same code in different actions of the controller in rails -- how to make DRY?

Question

I have a controller with two different actions, but both need this same code, which is a little long, how can I allow them access to this same behavior but keep it DRY?

   @list = Contact.find :all,
      :select => "companies.name AS co_name, 
                  companies.id AS comp_id, 
                  COUNT(contact_emails.id) AS email_count, 
                  COUNT(contact_calls.id) AS call_count, 
                  COUNT(contact_letters.id) AS letter_count, 
                  COUNT(contact_postalcards.id) AS postalcard_count",

      :conditions => ['contact_emails.date_sent < ? and contact_emails.date_sent > ?', 
                      report_end_date, report_start_date],

      :joins => [
        "LEFT JOIN companies ON companies.id = contacts.company_id",
        "LEFT JOIN contact_emails ON contact_emails.contact_id = contacts.id",
        "LEFT JOIN contact_letters ON contact_letters.contact_id = contacts.id",
        "LEFT JOIN contact_postalcards ON contact_postalcards.contact_id = contacts.id",
        "LEFT JOIN contact_calls ON contact_calls.contact_id = contacts.id"
      ],
      #:group => "companies.id"
       :group => "companies.name"
    puts @list[0].attributes.inspect

Answer 1

You should move this code to model:

# Contatct model

def self.get_list(report_start_date, report_end_date)
  self.find :all,
    :select => "companies.name AS co_name, 
              companies.id AS comp_id, 
              COUNT(contact_emails.id) AS email_count, 
              COUNT(contact_calls.id) AS call_count, 
              COUNT(contact_letters.id) AS letter_count, 
              COUNT(contact_postalcards.id) AS postalcard_count",

    :conditions => ['contact_emails.date_sent < ? and contact_emails.date_sent > ?', 
                  report_end_date, report_start_date],

    :joins => [
      "LEFT JOIN companies ON companies.id = contacts.company_id",
      "LEFT JOIN contact_emails ON contact_emails.contact_id = contacts.id",
      "LEFT JOIN contact_letters ON contact_letters.contact_id = contacts.id",
      "LEFT JOIN contact_postalcards ON contact_postalcards.contact_id = contacts.id",
      "LEFT JOIN contact_calls ON contact_calls.contact_id = contacts.id"
    ],
    #:group => "companies.id"
    :group => "companies.name"
end

Then you can use it in controllers:

@list = Contact.get_list(report_start_date, report_end_date)

Probably you can also split it to smaller parts and use scopes and defined associations instead of writing all of it on your own.

Answer 2

I would add a function for generating the count and join sql:

class Contact < ActiveRecord::Base
  def  self.get_list(report_start_date,    report_end_date)
    all(:select      => "companies.name AS co_name,
                        companies.id AS comp_id,
                        #{table_count_col(
                          :contact_emails, 
                          :contact_calls, 
                          :contact_letters, 
                          :contact_postalcards
                         )}",
        :conditions => ['contact_emails.date_sent < ?  AND
                         contact_emails.date_sent > ?',
                         report_end_date, report_start_date],
        :joins      => join_table(
                    :companies, 
                    :contact_emails, 
                    :contact_letters, 
                    :contact_postalcards, 
                    :contact_calls
                    ),
       )
  end
end

Where table_count_col and table_join are static methods inside Contact class:

  def self.table_count_col(*args)    
    args.collect do |table| 
      count_col = "#{table.to_s.gsub(/^contact_/,  '').singularize}_count"
      "COUNT(#{table}.id) AS #{count_col}"    
    end.join(",")
  end

  def self.table_join(*args)    
    args.collect do |table|
     "LEFT JOIN #{table} ON #{table}.id = contacts.company_id"
    end.join(",")
  end