Rack
Middleware

\\m/

NEED

CHOICE

Jon Crosby
http://joncrosby.me

CloudKit
http://getcloudkit.com

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

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

Free during HackFest

Discount for Sign Up

CGI

app.cgi

WARNING

Contains Perl

old skool perl cgi

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>” .
...

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>” .
...

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>” .
...

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>” .
...

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>” .
...

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>” .
...

Monolith

:-(

Rails

Merb
Sinatra
Mack
Ramaze
Waves

Authentication

Single Sign-On

Caching

Authentication Example:
OpenID + OAuth

Install Auth Plugin(s)

Install Auth Plugin(s)
Generate Controllers

Install Auth Plugin(s)
Generate Controllers
Generate Models

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

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

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

:-(

The Web

HTTP

Intermediaries
HTTP

Intermediaries App
HTTP

Intermediaries App
HTTP

Rack

HTTP

Intermediaries
HTTP

Middleware
HTTP

Middleware App
HTTP

Rack is the Web

The Web is Rack

WSGI

SPEC

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

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

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

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

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

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

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

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

config.ru

$ rackup config.ru

$ curl http://localhost:9292

Hello

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

SPEC

$ rake SPEC

Rack::Lint

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

env

REQUEST_METHOD

env[‘REQUEST_METHOD’]

GET
PUT
POST
DELETE
HEAD
OPTIONS
TRACE

PATH_INFO

/items/123

HTTP_*

HTTP_ACCEPT

application/json

rack.*

rack.input
(the input stream)

#gets
#each
#read
#rewind

yournamespace.*

request = Rack::Request.new(env)

request.post?

request.params[‘id’]

request[‘HTTP_IF_MATCH’]

\\m/

Middleware App
HTTP

use MiddlewareA
use MiddlewareB
use MiddlewareC
run app

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

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

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

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

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

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

Rack::Profiler

Rack::MailExceptions

Rack::JSONP

Rack::CSSHTTPRequest

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

Rack::NotFound

404

Middleware App
HTTP

use MiddlewareA
use MiddlewareB
use MiddlewareC
run app

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

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

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

use MiddlewareA
use MiddlewareB
use MiddlewareC
run app

Middleware App
HTTP

Middleware App
HTTP

Cooperative Middleware

URI Space

/*

/just-what-it-needs

CloudKit

Open Web
JSON
Appliance

expose :notes, :todos

expose :notes, :todos

contain :notes, :todos

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

CloudKit::OAuthFilter
/oauth/*

CloudKit::OpenIDFilter
/login
/logout
/openid_complete

CloudKit::Service
/notes/*
/todos/*

?

Browser
OAuth OpenID Service

Browser
OAuth OpenID Service

Browser
{...}
OAuth OpenID Service

Browser
OAuth OpenID Service

Browser
OAuth OpenID Service
{...}
Login

Browser
OAuth OpenID Service

Browser
OAuth OpenID Service

Browser
OAuth OpenID Service

Service or Desktop App
OAuth OpenID Service

Service or Desktop App
OAuth OpenID Service

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

Service or Desktop App
OAuth OpenID Service

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

Service or Desktop App
OAuth OpenID Service

Service or Desktop App
OAuth OpenID Service

Service or Desktop App
OAuth OpenID Service

Service or Desktop App
OAuth OpenID Service

Announcing
Middleware
Presence

HTTP
Via

Via: 1.0 ricky, 1.1 ethel, 1.1 fred

Via: 1.0 ricky, 1.1 ethel, 1.1 fred

Via: 1.0 ricky, 1.1 ethel, 1.1 fred

Via: 1.0 ricky, 1.1 ethel, 1.1 fred

env[‘cloudkit.auth’] = 1

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

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

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

Alternative Stacks

Rack::Map

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

Rack::Map + Sinatra

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

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

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

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

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

\\m/

use MySinatraApp
run SomeOtherApp

Rack::Cascade

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

Sinatra as Middleware
in Rails

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

CloudKit in Rails

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

Middleware App
HTTP

Middleware App
Rails
HTTP

Middleware App
Rails Merb
HTTP

Middleware App
Rails Merb *
HTTP

New Unit of Composition

\\m/