AngularJS REST服务调用：如何在提供者，控制器和指令之间交换数据？

Question

我有两个REST Web服务，我必须逐个调用。第一个返回一些我必须用于第二个REST服务调用的数据。第二个结果，我需要将它提供给我的指令，它应该显示值。

我以这种方式使用AngularJS构建控制器：

app.controller('MyRestCtrl', [$scope, 'RestScope', function($scope, RestScope) {
    RestScope.preGet().success(function(data) {
        /* success of the first REST call and do some calculations with this data */
        /* Question: I have to set the calculated data (data1 and data2) to the 
                     RestScope provider, how can I do this, so that the second call 
                     .get() has this data to make the request? */

        RestScope.get().success(function(response) {
            /* response has all the data which I need for my directive */
            /* Question: How can I provide this data into my directive? */
        });
    })
}]);

这是提供商：

app.provider('RestScope', function() {
    this.data1 = null;
    this.data2 = null;
    this.setData1 = function(_data1) {
        this.data1 = _data1;
    }
    this.setData2 = function(_data2) {
        this.data2 = _data2;
    }

    this.$get = ['$http', '$log', function($http, $log) {
        var _data1 = this.data1;
        var _data2 = this.data2;
        function get() {
            return $http.get('http://www.test.com/' + _data1 + '/?param=' + _data2);
        }
        function preGet() {
            return $http.get('http://www.test.com/getData/');
        }
        return {
            get: get,
            preGet: preGet
        };
    }];
});

这是我的指令：

app.directive('myDirective', function() {
    return {
        restrict: 'AEC', 
        replace: false, 
        templateUrl: 'path/to/my.html'
    };
});

首先，如何将preGet().success内部的一些数据设置到RestScope提供商？第二个问题，如果我得到第二个电话get().success的数据如何将其提供给我的指令？