Welcome To Ruby On Rails

Welcome to Ruby on Rails

Kevin Lawver | June 25, 2009http://uplaya.com

Friday, June 26, 2009

Hi, I’m Kevin Lawver

Chief Architect at Music Intelligence Solutions - http://uplaya.com (it’s a Rails app)

Worked at AOL for 13 years, launched two public Rails apps. Spent a lot of time on AOLserver using Tcl and Tomcat writing JSP’s.

Just launched http://ficly.com with a friend as an “art project” (also on Rails)

What is Ruby?

Object-oriented

Interpreted

Expressive

“principle of least surprise”

“They are focusing on machines. But in fact we need to focus on humans, on how humans care about doing programming or operating the application of the machines. We are the masters. They are the slaves.” -- Matz

Everything’s an Object

This confuses everyone at the beginning. Everything in Ruby is an object.

There are no primitives, they’re all objects!

For example, you can do things like 15.times or 24.hours.from_now

It makes for compact, human-readable code.

What’s Rails?

Web framework written by DHH in 2003 at 37signals for Basecamp

Takes most of the “grunt work” out of building web apps

“Optimized for programmer happiness and sustainable productivity”

Who Uses It?37signals: Basecamp, Backpack, Ta-da Lists, etc

Twitter

Yellowpages.com

iLike (and Jango too)

Hulu (and Vimeo)

And thousands of other sites...

Why Use It?

Convention over configuration

Quick prototyping - can turn into the “real” project without starting over

Convention makes it easy to share code and quick to get started

Because it’s Ruby, you can turn it into anything you want

Rails’ Components

ActiveRecord

ActionController

ActionView

ActiveResource

ActiveSupport

ActiveRecord

The “M” in MVC

Rails’ crown jewel - a great database abstraction layer.

Makes it really easy to work with databases.

In Rails, your models should contain 95% of your business logic.

ActionController

The “C” in MVC

Handles routing requests and processing them.

In Rails, your controllers should be light

ActionView

The “V” in MVC

Where you do all your HTML and most of your XML.

I’ve used a dozen different template systems over the years and Rails’ is by far my favorite.

ActiveResource

Rails’ built-in support for RESTful API’s

Makes it easy to do REST the right way

Provides a lot of the wrappers, error cases and connection code you need to do RESTy stuff.

ActiveSupport

All the extensions to Ruby’s base classes

A lot of “glue” for JSON and other things that don’t belong in the other pieces

My Favorite Things About Rails

I can go from idea to “real” in hours instead of days.

It’s easy to refactor single pieces without affecting the whole app.

Plugins solve major problems without requiring rewrites (see cache money)

Community is helpful and responsive

Getting Started

I don’t use Windows, so you’re on your own there.

If you use a Mac and have Leopard, you already have Ruby and Rails.

Linux? There are dozens of tutorials for your distro, don’t worry.

The 20 Minute Blog

Sorry if you’re following along online, I’m heading to terminal now.

What we’ll be doing

Create a new Rails app for our awesome new blog

Build a model, controller and view for it

Look at some helpful gems and plugins

Make a feed for it

Talk a little about ActiveRecord callbacks

What we won’t be doing

Talking about tests (they’re important, but I hate writing them)

Spending a lot of time on configuration

What we’ll be doing (redux)

Create a new Rails app for our awesome new blog

Build a model, controller and view for it

Look at some helpful gems and plugins

Make a feed for it

Talk a little about ActiveRecord callbacks

Wasn’t that fun? now let’s talk about myths!

Some Rails Myths

“Rails doesn’t scale”

“Ruby (or Rails) is too slow”

“Rails locks you into doing it its way”

“X is better!” (where X = “Python”, “PHP”, “Java” or whatever)

Myth: “Rails Doesn’t Scale”

Maybe 3 Years Ago

Back then, we had to use FastCGI or Mongrel.

Now, though, we can use Phusion Passenger! It’s an Apache plugin that does a great job of managing Rails instances.

And Ruby Enterprise Edition makes Rails use less memory and run faster.

Brilliant!

