Question

我在Ubuntu上使用Mongoose 4.12.4和Mongo v3.4.9运行Node v6.11.4。我有以下代码来添加新记录，然后回读以下内容。保存未执行（fluffy.save()）。

但是，如果我使用mongoose.connect将mongoose.createConnection行替换为它上面的两行，那么整个代码将按预期工作。

// getting-started.js
var mongoose = require('mongoose');

mongoose.Promise = require('bluebird');
var options = {promiseLibrary: require('bluebird')};

//mongoose.connect('mongodb://localhost/test',options);
//var db = mongoose.connection;
var db = mongoose.createConnection('mongodb://localhost/test', options);

db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', function () {
    console.log('We\'re Connected!');

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

// NOTE: methods must be added to the schema before compiling it with mongoose.model()
    kittySchema.methods.speak = function () {
        var greeting = this.name
                ? "Meow name is " + this.name
                : "I don't have a name";
        console.log(greeting);
    }

    var Kitten = mongoose.model('Kitten', kittySchema);

    var silence = new Kitten({name: 'Silence'});
    console.log(silence.name); // 'Silence'

    var fluffy = new Kitten({name: 'fluffy'});
    fluffy.speak(); // "Meow name is fluffy"

    fluffy.save(function (err, fluffy) {
        if (err)
            return console.error(err);
        fluffy.speak();
    }).then((val) => {
        console.log("result: " + val);
        Kitten.find({name: 'fluffy'}, function (err, kittens) {
            if (err)
                return console.error(err);
            console.log("All the kittens found: " + kittens);
        })
    }

    ).catch((err) => console.log("rejected:" + err));



});

使用mongoose.createConnection的结果：

We're Connected!
Silence
Meow name is fluffy

使用mongo.connect：

更新代码的结果

We're Connected!
Silence
Meow name is fluffy
result: { __v: 0, name: 'fluffy', _id: 59ed75e7c414e210bc074bf3 }
Meow name is fluffy
All the kittens found: { _id: 59ed635dbcefe203f07a4b35, name: 'fluffy', __v: 0 },{ _id: 59ed63bddfb1de04351704e5, name: 'fluffy', __v: 0 },{ _id: 59ed63ee6c7ca0046872ff4e, name: 'fluffy', __v: 0 },{ _id: 59ed6f5fc816670d3bc0a09e, name: 'fluffy', __v: 0 },{ _id: 59ed6fd49319d20d8944b7e2, name: 'fluffy', __v: 0 },{ _id: 59ed74785885cf0ff23ef0ee, name: 'fluffy', __v: 0 },{ _id: 59ed75e7c414e210bc074bf3, name: 'fluffy', __v: 0 }

Answer 1

您可以通过以下方式处理连接：

const mongoose = require("mongoose"),
  dbURI = "mongodb://your-host(ex - localhost):your port (ex - 27017)/yourDatabaseName";

mongoose.connect(dbURI);
conn = mongoose.connection;

conn.on("connected", function(){
    console.log("Mongoose connected to " + dbURI);
});

conn.on("error", function(err){
    console.log("Mongoose connection error" + err);
});

conn.on("disconnected", function(){
    console.log("Mongoose disconnected");
});

Answer 2

基于Queries hang when using mongoose.createConnection() vs mongoose.connect()中的答案，我们在使用createConnection（）时必须使用db.model（）而不是mongoose.model（）。 mongoose.model（）只能与connect（）一起使用。我已经粘贴了两个有效的解决方案。

使用connect（）的解决方案：

var mongoose = require('mongoose');
var util = require('util');

mongoose.Promise = require('bluebird');
var options = {promiseLibrary: require('bluebird'), useMongoClient: true};

var promise = mongoose.connect('mongodb://localhost/test', options);

promise.then(function (db) {
  console.log('We\'re Connected!');

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

  // NOTE: methods must be added to the schema before compiling it with mongoose.model()
  kittySchema.methods.speak = function () {
    var greeting = this.name
      ? "Meow name is " + this.name
      : "I don't have a name";
    console.log(greeting);
  }

  // NOTE: Use mongoose.model() instead of db.model() when using connect().
  var Kitten = mongoose.model('Kitten', kittySchema);

  var fluffy = new Kitten({name: 'fluffy'});
  fluffy.speak(); // "Meow name is fluffy"

  fluffy.save(function (err, fluffy) {
    if (err)
      return console.error(err);
    fluffy.speak();
  })
    .then((val) => {
      console.log("result: " + val);
      Kitten.find({name: 'fluffy'}, function (err, kittens) {
        if (err) {
          return console.error(err);
        }
        console.log("All the kittens found: " + kittens);
      })
    }

    )
    .catch((err) => {
      console.log("Mongo save rejected:" + err);
      process.exit(1);
    }
    );
});

使用createConnection（）解决方案：

var mongoose = require('mongoose');
var util = require('util');

mongoose.Promise = require('bluebird');
var options = {promiseLibrary: require('bluebird'), useMongoClient: true};

var promise = mongoose.createConnection('mongodb://localhost/test', options);

promise.then(function (db) {
  var kittySchema = mongoose.Schema({
    name: String
  });

  // NOTE: methods must be added to the schema before compiling it with mongoose.model()
  kittySchema.methods.speak = function () {
    var greeting = this.name
      ? "Meow name is " + this.name
      : "I don't have a name";
    console.log(greeting);
  }

  // NOTE use db.model() instead of mongoose.model when using mongoose.createConnection()
  var Kitten = db.model('Kitten', kittySchema);

  var fluffy = new Kitten({name: 'fluffy'});
  fluffy.speak(); // "Meow name is fluffy"

  fluffy.save(function (err, fluffy) {
    if (err)
      return console.error(err);
    fluffy.speak();
  })
    .then((val) => {
      console.log("result: " + val);
      Kitten.find({name: 'fluffy'}, function (err, kittens) {
        if (err) {
          return console.error(err);
        }
        console.log("All the kittens found: " + kittens);
      })
    })
    .catch((err) => {
      console.log("Mongo save rejected:" + err);
      process.exit(1);
    }
    );
})
  .catch((err) => {
    console.error(`Error connecting to MongoDB: ${err}`);
    process.exit(1);
  }
  );

promise.on("disconnected", function () {
  console.log("Mongoose disconnected");
  process.exit(1);
});

promise.on('err', function () {
  console.error(`Error connecting to MongoDB: ${err}`);
  process.exit(1);
});

使用mongoose.createConnection时未执行Mongoose回调

2 个答案: