def receive_file(self, filename: str, rng: Tuple[int, int], owner: tuple):
# telling the nodes we NEED a file, therefore idx=-1 and data=None.
msg = FileCommunication(self.name, owner[0], filename, rng)
temp_s = create_socket(give_port())
self.send_datagram(temp_s, msg, owner[1])
print(f"Node {self.name} has sent the start-of-transfer message to "
f"{owner[0]}.")
while True:
data, addr = temp_s.recvfrom(BUFFER_SIZE)
dg: UDPDatagram = crypto_unit.decrypt(data)
msg = Message.decode(dg.data)
# msg now contains the actual bytes of the data for that file.
# TODO some validation
if msg["filename"] != filename:
print(f"Wanted {filename} but received {msg['range']} range "
f"of {msg['filename']}")
return
if msg["idx"] == -1:
print(f"Node {self.name} received the end-of-transfer message "
f"from {owner[0]}.")
free_socket(temp_s)
return
self.received_files[filename].append(msg)
def handle_node(self, data, addr):
dg = crypto_unit.decrypt(data)
message = Message.decode(dg.data)
message_mode = message['mode']
if message_mode == modes.HAVE:
self.add_uploader(message, addr)
elif message_mode == modes.NEED:
self.search_file(message, addr)
elif message_mode == modes.EXIT:
self.exit_uploader(message, addr)
def search(self, filename: str) -> dict:
message = NodeToTracker(self.name, modes.NEED, filename)
temp_s = create_socket(give_port())
self.send_datagram(temp_s, message, TRACKER_ADDR)
while True:
data, addr = temp_s.recvfrom(BUFFER_SIZE)
dg: UDPDatagram = crypto_unit.decrypt(data)
if dg.src_port != TRACKER_ADDR[1]:
raise ValueError(f"Someone other than the tracker with "
f"port:{dg.src_port} sent {self.name} "
f"the search datagram.")
return Message.decode(dg.data)
def start_listening(self):
while True:
data, addr = self.rec_s.recvfrom(BUFFER_SIZE)
dg: UDPDatagram = crypto_unit.decrypt(data)
msg = Message.decode(dg.data)
if "size" in msg.keys() and msg["size"] == -1:
# meaning someone needs the file size
self.tell_file_size(dg, msg)
elif "range" in msg.keys() and msg["data"] is None:
print(f"Node {self.name} received the start-of-transfer "
f"message from Node {msg['src_name']}.")
self.send_file(msg["filename"], msg["range"], msg["src_name"],
dg.src_port)
def ask_file_size(self, filename: str, owner: tuple) -> int:
# size == -1 means asking the size
message = SizeInformation(self.name, owner[0], filename)
temp_s = create_socket(give_port())
self.send_datagram(temp_s, message, owner[1])
while True:
data, addr = temp_s.recvfrom(BUFFER_SIZE)
dg: UDPDatagram = crypto_unit.decrypt(data)
# TODO some validation
free_socket(temp_s)
return Message.decode(dg.data)["size"]