The document discusses Rack, a modular web server interface for Ruby that allows web applications and frameworks to be written as middleware stacks. It covers topics like Rack applications as middleware, common Rack middleware components, building applications with Rack and middleware, and integrating Rack middleware with frameworks like Rails.

1. Rack
Middleware

2. m/

3. NEED

4. CHOICE

5. Jon Crosby
http://joncrosby.me

6. CloudKit
http://getcloudkit.com

7. rack-contrib
http://github.com/rack/rack-contrib

9. Engine Yard Solo
“The platform for
on-demand management of your
Ruby on Rails application
in the cloud.”

10. Free during HackFest

11. Discount for Sign Up

12. CGI

13. app.cgi

14. WARNING

15. Contains Perl

16. old skool perl cgi

17. if ($cgi->param(‘action’) eq ‘all’) {
my $sql = “select * from customer”;
my $rows =
$dbh->selectall_arrayref($sql);
if (@$rows) {
print “<table border=1>” .
“<th>name</th>” .
...

18. if ($cgi->param(‘action’) eq ‘all’) {
my $sql = “select * from customer”;
my $rows =
$dbh->selectall_arrayref($sql);
if (@$rows) {
print “<table border=1>” .
“<th>name</th>” .
...

19. if ($cgi->param(‘action’) eq ‘all’) {
my $sql = “select * from customer”;
my $rows =
$dbh->selectall_arrayref($sql);
if (@$rows) {
print “<table border=1>” .
“<th>name</th>” .
...

20. if ($cgi->param(‘action’) eq ‘all’) {
my $sql = “select * from customer”;
my $rows =
$dbh->selectall_arrayref($sql);
if (@$rows) {
print “<table border=1>” .
“<th>name</th>” .
...

21. if ($cgi->param(‘action’) eq ‘all’) {
my $sql = “select * from customer”;
my $rows =
$dbh->selectall_arrayref($sql);
if (@$rows) {
print “<table border=1>” .
“<th>name</th>” .
...

22. if ($cgi->param(‘action’) eq ‘all’) {
my $sql = “select * from customer”;
my $rows =
$dbh->selectall_arrayref($sql);
if (@$rows) {
print “<table border=1>” .
“<th>name</th>” .
...

23. Monolith

24. :-(

25. Rails

26. Merb
Sinatra
Mack
Ramaze
Waves

27. Authentication

28. Single Sign-On

29. Caching

30. Authentication Example:
OpenID + OAuth

31. Install Auth Plugin(s)

32. Install Auth Plugin(s)
Generate Controllers

33. Install Auth Plugin(s)
Generate Controllers
Generate Models

34. Install Auth Plugin(s)
Generate Controllers
Generate Models
Generate Migrations

35. Install Auth Plugin(s)
Generate Controllers
Generate Models
Generate Migrations
Modify Existing Controllers

36. Install Auth Plugin(s)
Generate Controllers
Generate Models
Generate Migrations
Modify Existing Controllers
Monkey Patch Rails

37. :-(

38. The Web

40. HTTP

41. Intermediaries
HTTP

42. Intermediaries App
HTTP

43. Intermediaries App
HTTP

44. Rack

46. HTTP

47. Intermediaries
HTTP

48. Middleware
HTTP

49. Middleware App
HTTP

50. Rack is the Web

51. The Web is Rack

52. WSGI

53. SPEC

54. lambda { |env|
[
200,
{
‘Content-Type’ => ‘text/plain’,
‘Content-Length’ => ‘5’
},
[‘Hello’]
]
}

55. lambda { |env|
[
200,
{
‘Content-Type’ => ‘text/plain’,
‘Content-Length’ => ‘5’
},
[‘Hello’]
]
}

56. lambda { |env|
[
200,
{
‘Content-Type’ => ‘text/plain’,
‘Content-Length’ => ‘5’
},
[‘Hello’]
]
}

57. lambda { |env|
[
200,
{
‘Content-Type’ => ‘text/plain’,
‘Content-Length’ => ‘5’
},
[‘Hello’]
]
}

58. lambda { |env|
[
200,
{
‘Content-Type’ => ‘text/plain’,
‘Content-Length’ => ‘5’
},
[‘Hello’]
]
}

59. lambda { |env|
[
200,
{
‘Content-Type’ => ‘text/plain’,
‘Content-Length’ => ‘5’
},
[‘Hello’]
]
}

60. lambda { |env|
[
200,
{
‘Content-Type’ => ‘text/plain’,
‘Content-Length’ => ‘5’
},
[‘Hello’]
]
}

61. run lambda { |env|
[
200,
{
‘Content-Type’ => ‘text/plain’,
‘Content-Length’ => ‘5’
},
[‘Hello’]
]
}

62. config.ru

63. $ rackup config.ru

64. $ curl http://localhost:9292

65. Hello

66. class App
def call(env)
[200, {...}, [...]]
end
end

67. SPEC

68. $ rake SPEC

69. Rack::Lint

70. lambda { |env|
[
200,
{
‘Content-Type’ => ‘text/plain’,
‘Content-Length’ => ‘5’
},
[‘Hello’]
]
}

71. env

72. REQUEST_METHOD

73. env[‘REQUEST_METHOD’]

74. GET
PUT
POST
DELETE
HEAD
OPTIONS
TRACE

75. PATH_INFO

76. /items/123

77. HTTP_*

78. HTTP_ACCEPT

79. application/json

80. rack.*

81. rack.input
(the input stream)

82. #gets
#each
#read
#rewind

83. yournamespace.*

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

85. request.post?

