angularjs在我的指令中更改范围变量

Question

这是我在angularjs中编写的简单指令。我的指令很简单，$ http获取值和设置变量。当我运行此指令时，我有一个$ digest错误。为什么？我使用Angularjs 1.2.13。

我的代码：

link77.directive('dbLabel', ['$http', 'remoteconf', function ($http, remoteconf) {
  return {
    restrict: 'EA',
    require: 'ngModel',
    replace: true,
    template: '<legend>{{valdb}}</legend>',
    link: function (scope, elem, attrs, ctrl) {
      
      var table = attrs.dbTable;
      var field   = attrs.dbField;
      var where   = attrs.dbWhere;
      
      scope.$apply(function () {
              $http({ 
                method: 'POST', 
                url: remoteconf.init.appApiEntryPoint + attrs.ngModulo + '/api/service.php?x=getdbval', 
                data: { 
                  xtable: table,
                  xfield: field,
                  xwhere: where
                } 
              }).success(function(data, status, headers, config) {
                scope.valdb =  data.status;
                });
            });
        }

    }

}]);

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.13/angular.min.js"></script>

<db-label db-table="users" db-field="lastname" db-where="where id = {{user.id}}"/>