feat: middleware에서 wildcard 서브도메인 rewrite로직

src/app/(playground)/pg/[subdomain]/page.tsx

@@ -0,0 +1,3 @@
+export default function Page({ params }: { params: { subdomain: string } }) {
+  return <div>Subdomain: {params.subdomain}</div>;
+}

src/middleware.ts

@@ -0,0 +1,31 @@
+import type { NextRequest } from "next/server";
+import { NextResponse } from "next/server";
+
+export const config = {
+  matcher: ["/((?!api/|_next/|_static/|_vercel|[\\w-]+\\.\\w+).*)"],
+};
+
+export function middleware(request: NextRequest) {
+  const url = request.nextUrl;
+  const hostname = request.headers
+    .get("host")!
+    .replace(".localhost:3000", `.${process.env.NEXT_PUBLIC_ROOT_DOMAIN}`);
+  const searchParams = request.nextUrl.searchParams.toString();
+
+  const path = `${url.pathname}${
+    searchParams.length > 0 ? `?${searchParams}` : ""
+  }`;
+
+  const subDomain = hostname.split(".")[0];
+
+  switch (true) {
+    case subDomain !== hostname:
+      console.log(`/pg/${subDomain}${path}`);
+      return NextResponse.rewrite(
+        new URL(`/pg/${subDomain}${path}`, request.url),
+      );
+
+    default:
+      return NextResponse.rewrite(new URL(`${path}`, request.url));
+  }
+}