Session originally given at Scotch on the Rocks 2013 in Edinburgh. In this session we will explore how to build a RESTful-based application using the Sinatra framework, built on top of the Ruby programming language. We will explore installing Ruby, creating our first Sinatra application, the use of route definitions to handle multiple METHOD request types, including GET and POST requests, data persistence in a SQLite database, and how to return data in multiple formats including JSON and HTML. The RESTful approach and ease of use offered by Sinatra make it a great choice for underlying API requests which you can implement and call from any programming language of your choice.

1. == Sinatra has taken to the stage with backup from
Matt Gifford
@coldfumonkeh
www.monkehworks.com

2. “SWING WHEN YOU’RE WINNING”
AN INTRODUCTION TO
SINATRA & RUBY

3. I build stuff
and I write about building stuff too

5. WHAT WE’LL COVER:
Getting your first Sinatra project up and running
What is Sinatra?
Brief overview of a Sinatra application structure
Handling routes and formats
Deploying to Heroku *
* other options do exist

6. LIVE CODE DEMOS?
WHAT COULD POSSIBLY
GO WRONG?

7. NOT SURE IF I SHOULD BE HERE
OR WATCHING SOMEONE ELSE

8. WHAT ELSE IS ON?
Using personas in service design - continuously
Mura 6 for developers
Tuüli Aalto-Nyyssonen
Steve Withington

9. WAIT!
You’re a ColdFusion developer, aren’t you?
And this is a ColdFusion conference, isn’t it?

10. YES I AM!
(and proud of it)

15. BACK TO SINATRA

16. WHY NOT RAILS?
It is awesome though...
Rails is quite large and sometimes too much
monkeh$ rails create [stuff]
Ships with ORM, routes, test suites etc
Easily installed with RubyInstaller(.org)

17. SO WHY SINATRA?
Doesn’t force any framework
Extremely lightweight
A Domain Specific Language (DSL)
Incredibly quick and simple
(but plays well with others if you want to)

18. SO WHY SINATRA?
Runs on Rack
Can be a single file web application
Can use a number of JavaScript libraries
Can use a number of template engines
It also means I can show pictures like this...

19. MORE BOUNCE TO THE OUNCE

20. DEVELOPMENT IS QUICK!

21. “simplicityistheultimate
sophistication”
Leonardo da Vinci

22. SINATRA IS GREAT FOR
REST APIs
Small apps
useful for AJAX calls to data
Keeping your simple application simple
If it gets too big, consider using Rails (or CF)

23. HOW SIMPLE?

24. application.rb
require 'rubygems'
require 'sinatra'
get '/hi' do
"Hello World!"
end
THIS SIMPLE!

25. monkeh$ ruby application.rb
== Sinatra/1.4.2 has taken to the stage on 4567 for development with
backup from Thin
>> Thin web server (v1.5.1 codename Straight Razor)
>> Maximum connections set to 1024
>> Listening on localhost:4567, CTRL+C to stop
RUNNING THE APP

26. IMPRESSIVE, RIGHT?

28. require 'rubygems'
require 'sinatra'
get '/hi' do
"Hello World!"
end
WHAT’S GOING ON?

29. require 'rubygems'
require 'sinatra'
get '/hi' do
"Hello World!"
end
WHAT’S GOING ON?
<--- Ruby package manager

30. require 'rubygems'
require 'sinatra'
get '/hi' do
"Hello World!"
end
WHAT’S GOING ON?
<--- Ruby package manager
<--- Sinatra gem

31. require 'rubygems'
require 'sinatra'
get '/hi' do
"Hello World!"
end
WHAT’S GOING ON?
<--- Ruby package manager
<--- Sinatra gem
<--- GET request

32. require 'rubygems'
require 'sinatra'
get '/hi' do
"Hello World!"
end
WHAT’S GOING ON?
<--- Ruby package manager
<--- Sinatra gem
<--- GET request
<--- response

34. require 'rubygems'
require 'sinatra'
get '/hi' do
"Hello World!"
end
NO RETURN?
<--- the return is implied

35. get '/hi' do
"Hello World!"
end
ROUTE BLOCKS
<--- this is a route block
A route block is an HTTP method paired with
a URL-matching pattern.
Processing takes place within the block (database calls etc)
and the result is sent to the browser.

