Middleware

The Middleware (source code , Next.js docs ) is an execution layer on the backend that is executed just before a response is sent back to the client. It is mainly used for editing responses for redirection, authorization and some other stuff.

CurryBO uses middleware for

• displaying a page in the user’s preferred language, and
• forwarding to the login page if an unauthenticated user tries to visit any page except Main or Docs (or non-page routes).

The CurryBO middleware applies the following rules:

• If a user is logged in and trying to access the Login page, forward them to their callback or the main page if no callback was passed.
• Determine the desired locale
  • if: the pathname has a locale, keep it
  • else if: the referrer has a locale, keep it
  • else: take the locale from the user agent
• If a user is not logged in and trying to access a protected route, forward them to the Login page
• If none of the above triggered, let the request pass with the correct locale.

The Middleware matches any route that follows this regex:

"/((?!api|docs|static|.*\\..*|_next|favicon.ico|robots.txt|serviceWorker.js).*)"