Lightweight web services
with Sinatra and RestClient
Adam Wiggins &
Blake Mizerany
Rubyconf 2008

What for?

app lifecycle

Birth: small and beautiful

Fate: sprawling mess

web services

Rails?

Rails?
Too much.

Bare mongrel handler or
Rack app?

Bare mongrel handler or
Rack app?
Too little.

Sinatra - the classy
microframework for
Ruby

require 'rubygems'
require 'sinatra'
get '/' do
\"Hello, whirled\"
end

$ ruby hello.rb

require 'rubygems'
require 'sinatra'
require 'lib/posts'
post '/posts'
post = Post.create! params
redirect \"/posts/#{post.id}\"
do
get '/posts/:id' do
@post = Post.find(params[:id])
erb :post
end

‣Templating (erb, haml, builder)
‣Tests/specs (test/spec, rspec, test::unit)
‣Before filters
‣Helpers
‣Error handlers
‣Inline templates
‣Code reloading
‣HTTP caching (etag, last-modified)
‣Rack / inline middleware

A commitment to small

A commitment to small
Rails 87,990
Merb-core 12,417
Ramaze 11,796
Camping 1,704
Sinatra 1,576

Sinatra is a proud
Ruby citizen

examples

git-wiki
http://github.com/sr/git-wiki
355 lines
of Ruby

get '/:page' do
@page = Page.find(params[:page])
haml :show
end
__END__
@@ layout
%html
%body
%content=yield
@@ show
%h1= title
#page_content= @page.to_html

rifgraf
http://github.com/adamwiggins/rifgraf
61 lines
of Ruby

github-services
http://github.com/pjhyett/github-services
423 lines
of Ruby

scanty
http://github.com/adamwiggins/scanty
194 lines
of Ruby

client side

ActiveResource?

ActiveResource?
Too much.

Net::HTTP?

Net::HTTP?
Too little.

RestClient -
the Sinatra-inspired
microclient for Ruby

require 'rubygems'
require 'rest_client'
RestClient.get 'http://localhost:4567/posts'

require 'rubygems'
require 'rest_client'
RestClient.post 'http://localhost:4567/posts',
:author => 'Me', :title => 'First Post'

Console
$ restclient http://example.com
>> post '/resource', :value => 42
=> \"result\"

A better curl
$ restclient get http://example.com/posts > posts.xml
$ restclient post http://example.com/posts < post.xml
$ restclient put http://example.com/posts/1 < post.xml
$ restclient delete http://example.com/posts/1

Logging & replay
$ RESTCLIENT_LOG=stdout ruby myscript.rb
RestClient.get \"http://example.com/posts\"
# => 200 OK | text/html 3781 bytes
RestClient.post \"http://example.com/posts\",
\"title=First+post\"
# => 200 OK | text/html 40 bytes

examples

heroku-client
http://github.com/adamwiggins/heroku-client

couchrest
http://github.com/jchris/couchrest

principles

“lagom”

“lagom”
just the right amount

Fewer classes,
less inheritance

Controller object
mapping & routes
vs.
URLs

Controller object s !
RL
mapping & routes U e
r th
fea
vs.
n ’t
o
URLs
D

Exposed simplicity
instead of
hidden complexity

Small things,
loosely joined,
written fast
- Justin Gehtland @ Relevance

http://github.com/bmizerany/sinatra
http://rest-client.heroku.com/
http://adam.blog.heroku.com/
Adam Wiggins &
Blake Mizerany
Rubyconf 2008