javascript – 在feathers.js Hook中调用MongoDB

我想从feathers.js钩子中的集合中获取信息.
如何让钩子等待,直到mongodb呼叫完成？目前它发送挂钩而不等待呼叫完成,我尝试了返回和promieses,但没有任何工作

// Connection URL
const url = 'mongodb://localhost:27017/db';

//Use connect method to connect to the server

module.exports = function(hook) {
  MongoClient.connect(url, function(err, db) {
  const userCollection = db.collection('question');

  userCollection.count().then(function(N) {

    const R = Math.floor(Math.random() * N)

    const randomElement = userCollection.find().limit(1).skip(R).toArray(function(err, docs) {
    console.log("Found the following records");
    console.log(docs)
    //update hook with data from mongodb call
    hook.data.questionid = docs._id;
  });
  })
  })
};

解决方法:

理想的方法是制作hook asynchronous并返回一个用钩子对象解析的Promise：

// Connection URL
const url = 'mongodb://localhost:27017/db';
const connection = new Promise((resolve, reject) => {
  MongoClient.connect(url, function(err, db) {
    if(err) {
      return reject(err);
    }

    resolve(db);
  });
});

module.exports = function(hook) {
  return connection.then(db => {
      const userCollection = db.collection('question');
      return userCollection.count().then(function(N) {
        const R = Math.floor(Math.random() * N);

        return new Promise((resolve, reject) => {
          userCollection.find().limit(1)
            .skip(R).toArray(function(err, docs) {
              if(err) {
                return reject(err);
              }

              hook.data.questionid = docs._id;

              resolve(hook);
            });
        });
      });
    });
  });
};

标签：javascript,node-js,mongodb,feathersjs
来源： https://codeday.me/bug/20190608/1199020.html