Meteor+MongoDB:如何获取嵌套数据

Meteor + MongoDB: How to get nested data?

本文关键字：获取 嵌套 数据 何获取 Meteor+MongoDB      更新时间：2023-09-26

我是Meteor的新手，正在努力解决这个问题。

我正试图根据所经过的路线从"课程"集合加载数据。例如，如果/课程/level1/lesson1/1a通过，则显示数据

不幸的是，这不起作用。

我走的是正确的道路还是有更好的方法？

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{
  "_id": "YSgr3fvjpEBn7ncRa",
  "courseId": "level1",
  "lesson": [
    {
      "lessonId": "lesson1",
      "freeLesson": true,
      "title": "Lesson 1",
      "eachLesson": [
        {
          "eachLessonId": "1a",
          "title": "This is (masculine)",
          "video": "839843"
        },
        {
          "eachLessonId": "1b",
          "title": "That is (masculine)",
          "video": "839843"
        },
        {
          "eachLessonId": "1c",
          "title": "This is (feminine)",
          "video": "839843"
        },
        {
          "eachLessonId": "1d",
          "title": "That is (feminine)",
          "video": "839843"
        },
        {
          "eachLessonId": "1e",
          "title": "Getting to know you",
          "video": "839843"
        }
      ]
    }
  ]
}

路线

 Router.route("courses/:courseId/:lessonId/:eachLessonId", {
  path:"/courses/:courseId/:lessonId/:eachLessonId",
  layoutTemplate: "layoutLessons",
  template:"lessons",
  onBeforeAction:function(){
    var currentUser = Meteor.userId();
    if (currentUser) {
      Session.set('courseId', this.params.courseId);
      Session.set('lessonId', this.params.lessonId);
      Session.set('eachLessonId', this.params.eachLessonId);
      this.next();
     } else {
       Router.go('/')
     }
  },
});

模板助手

Template.lessons.onCreated(function(){
  Meteor.subscribe('listLessons');
});

Template.lessons.helpers({
  currentLesson: function() {
    var currentLesson = Session.get('eachLessonId');
    return Lessons.find({"lesson.eachLesson.eachLessonId" : currentLesson});
  },
});

HTML

{{#each currentLesson}}
  {{title}}
  {{video}}
{{/each}}

您可以使用Iron Router的waitOn和data选项，而不是将courseId、lessonId和eachLessonId存储为Session值。

例如，您可以按如下方式重写您的路线：

Router.route('/courses/:courseId/:lessonId/:eachLessonId', {
  name: 'lessons',
  layoutTemplate: 'layoutLessons',
  template: 'lessons',
  onBeforeAction: function() {
    let currentUser = Meteor.user();
    if (currentUser) this.next();
    else Router.go('/');
  },
  data: function() {
    var doc = Lessons.findOne({
      "courseId": this.params.courseId,
      "lesson.lessonId": this.params.lessonId,
      "lesson.eachLesson.eachLessonId": this.params.eachLessonId
    });
    if (doc) {
      var lesson = {};
      var lessonId = this.params.eachLessonId;
      _.each(doc.lesson, function(i) {
        lesson = _.find(i.eachLesson, function(j) {
          return j.eachLessonId == lessonId;
        });
      });
      return lesson;
    }
    return {};
  },
  waitOn: function() {
    return [
      Meteor.subscribe('lesson', this.params.courseId, this.params.lessonId, this.params.eachLessonId)
    ];
  }
});

这应该将数据上下文设置为请求的eachLesson对象。但是，您可以考虑将数据上下文设置为Lessons集合中的文档，然后只拾取某些eachLesson对象。此外，您应该创建一个发布函数，只返回请求的Lessons文档，而不是所有文档，就像您现在在listLessons出版物中可能做的那样。您可以将所有ID作为参数传递给相应的发布函数。

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