315 lines
12 KiB
Python
315 lines
12 KiB
Python
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import logging
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import random
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import time
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from coapthon.messages.message import Message
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from coapthon import defines
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from coapthon.messages.request import Request
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from coapthon.transaction import Transaction
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__author__ = 'Giacomo Tanganelli'
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logger = logging.getLogger(__name__)
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def str_append_hash(*args):
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""" Convert each argument to a lower case string, appended, then hash """
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ret_hash = ""
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for i in args:
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ret_hash += str(i).lower()
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return hash(ret_hash)
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class MessageLayer(object):
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"""
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Handles matching between messages (Message ID) and request/response (Token)
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"""
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def __init__(self, starting_mid):
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"""
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Set the layer internal structure.
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:param starting_mid: the first mid used to send messages.
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"""
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self._transactions = {}
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self._transactions_token = {}
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if starting_mid is not None:
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self._current_mid = starting_mid
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else:
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self._current_mid = random.randint(1, 1000)
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def fetch_mid(self):
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"""
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Gets the next valid MID.
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:return: the mid to use
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"""
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current_mid = self._current_mid
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self._current_mid += 1
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self._current_mid %= 65535
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return current_mid
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def purge(self):
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for k in self._transactions.keys():
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now = time.time()
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transaction = self._transactions[k]
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if transaction.timestamp + defines.EXCHANGE_LIFETIME < now:
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logger.debug("Delete transaction")
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del self._transactions[k]
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for k in self._transactions_token.keys():
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now = time.time()
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transaction = self._transactions_token[k]
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if transaction.timestamp + defines.EXCHANGE_LIFETIME < now:
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logger.debug("Delete transaction")
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del self._transactions_token[k]
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def receive_request(self, request):
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"""
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Handle duplicates and store received messages.
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:type request: Request
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:param request: the incoming request
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:rtype : Transaction
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:return: the edited transaction
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"""
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logger.debug("receive_request - " + str(request))
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try:
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host, port = request.source
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except AttributeError:
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return
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key_mid = str_append_hash(host, port, request.mid)
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key_token = str_append_hash(host, port, request.token)
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if key_mid in self._transactions.keys():
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# Duplicated
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self._transactions[key_mid].request.duplicated = True
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transaction = self._transactions[key_mid]
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else:
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request.timestamp = time.time()
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transaction = Transaction(request=request, timestamp=request.timestamp)
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with transaction:
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self._transactions[key_mid] = transaction
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self._transactions_token[key_token] = transaction
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return transaction
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def receive_response(self, response):
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"""
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Pair responses with requests.
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:type response: Response
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:param response: the received response
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:rtype : Transaction
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:return: the transaction to which the response belongs to
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"""
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logger.debug("receive_response - " + str(response))
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try:
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host, port = response.source
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except AttributeError:
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return
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key_mid = str_append_hash(host, port, response.mid)
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key_mid_multicast = str_append_hash(defines.ALL_COAP_NODES, port, response.mid)
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key_token = str_append_hash(host, port, response.token)
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key_token_multicast = str_append_hash(defines.ALL_COAP_NODES, port, response.token)
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if key_mid in self._transactions.keys():
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transaction = self._transactions[key_mid]
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if response.token != transaction.request.token:
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logger.warning("Tokens does not match - response message " + str(host) + ":" + str(port))
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return None, False
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elif key_token in self._transactions_token:
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transaction = self._transactions_token[key_token]
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elif key_mid_multicast in self._transactions.keys():
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transaction = self._transactions[key_mid_multicast]
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elif key_token_multicast in self._transactions_token:
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transaction = self._transactions_token[key_token_multicast]
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if response.token != transaction.request.token:
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logger.warning("Tokens does not match - response message " + str(host) + ":" + str(port))
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return None, False
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else:
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logger.warning("Un-Matched incoming response message " + str(host) + ":" + str(port))
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return None, False
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send_ack = False
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if response.type == defines.Types["CON"]:
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send_ack = True
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transaction.request.acknowledged = True
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transaction.completed = True
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transaction.response = response
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if transaction.retransmit_stop is not None:
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transaction.retransmit_stop.set()
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return transaction, send_ack
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def receive_empty(self, message):
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"""
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Pair ACKs with requests.
