feat: Add accept/markdown to apps/landing

apps/landing/src/middleware.ts

@@ -0,0 +1,34 @@
+import { NextResponse } from 'next/server';
+import type { NextRequest } from 'next/server';
+
+function acceptsMarkdown(accept: string): boolean {
+  for (const part of accept.split(',')) {
+    const segments = part.trim().split(';');
+    if (segments[0]?.trim().toLowerCase() !== 'text/markdown') continue;
+    const qParam = segments.slice(1).find(s => s.trim().startsWith('q='));
+    const q = qParam ? parseFloat((qParam.split('=')[1]) ?? '1') : 1;
+    return !isNaN(q) && q > 0;
+  }
+  return false;
+}
+
+export function middleware(request: NextRequest) {
+  const accept = request.headers.get('accept') ?? '';
+  const { pathname } = request.nextUrl;
+
+  if (acceptsMarkdown(accept)) {
+    const headers = new Headers(request.headers);
+    headers.set('x-md-path', pathname);
+    const response = NextResponse.rewrite(new URL('/api/md', request.url), { request: { headers } });
+    response.headers.set('Vary', 'Accept');
+    return response;
+  }
+
+  const response = NextResponse.next();
+  response.headers.set('Vary', 'Accept');
+  return response;
+}
+
+export const config = {
+  matcher: ['/((?!api|_next|favicon\\.ico|assets|.*\\.(?:png|jpg|jpeg|gif|svg|ico|webp|woff|woff2|ttf|css|js)).*)',],
+};