markdown-hub/internal/api/middleware.go

package api

import (
	"context"
	"net/http"
	"strings"

	"markdownhub/internal/auth"
)

type contextKey string

const (
	ctxUserID  contextKey = "userID"
	ctxIsAdmin contextKey = "isAdmin"
)

func (s *Server) requireAuth(next http.HandlerFunc) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		tokenStr := extractToken(r)
		if tokenStr == "" {
			http.Error(w, `{"error":"unauthorized"}`, http.StatusUnauthorized)
			return
		}
		userID, isAdmin, err := auth.ValidateToken(tokenStr, s.secret)
		if err != nil || userID == "" {
			http.Error(w, `{"error":"unauthorized"}`, http.StatusUnauthorized)
			return
		}
		ctx := context.WithValue(r.Context(), ctxUserID, userID)
		ctx = context.WithValue(ctx, ctxIsAdmin, isAdmin)
		next(w, r.WithContext(ctx))
	}
}

func (s *Server) requireAdmin(next http.HandlerFunc) http.HandlerFunc {
	return s.requireAuth(func(w http.ResponseWriter, r *http.Request) {
		isAdmin, _ := r.Context().Value(ctxIsAdmin).(bool)
		if !isAdmin {
			http.Error(w, `{"error":"forbidden"}`, http.StatusForbidden)
			return
		}
		next(w, r)
	})
}

func extractToken(r *http.Request) string {
	// Cookie first
	if c, err := r.Cookie("authToken"); err == nil && c.Value != "" {
		return c.Value
	}
	// Bearer header
	h := r.Header.Get("Authorization")
	if strings.HasPrefix(h, "Bearer ") {
		return h[7:]
	}
	return ""
}

func getUserID(r *http.Request) string {
	v, _ := r.Context().Value(ctxUserID).(string)
	return v
}