Live-World Examplesuplaya.com handles tens of thousands of requests a day on a couple tiny Amazon EC2 instances (we could do everything on one with room to spare, but I like having backup).

ficly.com handles tens of thousands of requests a day on a single quad core server - that’s not even breaking a sweat yet.

hundreds of other sites handle a lot more traffic with minimal hardware or fuss.

You will probably never need to

scale.

But if you do...

The Data Layer

Your database will fall over before your web server does.

Optimize your connection, queries and indexes

Protect your database by using memcached between your front-end and database

Cache, Cache, Cache

memcached is your friend

Disk-based caches don’t work once you grow beyond one server - same thing for in-memory caches

Caching hides a world of programming sins, and saves you from having to do ugly things like sharding.

You Don’t Want...

to be both read-heavy and write-heavy

to have complex queries that can’t be cached

to have to do multiple selects on a single request

The Most Important Thing

is to launch! If you never launch, you’ll never have users. If you never have users, you’ll never have to scale.

Rails helps me get from nothing to launch faster than anything else I’ve tried.

It helps me get from launch to scale pretty quickly as well.

Typical Rails Stack

Apache w/ Passenger

memcached * yMySQL Master

WriterSlave Readers * z

Myth: “Ruby is too slow!”

But, it’s fast enough for the

For all of my sites...

No request takes longer than 1 second

On uPlaya, the average time per request is 217 milliseconds.

On Ficly, the average time per request is 165 milliseconds.

That’s more than fast enough for the web.

The “Slow” in Rails

Is the same slow anywhere else:

Database

The Internet

CPU, Disk or RAM

Those factors affect everyone,

not just Rails

Performance GotchasDatabase indexes. If you’re selecting or sorting by a column, it should have an index! You won’t know you need them until it’s too late.

Compression and Caching. Make sure you set up mod_deflate and set up reasonable expire times for static assets. It helps a LOT with perceived performance!

Selects. Tune your cache so you can average zero reads per page view, if possible.

Myth: Rails makes you do things its way

It doesn’t makeyou.

It encouragesyou.

Plus, Rails’ way probably is the

right way.

And if not, you can write a

plugin to make it do it your way.

For example, things I don’t like...

Rails’ built-in javascript stuff. I prefer jQuery, and RJS gives me a headache

Routes, especially the name convention for generated routes

But...

I happily use jQuery with Rails. I just don’t use the javascript helpers. And now there’s a plugin that let’s you use the helpers with jQuery. Win!

I can live with the the route naming convention. It makes sense, even if I don’t like it. I could easily write a plugin to reverse route names if I strenuously objected.

Myth: “X is better!”

Your point is?

Religious battles over

programming languages are

stupid.

Use what makes you happy and productive.

Why You Shouldn’t Use Rails

You have a legacy database that you can’t change. You could make it work with Rails, but it probably wouldn’t be much fun.

You’re happy with what you’ve got and hate learning.

You don’t ever talk to a database. Rails pretty much is ActiveRecord, so if you’re not using it, you might be better off with something else.

Ruby-based Alternatives

Camping: http://wiki.github.com/why/camping/

Sinatra: http://sinatra.rubyforge.org/

webby: http://webby.rubyforge.org/

Halcyon: http://halcyon.rubyforge.org

gem sources -a http://gems.github.com

Pagination: mislav-will_paginate

Faster URLs: pauldix-typhoeus

Twitterness: hayesdavis-grackle

Faster XML or HTML parsing: nokogiri or hpricot

Rails Plugins FTW!cache-money: a write-through cache for ActiveRecord.

attachment_fu: great for handling uploads and storing them on s3

smurf: automatic minification of javascript and css

openid_enabled: just what it says, painless OpenId.

To Wrap Up

Rails is fun to work with. I’m way more productive now than I was before, happier too.

Rails is more flexible than it gets credit for.

It’s great for teams because it encourages good behavior

And now, a word from our sponsor:

We’re looking for interns! Development, design or office management, we want ‘em! So if you know any, please have them e-mail jobs@uplaya.com!

We’re also looking for a front-end developer and a Flash AS3 developer. If you know any of those, please have them send their resume to jobs@uplaya.com too!

And if you know anyone in a band

Please send them to...

uplaya.com!

Questions?

Thank you!

Contact Info

kevin@uplaya.com

@kplawver on twitter

http://uplaya.com

http://lawver.net

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