36. REST
Uniform Interface
Client-Server
Cacheable
HATEOAS
Layered System
Stateless
Hypermedia as the Engine
of Application State

37. SINATRA CAN DO THAT!
Caching
Multiple Routes
Content Types
All HTTP verbs supported
Good times!

38. REST
get '/' do
.. show something ..
end
post '/' do
.. create something ..
end
put '/' do
.. replace something ..
end
patch '/' do
.. modify something ..
end
delete '/' do
.. annihilate something ..
end
options '/' do
.. appease something ..
end
link '/' do
.. affiliate something ..
end
unlink '/' do
.. separate something ..
end

39. ROUTES
get '/' do
"Home page"
end
get '/hello' do
"Hello!"
end
get '/hello/:name' do
"Hello! #{params[:name]}"
end

40. ROUTES
get '/say/*/to/*' do
# matches /say/hello/to/world
params[:splat] # => ["hello", "world"]
end
get '/download/*.*' do
# matches /download/path/to/file.xml
params[:splat] # => ["hello", "world"]
end
get '/download*.*' do |path, ext|
# matches /download/path/to/file.xml
[path, ext] # => ["path/to/file", "xml"]
end

41. ROUTES
get %r{/hello/([w]+)} do
"Hello, #{params[:captures].first}!"
end
get '/posts.?:format?' do
# matches "/posts " and any extension
# eg "GET /posts.xml" or "GET /posts.json"
end

42. ROUTES
get '/hi', :agent => /Mozilla/(d.d)sw?/ do
"You’re using Mozilla version #{params[:agent][0]}"
end
get '/hi' do
# matches all non-Mozilla browsers
end

43. GETTING STARTED
Install Ruby
Bathe in Ruby deliciousness
Create your application file
Install the Sinatra gem

44. http://rvm.io

45. monkeh$ rvm install 1.9.3
monkeh$ rvm use --default 1.9.3
monkeh$ rvm use jruby
http://cheat.errtheblog.com/s/rvm

46. GEMS?

47. GEMS?
RubyGem distributes libraries
apt-get
Similar in functionality to:
A library is self-contained in a gem
portage
yum

48. GEMS!
monkeh$ gem install [gem]
monkeh$ gem uninstall [gem]
monkeh$ gem list
monkeh$ gem fetch [gem]

49. BACK TO SINATRA

50. INSTALLING
monkeh$ gem install sinatra
monkeh$ gem install shotgun

51. DEMO TIME

52. DIRECTORY STRUCTURE
| -- application.rb

53. SINGLE PAGE APP
application.rb
require 'rubygems'
require 'sinatra'
get '/' do
html = '<form method="post">'
html += '<input type="text" placeholder="Add the URL to shorten here..."'
html += 'name="url" id="url" />'
html += '<input type="submit" value="Shorten!" />'
html += '</form>'
html
end
post '/' do
html = '<p>Thanks for submitting a URL.</p>'
html
end

54. VIEWS
Multiple template languages available, including:
builder
erb
haml
sass
liquid
markdown

55. USING VIEWS
application.rb
require 'rubygems'
require 'sinatra'
get '/' do
erb :index
end
post '/' do
erb :index
end
views/index.erb
<form method="post">
<input type="text" placeholder="Add the URL to shorten here..."
name="url" id="url" />
<input type="submit" value="Shorten!" />
</form>

56. DIRECTORY STRUCTURE
| -- application.rb
| -- views
-- index.erb

57. LAYOUTS
A template that calls yield to draw in view data
Can also be managed through route blocks
A template called “layout” will be used by default

58. USING LAYOUTS
views/layout.erb
<!DOCTYPE html>
<html>
<head>
<title>Sinatra Intro</title>
</head>
<body>
<%= yield %>
</body>
</html>
views/index.erb
<form method="post">
<input type="text" placeholder="Add the URL to shorten here..."
name="url" id="url" />
<input type="submit" value="Shorten!" />
</form>

59. USING LAYOUTS
views/layout.erb
<!DOCTYPE html>
<html>
<head>
<title>Sinatra Intro</title>
</head>
<body>
<%= yield %>
</body>
</html>
views/index.erb
<form method="post">
<input type="text" placeholder="Add the URL to shorten here..."
name="url" id="url" />
<input type="submit" value="Shorten!" />
</form>

60. DIRECTORY STRUCTURE
| -- application.rb
| -- views
-- index.erb
-- layout.erb

61. STATIC CONTENT
All static content is stored within a new directory
“public”
This is primarily for
Javascript
CSS
Images

