This was something I've searched for in the past but have yet to find. It's a super simple server and I'm sure there's a few bugs left in it, but the idea is simple and in my opinion, necessary. It's easy to send email from websites, but receiving it still seems dubious.

I've simply used Peter's(http://snippets.dzone.com/user/peter) ultra simplistic SMTP server and routed the email to a database table called "Emails" via ActiveRecord. It's running GServer so it should be able to handle a decent load. Like I mentioned earlier, it's probably still got some bugs, but it's a decent start.

   1  
   2  require 'gserver'
   3  require 'rubygems'  
   4  require 'active_record'  
   5  require 'yaml'
   6     
   7  dbconfig = YAML::load_file(File.dirname(__FILE__) + '/config/database.yml')
   8  ActiveRecord::Base.establish_connection(dbconfig['development']) 
   9  
  10  class Email < ActiveRecord::Base   
  11  end 
  12  
  13  class SMTPServer < GServer
  14    def serve(io)
  15      @data_mode = false
  16      @email_message = ""
  17      puts "Connected"
  18      io.print "220 hello\r\n"
  19      loop do
  20        if IO.select([io], nil, nil, 0.1)
  21  	      data = io.readpartial(4096)
  22  	      puts ">>" + data
  23  	      @email_message << data
  24  	      ok, op = process_line(data)
  25  	      break unless ok
  26  	      puts "<<" + op
  27  	      io.print op
  28        end
  29        break if io.closed?
  30      end
  31      db_insert(@email_message)
  32      io.print "221 bye\r\n"
  33      io.close
  34    end
  35  
  36    def process_line(line)
  37      if (@data_mode) && (line.chomp =~ /^\.$/)
  38        @data_mode = false
  39        return true, "220 OK\r\n"
  40      elsif @data_mode
  41        return true, ""
  42      elsif (line =~ /^(HELO|EHLO)/)
  43        return true, "220 and..?\r\n"
  44      elsif (line =~ /^QUIT/)
  45        return false, "bye\r\n"
  46      elsif (line =~ /^MAIL FROM\:/)
  47        return true, "220 OK\r\n"
  48      elsif (line =~ /^RCPT TO\:/)
  49        return true, "220 OK\r\n"
  50      elsif (line =~ /^DATA/)
  51        @data_mode = true
  52        return true, "354 Enter message, ending with \".\" on a line by itself\r\n"
  53      else
  54        return true, "500 ERROR\r\n"
  55      end
  56    end
  57    
  58    def db_insert(email)
  59      mail_from = (/^MAIL FROM\:<(.+)>.*$/).match(email)[1]
  60      rcpt_to = (/^RCPT TO\:<(.+)>.*$/).match(email)[1]
  61      subject = (/^Subject\: (.+)$/).match(email)[1]
  62      Email.create(:mail_from => mail_from, :rcpt_to => rcpt_to, :subject => subject, :email => email)
  63    end
  64    
  65  end
  66  
  67  a = SMTPServer.new(25)
  68  a.start
  69  a.join