Ember适配器动态路径使用pathForType

Question

我正在扩展适配器：

import config from '../config/environment';
import Firebase from 'firebase';
import Ember from 'ember';
import ApplicationAdapter from './application';

export default ApplicationAdapter.extend({
  pathForType: function(type) {
    return "posts/" + this.get("session.auth.uid") + "/causeRecs";
  }
});

我希望适配器也能够使用要保存的记录的属性（record_A）动态设置pathForType：

return "posts/" + this.get("session.auth.uid") + "/causeRecs/" + this.get("record_A.path");

如何访问正在保存的记录的属性（record_A）？