mongotransaction.js

// For node-mongodb-native (npm install mongodb)
var mongodb = require('mongodb');

var MongoTransaction = function(db) {
  this.db = db;
  this.queue = [];
  this.running = false;
  this.failureFn = function(){};
}

MongoTransaction.prototype = {
  openDB: function() {
    this.queue.push(function(next) {
      this.db.open(function(err, client) {
        if (err) { throw err; }
        next(client);
      });
    });
    return this;
  },

  insert: function(collectionName, data) {
    this.queue.push(function(next, client) {
      var collection = new mongodb.Collection(client, collectionName);
      data.updatedAt = new Date();
      collection.insert(data, function(err, objects) {
        if (err) {
          console.warn(err.message);
        }
        if (err && err.message.indexOf('E11000 ') !== -1) {
          console.error('this _id was already inserted in the database');
        }
        next(client);
      });
    });
    return this;
  },

  removeAll: function(collectionName) {
    this.queue.push(function(next, client) {
      var collection = new mongodb.Collection(client, collectionName);
      collection.remove(function(err, result) {
        if (err) {
          console.warn(err.message);
        }
        next(client);
      });
    });
    return this;
  },

  find: function(collectionName, condition, option) {
    this.queue.push(function(next, client) {
      var collection = new mongodb.Collection(client, collectionName);
      collection.find(condition, option, function(err, cursor) {
        if (err) {
          throw err;
        }
        next(cursor);
      });
    });
    return this;
  },

  exec: function(fn) {
    var _this = this;
    this.queue.push(function(next, cx) {
      fn.call(_this, next, cx);
    });
    return this;
  },

  openCursor: function(method) {
    this.queue.push(function(next, cursor) {
      if (method) {
        cursor[method](function(err, arr) {
          if (err) {
            throw err;
          }
          next({
            arr: arr, 
            db: cursor.db
          });
        });
      } else {
        next({
          cursor: cursor, 
          db: cursor.db
        });
      }
    });
    return this;
  },

  closeDB: function() {
    this.queue.push(function(next) {
      this.db.close();
      next();
    });
    return this;
  },

  onFailure: function(fn) {
    this.failureFn = fn;
    return this;
  },

  start: function() {
    if (!this.running) {
      this.running = true;
      this._start();
    }
  },

  _start: function(p) {
    var fn = this.queue.shift();
    if (fn) {
      var _this = this;
      var callback = function(res) {
        _this._start(res);
      }
      try {
        fn.call(this, callback, p);
      } catch(e) {
        this.running = false;
        if (this.db && this.db.state == 'connected') {
          this.db.close();
        }
        this.failureFn(e);
      }
    } else {
      this.running = false;
    }
  }
}
exports.Transaction = MongoTransaction;

mongotransaction_test.js

var mongodb = require('mongodb');
var Transaction = require('./mongotransaction').Transaction;
var db;


var case1 = {};

/**
 *
 */
case1.setUp = function(next) {
  var server = new mongodb.Server("127.0.0.1", 27017, {});
  db = new mongodb.Db('test', server, {});
  next();
}

/**
 *
 */
case1["Open and close DB"] = function(test) {
  new Transaction(db)
    .exec(function(next) {
      test.equal(this.db.state, "notConnected");
      next();
    })
    .openDB()
    .exec(function(next, client) {
      test.equal(this.db.state, "connected");
      next(client);
    })
    .closeDB()
    .exec(function(next, client) {
      test.equal(this.db.state, "notConnected");
      test.done();
    })
    .start();
};

/**
 *
 */
case1["Insert document"] = function(test) {
  var colName = 'unitTest';

  new Transaction(db)
    .openDB()
    .removeAll(colName)
    .insert(colName, {name: 'Insert test'})
    .find(colName, {}, {})
    .openCursor('toArray')
    .exec(function(next, cx) {
      test.equal(cx.arr.length, 1);
      test.equal(cx.arr[0].name, 'Insert test');
      test.done();
      next(cx.db);
    })
    .closeDB()
    .start();
}

case1["Handle Exception and close DB"] = function(test) {
  var colName = 'unitTest';

  new Transaction(db)
    .openDB()
    .removeAll(colName)
    .find(colName, {}, {})
    .openCursor('toArray')
    .exec(function(next, cx) {
      // Throws exception (cx.arr[10] is undefined)
      cx.arr[10].toString();
      test.ok(false, "This line shoud not be called");
    })
    .onFailure(function(e) {
      test.equal(this.db.state, 'notConnected');
      test.ok(true, "handle failure succeeded");
      test.done();
    })
    .start();
}

module.exports = require('nodeunit').testCase(case1);