cauth/middleware.go

package cauth

import (
	"context"
	"github.com/lestrrat-go/jwx/jwk"
	"log"
	"net/http"
)

type contextKey string

const userContextKey = contextKey("user")

type Middleware struct {
	s  SessionStorer
	ck jwk.Set
}

func NewMiddleware(s SessionStorer, cognitoUrl string) *Middleware {
	cognitoKeySet, err := jwk.Fetch(context.Background(), cognitoUrl)
	if err != nil {
		log.Fatal(err)
	}
	return &Middleware{s, cognitoKeySet}
}

func (m *Middleware) AddUserInfo(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		session, err := m.s.Get(r)
		if err != nil {
			next.ServeHTTP(w, r)
			return
		}

		token := session.Values["access_token"]

		if token == "" || token == nil {
			next.ServeHTTP(w, r)
			return
		}
		userInfo := session.Values["user_info"]

		ctx := context.WithValue(r.Context(), userContextKey, userInfo)
		next.ServeHTTP(w, r.WithContext(ctx))
	})
}

// ProtectedRoute Checks if session and token are present, if not return a 401 response
func (m *Middleware) ProtectedRoute(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		session, err := m.s.Get(r)
		if err != nil {
			w.WriteHeader(http.StatusUnauthorized)
			return
		}

		token := session.Values["access_token"]

		if token == "" || token == nil {
			w.WriteHeader(http.StatusUnauthorized)
			return
		}

		next.ServeHTTP(w, r)
	})
}

// ProtectedRouteWithRedirect Checks if session and token are present, if not return a redirect to /login
func (m *Middleware) ProtectedRouteWithRedirect(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		session, err := m.s.Get(r)
		if err != nil {
			http.Redirect(w, r, "/login", http.StatusSeeOther)
			return
		}

		token := session.Values["access_token"]

		if token == "" || token == nil {
			http.Redirect(w, r, "/login", http.StatusSeeOther)
			return
		}

		next.ServeHTTP(w, r)
	})
}

// IsAdmin Checks if admin group is present
func IsAdmin(groups []string) bool {
	for _, group := range groups {
		if group == "admin" {
			return true
		}
	}
	return false
}

// AdminProtectedRoute Checks if user is member of admin group, if not return forbidden
func (m *Middleware) AdminProtectedRoute(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		userOptional := r.Context().Value(userContextKey)
		if userOptional != nil {
			user := userOptional.(UserClaims)
			if IsAdmin(user.Groups) {
				next.ServeHTTP(w, r)
				return
			}
		}

		http.Error(w, "Forbidden", http.StatusForbidden)
	})
}

func GetUserFromContext(r *http.Request) *UserClaims {
	userOptional := r.Context().Value(userContextKey)
	if userOptional != nil {
		user := userOptional.(UserClaims)
		return &user
	}

	return &UserClaims{}
}