CODEWITHSUNDEEP
ruby-on-railsruby
barelyknown
barelyknown

Reputation: 5560

How do I dynamically add setter methods in ruby that Rails will see as attributes for mass assignment?

I have a model with a handful of related date fields.

def started_at_date=(value)
  @started_at_date = value
end

def completed_at_date=(value)
  @completed_at_date = value
end

...

The getters are handled via method_missing and that works great.

def method_missing(method, *args, &block)
  if method =~ /^local_(.+)$/
    local_time_for_event($1)
  elsif method =~ /^((.+)_at)_date$/
    self.send :date, $1
  elsif method =~ /^((.+)_at)_time$/
    self.send :time, $1
  else
    super
  end
end

def date(type)
  return self.instance_variable_get("@#{type.to_s}_date") if self.instance_variable_get("@#{type.to_s}_date")
  if self.send type.to_sym
    self.send(type.to_sym).in_time_zone(eventable.time_zone).to_date.to_s
  end
end

...

I'd like to add the setters dynamically, but I'm not sure how to do so in a way that avoids ActiveRecord::UnknownAttributeErrors.

Upvotes: 0

Views: 2192

Answers (3)

jdoe
jdoe

Reputation: 15771

If I understand you correctly, try:

  # in SomeModel
  def self.new_setter(setter_name, &block)
      define_method("#{setter_name}=", &block)
      attr_accessible setter_name
  end

Usage:

 SomeModel.new_setter(:blah) {|val| self.id = val }

 SomeModel.new(blah: 5) # => SomeModel's instance with id=5
 # or
 @sm = SomeModel.new
 @sm.blah = 5

Upvotes: 1

coreyward
coreyward

Reputation: 80041

I think this would work:

def method_missing(method, *args, &block)
  super unless method =~ /_date$/
  class_eval { attr_accessor method }
  super
end

Upvotes: 3

Pasted
Pasted

Reputation: 864

Could you just use virtual attributes?

Class Whatever < ApplicationModel

  attr_accessor :started_at_date
  attr_accessor :completed_at_date

  #if you want to include these attributes in mass-assignment
  attr_accessible :started_at_date
  attr_accessible :completed_at_date


end

When you need to access the attributes later instead of calling @started_at_date you would call self.started_at_date, etc.

Upvotes: 1

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