CODEWITHSUNDEEP
node.jsmongodbmongoose
user994165
user994165

Reputation: 9512

Mongoose callback not executed when using mongoose.createConnection

I'm running Node v6.11.4 on Ubuntu with Mongoose 4.12.4 and Mongo v3.4.9. I have the following code to add a new record, then read back the following. The save is not getting executed (fluffy.save()).

However, if I replace mongoose.createConnection line with the two lines above it using mongoose.connect, then the whole code works as expected.

// 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));



});

Result using mongoose.createConnection:

We're Connected!
Silence
Meow name is fluffy

Result with the updated code using mongo.connect:

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 }

Upvotes: 0

Views: 2406

Answers (2)

user994165
user994165

Reputation: 9512

Based on the answer in Queries hang when using mongoose.createConnection() vs mongoose.connect(), we have to use db.model() not mongoose.model() when using createConnection(). mongoose.model() can only be using be used with connect(). I've pasted two working solutions.

Solution with connect():

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);
    }
    );
});

Solution with createConnection():

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);
});

Upvotes: 2

Valfar Developer
Valfar Developer

Reputation: 340

You can work with the connections in this way:

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");
});

Upvotes: 1

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