 2026

Uh oh!

CopilotAIJan 20, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

-constlocale=pathname.split('/')[1];
+constlocale=pathname.split('/')[1]||'';
+// If the extracted locale segment is empty or invalid, skip locale-specific handling
+if(!locale){
+returnNextResponse.next();
+}

	*-Forotherlanguages(cn): redirectsto"/cn/"
	*-Forotherlanguages(cn): redirectsto"/cn"

-returnNextResponse.next();
+constresponse=NextResponse.next();
+setLocaleCookie(response,locale);
+returnresponse;

		// Remove locale prefix more precisely to avoid issues with partial matches
		url.pathname = pathname.replace(new RegExp(`^/${i18n.defaultLanguage}(/\|$)`), '$1') \|\| '/';

-// Remove locale prefix more precisely to avoid issues with partial matches
-url.pathname=pathname.replace(newRegExp(`^/${i18n.defaultLanguage}(/|$)`),'$1')||'/';
+// Remove default locale prefix using string operations to avoid regex issues
+constdefaultPrefix=`/${i18n.defaultLanguage}`;
+if(pathname===defaultPrefix){
+url.pathname='/';
+}elseif(pathname.startsWith(`${defaultPrefix}/`)){
+url.pathname=pathname.slice(defaultPrefix.length)||'/';
+}else{
+// Fallback: if for some reason the pathname doesn't match the expected pattern, keep it as is
+url.pathname=pathname||'/';
+}

-returnNextResponse.rewrite(url);
+constresponse=NextResponse.rewrite(url);
+setLocaleCookie(response,preferredLanguage);
+returnresponse;

		const negotiatorHeaders = Object.fromEntries(request.headers.entries());
		const negotiator = new Negotiator({ headers: negotiatorHeaders });

-constnegotiatorHeaders=Object.fromEntries(request.headers.entries());
-constnegotiator=newNegotiator({headers: negotiatorHeaders});
+constacceptLanguage=request.headers.get('accept-language');
+if(!acceptLanguage){
+returni18n.defaultLanguage;
+}
+constnegotiator=newNegotiator({
+headers: {'accept-language': acceptLanguage},
+});

	path: '/',
	path: '/',
	secure: process.env.NODE_ENV==='production',

Uh oh!

Conversation

CopilotAI commented Jan 19, 2026• edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Changes

Implementation

Behavior

Screenshots

Uh oh!

vercelBot commented Jan 19, 2026• edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Uh oh!

CopilotAI left a comment

Choose a reason for hiding this comment

Pull request overview

Reviewed changes

Uh oh!

CopilotAIJan 20, 2026

Choose a reason for hiding this comment

Uh oh!

CopilotAIJan 20, 2026

Choose a reason for hiding this comment

Uh oh!

CopilotAIJan 20, 2026

Choose a reason for hiding this comment

Uh oh!

CopilotAIJan 20, 2026

Choose a reason for hiding this comment

Uh oh!

CopilotAIJan 20, 2026

Choose a reason for hiding this comment

Uh oh!

CopilotAIJan 20, 2026

Choose a reason for hiding this comment

Uh oh!

CopilotAIJan 20, 2026

Choose a reason for hiding this comment

Uh oh!

CopilotAIJan 20, 2026

Choose a reason for hiding this comment

Uh oh!

CopilotAIJan 20, 2026

Choose a reason for hiding this comment

Uh oh!

CopilotAIJan 20, 2026

Choose a reason for hiding this comment

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

CopilotAI commented Jan 19, 2026•
edited
Loading

vercelBot commented Jan 19, 2026•
edited
Loading