import logging
import time
from coapthon import defines
__author__ = 'Giacomo Tanganelli'
logger = logging.getLogger(__name__)
class ObserveItem(object):
def __init__(self, timestamp, non_counter, allowed, transaction):
"""
Data structure for the Observe option
:param timestamp: the timestamop of last message sent
:param non_counter: the number of NON notification sent
:param allowed: if the client is allowed as observer
:param transaction: the transaction
"""
self.timestamp = timestamp
self.non_counter = non_counter
self.allowed = allowed
self.transaction = transaction
[docs]class ObserveLayer(object):
"""
Manage the observing feature. It store observing relationships.
"""
def __init__(self):
self._relations = {}
[docs] def send_request(self, request):
"""
Add itself to the observing list
:param request: the request
:return: the request unmodified
"""
if request.observe == 0:
# Observe request
host, port = request.destination
key_token = hash(str(host) + str(port) + str(request.token))
self._relations[key_token] = ObserveItem(time.time(), None, True, None)
if request.observe == 1:
# Cancelling observe explicitly
self.remove_subscriber(request)
return request
[docs] def receive_response(self, transaction):
"""
Sets notification's parameters.
:type transaction: Transaction
:param transaction: the transaction
:rtype : Transaction
:return: the modified transaction
"""
host, port = transaction.response.source
key_token = hash(str(host) + str(port) + str(transaction.response.token))
if key_token in self._relations and transaction.response.type == defines.Types["CON"]:
transaction.notification = True
return transaction
[docs] def send_empty(self, message):
"""
Eventually remove from the observer list in case of a RST message.
:type message: Message
:param message: the message
:return: the message unmodified
"""
host, port = message.destination
key_token = hash(str(host) + str(port) + str(message.token))
if key_token in self._relations and message.type == defines.Types["RST"]:
del self._relations[key_token]
return message
[docs] def receive_request(self, transaction):
"""
Manage the observe option in the request end eventually initialize the client for adding to
the list of observers or remove from the list.
:type transaction: Transaction
:param transaction: the transaction that owns the request
:rtype : Transaction
:return: the modified transaction
"""
if transaction.request.observe == 0:
# Observe request
host, port = transaction.request.source
key_token = hash(str(host) + str(port) + str(transaction.request.token))
non_counter = 0
if key_token in self._relations:
# Renew registration
allowed = True
else:
allowed = False
self._relations[key_token] = ObserveItem(time.time(), non_counter, allowed, transaction)
elif transaction.request.observe == 1:
host, port = transaction.request.source
key_token = hash(str(host) + str(port) + str(transaction.request.token))
logger.info("Remove Subscriber")
try:
del self._relations[key_token]
except KeyError:
pass
return transaction
[docs] def receive_empty(self, empty, transaction):
"""
Manage the observe feature to remove a client in case of a RST message receveide in reply to a notification.
:type empty: Message
:param empty: the received message
:type transaction: Transaction
:param transaction: the transaction that owns the notification message
:rtype : Transaction
:return: the modified transaction
"""
if empty.type == defines.Types["RST"]:
host, port = transaction.request.source
key_token = hash(str(host) + str(port) + str(transaction.request.token))
logger.info("Remove Subscriber")
try:
del self._relations[key_token]
except KeyError:
pass
transaction.completed = True
return transaction
[docs] def send_response(self, transaction):
"""
Finalize to add the client to the list of observer.
:type transaction: Transaction
:param transaction: the transaction that owns the response
:return: the transaction unmodified
"""
host, port = transaction.request.source
key_token = hash(str(host) + str(port) + str(transaction.request.token))
if key_token in self._relations:
if transaction.response.code == defines.Codes.CONTENT.number:
if transaction.resource is not None and transaction.resource.observable:
transaction.response.observe = transaction.resource.observe_count
self._relations[key_token].allowed = True
self._relations[key_token].transaction = transaction
self._relations[key_token].timestamp = time.time()
else:
del self._relations[key_token]
elif transaction.response.code >= defines.Codes.ERROR_LOWER_BOUND:
del self._relations[key_token]
return transaction
[docs] def notify(self, resource, root=None):
"""
Prepare notification for the resource to all interested observers.
:rtype: list
:param resource: the resource for which send a new notification
:param root: deprecated
:return: the list of transactions to be notified
"""
ret = []
if root is not None:
resource_list = root.with_prefix_resource(resource.path)
else:
resource_list = [resource]
for key in self._relations.keys():
if self._relations[key].transaction.resource in resource_list:
if self._relations[key].non_counter > defines.MAX_NON_NOTIFICATIONS \
or self._relations[key].transaction.request.type == defines.Types["CON"]:
self._relations[key].transaction.response.type = defines.Types["CON"]
self._relations[key].non_counter = 0
elif self._relations[key].transaction.request.type == defines.Types["NON"]:
self._relations[key].non_counter += 1
self._relations[key].transaction.response.type = defines.Types["NON"]
self._relations[key].transaction.resource = resource
del self._relations[key].transaction.response.mid
del self._relations[key].transaction.response.token
ret.append(self._relations[key].transaction)
return ret
[docs] def remove_subscriber(self, message):
"""
Remove a subscriber based on token.
:param message: the message
"""
logger.debug("Remove Subcriber")
host, port = message.destination
key_token = hash(str(host) + str(port) + str(message.token))
try:
self._relations[key_token].transaction.completed = True
del self._relations[key_token]
except AttributeError:
logger.warning("No Transaction")
except KeyError:
logger.warning("No Subscriber")