为什么我收到错误“试图打开未关闭的连接。”？

Question

I am trying to connect my node app to mongodb via mongoose. It seems to be working, as I can add documents, but I get the error { [Error: Trying to open unclosed connection.] state: 2 } .

I created a very simple app, just to make sure everything is working properly before connecting my actual app.

Here is my simple app:

var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var timeSchema = new Schema({ timestamp: String });
var Time = mongoose.model('Time', timeSchema);

mongoose.connect('mongodb://localhost/mydb');

var db = mongoose.connection;

db.on('error', console.error.bind(console, 'connection error: '));
db.once('open', function () {

  var testA = new Test({ timestamp: Date() });

});

I also tried adding db.close() to the end, but it made no difference.

This is running on a Ubuntu 14.04 VPS with:

• Node.js v0.10.3
• MongoDB 2.6.3
• Mongoose 1.4.21

Answer 1

In my opinion, you are trying to create another connection without closing the current one. So, you might want to use:

createConnection() instead of connect() .

In your case, it would look like this:

db = mongoose.createConnection('mongodb://localhost/mydb');

Answer 2

I had the same issue and found that I had the below connection in another file, which was the reason why I couldn't connect with a different database name. The below createConnection is needed:

db = mongoose.createConnection('mongodb://localhost/mydb');

What I had in another file:

db = mongoose.Connection('mongodb://localhost/mydb');

Answer 3

just use mongoose.connect('...'); once .

maybe in your root app.js or index.js file, not in every model or database related files if your are importing (including) them.

Anyways, if you still have doubt you can check it by:

var mongoose = require('mongoose'); 
var db = mongoose.connection;

db.once('connected', function() {
  console.log('mongoDB is connected');
});

Answer 4

shouldn't your

db.once('open', function () {

  var testA = new Test({ timestamp: Date() });

});

be

db.once('open', function () {

  var testA = new Time({ timestamp: Date() });

});

If "Test" is a different schema based on a different connection, that might affect i think

Answer 5

I had the same issue, but it was due to a typo:

express-sessions instead of express-session