Rack: HTTP 200 OK

An introduction to HTTP and Ruby's Rack library.

Given to the RIT Society of Software Engineers in 2010. http://sse.se.rit.edu/

Transcript

1. rack: HTTP 200 OK nick quaranto
2. me 5th year SE/CS bills fan ruby fanatic gemcutter lead
3. this talk is about internets rubies unicorns
4. HTTP
5. history
6. tim berners-lee
7. the first web server
9. http 1.0: rfc1945 http 1.1: rfc2616
11. the protocol request => response stateless
12. requests: Request line, such as GET /images/logo.gif HTTP/1.1 Headers, such as Accept-Language: en An empty line An optional message body
13. verbs HEAD GET POST PUT DELETE etc...
14. response code (200, 404, 500) more headers body
15. codes
16. 200s
17. 200s 200 OK 201 Created 202 Accepted
18. 300s
19. 300s 301 Moved Permanently 302 Found 304 Not Modified
20. 400s
21. 400s 401 Unauthorized 403 Forbidden 404 Not Found 418 I'm a teapot
22. RFC 2324 HTCPCP/1.0 1 April 1998 In practice, most automated coffee pots cannot currently provide additions. 2.3.2 418 I'm a teapot Any attempt to brew coffee with a teapot should result in the error code "418 I'm a teapot". The resulting entity body MAY be short and stout.
23. 500s
24. 500s 500 Internal Server Error 502 Bad Gateway 503 Service Unavailable
25. headers Date: Wed, 09 Dec 2009 15:25:13 GMT Content-Type: text/html X-Served-By: Apache Content-Encoding: gzip
26. let's do this
27. tip of the iceberg sessions security caching proxies
28. rack
29. history servers and webapps can't talk to each other CGI (C, Perl, PHP, etc) WSGI (Python) Ruby....?
30. servers apache (passenger) mongrel thin unicorn and more...
31. frameworks rails merb sinatra and more...
33. what's in a response? code headers body
34. what's in a response? code => Integer headers => Hash body => String
35. [200, {'Content-Type' => 'text/plain'}, 'Hello!']
36. let's make a rack app
37. class Awesome def call(env) [200, {'Content-Type' => 'text/plain'}, 'AWESOME.'] end end
38. lambda { |env| [200, {'Content-Type' => 'text/plain'}, 'AWESOME.'] }
39. env what? a Hash of environment variables PATH_INFO QUERY_STRING REMOTE_ADDR REQUEST_URI
40. rackup comes with the rack gem starts a rack app looks at config.ru needs an endpoint
41. require 'rack/lobster' run Rack::Lobster.new
42. ,.---._ ,,,, / `, \\\\ / '\_ ; |||| /\/``-.__\;' ::::/\/_ {{`-.__.-'(`(^^(^^^(^ 9 `.=========' {{{{{{ { ( ( ( ( (-----:= {{.-'~~'-.(,(,,(,,,(__6_.'=========. ::::\/\ |||| \/\ ,-'/, //// \ `` _/ ; '''' \ ` .' `---'
43. # config.ru class Awesome def call(env) [200, {'Content-Type' => 'text/plain'}, 'AWESOME.'] end end run Awesome
44. middleware think of pancakes stack them up! instead of run, use mmm, pancakes
46. class PassThrough def initialize(app) @app = app end def call(env) @app.call(env) end end
47. I::Rack def call(env) if env["PATH_INFO"] == "/WMD" [ 404, {"Content-Type" => "text/plain"}, "Not found" ] else @app.call(env) end end
48. Rack::Obama def call(env) if env["CONTENT_TYPE"] == "nobel-prize/peace" [ 202, {"Content-Type" => "nobel-prize/peace"}, "Accepted" ] else @app.call(env) end end
49. Rack::Kanye
50. def call(env) request_uri = env['REQUEST_URI'] if request_uri =~ /kanye=true/ env['REQUEST_URI'].gsub!("&kanye=true","") @app.call(env) else req = "http://#{env['HTTP_HOST']}#{request_uri}&kanye=true" [ 302, {'Location' => "http://kanyelicious.appspot.com/" + req }, 'Redirecting...' ] end end
51. useful middlewares Rack::Cache Rack::Bug Rack::Maintenance too many to list !SLIDE @@@ text $ rake middleware use Rack::Lock use ActionController::Failsafe use ActionController::Session::CookieStore, # <Proc:0xb6f807d0@(eval):8> use ActionController::ParamsParser use Rack::MethodOverride use Rack::Head use ActiveRecord::ConnectionAdapters::ConnectionM use ActiveRecord::QueryCache run ActionController::Dispatcher.new @@@
52. real world use:
53. maintenance mode problem: serve gems when running long migrations rack promotes decoupled architectures enable when tmp/maintenanance.txt exists
54. normally # config.ru run Rack::Adapter::Rails.new(:environment => ENV['RAILS_ENV'])
55. require File.join('vendor', 'bundler_gems', 'environment') require File.join('config', 'environment') use Rack::Static, :urls => ["/index.html", "/favicon.ico", "/images", "/stylesheets"], :root => "public/maintenance" use Hostess use Rack::Maintenance, :file => File.join('public', 'maintenance', 'index.html') run Sinatra::Application
56. the point(s)
57. http is everywhere
58. use Rack
59. thanks