huiting/cloudfunctions/listMessages/index.js

// 云函数入口文件
const cloud = require('wx-server-sdk')

cloud.init()
const db = cloud.database()

// 云函数入口函数
exports.main = async (event, context) => {
  const {
    OPENID
  } = cloud.getWXContext()

  if (event.pub_id) {
    const messages = await db.collection('message')
      .aggregate()
      .match({
        pub_id: event.pub_id
      })
      .sort({
        publish_time: -1
      })
      .skip(event.page_token)
      .limit(event.page_size)
      .end()

    return {
      list: messages.list,
      next_page_token: event.page_token + messages.list.length,
      status: 'OK'
    }
  } else {
    const messages = await db.collection('message')
      .aggregate()
      .sort({
        publish_time: -1
      })
      .skip(event.page_token)
      .limit(event.page_size)
      .lookup({
        from: 'publisher',
        localField: 'pub_id',
        foreignField: '_id',
        as: 'publisher'
      })
      .end()

    for (let i = 0; i < messages.list.length; i++) {
      messages.list[i].publisher = messages.list[i].publisher[0]
    }

    return {
      list: messages.list,
      next_page_token: event.page_token + messages.list.length,
      status: 'OK'
    }
  }
}