排序和限制不适用于Mongo + Meteor [英] Sort and limit not working with Mongo + Meteor

问题描述

这是我发布收藏集的publish.js文件:

This is my publish.js file in which I publish my collection:

const tags = Tags.find({title: {
      $regex: `.*${searchString}.*`,
      $options: 'i'
    }}, {
      sort: { counts: -1 }, limit: 3
    });
    console.log(tags.count());

    return tags;

这是我正在订阅此收藏集的组件:

And this is my components which is subscribing to this collection:

this.tagsSubscription = this.subscribe('tags', () => [this.tag], function (err) {
    that.tags = Tags.find().fetch();
});

因此，我得到两个不同的错误:

So with this I get 2 different errors:

• 排序和限制不起作用:我有时会得到3个以上的结果，并且没有按计数"进行排序

• sort and limit are not working: I sometimes get more than 3 results and there are not sorted by 'counts'

回调无法正常工作.太快了，我在客户端和服务器上得到了不同的结果.我尝试使用onSuccess()和Meteor.autorun()这样，但是没有运气.如果使用setTimeout，我可以看到正确的光标

the callback is not working properly. It's too fast, I get different result on client and server. I tried with this way, onSuccess() and with Meteor.autorun() but with no luck. If I use a setTimeout I can see the correct cursor

标题搜索是唯一可行的方法.

The title search is the only thing that seems working.

推荐答案

首先，根据

First, according to documentation, .count() will ignore effects of .skip() and .limit(), so, for example, if you have 100 records in total, and your query options has { limit: 3 } then .count() for this cursor will return 100 instead of 3.

第二，查看您的代码，我假设您的出版物期望至少一个参数:searchString.但是您订阅的代码不会通过.我认为应该是这样的:

Second, looking at your code I assume that your publication expects at least one argument: searchString. But your code that subscribes to it doesn't pass it. I think it should be like that:

Meteor.subscribe('tags', this.tag, () => {
  that.tags = Tags.find().fetch();
});

最后，服务器端排序不会影响客户端集合中的文档排序.

And lastly, server-side sorting does not affect documents sorting in client-side collections.

例如，假设您找到的查询为{ num: { $gte: 1 } }，并且有3个满足此条件的文档，num s分别等于3，2和1.这3个文档将从该出版物发送到客户集合.

For example, let's assume that you have find query as { num: { $gte: 1 } } and there are 3 documents which satisfy this condition, with nums equal 3, 2 and 1 accordingly. These 3 documents will be sent to client collection from this publication.

现在，让我们使用num: 2.5将新文档添加到此mongo集合中.考虑到您将{ limit: 3 }作为查询选项，将会发生什么情况?该出版物将发送给客户端:removed事件(对于带有num: 1的文档)和added事件(对于带有num: 2.5的文档).客户端集合将按该顺序具有文档:3, 2, 2.5.

Now, let's add new document to this mongo collection, with num: 2.5. What will happen, considering you have { limit: 3 } as query options? The publication will send to client: removed event for document with num: 1 and added event for document with num: 2.5. And client-side collection will have documents in that order: 3, 2, 2.5.

在此之后，应该也应在客户端对文档进行排序，这应该是可以理解的.因此，在我上面的代码中，它应该是:

Following this, it should be understandable that you should sort your documents on client side as well. So, in my code above it should be:

that.tags = Tags.find({}, { sort: { counts: -1 } }).fetch();

另外，请参阅有关何时发生的文档发布参数已更改.

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