And the Greatest of These Is ... Space

And the Greatest of These Is...
Rack Support
Ben Scoﬁeld – Viget Labs

Saturday, July 25, 2009

Application Templates

Nested Attribute Assignment
ﬂickr: angelrays


ActiveRecord::Base#touch
ﬂickr: jjjohn


DB Seeding
ﬂickr: richardthomas78


Rack


def call(env)
[
status, # 200
headers, # {"Content-Type" => "text/html"}
body # ["<html>...</html>"]
]
end


request
application
response

request
middleware

application
middleware

response

Rack::Proﬁler
ﬂickr: oberazzi


Rack::MailExceptions
ﬂickr: warmnfuzzy


Rack::Cache
ﬂickr: timpatterson


rack::cascade

Rack::Cascade
ﬂickr: _at


Rack in Rails


> rake middleware
use Rack::Lock
use ActionDispatch::ShowExceptions, [true]
use ActionDispatch::Callbacks, [true]
use ActionDispatch::Rescue, [#<Method: ...>]
use ActionDispatch::Session::CookieStore, [{...}]
use ActionDispatch::ParamsParser
use Rack::MethodOverride
use Rack::Head
use ActiveRecord::ConnectionAdapters::ConnectionManagement
use ActiveRecord::QueryCache
run ActionController::Dispatcher.new


app = Rack::Builder.new {
use Rails::Rack::LogTailer unless options[:detach]
use Rails::Rack::Debugger if options[:debugger]

map "/" do
use Rails::Rack::Static
run ActionController::Dispatcher.new
end
}.to_app


Rails::Initializer.run do |config|
config.middleware.insert_before Rack::Head, Ben::Asplode
config.middleware.swap Rack::Lock, Ben::Lock
config.middleware.use Rack::MailExceptions
end


# in config/initializers/middlewares.rb
Rails::Initializer.run do |config|
config.middleware.insert_before Rack::Head, Ben::Asplode
ActionController::Dispatcher.middleware.insert_before 'Rack::Head', Appender
config.middleware.swap Rack::Lock, Ben::Lock
ActionController::Dispatcher.middleware.delete 'Rack::Lock'
config.middleware.use Rack::MailExceptions
ActionController::Dispatcher.middleware.use Prepender
end


Metal
ﬂickr: lrargerich


http://www.kiwibean.com/


PLEASE testing metalBY
EXPAND:
STAND
THIS IS ONLY A TEST


METAL
Sinatra


Cool Tricks


Rack::Bug
ﬂickr: catdancing


requires
</body>

Progressive Caching

class SessionsController < ApplicationController
def create
# ...
session[:personalize] = {
:logged_in => true,
:quicklist => current_user.quicklist.episode_ids,
:subscriptions => current_user.subscription_ids
}
end
end


class ChannelsController < ApplicationController
caches_page :show

def show
@channel = Channel.find(params[:id])
end
end


$(document).ready(function() {
$.getJSON('/personalize', function(data) {

// identify quicklisted episodes
$.each(data['quicklist'], function() {
$('#episode_'+this).addClass('listed');
});

// switch navigation
if (data['logged_in']) {
$('#logged_in_nav').show();
}

// etc.
});
});


class Personalizer
def self.call(env)
if env["PATH_INFO"] =~ /^/personalize/
[
200,
{"Content-Type" => "application/javascript"},
env['rack.session'][:personalize].to_json
]
else
[404, {"Content-Type" => "text/html"}, ["Not Found"]]
end
end
end


class PullList
def self.call(env)
if env["PATH_INFO"] =~ /^/pulls/
[
200,
[Pull.by_user(user).for_date(date).map {|i| i.item_id}.to_json]]
else
end
end
end

standard 0.617

progressive 0.039 0.096


class PullList
def self.call(env)
if env["PATH_INFO"] =~ /^/pulls/
[
200,
[env['rack.session'][:pulls].to_json]
]
else
end
end
end

standard 0.617

progressive 0.039 0.096

progressive v2 0.043 0.023


Rack::Embiggener

class Embiggener < Test::Unit::TestCase
def test_embiggener_should_embiggen_known_url
body = ["Hello! I'm at http://bit.ly/31IqMl"]
assert_equal ["Hello! I'm at http://cnn.com"],
Rack:: Embiggener.embiggen_urls(body)
end

