Couchbase自定义归约功能 [英] Couchbase custom reduce function

问题描述

我的Couchbase中有一些带有以下模板的文档:

I have some documents in my Couchbase with the following template:

{
  "id": 102750,
  "status": 5,
  "updatedAt": "2014-09-10T10:50:39.297Z",
  "points1": 1,
  "points2": -3,
  "user1": {
      "id": 26522,
      ...
  },
  "user2": {
      "id": 38383,
      ...
  },
  ....
}

我想要做的是将用户上的文档分组，并对每个用户的得分求和，然后显示上周的前100名用户.我一直在转悠，但没有任何解决方案.

What I want to do is to group the documents on the user and sum the points for each user and then show the top 100 users in the last week. I have been circling around but I haven't come with any solution.

我已经开始使用以下地图功能:

I have started with the following map function:

function (doc, meta) {
  if (doc.user1 && doc.user2) {
    emit(doc.user1.id, doc.points1);
    emit(doc.user2.id, doc.points2);
  }
}

然后尝试求和以减少结果，但显然我错了，因为我无法对这些点进行排序，而且我也无法包含date参数

and then tried the sum to reduce the results but clearly I was wrong because I wasn't able to sort on the points and I couldn't also include the date parameter

推荐答案

我已经通过服务器端脚本的帮助解决了此问题.我所做的是将地图功能更改为:

I have solved this issue by the help of a server side script. What I have done is I changed my map function to be like this:

function (doc, meta) {
  if (doc.user1 && doc.user2) {
    emit(dateToArray(doc.createdAt), { 'userId': doc.user1.id, 'points': doc.points1});
    emit(dateToArray(doc.createdAt), { 'userId': doc.user2.id, 'points': doc.points2});
  }
}

在脚本中，我用所需的参数查询视图，然后对它们进行分组和排序，然后发送前100名用户.

And in the script I query the view with the desired parameters and then I group and sort them then send the top 100 users.

我正在使用Node JS，所以我的脚本是这样的:(结果是我从沙发床视图中读取的内容)

I am using Node JS so my script is like this: (the results are what I read from couchbase view)

function filterResults(results) {
  debug('filtering ' + results.length + ' entries..');
  // get the values
  var values = _.pluck(results, 'value');
  var groupedUsers = {};

  // grouping users and sum their points in the games
  // groupedUsers will be like the follwoing:
  //  { 
  //     '443322': 33,
  //     '667788': 55,
  //     ...
  //   }
  for (var val in values) {
    var userId = values[val].userId;
    var points = values[val].points;
    if (_.has(groupedUsers, userId)) {
      groupedUsers[userId] += points;
    }
    else
      groupedUsers[userId] = points;
  }

  // changing the groupedUsers to array form so it can be sorted by points:
  // [['443322', 33], ['667788', 55], ...]
  var topUsers = _.pairs(groupedUsers);

  // sort descending
  topUsers.sort(function(a, b) {
    return b[1] - a[1];
  });

  debug('Number of users: ' + topUsers.length + '. Returning top 100 users');
  return _.first(topUsers, 100);
}

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