Passing variable from view to controller Rails 4

Question

I want to pass one variable which is introduced by the user in the front-end. I dont use any model (i dont need it, because im working with JSON data all in memory). I have looked many tutoriasl but almost all of them are focused on filling out a form. My application does not have any form nor tables. Any idea? Thank you.

{<div class="module1">
    <p>Mein Lastprofil berechnen</p>
    <div class="boxed">
      Jahreshausverbrauch (kWh)
      <%= text_field_tag "input", nil, placeholder: "3500" %>
      <%= button_to "Senden", root_path, :method => :get %>
     </div> 
</div>}

I want to save/pass the variable introduced when clickling the button.

Answer 1

By having a text field you implicitly already have a form.

Make it explicit by wrapping the text field and button:

<%= form_tag root_path, method: :get do %>
  <%= text_field_tag :input, placeholder: "3500" %>
  <%= submit_tag "Senden" %>
<% end %>

Then you can access the value as params[:input] in the controller.