Swing when you’re winning - an introduction to Ruby and Sinatra

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.

Transcript

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. “simplicity is the ultimate 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)\s\w?/ 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)