Meteor订阅和显示用户计数

Question

我正在尝试显示我的页脚中的用户数量,我希望实时显示这个数字.我认为正确的方法是在服务器中创建一个发布并从客户端订阅.

// server/publications.js
Meteor.publish("usersCount", function () {
    return Meteor.users.find();
});

// client/main.js
UsersCount = new Meteor.Collection("usersCount");
Meteor.subscribe('usersCount', [], function() {
    console.log('subscribed.');
});

// client/views/layout/footer.js
Template.footer.helpers({
    famecoiners: function(){
        return UsersCount.find().count();
    }
});

// client/views/layout/footer.html
<span>{{famecoiners}} Famecoiners!</span>

在chrome控制台中,我们可以看到回调函数中的"订阅"字符串.问题是:{{famecoiners}}总是在我的模板中返回0.

Answer 1

发布所有用户都可以,但这不实用.如果您有10,000个用户怎么办？你真正想要做的是创建一个客户端集合,它只包含一个代表计数的项目.如果您查看文档的" 发布和订阅"部分中的第二个示例,您将看到执行此操作的内容.我将在下面提供一个完整的工作示例:

$ meteor create test
$ cd test
$ rm test.*
$ mkdir server client
$ meteor remove autopublish
$ meteor add coffeescript

客户机/ client.coffee

# Create a client-side subscription for the count of users.
UsersCount = new Meteor.Collection 'users-count'

Meteor.subscribe 'usersCount'

Meteor.startup ->
  Meteor.setInterval (->
    # To show something working, read the users count every second.
    uc = UsersCount.findOne()
    console.log uc.count or 0
  ), 1000

服务器/ server.coffee

# Create a 'Users' group for this demo instead of using accounts-password.
Users = new Meteor.Collection 'users'

Meteor.publish 'usersCount', ->
  count = 0 # the count of all users
  initializing = true # true only when we first start
  handle = Users.find().observeChanges
    added: =>
      count++ # Increment the count when users are added.
      @changed 'users-count', 1, {count} unless initializing
    removed: =>
      count-- # Decrement the count when users are removed.
      @changed 'users-count', 1, {count}

  initializing = false

  # Call added now that we are done initializing. Use the id of 1 since
  # there is only ever one object in the collection.
  @added 'users-count', 1, {count}
  # Let the client know that the subscription is ready.
  @ready()

  # Stop the handle when the user disconnects or stops the subscription.
  # This is really important or you will get a memory leak.
  @onStop ->
    handle.stop()

Meteor.startup ->
  # To show something working, insert a new user ever 0.5 seconds.
  Meteor.setInterval (-> Users.insert {}), 500

对不起,如果您不喜欢CoffeeScript - 我希望代码紧凑.

$ meteor start

如果您打开控制台,您将看到用户数增加.为了好玩,您可以打开mongo shell并运行db.users.remove();并观看它重置.