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Rails Magic Exposed

Rails Magic Exposed

The Ruby that powers Rails.. LoneStarRubyConf 2012

Jesse Wolgamott

August 11, 2012
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  1. Rails
    magic
    Saturday, August 11, 12

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  2. EPFT
    NBHJD
    FYJTU
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  3. MFU`TBTL
    4$*&/$&
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  4. (PPHMF
    3FTVMUT
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  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
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  6. .BHJD3BUJP
    w1)1
    w+BWB
    w/&5
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  7. .BHJD3BUJP
    w%KBOHP
    w3BJMT
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  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
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  9. 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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  10. 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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  11. l"OZTVGpDJFOUMZ
    BEWBODFE
    UFDIOPMPHZJT
    JOEJTUJOHVJTIBCMF
    GSPNNBHJDz
    "SUIVS$$MBSL
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  12. dynamic
    finders
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  13. id = params[:customer_id]
    YourModel.find_by_customer_id id
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  14. 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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  15. magic
    columns
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  16. created_at and updated_at
    counter_caches
    type
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  17. def apply_it(items)
    items.map do |item|
    item.apply! if item.respond_to?
    (:apply!)
    end
    end
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  18. Active
    Record
    definition
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  19. class User < ActiveRecord::Base
    has_many :posts
    has_many :comments, through: :posts
    validates_presence_of :email
    end
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  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
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  21. auto
    loading
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  22. 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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  23. CFDBVTF
    "DUJWF4VQQPSU
    %FQFOEFODJFT
    VSM
    IUUQSLIJN
    DPEFSFMPBEJOH
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  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
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  25. "VUP-PBEJO"DUJPO
    HJUIVCKXP
    DMPBLFEUZSJPO
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  26. 4PNVDINPSF
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  27. class Foo
    @@foo ||= 42
    puts @@foo # 42
    end
    # reload...
    class Foo
    @@foo ||= 23
    puts @@foo # 42
    end
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  28. # reload...
    Object.send(:remove_const, :Foo)
    class Foo
    @@foo ||= 23
    puts @@foo # 23
    end
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  29. custom
    ruby
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  30. NPOLFZQBUDIJOH

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  31. numbers = (1..100).to_a
    numbers.first
    numbers.last
    numbers.forty_two
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  32. def forty_two
    self[41]
    end
    "MTPLOPXOBTBDDFTTJOHUIF
    SFEEJU
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  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
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  34. review
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  35. EZOBNJD@pOEFST
    NFUIPE@NJTTJOH
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  36. NBHJD@DPMVNOT
    SFTQPOE@UP
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  37. BS@EFpOJUJPOT
    DPNQJMF@UJNF@DPEF
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  38. BVUP@MPBEJOH
    DPOTU@NJTTJOH
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  39. NPOLFZ@QBUDIJOH
    PQFO@DMBTTFT
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  40. @@jwo
    ruby off
    rails
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