text: # Copyright (c) 2001-2004 Twisted Matrix Laboratories.
  # See LICENSE for details.
  
  """Implement standard (and unused) TCP protocols.
  
  These protocols are either provided by inetd, or are not provided at all.
  """
  
  # system imports
  import time, struct
  from zope.interface import implements
  
  # twisted import
  from twisted.internet import protocol, interfaces
  
  
  class Echo(protocol.Protocol):
      """As soon as any data is received, write it back (RFC 862)"""
      
      def dataReceived(self, data):
          self.transport.write(data)
  
  
  class Discard(protocol.Protocol):
      """Discard any received data (RFC 863)"""
      
      def dataReceived(self, data):
          # I'm ignoring you, nyah-nyah
          pass
  
  
  class Chargen(protocol.Protocol):
      """Generate repeating noise (RFC 864)"""
      noise = r'@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~ !"#$%&?'
  
      implements(interfaces.IProducer)
  
      def connectionMade(self):
          self.transport.registerProducer(self, 0)
  
      def resumeProducing(self):
          self.transport.write(self.noise)
  
      def pauseProducing(self):
          pass
  
      def stopProducing(self):
          pass
  
  
  class QOTD(protocol.Protocol):
      """Return a quote of the day (RFC 865)"""
      
      def connectionMade(self):
          self.transport.write(self.getQuote())
          self.transport.loseConnection()
  
      def getQuote(self):
          """Return a quote. May be overrriden in subclasses."""
          return "An apple a day keeps the doctor away.\r\n"
  
  class Who(protocol.Protocol):
      """Return list of active users (RFC 866)"""
      
      def connectionMade(self):
          self.transport.write(self.getUsers())
          self.transport.loseConnection()
      
      def getUsers(self):
          """Return active users. Override in subclasses."""
          return "root\r\n"
  
  
  class Daytime(protocol.Protocol):
      """Send back the daytime in ASCII form (RFC 867)"""
      
      def connectionMade(self):
          self.transport.write(time.asctime(time.gmtime(time.time())) + '\r\n')
          self.transport.loseConnection()
  
  
  class Time(protocol.Protocol):
      """Send back the time in machine readable form (RFC 868)"""
      
      def connectionMade(self):
          # is this correct only for 32-bit machines?
          result = struct.pack("!i", int(time.time()))
          self.transport.write(result)
          self.transport.loseConnection()
  
  