相同的代碼在控制器在軌道的不同動作 - 如何使DRY？

Question

我有一個控制器有兩個不同的動作，但都需要這個相同的代碼，這是有點長，我怎麼能讓他們訪問這個相同的行爲，但保持乾爽？

@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

您應該將此代碼移到模型：

# 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 

然後你就可以在控制器上使用它：

@list = Contact.get_list(report_start_date, report_end_date) 

也許你也可以把它拆分爲較小的部分，並使用範圍和定義的關聯，而不是自己編寫所有的關聯。

Answer 2

我想補充一個函數生成數和連接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 

凡table_count_col和table_join都在裏面Contact類的靜態方法：

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