snapshot belongsTo

adapters.server.js

import DS from 'ember-data';

export default DS.JSONAPIAdapter.extend({
  findRecord (store, type, id, snapshot) {
    return {
      data: {
        id: '1',
        type: 'servers',
        relationships: {
          user: {
            data: {
              id: '1',
              type: 'users'
            }
          }
        }
      }
    }
  },
  
  deleteRecord(store, type, snapshot) {
    console.log("delete called for server: " + snapshot.record.get('id'));
    let s = snapshot.belongsTo('user', {id: true});
    console.log("snapshot.belongsTo('user') returned: " + s);
    return null;
  }
});

adapters.user.js

import DS from 'ember-data';
import Ember from 'ember';
export default DS.JSONAPIAdapter.extend({
  findRecord (store, type, id, snapshot) {
    return new Ember.RSVP.Promise(resolve => {
      Ember.run.later(() => resolve({
        data: {
          id: '1',
          type: 'users',
          attributes: {
            'display-name': 'christian'
          }
        }
      }), 1000);
    });
  },
});

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

models.server.js

import Model from "ember-data/model";
import attr from "ember-data/attr";
import { belongsTo, hasMany } from "ember-data/relationships";

export default Model.extend({
  user: belongsTo('user'),
});

models.user.js

import Model from "ember-data/model";
import attr from "ember-data/attr";
import { belongsTo, hasMany } from "ember-data/relationships";

export default Model.extend({   
  displayName: attr('string'),
  servers: hasMany('server'),
});

routes.application.js

import Ember from 'ember';

export default Ember.Route.extend({
  model(param) {
    return this.store.find('server', '1');
  },
  actions: {
    deleteServer(serverId) {
      let self = this;
      this.store.find('server', serverId).then( function(server) {
        let userId = server.get('user.id');
        self.store.find('user', userId).then( user => {
          user.get('servers').then( servers => {
            servers.removeObject(server);
            server.deleteRecord();
            server.get('isDeleted');
            server.save();
        });
       });
      });
    }
  }
});

templates.application.hbs

<h3>Model:</h3>
<p>{{model}}</p>

<h3>Server id:</h3>
<p>{{model.id}}</p>

<h3>User Display name:</h3>
<p>{{model.user.displayName}}</p>

<h3>User id:</h3>
<p>{{model.user.id}}</p>

<h3>Actions</h3>
<button {{action "deleteServer" model.id}}>Delete server</button>

twiddle.json

{
  "version": "0.10.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.1.1/jquery.js",
    "ember": "2.11.0",
    "ember-data": "2.11.0",
    "ember-template-compiler": "2.11.0"
  },
  "addons": {}
}