Rails Simpleform with non-model inputs

Question

I have a normal form using simpleform. Now I'd like to add an input that does not have any corresponding field in the model, it will be processed by the controller. I tried

<%= simple_form_for @obj do |f| %>
  <%= f.input :name %>
  <%= f.input :attr, as: :string %>   <-- should just send "attr" as post data
<% end %>

but this gives a Method not found: attr_not_in_obj error. I could obviously use the standard rails helpers, but then I will miss all of the simpleform HTML around the input, and copying doesn't quite seem right.

In short: I'm looking for something like simpleform version of rails tag helpers, without any connection to a model. How do I add inputs that do not correspond to model attributes?

Answer 1

Why don't you add:

attr_accessor :attr

to your model's class definition? This way your code:

<%= f.input :attr %>

should work.

OR

If this solution isn't suitable, you can always pass some value to your input method directly:

<%= f.input :attr, input_html: {value: 'something'}  %>

Answer 2

Say you wanted to use a rails form helper but still wrap it in SimpleForm goodness? You can, by calling input with a block like so:

<%= simple_form_for @obj do |f| %>
  <%= f.input :name %>
  <%= f.input :attr do %>
    <%= text_field_tag 'attr' %>
  <% end %>
<% end %>

Answer 3

Yes, below are quote from simple_form wiki

String Input

app/inputs/fake_input.rb:

class FakeInput < SimpleForm::Inputs::StringInput
  # This method only create a basic input without reading any value from object
  def input(wrapper_options = nil)
    merged_input_options = merge_wrapper_options(input_html_options, wrapper_options)
    template.text_field_tag(attribute_name, nil, merged_input_options)
  end
end

Then you can do <%= f.input :thing, as: :fake %>