在MVC Express应用中创建数据库服务 [英] Creating a DB service in an MVC Express app

问题描述

我正在创建一个Node/Express/Mongo应用程序，并且希望具有MVC样式的文件布局以及单独的数据库服务.我希望我的路线(控制器)相当精简，并且在需要执行CRUD功能时只需从其他地方调用方法即可.

这篇很棒的帖子有很多可靠的答案.我将粘贴在 EddieDean 的答案下面，该答案似乎与我想做的最接近.

但是，当我尝试引用someFile.js文件中的mongo.js文件中定义的Users对象时，它返回为 undefined..我很确定我丢失了一些东西很明显，很想知道那是什么.

我可以获取对数据库连接本身的引用并调用dbConn.Users.addUser(x)，但是不能像下面的someFile.js示例中那样直接调用Users.addUser(x).

这似乎是次要的，但是我花了太多时间没有答案.称之为知识仇敌.

谢谢.

---

mongo.js

const { MongoClient } = require('mongodb');
const config = require('./config');
const Users = require('./Users');
const conf = config.get('mongodb');

class MongoBot {
  constructor() {
    const url = `mongodb://${conf.hosts.join(',')}`;

    this.client = new MongoClient(url, conf.opts);
  }
  async init() {
    await this.client.connect();
    console.log('connected');

    this.db = this.client.db(conf.db);
    this.Users = new Users(this.db);
  }
}

module.exports = new MongoBot();

Users.js

class User {
  constructor(db) {
    this.collection = db.collection('users');
  }
  async addUser(user) {
    const newUser = await this.collection.insertOne(user);
    return newUser;
  }
}
module.exports = User;

app.js

const mongo = require('./mongo');

async function start() {
  // other app startup stuff...
  await mongo.init();
  // other app startup stuff...
}
start();

someFile.js

const { Users } = require('./mongo');

async function someFunction(userInfo) {
  const user = await Users.addUser(userInfo);
  return user;
}

解决方案

如果在调用mongo.init方法之前需要someFile.js，则将创建mongoBot实例，但确实不会定义Users.如果需要在调用init方法之前需要someFile，则可以将已分解的分配移至someFunction方法内部.

I am creating a Node / Express / Mongo app and would like to have an MVC-style file layout with a separate database service. I'd like my routes (controllers) to be fairly lean and simply call methods from elsewhere when I need to perform CRUD functions.

This great post had a lot of solid answers. I'll paste below the the answer from EddieDean that seems to be closest to what I'd like to do.

However, when I'm trying to reference the Users object defined in the mongo.js file in my someFile.js file, it comes back as undefined. I am pretty sure I am missing something obvious and would love to know what that is.

I can get a reference to the DB connection itself and call dbConn.Users.addUser(x) but I cannot directly call Users.addUser(x) as in the someFile.js example below.

This seems minor but I've spent too much time on this to not have an answer. Call it a knowledge vendetta.

Thanks.

---

mongo.js

const { MongoClient } = require('mongodb');
const config = require('./config');
const Users = require('./Users');
const conf = config.get('mongodb');

class MongoBot {
  constructor() {
    const url = `mongodb://${conf.hosts.join(',')}`;

    this.client = new MongoClient(url, conf.opts);
  }
  async init() {
    await this.client.connect();
    console.log('connected');

    this.db = this.client.db(conf.db);
    this.Users = new Users(this.db);
  }
}

module.exports = new MongoBot();

Users.js

class User {
  constructor(db) {
    this.collection = db.collection('users');
  }
  async addUser(user) {
    const newUser = await this.collection.insertOne(user);
    return newUser;
  }
}
module.exports = User;

app.js

const mongo = require('./mongo');

async function start() {
  // other app startup stuff...
  await mongo.init();
  // other app startup stuff...
}
start();

someFile.js

const { Users } = require('./mongo');

async function someFunction(userInfo) {
  const user = await Users.addUser(userInfo);
  return user;
}

解决方案

If someFile.js is required before the mongo.init method is called, the mongoBot instance will have been created, but Users will indeed be undefined. If you need to require someFile before the init method is called, you can move your destructured assignment to inside your someFunction method.

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