wisski-cloud-distillery/internal/dis/component/auth/protect.go
2023-01-06 18:59:09 +01:00

72 lines
2.2 KiB
Go

package auth
import (
"context"
"net/http"
"net/url"
"github.com/FAU-CDI/wisski-distillery/pkg/httpx"
)
// Permission represents a permission for a user
//
// The nil permission represents any authenticated user.
type Permission func(user *AuthUser, r *http.Request) (ok bool, err error)
// Protect returns a new handler which requires a user to be logged in and pass the perm function.
//
// If an unauthenticated user attempts to access the returned handler, they are redirected to the login endpoint.
// If an authenticated user is missing permissions, a Forbidden response is called.
// If an authenticated calls the endpoint, and they have the given permissions, the original handler is called.
func (auth *Auth) Protect(handler http.Handler, perm Permission) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
// load the user in the session
user, err := auth.UserOf(r)
if err != nil {
goto err
}
// if there is no user in the session
// we need to login the user
if user == nil {
// we can't redirect anything other than GET
// (because it might be a form)
// => so we just return a forbidden
if r.Method != http.MethodGet {
goto forbidden
}
// redirect the user to the login endpoint, with the original URI as a return
dest := "/auth/login?next=" + url.QueryEscape(r.URL.RequestURI())
http.Redirect(w, r, dest, http.StatusSeeOther)
return
}
// if we have a permission check, we need to call it
// to find out if the user is actually allowed to access the page
if perm != nil {
ok, err := perm(user, r)
if err != nil {
goto err
}
if !ok {
goto forbidden
}
}
// store the user into the session
r = r.WithContext(context.WithValue(r.Context(), ctxUserKey, user))
handler.ServeHTTP(w, r)
return
forbidden:
httpx.HTMLInterceptor.Intercept(w, r, httpx.ErrForbidden)
return
err:
httpx.HTMLInterceptor.Fallback.ServeHTTP(w, r)
})
}
// Admin represents a permission that checks if a user is an administrator and has totp enabled.
var Admin Permission = func(user *AuthUser, r *http.Request) (ok bool, err error) {
return user != nil && user.Admin && user.TOTPEnabled, nil
}