def __init__(self):
self.parser = MessageParser()
self.queries = []
class KatCP(LineReceiver):
""" A base class for protocol implementation of KatCP on top of twisted
infrastructure. Specific subclasses provide client and server parts
(which are not shared).
"""
delimiter = '\n'
MAX_LENGTH = 64*(2**20) # 64 MB should be fine
def __init__(self):
self.parser = MessageParser()
self.queries = []
def send_request(self, name, *args):
if not self.transport.connected:
raise DeviceNotConnected()
d = Deferred()
self.send_message(Message.request(name, *args))
self.queries.append((name, d, []))
return d
def dataReceived(self, data):
# translate '\r' into '\n'
return LineReceiver.dataReceived(self, data.replace('\r', '\n'))
def lineReceived(self, line):
if not line:
return
msg = self.parser.parse(line)
if msg.mtype == msg.INFORM:
self.handle_inform(msg)
elif msg.mtype == msg.REPLY:
self.handle_reply(msg)
elif msg.mtype == msg.REQUEST:
self.handle_request(msg)
else:
assert False # this could never happen since parser should complain
# some default informs
def inform_version(self, msg):
if msg.arguments:
self.version = msg.arguments[0]
def inform_build_state(self, msg):
if msg.arguments:
self.build_state = msg.arguments[0]
def inform_disconnect(self, args):
pass # unnecessary, we have a callback on loseConnection
def handle_inform(self, msg):
# if we have a request being processed, store all the informs
# in a list of stuff to process
name = msg.name
name = name.replace('-', '_')
meth = getattr(self, 'inform_' + name, None)
if meth is not None:
meth(msg)
elif self.queries:
name, d, queue = self.queries[0]
if name != msg.name:
return # instead of raising WrongQueryOrder, we discard informs
# that we don't know about
queue.append(msg) # unespace?
else:
raise UnhandledMessage(msg)
def handle_request(self, msg):
name = msg.name
name = name.replace('-', '_')
try:
rep_msg = getattr(self, 'request_' + name, self._request_unknown)(msg)
if not isinstance(rep_msg, Message):
raise ShouldReturnMessage('request_' + name + ' should return a'
'message or raise AsyncReply, instead'
'it returned %r' % rep_msg)
self.send_message(rep_msg)
except FailReply, fr:
self.send_message(Message.reply(name, "fail", str(fr)))
except AsyncReply:
return
