在流星1.7+中可以订阅文本搜索光标吗

Question

MyCollection.find({ $text: { $search: 'foo' } }, {
  fields: {
    score: { $meta: "textScore" }
  },
  sort: {
    score: { $meta: "textScore" }
  }
});

I20180926-18:26:08.708(-4)? Exception from sub mysubscription id ZeSWJcoghED3t6Eq6 Error: Exception while polling query {"collectionName":"my-collection","selector":{"$text":{"$search":"foo"}},"options":{"transform":null,"limit":25,"sort":{"score":{"$meta":"textScore"}}}}: must have $meta projection for all $meta sort keys
I20180926-18:26:08.709(-4)?     at PollingObserveDriver._pollMongo (packages/mongo/polling_observe_driver.js:165:11)
I20180926-18:26:08.709(-4)?     at Object.task (packages/mongo/polling_observe_driver.js:93:12)
I20180926-18:26:08.710(-4)?     at Meteor._SynchronousQueue.SQp._run (packages/meteor.js:987:16)
I20180926-18:26:08.710(-4)?     at packages/meteor.js:964:12

collection.find({
    $text:
      {
        $search: filter,
        $caseSensitive: false,
        $diacriticSensitive: true
      }
    })
    .project({ score: { $meta: "textScore" } })
    .sort({score:{$meta:"textScore"}})

解决办法是什么？

Answer 1

下面有一个创建的迷你复制指南。它展示了如何执行一个（索引的）文本搜索，就像您最初报告的那样抛出一个错误。

因此，我们可以假设错误的来源，例如，在迁移到Meteor1.7+/Mongo3.6+时，或者在代码中。迁移很有可能包括原因，因为最近在论坛和SO上有许多关于升级到1.7的问题的帖子。

因此，这里有一个简短的清单，列出了可能出现的问题：

null

meteor:PRIMARY> db.texts.getIndexes()
[
    {
        "v" : 2,
        "key" : {
            "_id" : 1
        },
        "name" : "_id_",
        "ns" : "meteor.texts"
    },
    {
        "v" : 2,
        "key" : {
            "_fts" : "text",
            "_ftsx" : 1
        },
        "name" : "text_text",
        "ns" : "meteor.texts",
        "weights" : {
            "text" : 1
        },
        "default_language" : "english",
        "language_override" : "language",
        "textIndexVersion" : 3
    }
]

null

1. 创建一个新项目并安装faker（以快速创建一些文本）:

$ meteor create metasearch
$ cd metasearch
$ meteor npm install --save faker
$ meteor

import { Mongo } from "meteor/mongo"
export const Texts = new Mongo.Collection('texts')

import { Meteor } from 'meteor/meteor'
import { Texts } from '../imports/Texts'

Meteor.startup(() => {
  import { lorem } from 'faker'
  for (let i = 0; i < 5; i++) {
    Texts.insert({
      title: lorem.words(),
      text: lorem.text()
    })
  }
})

Meteor.publish('search', function searchpub (filter) {
  const cursor = Texts.find({
    $text: {
      $search: filter,
      $caseSensitive: false,
      $diacriticSensitive: false,
    }
  }, {
    fields: {
      score: {$meta: 'textScore'},
    },
    sort: {
      score: {$meta: 'textScore'},
    },
  })

  // fallback if cursor is undefined
  if (cursor && cursor.count && cursor.count() >= 0) {
    return cursor
  } else {
    this.ready()
  }
})

正如您所看到的，它使用默认的“在一个文档中查询、投影和排序”结构，就像您最初发布的那样。

import { Template } from 'meteor/templating';
import { ReactiveVar } from 'meteor/reactive-var';

import './main.html';

import {Texts} from '../imports/Texts'

Template.hello.onCreated(function helloOnCreated() {
  // counter starts at 0
  this.counter = new ReactiveVar(0);

  const instance = this
  instance.autorun(() => {
    const cursor = instance.subscribe('search', 'dolor') // use a word, that often occurs
    if (cursor.ready()) {
      console.log(Texts.find().fetch())
    }
  })
});

// ... rest of the file

$ meteor mongo
$ db.texts.createIndex({text:"text"})

输出应类似于：

{
    "createdCollectionAutomatically" : false,
    "numIndexesBefore" : 1,
    "numIndexesAfter" : 2,
    "ok" : 1,
    "operationTime" : Timestamp(1538031016, 1),
    "$clusterTime" : {
        "clusterTime" : Timestamp(1538031016, 1),
        "signature" : {
            "hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
            "keyId" : NumberLong(0)
        }
    }
}

同时，meteor.startup诱导的插入应该创建了大量的文档来搜索，但它们可能还没有添加到索引中。

您可以取消正在运行的实例并重新启动几次（或增加启动时要插入的文档数量）以获得大量匹配。

Array (51) […]
​
0: {…}
_id: "n2WhMskCXBm7ziZea"
score: 1.0416666666666667
text: "Dolor at sed et dolorem tenetur a dolore voluptate incidunt. Rerum corrupti officia aut tenetur nisi officiis voluptas soluta. Fugiat eos sed expedita inventore. Esse cupiditate qui. Facere dolor quisquam ipsa a facere praesentium. Aut sunt mollitia dolore tenetur."
title: "quia est fuga"
<prototype>: Object { … }
​
1: {…}
_id: "QjAcZQLTH8Mc3jDzS"
score: 1.0110294117647058
text: "Sequi dolores omnis sequi consequatur laborum et asperiores. Accusantium repellat magnam est aut suscipit enim iure. Qui qui aut cupiditate necessitatibus commodi qui quia. Ut tempore autem provident maiores cumque necessitatibus dolores accusantium. Nostrum ut ut sunt adipisci qui consequuntur explicabo voluptas. Minima praesentium sunt facere doloribus non at dolor dolore est."
title: "est explicabo omnis"
<prototype>: Object { … }