def test_embiggener_should_embiggen_multiple_urls
body = [
"Hello! I'm at http://bit.ly/31IqMl",
"And I'm at http://bit.ly/31IqMl"
]

assert_equal [
"Hello! I'm at http://cnn.com",
"And I'm at http://cnn.com"
], Rack::Embiggener.embiggen_urls(body)
end
end


module Rack
class Embiggener
def self.embiggen_urls(original_body, login, key)
new_body = []
original_body.each { |line|
bits = line.scan(/(http://bit.ly/(.{6}))/)

new_body << bits.uniq.inject(line) do |body, bit|
original_bit, hash = *bit
new_url = embiggened_url(hash, login, key)

body.gsub(original_bit, new_url) if new_url
end
}
new_body
end

# ...
end
end


module Rack
class Embiggener
# ...

def self.embiggened_url(hash, login, key)
url = [
"http://api.bit.ly/expand?version=2.0.1",
"shortUrl=http://bit.ly/#{hash}", "login=#{login}", "apiKey=#{key}"
].join('&')
response = JSON.parse(Net::HTTP.get_response(URI.parse(url)))

if response['statusCode'] = 'OK'
embiggened_url = response['results'][hash]['longUrl']
end
end

# ...
end
end


module Rack
class Embiggener
# ...

attr_accessor :api_login, :api_key

def initialize(app, api_login, api_key)
@app = app
@api_login = api_login
@api_key = api_key
end

def call(env)
status, headers, body = @app.call(env)
headers.delete('Content-Length')
response = Rack::Response.new(
Rack::Embiggener.embiggen_urls(body, api_login, api_hash),
status,
headers
)
response.finish
return response.to_a
end
end
end


module Rack
class Embiggener
def self.embiggen_urls(original_body, login, key)
new_body = []
original_body.each { |line|
bits = line.scan(/bit:(w+?)/)

new_body << bits.uniq.inject(line) do |body, bit|
hash = bit.first
original_bit = "bit:#{hash}"
new_url = embiggened_url(hash, login, key)

body.gsub(original_bit, new_url) if new_url
end
}
new_body

end

# ...
end
end


module Rack
class Embiggener
# ...

def self.embiggened_url(hash, login, key)
url = [
"http://api.bit.ly/expand?version=2.0.1",
"hash=#{hash}", "login=#{login}", "apiKey=#{key}"
].join('&')
response = JSON.parse(Net::HTTP.get_response(URI.parse(url)))

if response['statusCode'] = 'OK'
embiggened_url = response['results'][hash]['longUrl']
end
end

# ...
end
end


WARNING exception handling


formerly:

WARNING exception handling


Rack::Hoptoad*
* unoﬃcial; thoughtbot is not responsible for this middleware; do not taunt rack::hoptoad; pregnant women should consult their doctors before using rack::hoptoad


ActionController::Dispatcher.middleware.delete ActionDispatch::ShowExceptions
ActionController::Dispatcher.middleware.delete ActionDispatch::Rescue

ActionController::Dispatcher.middleware.use 'Rack::Hoptoad', 'my-api-key'
ActionController::Dispatcher.middleware.use 'Rack::ShowExceptions'


module Rack
class Hoptoad
def initialize(app, api_key)
@app = app
@api_key = api_key
end

def call(env)
@app.call(env)
rescue => exception
notify_hoptoad(exception, env)
raise exception
end

# ...
end
end


module Rack
class Hoptoad
def notify_hoptoad(exception, env)
headers = {
'Content-type' => 'application/x-yaml',
'Accept' => 'text/xml, application/xml'
}
url = URI.parse("http://hoptoadapp.com/notices")

http = Net::HTTP.new(url.host, url.port)

data = {
:api_key => @api_key,
:error_message => "#{exception.class}: #{exception}",
:backtrace => exception.backtrace,
:request => {},
:session => env['rack.session'],
:environment => env
}

response = http.post(
url.path,
stringify_keys(:notice => data).to_yaml,
headers
)

if response != Net::HTTPSuccess
# Hoptoad post failed
end
end
end
end


Intangibles


Thank You
ben scofield - @bscofield - http://www.viget.com/extend - http://www.speakerrate.com/bscofield

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