My introduction talk to Rack at ArrrrCamp (http://arrrrcamp.be)

1. SOMETHING SOMETHING RACK

2. OH, HI!
• Joren
• Openminds
• @joren
• tech.jorendegroof.be

3. OVERVIEW
• Rack what?
• Why Rack?
• How do you use it?
• Middleware

4. RACK WHAT?

5. RACK WHAT?
Rack is a specification (and implementation) of a minimal
abstract Ruby API that models HTTP

6. WHY RACK?
• Stop writing handlers for every webserver
• Keep the request and response simple

7. WHY RACK?
Supported web servers

8. WHY RACK?
Supported web frameworks

9. HOW DO YOU USE IT?
How to call it?
lambda { |env|
[
200,
{
‘Content-Type’ => ‘text/plain’,
‘Content-Lenght’ => ‘5’,
},
[‘Hello’]
]
}

10. HOW DO YOU USE IT?

11. HOW DO YOU USE IT?
How to call it?
lambda { |env|
[
200,
{
‘Content-Type’ => ‘text/plain’,
‘Content-Lenght’ => ‘5’,
},
[‘Hello’]
]
}

12. HOW DO YOU USE IT?
How to call it?
lambda { |env|
[
200,
{
‘Content-Type’ => ‘text/plain’,
‘Content-Lenght’ => ‘5’,
},
[‘Hello’]
]
}

13. HOW DO YOU USE IT?
How to call it?
lambda { |env|
[
200,
{
‘Content-Type’ => ‘text/plain’,
‘Content-Lenght’ => ‘5’,
},
[‘Hello’]
]
}

14. HOW DO YOU USE IT?
How to call it?
lambda { |env|
[
200,
{
‘Content-Type’ => ‘text/plain’,
‘Content-Lenght’ => ‘5’,
},
[‘Hello’]
]
}

15. HOW DO YOU USE IT?
How to call it?
lambda { |env|
[
200,
{
‘Content-Type’ => ‘text/plain’,
‘Content-Lenght’ => ‘5’,
},
[‘Hello’]
]
}

16. HOW DO YOU USE IT?
How to call it?
lambda { |env|
[
200,
{
‘Content-Type’ => ‘text/plain’,
‘Content-Lenght’ => ‘5’,
},
[‘Hello’]
]
}

17. HOW DO YOU USE IT?
How to call it?
run lambda { |env|
[
200,
{
‘Content-Type’ => ‘text/plain’,
‘Content-Lenght’ => ‘5’,
},
[‘Hello’]
]
}

18. config.ru

19. $ rackup config.ru

20. $ curl http://localhost:9292

21. Hello

22. HOW DO YOU USE IT?
class HelloWorld
def call(env)
[200, {"Content-Type" => "text/plain"}, ["Hello World!"]]
end
end

23. env

24. REQUEST_METHOD

25. env[‘REQUEST_METHOD’]

26. GET
PUT
POST
DELETE
HEAD
OPTIONS
TRACE

27. PATH_INFO

28. /items/123

29. HTTP_*

30. HTTP_ACCEPT

31. rack.*

32. yournamespace.*

33. request = Rack::Request.new(env)

34. request.post?

35. HOW DO YOU USE IT?
Example

36. MIDDLEWARE
Middleware App
HTTP

37. use Middleware A
use Middleware B
use Middleware C
run app

38. class GoSlower
def initialize(app)
@app = app
end
def call(env)
sleep(1)
@app.call(env)
end
end

39. class GoSlower
def initialize(app)
@app = app
end
def call(env)
sleep(1)
@app.call(env)
end
end

40. class GoSlower
def initialize(app)
@app = app
end
def call(env)
sleep(1)
@app.call(env)
end
end

41. class GoSlower
def initialize(app)
@app = app
end
def call(env)
sleep(1)
@app.call(env)
end
end

42. IN YOUR RAILS APP
#environment.rb
config.middleware.use “Rack::GoSlower”
config.middleware.use “Rack::Cache”,
:verbose => true,
:metastrore => ‘file:/path/to/dir’,
:entitystore => 'memcached://localhost:11211/body'

43. EXAMPLES

44. RACK::HONEYPOT
http://github.com/sunlightlabs/rack-honeypot

45. RACK::CACHE
http://github.com/rtomayko/rack-cache

46. WARDEN + DEVISE
http://github.com/hassox/warden
http://github.com/plataformatec/devise

47. RACK::DEBUG
http://github.com/ddollar/rack-debug

48. RACK::GEOIP
http://github.com/b/rack-geoip

49. RACK::GOOGLE-ANALYTICS
http://github.com/leehambley/rack-google-analytics

50. RACK::REWRITE
http://github.com/jtrupiano/rack-rewrite

51. RACK::MOBILE-DETECT
http://github.com/talison/rack-mobile-detect

52. RACK::CONTRIB
http://github.com/rack/rack-contrib

53. QUESTIONS?