############################################################################ # # Copyright (c) 2007, 2008 Nexedi SARL and Contributors. All Rights Reserved. # Vincent Pelletier <vincent@nexedi.com> # # WARNING: This program as such is intended to be used by professional # programmers who take the whole responsability of assessing all potential # consequences resulting from its eventual inadequacies and bugs # End users who are looking for a ready-to-use solution with commercial # garantees and support are strongly adviced to contract a Free Software # Service Company # # This program is Free Software; you can redistribute it and/or # modify it under the terms of the GNU General Public License # as published by the Free Software Foundation; either version 2 # of the License, or (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. # ############################################################################## class ClientDisconnected(Exception): pass class ExchangeProtocol: """ Handle data exchange between client and server. Kinds of data which can be exchanged: - str send_field recv_field - int send_int recv_int - list of str send_list recv_list - list of int send_int_list recv_int_list - dict (key: str, value: int) send_dict recv_dict Forbidden chars: Send (raise if present): \\n (field separator) Receive (stripped silently): \\n (field separator) \\r (for compatibility) """ def __init__(self, socket): self._socket = socket def send_field(self, to_send): if type(to_send) is not str: raise ValueError, 'Value is not of str type: %r' % (type(to_send), ) if '\n' in to_send: raise ValueError, '\\n is a forbidden value.' self._socket.send(to_send) self._socket.send('\n') def recv_field(self): received = None result = [] append = result.append while received != '\n': received = self._socket.recv(1) if len(received) == 0: raise ClientDisconnected if received != '\r': append(received) return ''.join(result[:-1]) def send_int(self, to_send): self.send_field(str(to_send)) def recv_int(self): return int(self.recv_field()) def send_list(self, to_send, send_length=True): assert isinstance(to_send, (tuple, list)) if send_length: self.send_int(len(to_send)) for field in to_send: self.send_field(field) def send_int_list(self, to_send, *args, **kw): self.send_list([str(x) for x in to_send], *args, **kw) def recv_list(self, length=None): result = [] append = result.append if length is None: length = int(self.recv_field()) for field_number in xrange(length): append(self.recv_field()) return result def recv_int_list(self, *args, **kw): return [int(x) for x in self.recv_list(*args, **kw)] def send_dict(self, to_send): """ Key: string Value: int """ assert isinstance(to_send, (dict)) if len(to_send) == 0: key_list = value_list = [] else: key_list, value_list = zip(*to_send.items()) self.send_list(key_list) self.send_int_list(value_list, send_length=False) def recv_dict(self): """ Key: string Value: int """ key_list = self.recv_list() value_list = self.recv_int_list(len(key_list)) result = dict(zip(key_list, value_list)) return result