Module: H::ActiveRecordExtensions

Defined in:
lib/h/active_record_extensions.rb

Overview

Allow declaration of H conversion for Model attributes like this:

date_h :start
number_h :speed, :precision=>3

The first argumet to each declaration is the attribute name; the rest of parameters are passed to the H conversion methods

Instance Method Summary collapse

Instance Method Details

#_h(prefix, attr, *args) ⇒ Object

Generic H field declarator



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# File 'lib/h/active_record_extensions.rb', line 12

def _h(prefix, attr, *args)

  options = args.extract_options!
  actual_attr = options.delete(:attribute) || attr
  args << options unless options.empty?

  instance_variable_set :"@#{attr}_h_options", args

  class_eval do

    if table_exists? && columns.detect{|c| c.name == actual_attr.to_s}
      validates_each actual_attr do |record, attr_name, value|
        if attr_name.to_s==actual_attr.to_s && record.send(:"#{attr}_h_invalid?")
          record.errors.add :"#{attr}_h"
        end
      end
    end

    if attr != actual_attr
      define_method :"#{attr}" do
        self.send :"#{actual_attr}"
      end
      define_method :"#{attr}=" do |v|
        self.send :"#{actual_attr}=", v
      end
    end

    if method_defined?(:"#{actual_attr}=")
      define_method :"#{actual_attr}_with_#{prefix}_h=" do |v|
        send :"#{actual_attr}_without_#{prefix}_h=", v
        instance_variable_set "@#{attr}_h", nil
      end
      alias_method_chain :"#{actual_attr}=", :"#{prefix}_h"
    else
      define_method :"#{actual_attr}=" do |v|
        write_attribute actual_attr, v
        instance_variable_set "@#{attr}_h", nil
      end
    end

    # attr_h
    define_method :"#{attr}_h" do
      unless  (instance_variable_defined? "@#{attr}_h") && (h=instance_variable_get("@#{attr}_h")) && instance_variable_get("@#{attr}_h_locale")==I18n.locale
        h = H.send(:"#{prefix}_to", send(attr), *self.class.instance_variable_get(:"@#{attr}_h_options"))
        instance_variable_set "@#{attr}_h", h
        instance_variable_set "@#{attr}_h_locale", I18n.locale
      end
      h
    end

    # attr_h=(txt)
    define_method :"#{attr}_h=" do |txt|
      instance_variable_set "@#{attr}_h_invalid", false
      unless txt.blank?
        begin
           v = H.send(:"#{prefix}_from", txt, *self.class.instance_variable_get(:"@#{attr}_h_options"))
        rescue
           v = nil
        end
        instance_variable_set "@#{attr}_h_invalid", true if v.nil?
      end
      send :"#{attr}=", v
      instance_variable_set "@#{attr}_h", txt
      instance_variable_set "@#{attr}_h_locale", I18n.locale
    end

    # attr_h? (returns true if it is valid and not blank)
    define_method :"#{attr}_h?" do
      !instance_variable_get("@#{attr}_h_invalid") && send(:"#{attr}_h")
    end

    # attr_h_invalid?
    define_method :"#{attr}_h_invalid?" do
      instance_variable_get "@#{attr}_h_invalid"
    end

    # attr_h_valid?
    define_method :"#{attr}_h_valid?" do
      !instance_variable_get "@#{attr}_h_invalid"
    end

  end

end

#latitude_h(attr, *args) ⇒ Object 



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# File 'lib/h/active_record_extensions.rb', line 109

def latitude_h(attr, *args)
  options = args.extract_options!
  options[:latitude] = true
  _h prefix, attr, *(args<<options)
end

#longitude_h(attr, *args) ⇒ Object 



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# File 'lib/h/active_record_extensions.rb', line 103

def longitude_h(attr, *args)
  options = args.extract_options!
  options[:longitude] = true
  _h prefix, attr, *(args<<options)
end

#units_h(name, units, options = {}) ⇒ Object

TODO: support special suffix form of units, e.g. _m2 for m^2, for attribute names

Raises:

  • (ArgumentError) 


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# File 'lib/h/active_record_extensions.rb', line 117

def units_h(name, units, options={})
  norm_units = H::Units.normalize_units(units)
  raise ArgumentError, "invalid units #{units}" unless norm_units
  options[:units] = norm_units
  _h :magnitude, name, options
  short_name = name.to_s.chomp("_#{units}")
  class_eval do
    define_method :"#{short_name}_measure" do
      # ::Units::Measure[send(name), units.to_s]
      v = send(name)
      v && v*::Units.u(norm_units)
    end
    define_method :"#{short_name}_measure=" do |v|
      # Units::Measure[send(name), units.to_s]
      send :"#{name}=", v && v.in(norm_units)
    end
  end
end