Middleware Chain Lab

Build a three-layer middleware chain for an HTTP server tested with httptest.

Middleware to implement

1. RequestID(next http.Handler) http.Handler — generates a unique request ID (use a simple counter or fmt.Sprintf("req-%d", n)), sets it in the request context under key ctxKey("requestID"), and adds X-Request-ID header to the response.

2. Logger(next http.Handler) http.Handler — reads the request ID from context and prints [requestID] METHOD PATH.

3. RequireToken(next http.Handler) http.Handler — checks X-Token header equals "secret". Returns 403 if not.

Chain

main()

Test the chain with two httptest requests:

• One with X-Token: secret → should succeed (print request ID log + "hello")
• One without token → should return 403

Expected output (approximate)