如何在 Meteor 中读取依赖于另一个集合的集合 [英] How to read a collection that depends on another one in Meteor

问题描述

我正在尝试从一个集合中加载最新的帖子，同时加载该帖子的所有评论.该集合具有引用而不是将整个文档存储在彼此内部:

I'm trying to load the latest post from a collection and at the same time all of the comments of that same post. The collection have references instead of storing the whole documents inside each other:

Post { title, body, etc..}
Comment { postId, body, etc.. }

我使用 Iron-router 作为路由包，并且在我的页面的路由中我以这种方式订阅:

I'm using iron-router as the routing package and in the route of my page I'm subscribing with this way:

this.route('home', {
    path: '/',
    template: 'home',
    waitOn: function () {
        return [
            Meteor.subscribe('latestPost'),
            Meteor.subscribe('lastReadPost')
            ];
    }
});

检索帖子的代码很简单:

The code that retrieves the post is simply:

Posts.findOne({}, {sort:{createdAt:-1, limit:1}});

现在的问题是我不知道如何在不阅读整个集合的情况下检索评论.我无法在路由器中订阅，因为我仍然没有帖子 ID 来查询 Comments 集合.我猜我可以从模板中做到这一点，但是当然，如​​果我查询 Comments 集合，它仍然是空的.但我确实有 postId，因为它当时在 Posts 集合中.但我需要从模板触发订阅，这听起来不是一个干净的解决方案.

Now the problem is that I don't know how to retrieve the comments without reading the whole collection. I can't subscribe in the router as I still do not have the post ID to query the Comments collection. I guessed I could do that from the Template, but of course if I query the Comments collection, it's still empty. But I do have the postId as it's inside the Posts collection at that time. But I would need to trigger a subscription from the Template and that doesn't sound like a clean solution.

最佳实践是什么?谢谢！

What would the best practice be? Thanks!

推荐答案

服务器端代码:

Meteor.publish("latestPost", function () {
  var post = Posts.find({}, {sort:{created:-1}}).fetch()[0];
  console.log("publish : " + post.title);
  return [
    Posts.find({_id: post._id}),
    Comments.find({postId: post._id})
  ];
});

客户端代码:

 this.route('home', {
    path: '/',
    template: 'home',
    waitOn: function () {
      return [
        Meteor.subscribe('latestPost')
      ];
    },
    data:function(){
      return {
       post:Posts.findOne(),
       comments:Comments.find()
      };
    }
   });

检查这个存储库以查看整个例子.

Check this repository to see whole example.

在用户更改到另一条路线后，订阅将自动停止.

After user changes to another route, then subcriptions are being automatically stopped.

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