feat: override traffic to cf

packages/webapp/middleware.ts

@@ -0,0 +1,48 @@
+import { NextRequest, NextResponse } from 'next/server';
+
+const trafficPercentage = 10;
+
+const cfCookieName = 'cf-override';
+
+const isDev = process.env.NODE_ENV !== 'production';
+
+const middleware = async (req: NextRequest): Promise<NextResponse> => {
+  let cfCookie = req.cookies.get(cfCookieName)?.value;
+
+  const nextResponse = NextResponse.next();
+
+  if (typeof cfCookie === 'undefined') {
+    const shouldOverride = Math.random() < trafficPercentage / 100;
+
+    nextResponse.cookies.set(cfCookieName, shouldOverride ? 'true' : 'false', {
+      path: '/',
+      maxAge: 1 * 60 * 60,
+      secure: !isDev,
+      httpOnly: true,
+    });
+
+    cfCookie = 'true';
+  }
+
+  if (cfCookie === 'true') {
+    const cfUrl = new URL(
+      `${req.nextUrl.pathname}${req.nextUrl.search}`,
+      'https://cf.daily.dev',
+    );
+
+    if (!isDev) {
+      return NextResponse.rewrite(cfUrl, nextResponse);
+    }
+  }
+
+  return nextResponse;
+};
+
+export const config = {
+  matcher: [
+    '/((?!api|_next/static|_next/image|favicon|manifest.json|robots.txt|android-chrome).*)',
+    '/',
+  ],
+};
+
+export { middleware };