Setting up singleton connection with node.js and mongo

Question

Previously I used mongodb with php and to query a database I was using a singleton. This way I instantiated connection only once and then reused it:

class MD         


        

Answer 1

I upvoted Scampbell's solution, but his solution should be enhanced imho. Currently it is not async, both InitDB and GetDB() should have a callback attribute.

So whenever you change a database to connect, it fails, because it returns before it would have a chance to connect to the database. The bug is not present if you connect always to the same database (so return Database.db is always successful)

This is my bugfix/enhancement to his solution:

Database.InitDB = function (callback) {

  if (_curDB === null || _curDB === undefined ||_curDB === '') {
    _curDB = _dbName;
  }

  Database.db = new Db(_curDB,
                   new Server(_dbHost, _dbPort, {}, {}),
                              { safe: false, auto_reconnect: true });

  Database.db.open(function (err, db) {
    if (err) {
        console.log(err);
    } else {
        console.log('connected to database :: ' + _curDB);
        if (callback !== undefined) {callback(db);}
    }
  });
};

The same goes to the rest of his functions. Also note the if (callback part, it allows Database.InitDB() to be called without argument in the beginning of app.js/server.js whatever is your main file.

((I should have written my reply as a comment to Scampbell's solution, but I don't have enough reputation to do so. Also kudos to him for his solution, was a nice starting point))