Rails Magic Exposed

Transcript

1. 1.

   Rails magic Saturday, August 11, 12

2. 2.

   EPFT
   NBHJD FYJTU Saturday, August 11, 12

3. 3.

   MFU`T
   BTL
   4$*&/$& Saturday, August 11, 12

4. 4.

   (PPHMF
   3FTVMUT Saturday, August 11, 12

5. 5.

   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 Saturday, August 11, 12
6. 6.

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    Saturday, August 11, 12

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    Saturday, August 11, 12

8. 8.

   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 Saturday, August 11, 12
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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 Saturday, August 11, 12
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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 Saturday, August 11, 12
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12. 12.

    dynamic finders Saturday, August 11, 12

13. 13.

    id = params[:customer_id] YourModel.find_by_customer_id id Saturday, August 11, 12

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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 Saturday, August 11, 12
15. 15.

    magic columns Saturday, August 11, 12

16. 16.

    created_at and updated_at counter_caches type Saturday, August 11, 12

17. 17.

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

    end Saturday, August 11, 12
18. 18.

    Active Record definition Saturday, August 11, 12

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    class User < ActiveRecord::Base has_many :posts has_many :comments, through: :posts

    validates_presence_of :email end Saturday, August 11, 12
20. 20.

    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 Saturday, August 11, 12
21. 21.

    auto loading Saturday, August 11, 12

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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' Saturday, August 11, 12
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    CFDBVTF
    "DUJWF4VQQPSU %FQFOEFODJFT VSM IUUQSLIJN DPEFSFMPBEJOH Saturday, August 11, 12

24. 24.

    # 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 Saturday, August 11, 12
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    KXP DMPBLFEUZSJPO Saturday, August 11, 12

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    4P
    NVDI
    NPSF Saturday, August 11, 12

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    class Foo @@foo ||= 42 puts @@foo # 42 end

    # reload... class Foo @@foo ||= 23 puts @@foo # 42 end Saturday, August 11, 12
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    # reload... Object.send(:remove_const, :Foo) class Foo @@foo ||= 23 puts

    @@foo # 23 end Saturday, August 11, 12
29. 29.

    custom ruby Saturday, August 11, 12

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    NPOLFZ
    QBUDIJOH Saturday, August 11, 12

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    numbers = (1..100).to_a numbers.first numbers.last numbers.forty_two Saturday, August 11, 12

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    def forty_two self[41] end "MTP
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    SFEEJU Saturday, August 11, 12

33. 33.

    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 Saturday, August 11, 12
34. 34.

    review Saturday, August 11, 12

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    EZOBNJD@pOEFST
    NFUIPE@NJTTJOH Saturday, August 11, 12

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    NBHJD@DPMVNOT
    SFTQPOE@UP Saturday, August 11, 12

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    BS@EFpOJUJPOT
    DPNQJMF@UJNF@DPEF Saturday, August 11, 12

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    BVUP@MPBEJOH
    DPOTU@NJTTJOH Saturday, August 11, 12

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    NPOLFZ@QBUDIJOH
    PQFO@DMBTTFT Saturday, August 11, 12

40. 40.

    @@jwo ruby off rails Saturday, August 11, 12