When to use Node? Lessons learned

When to use Node.js?
Lessons learned
Coen Stevens - Amsterdam Node Meetup 2012

@beatlevic BeatleTech.com

Saturday, March 31, 12

Why not Node.js
• We never heard of Node.js at the time (2009)
and were experienced in Ruby
• Lots of server-side computations / statistics /
map-reduce (blocking the node event-loop)
• Typical dashboard (view on a database)
• Not that many concurrent users
• No need for open connections
Yes, I would use Ruby again

Pivot: Penny auctions

• Swoopo and Bigdeal (real goods)
• Newcope a platform for pay-per-bid
auction games for virtual goods


Flash game platform

http://newcope-heyzap.heroku.com/home

• The Broth: BarnBuddy
• Facebook app
• Similar to Farmville
• Over 1 million active users per month


Challenge

• Build iframe / facebook app solution
• Have the auctions as realtime as possible
• Long polling (later websockets) vs pulling
• Lots of users with open connections
• Scalable


Languages considered

• Ruby (Eventmachine, no Goliath yet)
• JRuby
• Scala (Twitter had just moved from ruby)
• Erlang
• Javascript Node.js


Node.js experiences
• Functional programming

• Javascript for both client and server

• Very good performance (30k users the ﬁrst day)

• Node v0.1.25 and no packet manager (npm)

• MySQL with DBSlayer (later Mongodb)

• Nginx to serve static ﬁles

• Easy to setup/deploy on EC2 (upstart deamon)

• Everything async (annoying to test)

• Fun!
Yes, I would use Node.js again

Auction.prototype.startTimer = function() {
var self = this;
if (this.timer) clearTimeout(this.timer);
  this.emit("start");
  this.timer = setTimeout(function() {
    self.emit("end");
  }, self.timeLeft() * 1000);
}

Auction.prototype.bid = function(user) {
    var self = this;
    return function (callback, errback) {
     if (user.bid_count > 0 && self.status() === "running") {
        user.bid_count -= 1;
        dbUser.updateUser(user.id, {'bid_count': user.bid_count})(function(result){
          if (self.timeLeft() < self.bidTimeDelta) {
            self.setTime(me.bidTimeDelta);
          };
          self.price += self.bidPriceDelta;
          var bid = { user: user, ts: new Date() }
          self.bids.push(bid);
          self.bidCount++;
          callback(self);
        }, function(error) {
          user.bid_count += 1;
          errback("Could not update new bid count");
        })
     } else {
        errback("Bid could not be placed");
     }
  };
}


// continuation style
var bid = function(user) {
return function (callback, errback) {
if (!user) return errback("No user")
callback(user)
}
}

bid(user)(function(result){
console.log(result)
}, function(error) {
console.log(error)
})


// promise style
var bid = function(user) {
var promise = new Promise()
if (!user) {
promise.emitError("No user")
} else {
promise.emitSuccess(user)
}
return promise
}

var promise = bid(user)
promise.addErrback(function(error){
console.log(error)
})
promise.addCallback(function(result) {
console.log(result)
})


• // callback style
var bid = function(user, callback) {
if (!user) return callback("No user")
callback(null, user);
}

bid(user, function(err, result){
if (err) console.log(err)
console.log(result)
})


• Bottlenose is the smartest social media
dashboard.
• Helping you manage the information overload
on streams like twitter and Facebook
• Bottlenose analyzes and ﬁlters messages using
NLP and clustering techniques
• Beta launched December 2011
http://bottlenose.com

Why Node.js?
• It began (2009) with NLP in javascript, run
it both on the client and the server
• Fat client and lean server
• Realtime stream updates
• Lots of users (with open connections)
• Alternatives?
Yes, I would use Node.js again

Summary:
When to use Node?
• When you are building more of an app than a
website and require lots of open connections to
the server
• When you want your users to get data in
realtime (chat, streams)
• When you have to serve lots of requests that do
not take too many cpu cycles (blocking the loop)
• When you like to work with Javascript all the way

Thanks!

@beatlevic

When to use Node? Lessons learned

Empfohlen

Empfohlen

Weitere ähnliche Inhalte

Andere mochten auch

Andere mochten auch (20)

Ähnlich wie When to use Node? Lessons learned

Ähnlich wie When to use Node? Lessons learned (20)

Kürzlich hochgeladen

Kürzlich hochgeladen (20)

When to use Node? Lessons learned