# documentación de Django - 1.10.7

# Código fuente para django.contrib.auth.decorators

    from functools import wraps

    from django.conf import settings
    from django.contrib.auth import REDIRECT_FIELD_NAME
    from django.core.exceptions import PermissionDenied
    from django.shortcuts import resolve_url
    from django.utils import six
    from django.utils.decorators import available_attrs
    from django.utils.six.moves.urllib.parse import urlparse

    def user_passes_test(test_func, login_url=None, redirect_field_name=REDIRECT_FIELD_NAME):
        """
        Decorator for views that checks that the user passes the given test,
        redirecting to the log-in page if necessary. The test should be a callable
        that takes the user object and returns True if the user passes.
        """

        def decorator(view_func):
            @wraps(view_func, assigned=available_attrs(view_func))
            def _wrapped_view(request, *args, **kwargs):
                if test_func(request.user):
                    return view_func(request, *args, **kwargs)
                path = request.build_absolute_uri()
                resolved_login_url = resolve_url(login_url or settings.LOGIN_URL)
                # If the login url is the same scheme and net location then just
                # use the path as the "next" url.
                login_scheme, login_netloc = urlparse(resolved_login_url)[:2]
                current_scheme, current_netloc = urlparse(path)[:2]
                if ((not login_scheme or login_scheme == current_scheme) and
                        (not login_netloc or login_netloc == current_netloc)):
                    path = request.get_full_path()
                from django.contrib.auth.views import redirect_to_login
                return redirect_to_login(
                    path, resolved_login_url, redirect_field_name)
            return _wrapped_view
        return decorator

    def login_required(function=None, redirect_field_name=REDIRECT_FIELD_NAME, login_url=None):
        """
        Decorator for views that checks that the user is logged in, redirecting
        to the log-in page if necessary.
        """
        actual_decorator = user_passes_test(
            lambda u: u.is_authenticated,
            login_url=login_url,
            redirect_field_name=redirect_field_name
        )
        if function:
            return actual_decorator(function)
        return actual_decorator

    def permission_required(perm, login_url=None, raise_exception=False):
        """
        Decorator for views that checks whether a user has a particular permission
        enabled, redirecting to the log-in page if necessary.
        If the raise_exception parameter is given the PermissionDenied exception
        is raised.
        """
        def check_perms(user):
            if isinstance(perm, six.string_types):
                perms = (perm, )
            else:
                perms = perm
            # First check if the user has the permission (even anon users)
            if user.has_perms(perms):
                return True
            # In case the 403 handler should be called raise the exception
            if raise_exception:
                raise PermissionDenied
            # As the last resort, show the login form
            return False
        return user_passes_test(check_perms, login_url=login_url)