Question

I am new to both Node.js and MongoDB, but I intend to create a very basic real time geolocation based web app. Here is my attempt at figuring out how Node and MongoDB interact:

var mongo = require('mongodb');

var db = new mongo.Db('test', new mongo.Server('localhost',22892, {}), {});

db.open(function(){});

db.collection('docs', function(err,collection){
    doc = {"foo":"bar"};
    collection.insert(doc, function(){});
});

I can see that this is connecting:

Thu Apr 14 15:24:12 [initandlisten] connection accepted from 127.0.0.1:46968 #26
Thu Apr 14 15:24:12 [conn26] building new index on { _id: 1 } for test.docs
Thu Apr 14 15:24:12 [conn26] done for 0 records 0secs

But it’s not inserting any documents into the database. Can anyone tell me what I am doing wrong?

Thanks

Answer 1

db.open(function(err, client){
    client.createCollection("docs", function(err, col) {
         client.collection("docs", function(err, col) {
             for (var i = 0; i < 100; i++) {
                 col.insert({c:i}, function() {});
             }
         });
    });
});

You forgot to do everything in your open callback. This is important otherwise your code runs before your connection to the database is open. You have to do everything asynchronous. It’s also best to create the collection if it does not exist.

Take a look at the extensive examples at the github page

Now this looks like callback spaghetti so we use flowcontrol like Step to make it pretty.

Step(
    function() {
        db.open(this);
    },
    function(err, client) {
        client.createCollection("docs", this);
    },
    function(err, col) {
        for (var i = 0; i < 100; i++) {
            col.insert({c:i});
        }
    }
);