def _create_nameless_data_packet(self, payload_value):
payload_tlv = ccnpy.Payload(payload_value)
nameless = ccnpy.ContentObject.create_data(name=None,
payload=payload_tlv,
expiry_time=self._tree_options.data_expiry_time)
packet = ccnpy.Packet.create_content_object(nameless)
assert len(packet) <= self._max_packet_size
return packet
def _calculate_nameless_data_payload_size(self):
"""
Create a nameless object with empty payload and see how much space we have left.
:return: payload size of a nameless data object
"""
nameless = ccnpy.ContentObject.create_data(name=None,
expiry_time=self._tree_options.data_expiry_time,
payload=ccnpy.Payload([]))
packet = ccnpy.Packet.create_content_object(body=nameless)
if len(packet) >= self._max_packet_size:
raise ValueError("An empty nameless ContentObject is %r bytes, but max_size is only %r" %
(len(packet), self._max_packet_size))
payload_size = self._max_packet_size - len(packet)
return payload_size
def create_manifest(cls, manifest, name=None, expiry_time=None):
"""
:param name: ccnpy.Name
:param manifest: A serializable object to put in the payload
:param expiry_time: A python datetime
:return: A ccnpy.ContentObject
"""
if manifest is None:
raise ValueError("manifest must not be None")
payload_type = ccnpy.PayloadType.create_manifest_type()
payload = ccnpy.Payload(manifest.serialize())
if expiry_time is not None:
if not isinstance(expiry_time, datetime):
raise TypeError("expiry_time must be datetime")
expiry_time = ccnpy.ExpiryTime.from_datetime(expiry_time)
return cls(name=name,
payload_type=payload_type,
payload=payload,
expiry_time=expiry_time)
def create_data(cls, name=None, payload=None, expiry_time=None):
"""
:param name: ccnpy.Name
:param payload: A byte array (array.array("B", ...)) or ccnpy.Payload
:param expiry_time: A python datetime
:return: A ccnpy.ContentObject
"""
payload_type = None
if payload is not None:
payload_type = ccnpy.PayloadType.create_data_type()
if not isinstance(payload, ccnpy.Payload):
payload = ccnpy.Payload(payload)
if expiry_time is not None:
if not isinstance(expiry_time, datetime):
raise TypeError("expiry_time must be datetime")
expiry_time = ccnpy.ExpiryTime.from_datetime(expiry_time)
return cls(name=name,
payload_type=payload_type,
payload=payload,
expiry_time=expiry_time)
def _create_data_packet(application_data):
payload = ccnpy.Payload(application_data)
packet = ccnpy.Packet.create_content_object(
ccnpy.ContentObject.create_data(payload=payload))
return packet