rails loop through required attributes in a form

Question

In my Ruby on Rails project I have a module called Node. In that module I have different classes such as playback , if , hangup , etc. They are created using Node::Playback , for example. Each of these classes has different required attributes. Node has the following declaration as part of it:

class Node < ActiveRecord::Base
 ...Other irrelevant code
 class << self
  attr_accessor :required_attrs
  attr_accessor :optional_attrs

  def acts_as_node required_attrs=[], optional_attrs=[]
    @required_attrs = required_attrs
    @optional_attrs = optional_attrs
    (required_attrs + optional_attrs).each do |attr|
      attr_accessor attr
    end

    required_attrs.each do |attr|
      validates attr, presence: true
    end
  end
end
end

As an example, playback , declared as class Node::Playback , has the following in its model:

class Node::Playback < Node
  acts_as_node [ :body, :author ]
end

In my view for creating a playback node, I want to loop through all the required attributes, ie [:body, :author] . It is important that I do this dynamically and not hard code it because Node has many different classes, not just playback.

= form_for([@callflow, @new_node]) do |f|
  h2 | Fill All Required Attributes Below
  - @node_type.required_attrs.each do |ra|
    .form-group
      = f.label ra
      = f.text_area(ra)
  h2 | Fill Optional Attributes Below
  - @node_type.optional_attrs.each do |oa|
    .form-group
      = f.label oa
      /= f.text_area oa
  .form-group
    = f.submit class: 'btn btn-success'

In the above code, @node_type.required_attrs returned [:body, :author] when I byebugged it in the controller. I also checked that the elements in the array are of class 'Symbol'. @new_node was created using Node.new(callflow: @callflow) and @node_type was created using "Node::Playback".constantize

f.label ra would put the correct label in my view(ie. correctly put a label in my form when I comment out the line below it). However, when I did f.text_area ra or f.text_area(ra) it would say undefined method body' for #<Node:0x00007f271df3bc18>

Any suggestions?

Answer 1

@new_node appears to be an instance of Node . I don't see a definition for @node_type , but based on the error, I'm assuming it's a Node::Playback instance.

The Node instance won't have the required attributes of Node::Playback , so when you ask the form renderer f (which represents a Node instance) to render the required attribute ra of a Node::Playback instance you're getting the error.

Try this instead:

= form_for([@callflow, @new_node]) do |f|
  h2 | Fill All Required Attributes Below
  - f.object.required_attrs.each do |ra|
    .form-group
      = f.label ra
      = f.text_area(ra)

Then make sure that the @new_node instance is of the appropriate type (eg Node::Playback )