62. DIRECTORY STRUCTURE
| -- application.rb
| -- views
-- index.erb
-- layout.erb
| -- public
-- css
-- style.css
-- javascript

63. STATIC CONTENT?

64. HELPERS
application.rb
helpers do
def random_string(length
)
rand(36**length).to_s(36)
end
def get_site_url(short_url
)
'http://' + request.host + '/' + short_url
end
def generate_short_url(long_url
@shortcode = random_string 5
get_site_url(@shortcode)
end
end

65. FILTERS
application.rb
# This code will run before each event
# Very useful for debugging parameters sent via the console
before do
puts '[Params]'
p params
end
# This code will run after each event
after do
puts response.status
end

66. CONFIGURATION
Will run once at startup
Can be used to
set application-wide values and options
perform certain processes per environment

67. CONFIGURATION
configure do
# All environments
end
configure :production do
# Production only
end
configure :development, :test do
# Development and Test
end

68. CONFIGURATION
configure do
set :variable, 'foo'
# multiple options
set :variable1 => 'Hello', :variable2 => 'world'
# same as set :option, true
enable :option
# same as set :option, false
disable :option
end
get '/' do
settings.variable? # => true
settings.variable # => 'foo'
end

69. CONFIGURATION
configure :development do
# very useful for debugging parameters sent via the console
before do
puts '[Params]'
p params
end
end

71. DATAMAPPER
Same API can talk to multiple datastores
Uses adapters to achieve this
sqlite
mysql
postgresql

72. DATAMAPPER
Define mappings in your model
Comes bundled with tools to assist with
migration
constraints
transactions
timestamps
validations
...and more!

73. INCLUDE THE LIBRARY
application.rb
require 'rubygems'
require 'sinatra'
require 'data_mapper' <--- DataMapper gem

74. CONFIGURATION
application.rb
configure do
# load models
$LOAD_PATH.unshift("#{File.dirname(__FILE__)}/lib"
)
Dir.glob("#{File.dirname(__FILE__)}/lib/*.rb") { |lib|
require File.basename(lib, '.*')
}
DataMapper::setup(:default, "sqlite3://#{Dir.pwd}/myDatabase.db")
DataMapper.finalize
DataMapper.auto_upgrade!
end

75. MODEL
lib/short_url.rb
class ShortURL
include DataMapper::Resource
property :short_url, String, key: true, unique_index: true, required: true
property :url, Text, required: true
property :created_at, DateTime
property :updated_at, DateTime
end

76. SAVING DATA
application.rb
def generate_short_url(long_url
@shortcode = random_string 5
su = ShortURL.first_or_create(
{ :url => long_url },
{
:short_url => @shortcode,
:created_at => Time.now,
:updated_at => Time.now
})
get_site_url(su.short_url)
end

77. GETTING DATA
application.rb
# root page
get '/' do
# get the current object of all links stored
@urls = ShortURL.all;
erb :index
end
views/index.erb
<h1>Serving <%= @urls.count %> links</h1>

78. GETTING DATA
application.rb
get '/:short_url' do
@URLData = ShortURL.get(params[:short_url])
end

79. DIRECTORY STRUCTURE
| -- application.rb
| -- views
-- index.erb
-- layout.erb
| -- public
-- css
-- style.css
-- javascript
| -- lib
-- shorturl.rb

80. CONTENT TYPES
Return content in a number of formats, including
JSON
XML
HTML
monkeh$ gem install json
May need some more gems to process

81. CONTENT TYPE
application.rb
get '/' do
if params[:url] and not params[:url].empty?
@shortURL = generate_short_url(params[:url])
content_type :json
{
:original_url => params[:url],
:short_url => @shortURL
}.to_json
else
# get the current count of all links stored
@urls = ShortURL.all;
erb :index
end
end

82. TESTING

83. WHY?

84. BECAUSE!

85. TESTING GEMS
monkeh$ gem install rspec
monkeh$ gem install rack
monkeh$ gem install rack/test

86. TESTING WITH RSPEC
spec/application_rspec.rb
require_relative '../application.rb'
require 'rack/test'
set :environment, :test
def app
Sinatra::Application
end
describe 'URL Shortening Service' do
include Rack::Test::Methods
it "should load the home page" do
get '/'
last_response.should be_ok
end
end

