NNTP Connection Class in Ruby

nntp_connection.rb

#
# Example usage:
#
# require 'rubygems'
# require 'date'
# require 'socket'
# require 'celluloid'
# require 'nntp_connection'
#
# nntp = NNTPConnection.new('news.supernews.com', 119, 'username', 'password')
# group = nntp.group('alt.binaries.boneless')
# 
# nntp.xover(group.high - 50, group.high)
#  ==> articles returned!



require 'iconv'

class NNTPGroup
  attr_reader :name, :count, :low, :high

  def initialize(name, count, low, high)
    @name = name
    @count = count
    @low = low
    @high = high
  end
end

class NNTPOverview
  attr_accessor :articles, :group, :low, :high

  def initialize(response)
    @articles = []

    @low = nil
    @high = nil

    response.split("\n").each do |row|
      fields = row.strip.split("\t")
      if !fields.empty?
        number, subject, author, created_at, message_id = fields

        @low = number if @low.nil? or number < low
        @high = number if @high.nil? or number > high

        @articles << NNTPArticle.new(number, subject, author, created_at, message_id)
      end
    end
  end

end

class NNTPArticle
  attr_accessor :number, :subject, :author, :created_at, :message_id
  def initialize(number, subject, author, created_at, message_id)
    @number = number

    ic = Iconv.new('UTF-8//IGNORE', 'UTF-8')
    @subject = ic.iconv(subject + ' ')[0..-2]
    @author = ic.iconv(author + ' ')[0..-2]
    @created_at = DateTime.parse(created_at)
    @message_id = message_id
  end

end

class NNTPConnection
  include Celluloid::Logger

  def initialize(host, port, username, password)
    @host = host
    @port = port

    info "Opening connection to #{host}:#{port}"
    @socket = TCPSocket.new @host, @port
    recv_response

    # Authentifcate
    command("AUTHINFO USER #{username}", true)
    command("AUTHINFO PASS #{password}")
  end

  def recv_response(allow_continue=false)
    stat = ''
    while true
      line = @socket.readline
      stat << line << "\n"
      break unless line[3] == ?-   # "210-PIPELINING"
    end
    return stat if /\A1/ === stat       # 1xx info msg
    return stat if /\A2/ === stat       # 2xx cmd k
    return stat if allow_continue and /\A[35]/ === stat # 3xx cmd k, snd rst
    raise "NNTP Error: #{stat}"    
  end

  def command(cmd, allow_continue=false)
    @socket.puts(cmd)
    recv_response(allow_continue)
  end

  def group(name)
    result = command("GROUP #{name}")  
    chunks = result.split
    NNTPGroup.new(chunks[4], chunks[1].to_i, chunks[2].to_i, chunks[3].to_i)
  end

  def multiline_command(cmd, *args)
    result = ""
    if stat = command(cmd, *args)
      while true
        line = @socket.readline
        break if line =~ /^\.\s*$/
        line = line[1..-1] if line.to_s[0...2] == '..'
        result << line + $/
      end
    end

    return result
  end

  def xover(low, high)
    response = multiline_command("XOVER #{low}-#{high}")
    NNTPOverview.new(response)
  end

  def capabilities
    multiline_command('CAPABILITIES')
  end

  def close
    @socket.close
  end

end