86. request.params[‘id’]

87. request[‘HTTP_IF_MATCH’]

88. m/

89. Middleware App
HTTP

90. use MiddlewareA
use MiddlewareB
use MiddlewareC
run app

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

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

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

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

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

96. rack-contrib
http://github.com/rack/rack-contrib

97. Rack::Profiler

98. Rack::MailExceptions

99. Rack::JSONP

100. Rack::CSSHTTPRequest

101. Rack::Cache
http://github.com/rtomayko/rack-cache

102. Rack::NotFound

103. 404

104. Middleware App
HTTP

105. use MiddlewareA
use MiddlewareB
use MiddlewareC
run app

106. class App
def call(env)
[200, {...}, [...]]
end
end

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

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

109. use MiddlewareA
use MiddlewareB
use MiddlewareC
run app

110. Middleware App
HTTP

111. Middleware App
HTTP

112. Cooperative Middleware

113. URI Space

114. /*

115. /just-what-it-needs

116. CloudKit

117. Open Web
JSON
Appliance

118. expose :notes, :todos

119. expose :notes, :todos

120. contain :notes, :todos

121. use Rack::Pool::Session
use CloudKit::OAuthFilter
use CloudKit::OpenIDFilter
use CloudKit::Service, :collections => [:notes, :todos]
(run DefaultApp)

122. CloudKit::OAuthFilter
/oauth/*

123. CloudKit::OpenIDFilter
/login
/logout
/openid_complete

124. CloudKit::Service
/notes/*
/todos/*

125. ?

126. Browser
OAuth OpenID Service

127. Browser
OAuth OpenID Service

128. Browser
{...}
OAuth OpenID Service

129. Browser
OAuth OpenID Service

130. Browser
OAuth OpenID Service
{...}
Login

131. Browser
OAuth OpenID Service

132. Browser
OAuth OpenID Service

133. Browser
OAuth OpenID Service

134. Service or Desktop App
OAuth OpenID Service

135. Service or Desktop App
OAuth OpenID Service

136. Service or Desktop App
{...}
OAuth OpenID Service

137. Service or Desktop App
OAuth OpenID Service

138. Service or Desktop App
OAuth OpenID Service
{...}
Login

139. Service or Desktop App
OAuth OpenID Service

140. Service or Desktop App
OAuth OpenID Service

141. Service or Desktop App
OAuth OpenID Service

142. Service or Desktop App
OAuth OpenID Service

143. Announcing
Middleware
Presence

144. HTTP
Via

145. Via: 1.0 ricky, 1.1 ethel, 1.1 fred

146. Via: 1.0 ricky, 1.1 ethel, 1.1 fred

147. Via: 1.0 ricky, 1.1 ethel, 1.1 fred

148. Via: 1.0 ricky, 1.1 ethel, 1.1 fred

149. env[‘cloudkit.auth’] = 1

150. env[‘cloudkit.via’] << ‘cloudkit.filter.oauth’

151. env[‘cloudkit.via’] << ‘cloudkit.filter.openid’

152. env[‘cloudkit.user’] = ‘http://joncrosby.me’

153. Alternative Stacks

154. Rack::Map

155. map “/” do
run Blog::Public
end
map “/db” do
run Blog::DBAdmin
end

156. Rack::Map + Sinatra

157. require ‘sinatra/base’
module Blog
class Public < Sinatra::Base
get ‘/’ do
erb :index
end
end
end

158. require ‘sinatra/base’
module Blog
class Public < Sinatra::Base
get ‘/’ do
erb :index
end
end
end

159. require ‘sinatra/base’
module Blog
class Public < Sinatra::Base
get ‘/’ do
erb :index
end
end
end

160. require ‘sinatra’
for “apps”
/* URI space

161. require ‘sinatra/base’
MyClass < Sinatra::Base
Minimal Sinatra (routing, rendering, etc.)

162. m/

163. use MySinatraApp
run SomeOtherApp

164. Rack::Cascade

165. app1 = lambda { ... }
app2 = lambda { ... }
run Rack::Cascade.new([app1, app2])

166. Sinatra as Middleware
in Rails

167. class X < Sinatra::Base
get ‘/what’ do
‘what’
end
end
Rails::Initializer.run do |config|
config.use.middleware ‘X’
end

168. CloudKit in Rails

169. Rails::Initializer.run do |config|
config.use.middleware ‘CloudKit::Service’, :collections => [:notes, :todos]
end

170. Middleware App
HTTP

171. Middleware App
Rails
HTTP

172. Middleware App
Rails Merb
HTTP

173. Middleware App
Rails Merb *
HTTP

174. New Unit of Composition

175. m/