Module: Platanus::ModelShims::ClassMethods

Defined in:
lib/platanus/model_shims.rb

Instance Method Summary collapse

Instance Method Details

#shims_for(_name, _options = {}) ⇒ Object

Generate shims for a given model.

  • class_name: if given, the shims model class name, if no the camelize _name is used.

  • prefix: prefix to be used in shims, defaults to ”.

  • proxy: an attribute to be proxied, if given then getter shims will return the proxie’s

value for the property if not set.

  • sync_to: same as proxy, but also call proxy_will_change! if any shimmed attribute is set.



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# File 'lib/platanus/model_shims.rb', line 32

def shims_for(_name, _options={})

  # TODO: detect if _name is an association and use the association's settings.
  # TODO: overriding options.

  name = _name.to_s
  model = _options.fetch(:class_name, name.camelize).constantize
  cache_var = _options.fetch :into, "@_#{name}_shims"
  prefix = _options[:prefix]
  sync_to = _options[:sync_to]
  sync_to_fk = self.reflections[sync_to.to_sym].foreign_key if sync_to
  proxy = _options.fetch :proxy, sync_to

  model.accessible_attributes.each do |attr_name|

    full_attr_name = if prefix then "#{prefix}#{attr_name}" else attr_name end

    if method_defined? full_attr_name
      Rails.logger.warn "shims_for: overriding getter for #{full_attr_name} in #{self.to_s}"
    end

    if method_defined? "#{full_attr_name}="
      Rails.logger.warn "shims_for: overriding setter for #{full_attr_name} in #{self.to_s}"
    end

    # override getter
    define_method full_attr_name do
      cache = instance_variable_get(cache_var)
      return cache[attr_name] if cache and cache.has_key? attr_name
      if proxy
        child = send(proxy)
        if child then child.send(attr_name) else nil end
      end
    end

    # override setter
    define_method "#{full_attr_name}=" do |value|
      cache = instance_variable_get(cache_var)
      cache = instance_variable_set(cache_var, {}) if cache.nil?
      cache[attr_name] = value
      send "#{sync_to_fk}_will_change!" if sync_to # force update if synced
    end
    attr_accessible full_attr_name

  end

  define_method("#{name}_shims_changed?") do
    not instance_variable_get(cache_var).nil?
  end

  define_method("#{name}_shims_flush") do
    cache = instance_variable_get(cache_var)
    instance_variable_set(cache_var, nil)
    return cache
  end
end