gistfile1.rb

# Admin CodesController

class Admin::CodesController < AdminController
  def index
  end
  def show
    @code = Code.find(params[:id])
  end
  def edit
    @code = Code.find(params[:id])
  end
  def new
    @code = Code.new
  end
  def update
    @code = Code.update_attributes(params[:code])
  end
  def preview
    # stuff I'm returning as a preview
  end
end


# routes.rb

namespace :admin do

    resources :codes, :path => "/code/"
    post "codes/preview", to: "codes#preview" #preview route 404s on "edit" view, works fine on "new"

end



# The following code is in both the "new" and "edit" views for admin/codes_controller

<script>

$(function(){
	var form = $("#code-form form");
    $(".code-preview").click(function (){
        $.ajax({
          type: "POST",
          url: "<%= admin_codes_preview_path %>",
          headers: { 'X-CSRF-Token': $('meta[name="csrf-token"]').attr('content') },
          data: $(form).serialize(),
          dataType: "html",
          success: function(data){
		        $(".result").html(data);
              }
        });
    });
});

</script>


<div id="code-form">
<%= form_for @code do |f| %>
	<%= f.text_field :name %>
	<%= f.text_area :body_input %>
	<%= f.submit %>
<% end %>
</div>

<div class="result">Here's the result:</div>
<button class="code-preview">Preview</button>


# routes

new_admin_user_session GET    /admin_users/sign_in(.:format)          devise/sessions#new
        admin_user_session POST   /admin_users/sign_in(.:format)          devise/sessions#create
destroy_admin_user_session DELETE /admin_users/sign_out(.:format)         devise/sessions#destroy
       admin_user_password POST   /admin_users/password(.:format)         devise/passwords#create
   new_admin_user_password GET    /admin_users/password/new(.:format)     devise/passwords#new
  edit_admin_user_password GET    /admin_users/password/edit(.:format)    devise/passwords#edit
                           PATCH  /admin_users/password(.:format)         devise/passwords#update
                           PUT    /admin_users/password(.:format)         devise/passwords#update
                     admin GET    /admin(.:format)                        admin/admin_users#index
               admin_users GET    /admin/users(.:format)                  admin/admin_users#index
                           POST   /admin/users(.:format)                  admin/admin_users#create
            new_admin_user GET    /admin/users/new(.:format)              admin/admin_users#new
           edit_admin_user GET    /admin/users/:id/edit(.:format)         admin/admin_users#edit
                admin_user GET    /admin/users/:id(.:format)              admin/admin_users#show
                           PATCH  /admin/users/:id(.:format)              admin/admin_users#update
                           PUT    /admin/users/:id(.:format)              admin/admin_users#update
                           DELETE /admin/users/:id(.:format)              admin/admin_users#destroy
               admin_codes GET    /admin/code(.:format)                   admin/codes#index
                           POST   /admin/code(.:format)                   admin/codes#create
            new_admin_code GET    /admin/code/new(.:format)               admin/codes#new
           edit_admin_code GET    /admin/code/:id/edit(.:format)          admin/codes#edit
                admin_code GET    /admin/code/:id(.:format)               admin/codes#show
                           PATCH  /admin/code/:id(.:format)               admin/codes#update
                           PUT    /admin/code/:id(.:format)               admin/codes#update
                           DELETE /admin/code/:id(.:format)               admin/codes#destroy
       admin_codes_preview POST   /admin/codes/preview(.:format)          admin/codes#preview