Question

I have an API which is fairly restful but am struggling to work out how to implement a search cleanly. I want to be able to search for all the records between two date-times, the date-times are allowed to be a maximum of 6 hours apart. At the moment in my controller method I have the following:

required_params = [:start_time, :end_time]
if check_required_params(required_params, params) and check_max_time_bound(params, 6.hours)
   ... rest of controller code here ...
end

check_required_params is an application method that looks like this:

def check_required_params(required_params, params_sent)
required_params.each do |param|
  unless has_param(param, params_sent)
    unprocessable_entity
    return false
  end
end
  true
end

check_max_time is fairly similar.

I know it’s against best practices to do validation in the controller but I can’t see how I can add it to the model cleanly.

Answer 1

Actually what you are doing is (almost) best practice and will (almost) be incorporated in Rails 4 with strong parametsers. (I say almost because your check_max_time looks like it should be a validation in your model.)

You should go ahead and pull in the feature today and make upgrades easier on yourself. Strong Parameters https://github.com/rails/strong_parameters

Documentation is there, but here is how you incorporate it.

class SearchController < ApplicationController
  include ActiveModel::ForbiddenAttributesProtection

  def create
    # Doesn't have to be an ActiveRecord model
    @results = Search.create(search_params)
    respond_with @results
  end

  private

  def search_params
    # This will ensure that you have :start_time and :end_time, but will allow :foo and :bar
    params.require(:start_time, :end_time).permit(:foo, :bar #, whatever else)
  end
end

class Search < ActiveRecord::Base
  validates :time_less_than_six_hours

  private

  def time_less_than_six_hours
    errors.add(:end_time, "should be less than 6 hours from start") if (end_time - start_time) > 6.hours
  end
end