Rails 4 searching multiple models in a separate controller

I am trying to implement a complex model search in a separate controller. I have a student model. The whole app has a front page handled by a separate main_controller that doesn't have a model. Master_controller and its associated index pointer should provide the first page and display data from multiple models.

Now I want to search for a model with multiple search criteria of different types. Search criteria: string comparison, number comparison, and boolean (e.g. active if true, only active students show all students). Railscast # 111 showed how to create such a search based on a model and a separate search controller. I created a controller like this and it works great. I am stuck showing the relevant parts in my main / index.

Here is the code:

Main / index.html.haml

 - model_class = Adult
 - model_class = Pupil
 - model_class = MainSearch

.page-header
= render :partial => 'main_searches/form', :main_search => MainSearch.new

      

        
        
        
      

    

Only the form call is here at the moment.

models / main_search.rb

class MainSearch < ActiveRecord::Base

  def pupils
    @pupils ||= find_pupils
  end

  private
    def find_pupils
      pupils = Pupil.order(:name_sur)
      pupils = pupils.where(id: id_search) if id_search.present?
      pupils = pupils.where("name_first like ?", "%#{name_first}%") if name_first.present?
      pupils = pupils.where("name_sur like ?", "%#{name_sur}%") if name_sur.present?
      pupils = pupils.where(active: "true") if active == true  #show only active or all
      pupils
    end
end

      

        
        
        
      

    

This defines the search.

Controllers / main_searches_controller.rb

class MainSearchesController < ApplicationController
  before_action :set_main_search, only: [:show, :update, :destroy]

  def show
    @main_search = MainSearch.find(params[:id])
  end

  def new
    @main_search = MainSearch.new
  end

  def create
    @main_search = MainSearch.new(main_search_params)

    if @main_search.save
      redirect_to root_path, notice: 'Main search was successfully created.'
    else
      render action: 'new'
    end
  end
end

      

        
        
        
      

    

As shown in railscast.

view / main_searches / _form.html.haml

%h1 Advanced Search

  = form_for :main_search, :url => main_searches_path do |f|
    .field
      = f.label :id_search
      %br/
      = f.text_field :id_search
    [... ommitted some fields here ...]
    .field
      = f.label :active
      %br/
      = f.check_box :active, {}, true, false


  .actions= f.submit "Search"

      

        
        
        
      

    

Displays in a new view.

view / main_searches / _results.html.haml

%h1 Search Results

.container-fluid
  .row-fluid
    .span4

      %table.table{style: "table-layout:fixed"}
        %thead
          %tr
            %th= "id"
            %th= "name_sur"
            %th= "name first"
            %th= "a"
      %div{style: "overflow-y:scroll; height: 200px"}
        %table.table.table-striped{style: "table-layout:fixed"}
          %tbody
            - @main_search.pupils.each do |pupil|
              %tr
                %td= pupil.id
                %td= link_to pupil.name_sur, pupil_path(pupil)
                %td= pupil.name_first
                %td= pupil.active

      

        
        
        
      

    

Displays the results.

So basically everything works for one model, as shown on railscast. What I need now is to allow the user to handle everything in the main_controller. At the moment, I cannot get the @main_search object passed to the _results.html.haml particle. What am I missing here? Or is this even the correct way to do such a search?

Thanks for your help in advance.