ransack search form in header partial: No Ransack::Search object was provided to search_form_for

Question

First of all, I'm new to RoR, so the answer may be obvious, in which case I apologize. I've looked around and haven't found anything that helps.

I'm trying to have a search form at the header of every web page on my app that will search through the names of all my "buckets". Here is the relevant code:

In app/views/layouts/_header.html.erb (within a nav bar):

<% search_form_for @q do |f| %>
  <%= f.label :name_cont %>
  <%= f.text_field :name_cont %>
  <%= f.submit %>
<% end %>

In app/controllers/buckets_controller.rb:

def index
  unless params[:q].blank?
    @q = Bucket.search(params[:q])
    @buckets = @q.result.paginate(:page => params[:page])
  else
    @buckets = Bucket.find(:all, :limit => 5).paginate(:page => params[:page])
  end
end

I understand the last part isn't that great: what I'm trying to do is if I'm just accessing the bucket index page (not by searching), i display the 5 most recently created buckets. When I search for something in the header form, I access the index page but only show the buckets that hit the search. (would a better way to handle it to have a search page separate from my index page?)

I found this issue which is pretty much identical, but I still don't see how I handle @q if every page is going to have the form on it--surely I don't have to alter every controller's every action?

Sorry in advance for any frustration my noobishness my cause you!

Answer 1

As others have said, you need to utilize the ApplicationController's before_filter. Though ernie himself seems not to recommend this, the implementation is simple.

First, use the advanced Ransack options to set your path for your search thusly

#config/routes.rb
  resources :buckets do
    collection do
      match 'search' => 'buckets#search', via: [:get, :post], as: :search
    end
  end

Second, update your BucketsController to include the following custom action:

#controllers/buckets_controller.rb
  def search
    index
    render :index
  end

Nothing yet out of the ordinary. If you currently try to search you will get the error from your original question. Your definition of the variable q is correctly implemented, but you will have to move it to the ApplicationController like so:

#controllers/application_controller.rb
before_filter :set_global_search_variable

  def set_global_search_variable
    @q = Bucket.search(params[:q])
  end

Finally, update your search form to pass in the correct search options

#layouts/_header.html.erb

    <% search_form_for @q, url: search_buckets_path, html: { method: :post }  do |f| %>
      <%= f.label :name_cont %>
      <%= f.text_field :name_cont %>
      <%= f.submit %>
    <% end %>

Answer 2

No, you do not need to edit all your controllers.

You can use ApplicationController for all your "common" controller needs. Read up on it in the guides http://guides.rubyonrails.org/action_controller_overview.html and the API docs http://api.rubyonrails.org/classes/ActionController/Base.html

The key here is, when you generated your new rails app, you'll notice it created the file .../app/controllers/action_controller.rb and that class derives from ActionController::Base. Then, if you again use the rails generator to create a controller for your app, you'll notice your new controller class derives from ApplicationController (not ::Base). That means that the application_controller.rb is the parent controller class for your app. That means everything in it is available to all your app controllers. It's easy to abuse, so be judicious.