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0a12a5f816
Don't use this:
scope :red, where(color: 'red')
default_scope where(color: 'red')
Use this:
scope :red, -> { where(color: 'red') }
default_scope { where(color: 'red') }
The former has numerous issues. It is a common newbie gotcha to do
the following:
scope :recent, where(published_at: Time.now - 2.weeks)
Or a more subtle variant:
scope :recent, -> { where(published_at: Time.now - 2.weeks) }
scope :recent_red, recent.where(color: 'red')
Eager scopes are also very complex to implement within Active
Record, and there are still bugs. For example, the following does
not do what you expect:
scope :remove_conditions, except(:where)
where(...).remove_conditions # => still has conditions
41 lines
1 KiB
Ruby
41 lines
1 KiB
Ruby
class Bulb < ActiveRecord::Base
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default_scope { where(:name => 'defaulty') }
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belongs_to :car
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attr_protected :car_id, :frickinawesome
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attr_reader :scope_after_initialize, :attributes_after_initialize
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after_initialize :record_scope_after_initialize
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def record_scope_after_initialize
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@scope_after_initialize = self.class.scoped
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end
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after_initialize :record_attributes_after_initialize
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def record_attributes_after_initialize
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@attributes_after_initialize = attributes.dup
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end
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def color=(color)
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self[:color] = color.upcase + "!"
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end
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def self.new(attributes = {}, options = {}, &block)
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bulb_type = (attributes || {}).delete(:bulb_type)
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if options && options[:as] == :admin && bulb_type.present?
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bulb_class = "#{bulb_type.to_s.camelize}Bulb".constantize
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bulb_class.new(attributes, options, &block)
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else
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super
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end
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end
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end
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class CustomBulb < Bulb
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after_initialize :set_awesomeness
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def set_awesomeness
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self.frickinawesome = true if name == 'Dude'
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end
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end
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