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############################################################################
#
# 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