fix(viewer): 🐛 Forwarded host checking

apps/viewer/pages/[[...publicId]].tsx

@@ -1,3 +1,4 @@
+import { IncomingMessage } from 'http'
 import { NotFoundPage } from 'layouts/NotFoundPage'
 import { PublicTypebot } from 'models'
 import { GetServerSideProps, GetServerSidePropsContext } from 'next'
@@ -11,17 +12,14 @@ export const getServerSideProps: GetServerSideProps = async (
   let typebot: Omit<PublicTypebot, 'createdAt' | 'updatedAt'> | null
   const isIE = /MSIE|Trident/.test(context.req.headers['user-agent'] ?? '')
   const pathname = context.resolvedUrl.split('?')[0]
+  const host = getHost(context.req)
   try {
-    if (!context.req.headers.host) return { props: {} }
+    if (!host) return { props: {} }
     const viewerUrls = (process.env.NEXT_PUBLIC_VIEWER_URL ?? '').split(',')
     const isMatchingViewerUrl = viewerUrls.some((url) =>
-      (context.req.headers.host ?? '')
-        .split(':')[0]
-        .includes(url.split('//')[1].split(':')[0])
+      host.split(':')[0].includes(url.split('//')[1].split(':')[0])
     )
-    const customDomain = `${context.req.headers.host}${
-      pathname === '/' ? '' : pathname
-    }`
+    const customDomain = `${host}${pathname === '/' ? '' : pathname}`
     typebot = isMatchingViewerUrl
       ? await getTypebotFromPublicId(context.query.publicId?.toString())
       : await getTypebotFromCustomDomain(customDomain)
@@ -35,7 +33,7 @@ export const getServerSideProps: GetServerSideProps = async (
       props: {
         typebot,
         isIE,
-        url: `https://${context.req.headers.host}${pathname}`,
+        url: `https://${host}${pathname}`,
       },
     }
   } catch (err) {
@@ -44,7 +42,7 @@ export const getServerSideProps: GetServerSideProps = async (
   return {
     props: {
       isIE,
-      url: `https://${context.req.headers.host}${pathname}`,
+      url: `https://${host}${pathname}`,
     },
   }
 }
@@ -66,6 +64,20 @@ const getTypebotFromCustomDomain = async (customDomain: string) => {
   return omit(typebot as unknown as PublicTypebot, 'createdAt', 'updatedAt')
 }
 
+const getHost = (req?: IncomingMessage): string | undefined => {
+  let host = req?.headers ? req.headers.host : window.location.host
+  if (!host) return
+  if (
+    req &&
+    req.headers['x-forwarded-host'] &&
+    typeof req.headers['x-forwarded-host'] === 'string'
+  ) {
+    host = req.headers['x-forwarded-host']
+  }
+
+  return host
+}
+
 const App = ({ typebot, ...props }: TypebotPageProps) =>
   isDefined(typebot) ? (
     <TypebotPage typebot={typebot} {...props} />