Question

How can I search/filter by multiple parameters that are each optional in Rails 3.2? With the setup below, I am currently getting the following error. Any help is greatly appreciated.

undefined method `paginate' for nil:NilClass

Application Trace | Framework Trace | Full Trace
app/controllers/contacts_controller.rb:50:in `index'

Here is the index action in my contacts_controller:

def index
  city = params[:city]
  state = params[:state]
  zip = params[:zip]
  @contacts = Contact.search(city,state,zip).paginate(:page => params[:page], :per_page => items_per_page)
end

And here is the search method in my Contact model:

def self.search(city, state, zip)
  joins(:profile => :addresses)
  .where("city like ?", "%#{city}%") unless city.blank?
  .where("state = ?", state) unless state.blank?
  .where("zip like ?", "%#{zip}%") unless zip.blank?
end

Answer 1

Try to return more explicitely, e.g. like that:

def self.search(city, state, zip)
  query_obj = joins(:profile => :addresses)
  query_obj = query_obj.where("city like ?", "%#{city}%") unless city.blank?
  query_obj = query_obj.where("state = ?", state) unless state.blank?
  query_obj = query_obj.where("zip like ?", "%#{zip}%") unless zip.blank?

  query_obj
end