break down a complex search query in Rails 3

Question

I have a controller which has a lot of options being sent to it via a form and I'm wondering how best to separate them out as they are not all being used simultaneously. Ie sometimes no, tags, sometimes no price specified. For prices I have a default price set so I can work around with it always being there, but the tags either need to be there, or not. etc.

@locations = Location.find(params[:id])

@location = @locations.places.active.where("cache_price BETWEEN ? AND ?",price_low,price_high).tagged_with([params[:tags]).order(params[:sort]).paginate :page => params[:page]

I haven't seen any good examples of this, but I'm sure it must happen often... any suggestions? Also, even will_paginate which gets tacked on last should be optional as the results either go to a list or to a google map, and the map needs no pagination.

Answer 1

Hi,

the first thing to do when refactoring a complex search action is to use an anonymous scope.

Ie :

fruits = Fruit.scoped
fruits = fruits.where(:colour => 'red') if options[:red_only]
fruits = fruits.where(:size => 'big') if options[:big_only]
fruits = fruits.limit(10) if options[:only_first]
...

If the action controller still remains too big, you may use a class to handle the search. Moreover, by using a class with Rails 3 and ActiveModel you'll also be able to use validations if you want...

Take a look at one of my plugins : http://github.com/novagile/basic_active_model that allows you to easily create classes that may be used in forms.

Also take a look at http://github.com/novagile/scoped-search another plugin more specialized in creating search objects by using the scopes of a model.