Authentication Chapter (Chapter 14) Bug: Middleware Fails to Guard Routes

[chirino-cm]

This report identifies three related issues in the authentication setup that collectively prevent the core security middleware from functioning correctly in current Next.js versions (tested on a recent version running Turbopack).

1. Critical Error: Middleware File Name Convention Failure
   Issue: The global request interceptor (middleware) is non-functional because the required file name is not being used, causing the entire security layer to fail.

Observed Behavior: When the file is named proxy.ts (as used or implied in the tutorial), the Next.js console does not log a middleware compilation step, and the application allows unauthorized access to protected routes (e.g., /dashboard).

Fix Required: The file must be named middleware.ts. Upon renaming the file to middleware.ts and restarting the server, the console correctly logs ✓ Compiled middleware..., and the security logic is executed.

Impact: High. This breaks the core security feature of the entire lesson.

2. Logic Error: Incomplete Matcher Regular Expression
   Issue: The provided regex in the middleware.ts file's export const config is incomplete, which is inefficient and required manual correction to achieve a clean redirect flow.

Provided Regex (Needs correction):

matcher: ["/((?!api|_next/static|_next/image|.\.png$).)"],

Problem: The |login path is missing from the exclusion list. This ensures the middleware runs efficiently and does not perform checks on the public login page.

Suggested Fix: The regex should be updated to explicitly exclude the login page:

matcher: ['/((?!api|_next/static|_next/image|favicon.ico|login|.\.png$).)'],

Impact: Medium-High. Required for a clean, reliable, and efficient security implementation.

3. Implementation Gap: Post-Login callbackUrl Redirect Usage
   Issue: The tutorial needs to ensure it explicitly includes the code to use the callbackUrl (passed as redirectTo in the form) for the final post-login navigation, as this step is crucial for completing the feature.

Suggested Fix: Ensure the final code for the authenticate Server Action explicitly shows how to retrieve the hidden redirectTo field from formData and calls redirect(redirectTo) upon success.

Next v15.3.2