Code reviewMediumcr-g431

Subject Jwt misuseLevel Mid–Senior~18 minCommon in Code quality & review interviewsIndustries Software development, Technology

Question

Review this Go JWT middleware.

What a strong answer looks like

Separate real bugs from style. Rank issues by severity, point at the root cause rather than the symptom, and suggest a concrete fix — specific and kind.

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Code to reviewgo

1func Authenticate(next http.Handler) http.Handler {2	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {3		raw := strings.TrimPrefix(r.Header.Get("Authorization"), "Bearer ")4		tok, err := jwt.Parse(raw, func(t *jwt.Token) (interface{}, error) {5			if _, ok := t.Method.(*jwt.SigningMethodHMAC); !ok {6				return nil, errors.New("bad alg")7			}8			return hmacKey, nil9		})10		claims := tok.Claims.(jwt.MapClaims)11		r = r.WithContext(context.WithValue(r.Context(), userKey, claims["sub"]))12		next.ServeHTTP(w, r)13	})14}

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