Ruby on Rails 4.1 : Adding a Search Form using a Form Object

app_controllers_search_controller.rb

class SearchController < ApplicationController

  skip_before_filter :verify_authenticity_token

  def results
    @search_form = SearchForm.new(params.require(:search_form).permit(:q))
    if (@search_form.valid?)
      # This sample assumes a model called Contacts with a column field called name
      @results = @search_form.search_within (Contacts.all, :name)
    end
  end
end

app_models_search_form.rb

class SearchForm
  include ActiveModel::Model

  #Generic Search Parameter
  attr_accessor :q 
  validates_length_of :q, minimum: 3, message: 'Please enter at least 3 letters to search'

  # Add your other search params or validations here

  def persisted?
    false
  end

  def search_within scope, column_name
    
    #example where scope: only added when the q param is present
    unless self.q.blank?
      scope = scope.where(column_name: self.q)
    end
    
    #Add your own filters here
    
    scope
  end
end

app_views_search_results.html.erb

<%= form_for(@search_form, url: search_results_path, method: :get, authenticity_token: false) do |f| %>
  <div class="input-group">
    <%= f.text_field :q, class: 'form-control', placeholder: 'Name Search' %>
    <div class="input-group-btn">
      <button class="btn btn-default" type="submit"><i class="glyphicon glyphicon-search"></i></button>
    </div>
  </div>
<% end %>

<hr/>

<% if @results %>
<%# A functional but unappealing results view %>
<div class="results">
  <% @results.each do |result| %>
  <div>
    <%# Customize this based on your model class %>
    <%= link_to result.name, result %>
  </div>
  <% end %>
</div>  
<% elsif %>
<div class="no-results">No Matching Results</div>
<% end %>