访问在json服务器响应中传递的元信息 [英] Accessing meta information passed in a json server response

问题描述

我正在使用Ember-Data Rest-Adapter，从我的服务器返回的JSON看起来基本上就像 Active模型序列化器文档

  {
meta：{total：10}，
posts：[
 {title：Post 1，body：Hello！ }，
 {title：Post 2，body：再见！ 
] 
} 
  

从服务器获取数据工作，但不幸的是我无法确定我可以从我的JSON响应中访问元信息。

根据我对ember-data的github问题的研究，对元信息的支持似乎实施，提交 1787bff 。

但即使有测试用例，我也无法弄清楚如何访问元信息。

  App.PostController = Ember.ArrayController.extend（{
 .... 
 requestSearchData：function（searchParams）{
 posts = App.Post.find （searchParams）; 
 this.set（'content'，posts）; 
 //不知道如何访问meta [total] 
 //但是我想做某事像这样：
 // this.set（'totalCount'，meta [total]）
} 
}）
  

请问有人可以给我看看吗？我知道Ember api正在快速移动，但我确信我只是错过了一小部分，这实际上是可能的。

解决方案

我发现一个更清洁的方法来从服务器响应中提取ember数据的元信息。

我们必须告诉序列化程序需要哪些元信息这个案例分页）：

  App.serializer = DS.RESTSerializer.create（）; 
 
 App.serializer.configure（{pagination：'pagination'}）; 
 
 App.CustomAdapter = DS.RESTAdapter.extend（{
 serializer：App.serializer 
}）; 
 
 App.Store = DS.Store.extend（{
 adapter：'App.CustomAdapter'
}）;之后，每次服务器发送一个带有分页对象的元属性时，这个对象将被添加到商店的 TypeMaps 属性。 
 
 
 
例如，使用以下响应：
  {
'meta'：{'pagination'：{'page'：1，'total'：10}}，
'posts'：[
 ... 
] 
 } 
  
 App.Post的 TypeMap  -Model将在帖子加载后包含分页对象。
 
 
 
您不能直接观察到商店的TypeMaps属性，所以我将一个计算属性添加到PostsController访问请求分页元信息：
  App.PostsController = Ember.ArrayController.extend（{
 pagination ：function（）{
 if（this.get（'model.isLoaded'））{
 modelType = this.get（'model.type'）; 
 this.get（'store '）.typeMapFor（modelType）.metadata.pagination 
} 
} .property（'model.isLoaded'）
}）; 
  
我真的不认为这是元信息问题的一个很好的解决方案，但这是最好的解决方案我可以想出Ember-Data。也许这将来会更容易。
 
I am using the Ember-Data Rest-Adapter and the JSON returned from my server looks basically like the one in the Active Model Serializers Documentation
{
  "meta": { "total": 10 },
  "posts": [
    { "title": "Post 1", "body": "Hello!" },
    { "title": "Post 2", "body": "Goodbye!" }
  ]
}
Fetching the data from the server works but unfortunately I am not able to figure out where I can access the meta information from my JSON response.

Based on my research in ember-data's github issue, support for meta information seems to be implemented with commit 1787bff. 

But even with the test cases I was not able to figure out how to access the meta information.
App.PostController = Ember.ArrayController.extend({
   ....
   requestSearchData: function(searchParams){
      posts = App.Post.find(searchParams);
      this.set('content', posts);
      // don't know how to access meta["total"]
      // but I want to do something like this:
      // this.set('totalCount', meta["total"])
   }
})
Can anybody of you shed some light on this for me, please? I am aware that the Ember api is moving fast but I am sure I am just missing a small part and that this is actually possible.
解决方案
I found a cleaner approach for extracting meta information from the server response with ember-data.

We have to tell the serializer which meta-information to expect (in this case pagination):
 App.serializer = DS.RESTSerializer.create();

 App.serializer.configure({ pagination: 'pagination' });

 App.CustomAdapter = DS.RESTAdapter.extend({
   serializer: App.serializer
 });

 App.Store = DS.Store.extend({
   adapter: 'App.CustomAdapter'
 });
After that every time the server sends a meta-property with a pagination object this object will be added to the store's TypeMaps property for the requested Model-Class. 

For example with the following response:
  {
    'meta': {'pagination': { 'page': 1, 'total': 10 } },
    'posts':[
      ...
    ]
  }
The TypeMap for the App.Post-Model would include the pagination object after the posts have loaded.

You can't observe the TypeMaps-property of the store directly so I added an computed property to the PostsController to have access to the requests pagination meta information:
 App.PostsController = Ember.ArrayController.extend({
    pagination: function () {
      if (this.get('model.isLoaded')) {
        modelType = this.get('model.type');
        this.get('store').typeMapFor(modelType).metadata.pagination
      }
    }.property('model.isLoaded')
 });
I really don't think that's a great solution to the meta information problem but this is the best solution I was able to come up with yet with Ember-Data. Maybe this will be easier in the future.

                        
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