PixelPilot: Instructions file for GitHub Copilot

Internationalization Routing Skill

URL-based language routing with seamless switching.

---

URL PATTERNS

Recommended: Language prefix in URL path.

https://example.com/en/about      → English
https://example.com/fr/about      → French
https://example.com/de/about      → German
https://example.com/about         → Default language (redirects to /en/about)

---

NEXT.JS APP ROUTER

Folder Structure

app/
├── [lang]/
│   ├── layout.tsx
│   ├── page.tsx
│   ├── about/
│   │   └── page.tsx
│   └── contact/
│       └── page.tsx
├── dictionaries/
│   ├── en.json
│   ├── fr.json
│   └── de.json
└── middleware.ts

Middleware for Language Detection

// middleware.ts
import { NextRequest, NextResponse } from 'next/server';

const locales = ['en', 'fr', 'de', 'es'];
const defaultLocale = 'en';

function getLocale(request: NextRequest): string {
  // Check cookie first
  const cookieLocale = request.cookies.get('NEXT_LOCALE')?.value;
  if (cookieLocale && locales.includes(cookieLocale)) {
    return cookieLocale;
  }

  // Check Accept-Language header
  const acceptLanguage = request.headers.get('Accept-Language');
  if (acceptLanguage) {
    const preferred = acceptLanguage
      .split(',')
      .map(lang => lang.split(';')[0].trim().substring(0, 2))
      .find(lang => locales.includes(lang));
    
    if (preferred) return preferred;
  }

  return defaultLocale;
}

export function middleware(request: NextRequest) {
  const { pathname } = request.nextUrl;

  // Check if pathname already has locale
  const pathnameHasLocale = locales.some(
    locale => pathname.startsWith(`/${locale}/`) || pathname === `/${locale}`
  );

  if (pathnameHasLocale) return;

  // Skip static files and API routes
  if (
    pathname.startsWith('/_next') ||
    pathname.startsWith('/api') ||
    pathname.includes('.')
  ) {
    return;
  }

  // Redirect to locale-prefixed path
  const locale = getLocale(request);
  const newUrl = new URL(`/${locale}${pathname}`, request.url);
  
  return NextResponse.redirect(newUrl);
}

export const config = {
  matcher: ['/((?!_next|api|.*\\..*).*)'],
};