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src/proxy.ts

@@ -0,0 +1,69 @@
+import { NextRequest, NextResponse } from 'next/server';
+
+const LOCAL_HOSTNAMES = new Set(['localhost', '127.0.0.1', '::1']);
+const HSTS_HEADER = 'max-age=31536000; includeSubDomains';
+
+const getForwardedProtocol = (request: NextRequest) => {
+  const forwardedProtocol = request.headers.get('x-forwarded-proto');
+  if (forwardedProtocol) {
+    return forwardedProtocol.split(',')[0]?.trim().toLowerCase();
+  }
+
+  return request.nextUrl.protocol.replace(':', '').toLowerCase();
+};
+
+const getRequestHost = (request: NextRequest) => {
+  const forwardedHost = request.headers.get('x-forwarded-host');
+  if (forwardedHost) {
+    return forwardedHost.split(',')[0]?.trim();
+  }
+
+  return request.headers.get('host') || request.nextUrl.host;
+};
+
+const getHostname = (host: string) => {
+  if (host.startsWith('[')) {
+    return host.slice(1, host.indexOf(']'));
+  }
+
+  return host.split(':')[0];
+};
+
+const getRedirectHost = (host: string) => {
+  if (host.startsWith('[')) {
+    return host.slice(0, host.indexOf(']') + 1);
+  }
+
+  return getHostname(host);
+};
+
+const isLocalRequest = (hostname: string) => {
+  return LOCAL_HOSTNAMES.has(hostname) || hostname.endsWith('.localhost');
+};
+
+export function proxy(request: NextRequest) {
+  const protocol = getForwardedProtocol(request);
+  const requestHost = getRequestHost(request);
+  const hostname = getHostname(requestHost);
+
+  if (!isLocalRequest(hostname) && protocol === 'http') {
+    const redirectUrl = request.nextUrl.clone();
+    redirectUrl.protocol = 'https:';
+    redirectUrl.host = getRedirectHost(requestHost);
+    redirectUrl.port = '';
+
+    return NextResponse.redirect(redirectUrl, 301);
+  }
+
+  const response = NextResponse.next();
+
+  if (!isLocalRequest(hostname)) {
+    response.headers.set('Strict-Transport-Security', HSTS_HEADER);
+  }
+
+  return response;
+}
+
+export const config = {
+  matcher: ['/((?!_next/static|_next/image|favicon.ico).*)'],
+};