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:type message: Message
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:param message: the received message
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:rtype : Transaction
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:return: the transaction to which the message belongs to
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"""
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logger.debug("receive_empty - " + str(message))
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try:
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host, port = message.source
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except AttributeError:
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return
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key_mid = str_append_hash(host, port, message.mid)
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key_mid_multicast = str_append_hash(defines.ALL_COAP_NODES, port, message.mid)
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key_token = str_append_hash(host, port, message.token)
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key_token_multicast = str_append_hash(defines.ALL_COAP_NODES, port, message.token)
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if key_mid in self._transactions.keys():
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transaction = self._transactions[key_mid]
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elif key_token in self._transactions_token:
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transaction = self._transactions_token[key_token]
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elif key_mid_multicast in self._transactions.keys():
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transaction = self._transactions[key_mid_multicast]
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elif key_token_multicast in self._transactions_token:
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transaction = self._transactions_token[key_token_multicast]
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else:
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logger.warning("Un-Matched incoming empty message " + str(host) + ":" + str(port))
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return None
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if message.type == defines.Types["ACK"]:
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if not transaction.request.acknowledged:
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transaction.request.acknowledged = True
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elif (transaction.response is not None) and (not transaction.response.acknowledged):
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transaction.response.acknowledged = True
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elif message.type == defines.Types["RST"]:
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if not transaction.request.acknowledged:
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transaction.request.rejected = True
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elif not transaction.response.acknowledged:
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transaction.response.rejected = True
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elif message.type == defines.Types["CON"]:
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#implicit ACK (might have been lost)
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logger.debug("Implicit ACK on received CON for waiting transaction")
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transaction.request.acknowledged = True
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else:
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logger.warning("Unhandled message type...")
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if transaction.retransmit_stop is not None:
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transaction.retransmit_stop.set()
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return transaction
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def send_request(self, request):
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"""
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Create the transaction and fill it with the outgoing request.
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:type request: Request
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:param request: the request to send
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:rtype : Transaction
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:return: the created transaction
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"""
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logger.debug("send_request - " + str(request))
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assert isinstance(request, Request)
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try:
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host, port = request.destination
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except AttributeError:
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return
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request.timestamp = time.time()
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transaction = Transaction(request=request, timestamp=request.timestamp)
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if transaction.request.type is None:
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transaction.request.type = defines.Types["CON"]
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if transaction.request.mid is None:
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transaction.request.mid = self.fetch_mid()
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key_mid = str_append_hash(host, port, request.mid)
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self._transactions[key_mid] = transaction
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key_token = str_append_hash(host, port, request.token)
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self._transactions_token[key_token] = transaction
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return self._transactions[key_mid]
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def send_response(self, transaction):
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"""
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Set the type, the token and eventually the MID for the outgoing response
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:type transaction: Transaction
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:param transaction: the transaction that owns the response
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:rtype : Transaction
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:return: the edited transaction
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"""
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logger.debug("send_response - " + str(transaction.response))
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if transaction.response.type is None:
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if transaction.request.type == defines.Types["CON"] and not transaction.request.acknowledged:
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transaction.response.type = defines.Types["ACK"]
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transaction.response.mid = transaction.request.mid
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transaction.response.acknowledged = True
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transaction.completed = True
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elif transaction.request.type == defines.Types["NON"]:
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transaction.response.type = defines.Types["NON"]
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else:
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transaction.response.type = defines.Types["CON"]
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transaction.response.token = transaction.request.token
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if transaction.response.mid is None:
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transaction.response.mid = self.fetch_mid()
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try:
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host, port = transaction.response.destination
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except AttributeError:
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return
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key_mid = str_append_hash(host, port, transaction.response.mid)
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self._transactions[key_mid] = transaction
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transaction.request.acknowledged = True
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return transaction
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def send_empty(self, transaction, related, message):
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"""
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Manage ACK or RST related to a transaction. Sets if the transaction has been acknowledged or rejected.
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:param transaction: the transaction
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:param related: if the ACK/RST message is related to the request or the response. Must be equal to
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transaction.request or to transaction.response or None
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:type message: Message
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:param message: the ACK or RST message to send
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"""
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logger.debug("send_empty - " + str(message))
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if transaction is None:
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try:
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host, port = message.destination
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except AttributeError:
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return
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key_mid = str_append_hash(host, port, message.mid)
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key_token = str_append_hash(host, port, message.token)
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if key_mid in self._transactions:
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transaction = self._transactions[key_mid]
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related = transaction.response
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elif key_token in self._transactions_token:
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transaction = self._transactions_token[key_token]
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related = transaction.response
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else:
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return message
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if message.type == defines.Types["ACK"]:
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if transaction.request == related:
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transaction.request.acknowledged = True
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transaction.completed = True
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message.mid = transaction.request.mid
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message.code = 0
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message.destination = transaction.request.source
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elif transaction.response == related:
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transaction.response.acknowledged = True
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transaction.completed = True
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message.mid = transaction.response.mid
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message.code = 0
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message.token = transaction.response.token
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message.destination = transaction.response.source
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elif message.type == defines.Types["RST"]:
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if transaction.request == related:
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transaction.request.rejected = True
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message._mid = transaction.request.mid
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message.code = 0
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message.token = transaction.request.token
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message.destination = transaction.request.source
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elif transaction.response == related:
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transaction.response.rejected = True
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transaction.completed = True
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message._mid = transaction.response.mid
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message.code = 0
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message.token = transaction.response.token
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message.destination = transaction.response.source
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return message
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