在猫鼬中跨整个应用程序共享数据库连接 [英] sharing db connection across entire app in mongoose

问题描述

使用最新的猫鼬更新，您将无法再按照我的方式对用户进行建模.我需要在整个应用程序中共享相同的数据库连接.

With the latest mongoose update, you can no longer user models the way I've been doing. I need to share the same db connection across my entire app.

https://github.com/LearnBoost/mongoose/issues/1249

这是不再有效的旧方法:

Here is the old way which no longer works:

./models/user.js

./models/user.js

var mongoose = require('mongoose'), cfg = require('../config')
, Schema = mongoose.Schema
, db = mongoose.createConnection(cfg.mongo.uri, cfg.mongo.db);
...

module.exports = db.model('Item', ItemSchema);

如何按照上面github问题中的建议重新使用数据库连接?

How can I re-use db connection as suggested in github issue above?

我在代码库中的多个不同位置使用了var User = require('./models/user');.

I'm using var User = require('./models/user'); in several different places in my code base.

推荐答案

选项1:使用共享对象

我的模型代码看起来很相似，但是没有重复需要模块，而是在应用程序启动时只需要它们一次，然后将结果分配给共享对象.例如，如果您使用快递应用，则可以使用app.locals.models.User = require('./models/user');之类的东西.这样，任何有权访问app的人都可以看到您的模型，而无需要求.

Option 1: Use a shared object

My model code looks similar, but instead of repeatedly requiring the modules I just require them once when the application starts and then assign the results to a shared object. For example if you are using an express app you could just so something like app.locals.models.User = require('./models/user');. Then anything with access to the app can see your models without needing a require.

您可以这样定义用户模块:

You can define your user module like so:

var mongoose = require('mongoose');

var userSchema = new mongoose.Schema({name: String});

var User = null;

module.exports = function(db) {
  if (db && User === null) {
    User = db.model('User', userSchema);
  }
  return User;
};

启动应用程序时，您只需要:require('./models/user')(db).您的应用程序中的其他模块随后需要删除db参数，因为User只会被设置一次.

When you start your application you simply need to: require('./models/user')(db). Subsequent requires by other modules in your application can drop the db paramater, as User will only be set once.

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