Fix use of server actions with proxied domains by using middleware (#2913)

packages/gitbook-v2/next.config.mjs

@@ -6,12 +6,6 @@
 const nextConfig = {
     experimental: {
         useCache: true,
-        serverActions: {
-            // Allow all origins for server actions
-            // as we serve content on a lot of domains
-            // Server actions are secured by the middleware.
-            allowedOrigins: ['*', '*.*', '*.*.*', '*.*.*.*', '*.*.*.*.*'],
-        },
     },
 
     env: {

packages/gitbook-v2/src/middleware.ts

@@ -77,6 +77,10 @@ async function serveSiteByURL(request: NextRequest, urlWithMode: URLWithMode) {
         }
     }
 
+    // Pass a x-forwarded-host and origin that are equal to ensure Next doesn't block server actions when proxied
+    requestHeaders.set('x-forwarded-host', request.nextUrl.host);
+    requestHeaders.set('origin', request.nextUrl.origin);
+
     const route = [
         'sites',
         routeType,
@@ -87,7 +91,8 @@ async function serveSiteByURL(request: NextRequest, urlWithMode: URLWithMode) {
 
     console.log(`rewriting to ${route}`);
 
-    const response = NextResponse.rewrite(new URL(`/${route}`, request.url), {
+    const rewrittenURL = new URL(`/${route}`, request.nextUrl.toString());
+    const response = NextResponse.rewrite(rewrittenURL, {
         request: {
             headers: requestHeaders,
         },

packages/gitbook/e2e/customers.spec.ts

@@ -225,11 +225,6 @@ const testCases: TestsCase[] = [
         baseUrl: 'https://docs.raydium.io',
         tests: [{ name: 'Home', url: '/' }],
     },
-    {
-        name: 'docs.solv.finance',
-        baseUrl: 'https://docs.solv.finance',
-        tests: [{ name: 'Home', url: '/' }],
-    },
     {
         name: 'docs.fluentbit.io',
         baseUrl: 'https://docs.fluentbit.io',