# this is a prototype
# Time-stamp: <02/02/15 01:14:47 drt@un.bewaff.net>

"""Gopher+ Protocol implementation.

for twisted 0.15.0

See RfC 1436 and http://iubio.bio.indiana.edu/soft/util/gopher/Gopher+-spec.text

  --drt@un.bewaff.net
"""

import string
from twisted.protocols import protocol
from twisted.protocols import basic
from cStringIO import StringIO

# TYPES                                      
FILE            = '0'   # Item is a (text) file
DIRECTORY       = '1'   # Item is a directory 
CSOPHONEBOOK    = '2'   # Item is a CSO phone-book server
ERROR           = '3'   # Error
BINHEX          = '4'   # Item is a BinHexed Macintosh file.
DOSBIN          = '5'   # Item is DOS binary archive of some sort.
                        # Client must read until the TCP connection closes.  Beware.
UUENCODE        = '6'   # Item is a UNIX uuencoded file.
SEARCHSERVER    = '7'   # Item is an Index-Search server.
TELNET          = '8'   # Item points to a text-based telnet session.
BINARY          = '9'   # Item is a binary file!
                        # Client must read until the TCP connection closes.  Beware.
REDUNDANTSERVER = '+'   # Item is a redundant server
TN3270          = 'T'   # Item points to a text-based tn3270 session.
GIF             = 'g'   # Item is a GIF format graphics file.
IMAGE           = 'I'   # Item is some kind of image file.  Client decides how to display.
UNKNOWN         = '?'   
BITMAP          = ':'   # Gopher+ Bitmap response
MOVIE           = ';'   # Gopher+ Movie response
SOUND           = '<'   # Gopher+ Sound response
# Seen in the Wild
HTML            = 'h'   # WWW-stuff
INFO            = 'i'   # Greeting / BLURB

responses = { FILE            : 'File',
              DIRECTORY       : 'Directory',
              CSOPHONEBOOK    : 'CSO phone-book server',
              ERROR           : 'Error',
              BINHEX          : 'BinHexed Macintosh file',
              DOSBIN          : 'DOS binary archive',
              UUENCODE        : 'UNIX UUEncoded file',
              SEARCHSERVER    : 'Index-Search server',
              TELNET          : 'Telnet session',
              BINARY          : 'Binary File',
              REDUNDANTSERVER : 'Redundant server',
              TN3270          : 'tn3270 session',
              GIF             : 'GIF File',
              IMAGE           : 'Image File',
              UNKNOWN         : 'Unknown Data',   
              BITMAP          : 'Bitmap Image',
              MOVIE           : 'Movie',
              SOUND           : 'Sound',
              HTML            : 'HTML File',
              INFO            : 'Blurb'
              }

# Filetypes which will not end with a footer
binary = [DOSBIN, BINARY, GIF, IMAGE, UNKNOWN, BITMAP, MOVIE, SOUND]

class gopherClient(basic.LineReceiver):
    """A client for the Gopher (Rfc 1436) Protocol."""

    # TODO: support for ASK
    # TODO: Searching support
    
    def __init__(self, binary = 0):
        """Create a gopher client instance.

        The optional Parameter indicates that you await binary date like '5', '9', 'I' and 'g'
        """
        self.binary = binary
        self.__buffer = ''
        self.selectorSend = 0
        self.transmissionFinished = 0
        basic.LineReceiver.__init__(self)
  
    def sendSelector(self, selector):
        """Send a selector to request data from the server."""
        if self.selectorSend:
            raise runtimeError, "Selector (%r) can't be send twice." % (selector) 
        self.transport.write('%s\r\n' % (selector))
        self.selectorSend = 1
        if self.binary:
            self.setRawMode()

    def lineReceived(self, line):
        if self.transmissionFinished:
            # the server still sends data - is this a problem?
            raise runtimeError, "Server is sending still data after EOT marker."
        if line == '.':
            # finished
            self.transport.loseConnection()
            self.transmissionFinished = 1
        else:
            self.__buffer = self.__buffer + data
    
    def rawDataReceived(self, data):
        self.__buffer = self.__buffer + data
   
    def connectionLost(self):
        if not binary:
            # with non binary Data we have to strip the EOD marker
            pos = rfind(self.__buffer, "\r\n.\r\n")
            if pos == -1:
                # No EOD marker - how to handle that?
                pass
            else:
                self.__buffer = self.__buffer[0:pos]                               
        self.handleResponse(self.__buffer)

    def connectionMade(self):
        # no action nesessary
        pass

    def handleResponse(self, buffer):
        raise NotImplementedError, repr(buffer);
    

class gopher(basic.LineReceiver):
    """A receiver for gopher requests.

    goppher+ is in the works.
    """
    selector = None

    def __init__(self):
        pass
    
    def lineReceived(self, line):
        # This should be called only once since the client SHOULD send
        # only a single line

        # gopher+ clients might send more than a simple selector. For
        # now we just ignore it.
        line = line.split('\t')[0]
        self.selector = line
        self.selectorReceived(line)

    def selectorReceived(self, selector):
        """Do pre-processing (for content-length) and store this header away.
        """

        # dummy
        self.transport.write('iThis is a dummy Server, you selected %r\tfake\t(NONE)\t\r\n1Test\tfake\t(NONE)\t\r\n.\r\n' % (selector))
        self.transport.loseConnection()


# crude test
if __name__ == '__main__':

    from twisted.protocols import protocol
    from twisted.internet import main, tcp
    from twisted.protocols import telnet
 
    factory = protocol.Factory()
    factory.protocol = gopher
    port = tcp.Port(8070, factory)
    app = main.Application("gopher")
    app.addPort(port)
    # for our debuggin pleasure:
    ts = telnet.ShellFactory()
    app.addPort(tcp.Port(8023, ts))
    app.run()