87. AUTO TESTING
monkeh$ gem install ZenTest

88. AUTO TESTING NOTIFICATIONS
monkeh$ gem install autotest-growl
monkeh$ gem install autotest-fsevent

89. DIRECTORY STRUCTURE
| -- application.rb
| -- views
-- index.erb
-- layout.erb
| -- public
-- css
-- style.css
-- javascript
| -- lib
-- shorturl.rb
| -- spec
-- application_rspec.rb

91. http://gembundler.com/v1.3/gemfile.html
monkeh$ gem install bundler

92. Gemfile
source 'https://rubygems.org'
gem 'sinatra'
gem 'json'
gem 'dm-core'
gem 'dm-migrations'
gem 'dm-postgres-adapter'
group :development do
gem 'shotgun'
end
group :production do
gem 'thin'
end
GEMFILE

93. monkeh$ bundle install
monkeh$ git add Gemfile Gemfile.lock
BUNDLE TIME

94. CONFIG.RU
Many reasons to use, but especially if..
you are deploying to a different Rack handler
Heroku
Passenger

95. config.ru
require './application.rb'
run Sinatra::Application
CONFIG.RU

96. Procfile
web: bundle exec thin -R config.ru start -p $PORT -e $RACK_ENV
PROCFILE

97. HEROKU DEPLOYMENT
monkeh$ git init
monkeh$ git add .
monkeh$ git commit -m "Initial commit"

98. monkeh$ heroku create urlshrinkapp
Creating urlshrinkapp... done, stack is cedar
http://urlshrinkapp.herokuapp.com/ | git@heroku.com:urlshrinkapp.git
Git remote heroku added
HEROKU

99. monkeh$ git push heroku master
Total 19 (delta 2), reused 0 (delta 0)
-----> Ruby/Rack app detected
-----> Installing dependencies using Bundler version 1.3.2
Running: bundle install --without development:test --path vendor/bundle --binstubs
vendor/bundle/bin --deployment
Fetching gem metadata from https://rubygems.org/.........
Fetching gem metadata from https://rubygems.org/..
Installing data_objects (0.10.13)
Installing dm-core (1.2.0)
Installing dm-do-adapter (1.2.0)
Installing dm-migrations (1.2.0)
Installing do_postgres (0.10.13)
Installing dm-postgres-adapter (1.2.0)
Installing eventmachine (1.0.3)
Installing json (1.8.0)
Installing rack (1.5.2)
Installing rack-protection (1.5.0)
Installing tilt (1.4.1)
Installing sinatra (1.4.2)
Using bundler (1.3.2)
Your bundle is complete! It was installed into ./vendor/bundle
Cleaning up the bundler cache.
-----> Discovering process types
Procfile declares types -> web
Default types for Ruby/Rack -> console, rake
-----> Compiled slug size: 3.0MB
-----> Launching... done, v4
http://urlshrinkapp.herokuapp.com deployed to Heroku
To git@heroku.com:urlshrinkapp.git
* [new branch] master -> master
HEROKU

100. monkeh$ heroku addons:add heroku-postgresql:dev
Adding heroku-postgresql:dev on urlshrinkapp... done, v5 (free)
Attached as HEROKU_POSTGRESQL_BROWN_URL
Database has been created and is available
heroku pg:promote HEROKU_POSTGRESQL_BROWN_URL
Promoting HEROKU_POSTGRESQL_BROWN_URL to DATABASE_URL... done
HEROKU

101. monkeh$ heroku run console
Running `console` attached to terminal... up, run.2858
irb(main):001:0> require './application.rb'
=> true
irb(main):002:0> DataMapper.auto_upgrade!
=> #<DataMapper::DescendantSet:0x000000035aacf0
@descendants=#<DataMapper::SubjectSet:0x000000035aaca0
@entries=#<DataMapper::OrderedSet:0x000000035aac78
@cache=#<DataMapper::SubjectSet::NameCache:0x000000035aac50
@cache={"ShortURL"=>0}>, @entries=[ShortURL]>>>
irb(main):003:0> exit
HEROKU

102. monkeh$ heroku open
Opening urlshrinkapp... done
HEROKU

103. DIRECTORY STRUCTURE
| -- application.rb
| -- views
-- index.erb
-- layout.erb
| -- public
-- css
-- style.css
-- javascript
| -- Gemfile
| -- lib
| -- spec
| -- config.ru
| -- Procfile

104. BACK TO SINATRA

106. USEFUL LINKS
http://sinatrarb.com
https://github.com/sinatra/sinatra
http://rvm.io

108. == Sinatra has ended his set (crowd applauds)