Rails Magic Exposed

Rails
magic
Saturday, August 11, 12

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EPFT
NBHJD
FYJTU

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MFU`TBTL
4$*&/$&

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(PPHMF
3FTVMUT

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Framework Magic Total
php (1994) 132000 2.527E+10
java (1995) 45900 960000000
.net (2002) 4400 250000000
django (2004) 9370 44300000
rails (2005) 7040 20300000

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.BHJD3BUJP
w1)1
w+BWB
w/&5

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.BHJD3BUJP
w%KBOHP
w3BJMT

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0
1
2
3
4
php (1994) java (1995) .net (2002) django (2004) rails (2005)
0.052
0.478
0.176
2.115
3.468
Magic over Time
Frequency / 10000

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0
1
2
3
4
php (1994) java (1995) .net (2002) django (2004) rails (2005) Node
0.052
0.478
0.176
2.115
3.468
2.031
A Step Back

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0
100
200
300
400
php (1994) .net (2002) rails (2005) Meteor.js
0.052 0.478 0.176 2.115 3.468 2.031
345.810
MAGIC of Meteor

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l"OZTVGpDJFOUMZ
BEWBODFE
UFDIOPMPHZJT
JOEJTUJOHVJTIBCMF
GSPNNBHJDz
"SUIVS$$MBSL

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dynamic
finders

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id = params[:customer_id]
YourModel.find_by_customer_id id

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def method_missing(method_id, *arguments)
if match = /find_(all_by|by)_([_a-zA-Z]\w*)/.
match(method_id.to_s)
# find...
elsif match = /find_or_create_by_([_a-zA-Z]
\w*)/.
match(method_id.to_s)
# find_or_create...
else
super
end
end

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magic
columns

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created_at and updated_at
counter_caches
type

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def apply_it(items)
items.map do |item|
item.apply! if item.respond_to?
(:apply!)
end
end

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Active
Record
definition

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class User < ActiveRecord::Base
has_many :posts
has_many :comments, through: :posts
validates_presence_of :email
end

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class SuperWo
20.times {|i| puts "This is the #{i}”}
def wat!
puts "hi"
end
end
SuperWo.new.wat!
Try it out: http://rubyfiddle.com/riddles/a63dd

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auto
loading

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Dir.glob('./app/models/*').each do |file|
require file
end
require_relative 'db/setup'
require_relative 'models/page'
require_relative 'models/book'

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CFDBVTF
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%FQFOEFODJFT
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DPEFSFMPBEJOH

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# Extremely simple autoloading implementation
class Module
alias const_missing_without_autoloading const_missing
def const_missing(const)
path = “./#{name.gsub('::', '/')}/#{const}"
path.gsub!(/([a-z\d])([A-Z])/,'\1_\2')
require path.downcase
const_defined?(const) ? const_get(const) : super
rescue LoadError => error
warn(error.message)
super
end
end

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"VUP-PBEJO"DUJPO
HJUIVCKXP
DMPBLFEUZSJPO

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4PNVDINPSF

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class Foo
@@foo ||= 42
puts @@foo # 42
end
# reload...
class Foo
@@foo ||= 23
puts @@foo # 42
end

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# reload...
Object.send(:remove_const, :Foo)
class Foo
@@foo ||= 23
puts @@foo # 23
end

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custom
ruby

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NPOLFZQBUDIJOH


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numbers = (1..100).to_a
numbers.first
numbers.last
numbers.forty_two

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def forty_two
self[41]
end
"MTPLOPXOBTBDDFTTJOHUIF
SFEEJU

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class Enumerable
def standard_dev
Math.sqrt(sample_variance)
end
def sample_variance
mean = sum.to_f / size.to_f
sum{|i| (i-mean)**2} / size
end
end

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Rails Magic Exposed

Rails Magic Exposed

Jesse Wolgamott

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