#!/usr/bin/python
#
# NNTP protocol handling
import sys, os, re, codecs
import settings, group
logger = settings.get_logger('pnntprss.nntp')
# RFC977: commands with parameters must separate the parameters from
# each other and from the command by one or more space or tab
# characters.
separator_re = re.compile(r'\s+')
class NNTPServer:
"""An object representing the server side of an NNTP connection."""
def __init__(self, input, output):
self.finished = False
self.current_group = None
self.current_article_number = None
# reopen input with universal line ending support
self.input = os.fdopen(input.fileno(), "rU", 0)
self.output = codecs.getwriter("utf-8")(output)
def debug_in(self, l):
logger.debug("< " + l)
def debug_out(self, l):
logger.debug("> " + l)
def readlines(self):
"""A generator yielding the lines sent by the NNTP client."""
# avoid using file as iterator, since it implies buffering
while True:
l = self.input.readline()
if not l:
break
# remove trailing newline
if l[-1] == '\n':
l = l[0:-1]
logger.debug("< " + l)
yield l
def writeline(self, l):
"""Write a line to the NNTP client."""
self.debug_out(l)
self.output.write(l)
self.output.write('\r\n')
self.output.flush()
def write(self, data):
"""Write some data to the NNTP client."""
lines = data.split("\r\n")
for l in lines[:-1]:
self.debug_out(l)
if lines[-1]:
self.debug_out(lines[-1])
self.output.write(data)
self.output.flush()
def process_commands(self):
"""Process NNTP commands comming from the client, until it
terminates the connection."""
self.writeline('201 server ready - no posting allowed')
for l in self.readlines():
tokens = separator_re.split(l)
if not tokens:
self.writeline('501 command syntax error')
m = getattr(self, 'do_' + tokens[0].upper(), None)
if m:
m(tokens[1:])
else:
self.writeline('500 command not recognized')
if self.finished:
break
# each do_* method handles the corresponding NNTP command.
def do_MODE(self, params):
if params and params[0].upper() == 'READER':
self.writeline("201 Hello, you can't post")
else:
self.writeline('501 command syntax error')
def do_QUIT(self, params):
if params:
self.writeline('501 command syntax error')
return
self.writeline('205 closing connection - goodbye!')
self.finished = True
def do_LIST(self, params):
if params:
self.writeline('501 command syntax error')
return
self.writeline('215 list of newsgroups follows')
for g in group.groups():
(lowest, highest, count) = g.article_range()
self.writeline('%s %s %s n' % (g.name, highest, lowest))
self.writeline('.')
def do_GROUP(self, params):
if len(params) != 1:
self.writeline('501 command syntax error')
return
try:
g = group.Group(params[0])
except group.NoSuchGroupError:
self.writeline('411 no such news group')
return
(lowest, highest, count) = g.article_range()
self.writeline('211 %s %s %s %s group selected'
% (count, lowest, highest, g.name))
if lowest <= highest:
self.current_group = g
self.current_article_number = lowest
else:
self.current_group = None
self.current_article_number = None
def do_XOVER(self, params):
if len(params) > 1:
self.writeline('501 command syntax error')
return
if self.current_group == None:
self.writeline('412 no newsgroup has been selected')
return
# xXX prope range handling, including msgid and current
# article forms
range = params[0]
dash = range.find('-')
try:
if dash < 0:
range = [int(range)]
elif dash == len(range)-1:
range = group.Range(lo=int(range[0:dash]))
else:
range = group.Range(lo=int(range[0:dash]),
hi=int(range[dash+1:]))
except:
self.writeline('501 command syntax error')
return
arts = self.current_group.articles(range)
if not arts:
self.writeline('420 no articles in range')
return
self.writeline('224 xover lines follow')
# XXX encoding
for art in arts:
fields = [str(art.number()), art.subject(), art.author(),
art.date(), art.message_id(), '', '', '']
self.writeline("\t".join([f.replace("\t", " ") for f in fields]))
self.writeline('.')
def retrieve_article(self, params):
"""Fetch an Article according to the parameters of
ARTICLE, HEAD, BODY, and STAT."""
if len(params) > 1:
self.writeline('501 command syntax error')
return None
if self.current_group == None:
self.writeline('412 no newsgroup has been selected')
return None
if len(params) == 1:
self.current_article_number = int(params[0])
elif self.current_article_number == None:
self.writeline('420 no current article has been selected')
return None
art = self.current_group.article(self.current_article_number)
if art == None:
self.writeline('423 no such article number in this group')
return None
return art
def do_ARTICLE(self, params):
art = self.retrieve_article(params)
if not art:
return
self.writeline('220 %s %s article retrieved - head and body follow'
% (art.number(), art.message_id()))
msg = art.make_message()
self.write(msg.header_bytes())
self.writeline('')
self.write(msg.dot_stuffed_body())
def do_HEAD(self, params):
art = self.retrieve_article(params)
if not art:
return
self.writeline('221 %s %s article retrieved - head follows'
% (art.number(), art.message_id()))
self.write(art.make_message().header_bytes())
self.writeline('.')
def do_BODY(self, params):
art = self.retrieve_article(params)
if not art:
return
self.writeline('222 %s %s article retrieved - body follows'
% (art.number(), art.message_id()))
self.write(art.make_message().dot_stuffed_body())
def do_STAT(self, params):
art = self.retrieve_article(params)
if not art:
return
self.writeline('223 %s %s article exists'
% (art.number(), art.message_id()))
) is private.
