If you are deploying to Vercel for production and you have set up a custom domain, you can access the same page from the following three URLs.
1. https://[vercelProjectName]-[vercelUserName].vercel.app
2. https://[vercelProjectName]-[deployId]-[vercelUserName].vercel.app
3. https://[myDomain].com
Furthermore, all of them exist independently, without being redirected to a custom domain.
However, it seems that URLs in 1. are not registered with search engines, so you can leave them alone.
Are Vercel Preview Deployments indexed by search engines? – Vercel Docs
Still, the URLs for 2. and 3. are duplicated.
Is there any way to redirect the user to URL 3. when accessing URL 2. ?
Detail
I'm deploying an application consisting of Next.js, Firebase and Sentry to Vercel.
In addition, I use Firebase App Check to make sure that Firebase storage cannot be manipulated by anyone other than authorized domains.
And yesterday, when I installed Sentry, I had the following error in URL2.
@firebase/app-check: FirebaseError: AppCheck: Fetch server returned an HTTP error status. HTTP status: 403. (appCheck/fetch-status-error).
The URL in 2. is not allowed by App Check, which is probably causing the above error.
Also, the above error occurs once per 15 to 30 minutes.
The error is caused by the following execution environment.
I don't know if it's Google's crawler or what, but there's something running around.
I want to redirect this guy running around who came to URL 2. to URL 3.
The URLs in 1. 2. 3. have canonical set in the head as shown below.
<link rel="canonical" href="https://[myDomain].com">
However, the noindex is not included in the head tags of pages 1. and 2.
